drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/pm_domain.h>
  25 #include <linux/property.h>
  26 #include <linux/export.h>
  27 #include <linux/sched/rt.h>
  28 #include <uapi/linux/sched/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/kthread.h>
  31 #include <linux/ioport.h>
  32 #include <linux/acpi.h>
  33 #include <linux/highmem.h>
  34 #include <linux/idr.h>
  35 #include <linux/platform_data/x86/apple.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/spi.h>
  39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  41
  42 #include "internals.h"
  43
  44 static DEFINE_IDR(spi_master_idr);
  45
  46 static void spidev_release(struct device *dev)
  47 {
  48         struct spi_device       *spi = to_spi_device(dev);
  49
  50         /* spi controllers may cleanup for released devices */
  51         if (spi->controller->cleanup)
  52                 spi->controller->cleanup(spi);
  53
  54         spi_controller_put(spi->controller);
  55         kfree(spi->driver_override);
  56         kfree(spi);
  57 }
  58
  59 static ssize_t
  60 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  61 {
  62         const struct spi_device *spi = to_spi_device(dev);
  63         int len;
  64
  65         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  66         if (len != -ENODEV)
  67                 return len;
  68
  69         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  70 }
  71 static DEVICE_ATTR_RO(modalias);
  72
  73 static ssize_t driver_override_store(struct device *dev,
  74                                      struct device_attribute *a,
  75                                      const char *buf, size_t count)
  76 {
  77         struct spi_device *spi = to_spi_device(dev);
  78         const char *end = memchr(buf, '\n', count);
  79         const size_t len = end ? end - buf : count;
  80         const char *driver_override, *old;
  81
  82         /* We need to keep extra room for a newline when displaying value */
  83         if (len >= (PAGE_SIZE - 1))
  84                 return -EINVAL;
  85
  86         driver_override = kstrndup(buf, len, GFP_KERNEL);
  87         if (!driver_override)
  88                 return -ENOMEM;
  89
  90         device_lock(dev);
  91         old = spi->driver_override;
  92         if (len) {
  93                 spi->driver_override = driver_override;
  94         } else {
  95                 /* Emptry string, disable driver override */
  96                 spi->driver_override = NULL;
  97                 kfree(driver_override);
  98         }
  99         device_unlock(dev);
 100         kfree(old);
 101
 102         return count;
 103 }
 104
 105 static ssize_t driver_override_show(struct device *dev,
 106                                     struct device_attribute *a, char *buf)
 107 {
 108         const struct spi_device *spi = to_spi_device(dev);
 109         ssize_t len;
 110
 111         device_lock(dev);
 112         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 113         device_unlock(dev);
 114         return len;
 115 }
 116 static DEVICE_ATTR_RW(driver_override);
 117
 118 #define SPI_STATISTICS_ATTRS(field, file)                               \
 119 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 120                                              struct device_attribute *attr, \
 121                                              char *buf)                 \
 122 {                                                                       \
 123         struct spi_controller *ctlr = container_of(dev,                 \
 124                                          struct spi_controller, dev);   \
 125         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 126 }                                                                       \
 127 static struct device_attribute dev_attr_spi_controller_##field = {      \
 128         .attr = { .name = file, .mode = 0444 },                         \
 129         .show = spi_controller_##field##_show,                          \
 130 };                                                                      \
 131 static ssize_t spi_device_##field##_show(struct device *dev,            \
 132                                          struct device_attribute *attr, \
 133                                         char *buf)                      \
 134 {                                                                       \
 135         struct spi_device *spi = to_spi_device(dev);                    \
 136         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 137 }                                                                       \
 138 static struct device_attribute dev_attr_spi_device_##field = {          \
 139         .attr = { .name = file, .mode = 0444 },                         \
 140         .show = spi_device_##field##_show,                              \
 141 }
 142
 143 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 144 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 145                                             char *buf)                  \
 146 {                                                                       \
 147         unsigned long flags;                                            \
 148         ssize_t len;                                                    \
 149         spin_lock_irqsave(&stat->lock, flags);                          \
 150         len = sprintf(buf, format_string, stat->field);                 \
 151         spin_unlock_irqrestore(&stat->lock, flags);                     \
 152         return len;                                                     \
 153 }                                                                       \
 154 SPI_STATISTICS_ATTRS(name, file)
 155
 156 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 157         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 158                                  field, format_string)
 159
 160 SPI_STATISTICS_SHOW(messages, "%lu");
 161 SPI_STATISTICS_SHOW(transfers, "%lu");
 162 SPI_STATISTICS_SHOW(errors, "%lu");
 163 SPI_STATISTICS_SHOW(timedout, "%lu");
 164
 165 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 166 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 167 SPI_STATISTICS_SHOW(spi_async, "%lu");
 168
 169 SPI_STATISTICS_SHOW(bytes, "%llu");
 170 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 171 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 172
 173 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 174         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 175                                  "transfer_bytes_histo_" number,        \
 176                                  transfer_bytes_histo[index],  "%lu")
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 192 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 193 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 194
 195 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 196
 197 static struct attribute *spi_dev_attrs[] = {
 198         &dev_attr_modalias.attr,
 199         &dev_attr_driver_override.attr,
 200         NULL,
 201 };
 202
 203 static const struct attribute_group spi_dev_group = {
 204         .attrs  = spi_dev_attrs,
 205 };
 206
 207 static struct attribute *spi_device_statistics_attrs[] = {
 208         &dev_attr_spi_device_messages.attr,
 209         &dev_attr_spi_device_transfers.attr,
 210         &dev_attr_spi_device_errors.attr,
 211         &dev_attr_spi_device_timedout.attr,
 212         &dev_attr_spi_device_spi_sync.attr,
 213         &dev_attr_spi_device_spi_sync_immediate.attr,
 214         &dev_attr_spi_device_spi_async.attr,
 215         &dev_attr_spi_device_bytes.attr,
 216         &dev_attr_spi_device_bytes_rx.attr,
 217         &dev_attr_spi_device_bytes_tx.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 232         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 233         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 234         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 235         &dev_attr_spi_device_transfers_split_maxsize.attr,
 236         NULL,
 237 };
 238
 239 static const struct attribute_group spi_device_statistics_group = {
 240         .name  = "statistics",
 241         .attrs  = spi_device_statistics_attrs,
 242 };
 243
 244 static const struct attribute_group *spi_dev_groups[] = {
 245         &spi_dev_group,
 246         &spi_device_statistics_group,
 247         NULL,
 248 };
 249
 250 static struct attribute *spi_controller_statistics_attrs[] = {
 251         &dev_attr_spi_controller_messages.attr,
 252         &dev_attr_spi_controller_transfers.attr,
 253         &dev_attr_spi_controller_errors.attr,
 254         &dev_attr_spi_controller_timedout.attr,
 255         &dev_attr_spi_controller_spi_sync.attr,
 256         &dev_attr_spi_controller_spi_sync_immediate.attr,
 257         &dev_attr_spi_controller_spi_async.attr,
 258         &dev_attr_spi_controller_bytes.attr,
 259         &dev_attr_spi_controller_bytes_rx.attr,
 260         &dev_attr_spi_controller_bytes_tx.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 275         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 276         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 277         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 278         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 279         NULL,
 280 };
 281
 282 static const struct attribute_group spi_controller_statistics_group = {
 283         .name  = "statistics",
 284         .attrs  = spi_controller_statistics_attrs,
 285 };
 286
 287 static const struct attribute_group *spi_master_groups[] = {
 288         &spi_controller_statistics_group,
 289         NULL,
 290 };
 291
 292 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 293                                        struct spi_transfer *xfer,
 294                                        struct spi_controller *ctlr)
 295 {
 296         unsigned long flags;
 297         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 298
 299         if (l2len < 0)
 300                 l2len = 0;
 301
 302         spin_lock_irqsave(&stats->lock, flags);
 303
 304         stats->transfers++;
 305         stats->transfer_bytes_histo[l2len]++;
 306
 307         stats->bytes += xfer->len;
 308         if ((xfer->tx_buf) &&
 309             (xfer->tx_buf != ctlr->dummy_tx))
 310                 stats->bytes_tx += xfer->len;
 311         if ((xfer->rx_buf) &&
 312             (xfer->rx_buf != ctlr->dummy_rx))
 313                 stats->bytes_rx += xfer->len;
 314
 315         spin_unlock_irqrestore(&stats->lock, flags);
 316 }
 317 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 318
 319 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 320  * and the sysfs version makes coldplug work too.
 321  */
 322
 323 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 324                                                 const struct spi_device *sdev)
 325 {
 326         while (id->name[0]) {
 327                 if (!strcmp(sdev->modalias, id->name))
 328                         return id;
 329                 id++;
 330         }
 331         return NULL;
 332 }
 333
 334 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 335 {
 336         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 337
 338         return spi_match_id(sdrv->id_table, sdev);
 339 }
 340 EXPORT_SYMBOL_GPL(spi_get_device_id);
 341
 342 static int spi_match_device(struct device *dev, struct device_driver *drv)
 343 {
 344         const struct spi_device *spi = to_spi_device(dev);
 345         const struct spi_driver *sdrv = to_spi_driver(drv);
 346
 347         /* Check override first, and if set, only use the named driver */
 348         if (spi->driver_override)
 349                 return strcmp(spi->driver_override, drv->name) == 0;
 350
 351         /* Attempt an OF style match */
 352         if (of_driver_match_device(dev, drv))
 353                 return 1;
 354
 355         /* Then try ACPI */
 356         if (acpi_driver_match_device(dev, drv))
 357                 return 1;
 358
 359         if (sdrv->id_table)
 360                 return !!spi_match_id(sdrv->id_table, spi);
 361
 362         return strcmp(spi->modalias, drv->name) == 0;
 363 }
 364
 365 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 366 {
 367         const struct spi_device         *spi = to_spi_device(dev);
 368         int rc;
 369
 370         rc = acpi_device_uevent_modalias(dev, env);
 371         if (rc != -ENODEV)
 372                 return rc;
 373
 374         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 375 }
 376
 377 struct bus_type spi_bus_type = {
 378         .name           = "spi",
 379         .dev_groups     = spi_dev_groups,
 380         .match          = spi_match_device,
 381         .uevent         = spi_uevent,
 382 };
 383 EXPORT_SYMBOL_GPL(spi_bus_type);
 384
 385
 386 static int spi_drv_probe(struct device *dev)
 387 {
 388         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 389         struct spi_device               *spi = to_spi_device(dev);
 390         int ret;
 391
 392         ret = of_clk_set_defaults(dev->of_node, false);
 393         if (ret)
 394                 return ret;
 395
 396         if (dev->of_node) {
 397                 spi->irq = of_irq_get(dev->of_node, 0);
 398                 if (spi->irq == -EPROBE_DEFER)
 399                         return -EPROBE_DEFER;
 400                 if (spi->irq < 0)
 401                         spi->irq = 0;
 402         }
 403
 404         ret = dev_pm_domain_attach(dev, true);
 405         if (ret)
 406                 return ret;
 407
 408         ret = sdrv->probe(spi);
 409         if (ret)
 410                 dev_pm_domain_detach(dev, true);
 411
 412         return ret;
 413 }
 414
 415 static int spi_drv_remove(struct device *dev)
 416 {
 417         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 418         int ret;
 419
 420         ret = sdrv->remove(to_spi_device(dev));
 421         dev_pm_domain_detach(dev, true);
 422
 423         return ret;
 424 }
 425
 426 static void spi_drv_shutdown(struct device *dev)
 427 {
 428         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 429
 430         sdrv->shutdown(to_spi_device(dev));
 431 }
 432
 433 /**
 434  * __spi_register_driver - register a SPI driver
 435  * @owner: owner module of the driver to register
 436  * @sdrv: the driver to register
 437  * Context: can sleep
 438  *
 439  * Return: zero on success, else a negative error code.
 440  */
 441 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 442 {
 443         sdrv->driver.owner = owner;
 444         sdrv->driver.bus = &spi_bus_type;
 445         if (sdrv->probe)
 446                 sdrv->driver.probe = spi_drv_probe;
 447         if (sdrv->remove)
 448                 sdrv->driver.remove = spi_drv_remove;
 449         if (sdrv->shutdown)
 450                 sdrv->driver.shutdown = spi_drv_shutdown;
 451         return driver_register(&sdrv->driver);
 452 }
 453 EXPORT_SYMBOL_GPL(__spi_register_driver);
 454
 455 /*-------------------------------------------------------------------------*/
 456
 457 /* SPI devices should normally not be created by SPI device drivers; that
 458  * would make them board-specific.  Similarly with SPI controller drivers.
 459  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 460  * with other readonly (flashable) information about mainboard devices.
 461  */
 462
 463 struct boardinfo {
 464         struct list_head        list;
 465         struct spi_board_info   board_info;
 466 };
 467
 468 static LIST_HEAD(board_list);
 469 static LIST_HEAD(spi_controller_list);
 470
 471 /*
 472  * Used to protect add/del opertion for board_info list and
 473  * spi_controller list, and their matching process
 474  * also used to protect object of type struct idr
 475  */
 476 static DEFINE_MUTEX(board_lock);
 477
 478 /**
 479  * spi_alloc_device - Allocate a new SPI device
 480  * @ctlr: Controller to which device is connected
 481  * Context: can sleep
 482  *
 483  * Allows a driver to allocate and initialize a spi_device without
 484  * registering it immediately.  This allows a driver to directly
 485  * fill the spi_device with device parameters before calling
 486  * spi_add_device() on it.
 487  *
 488  * Caller is responsible to call spi_add_device() on the returned
 489  * spi_device structure to add it to the SPI controller.  If the caller
 490  * needs to discard the spi_device without adding it, then it should
 491  * call spi_dev_put() on it.
 492  *
 493  * Return: a pointer to the new device, or NULL.
 494  */
 495 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 496 {
 497         struct spi_device       *spi;
 498
 499         if (!spi_controller_get(ctlr))
 500                 return NULL;
 501
 502         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 503         if (!spi) {
 504                 spi_controller_put(ctlr);
 505                 return NULL;
 506         }
 507
 508         spi->master = spi->controller = ctlr;
 509         spi->dev.parent = &ctlr->dev;
 510         spi->dev.bus = &spi_bus_type;
 511         spi->dev.release = spidev_release;
 512         spi->cs_gpio = -ENOENT;
 513
 514         spin_lock_init(&spi->statistics.lock);
 515
 516         device_initialize(&spi->dev);
 517         return spi;
 518 }
 519 EXPORT_SYMBOL_GPL(spi_alloc_device);
 520
 521 static void spi_dev_set_name(struct spi_device *spi)
 522 {
 523         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 524
 525         if (adev) {
 526                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 527                 return;
 528         }
 529
 530         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 531                      spi->chip_select);
 532 }
 533
 534 static int spi_dev_check(struct device *dev, void *data)
 535 {
 536         struct spi_device *spi = to_spi_device(dev);
 537         struct spi_device *new_spi = data;
 538
 539         if (spi->controller == new_spi->controller &&
 540             spi->chip_select == new_spi->chip_select)
 541                 return -EBUSY;
 542         return 0;
 543 }
 544
 545 /**
 546  * spi_add_device - Add spi_device allocated with spi_alloc_device
 547  * @spi: spi_device to register
 548  *
 549  * Companion function to spi_alloc_device.  Devices allocated with
 550  * spi_alloc_device can be added onto the spi bus with this function.
 551  *
 552  * Return: 0 on success; negative errno on failure
 553  */
 554 int spi_add_device(struct spi_device *spi)
 555 {
 556         static DEFINE_MUTEX(spi_add_lock);
 557         struct spi_controller *ctlr = spi->controller;
 558         struct device *dev = ctlr->dev.parent;
 559         int status;
 560
 561         /* Chipselects are numbered 0..max; validate. */
 562         if (spi->chip_select >= ctlr->num_chipselect) {
 563                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 564                         ctlr->num_chipselect);
 565                 return -EINVAL;
 566         }
 567
 568         /* Set the bus ID string */
 569         spi_dev_set_name(spi);
 570
 571         /* We need to make sure there's no other device with this
 572          * chipselect **BEFORE** we call setup(), else we'll trash
 573          * its configuration.  Lock against concurrent add() calls.
 574          */
 575         mutex_lock(&spi_add_lock);
 576
 577         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 578         if (status) {
 579                 dev_err(dev, "chipselect %d already in use\n",
 580                                 spi->chip_select);
 581                 goto done;
 582         }
 583
 584         /* Descriptors take precedence */
 585         if (ctlr->cs_gpiods)
 586                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 587         else if (ctlr->cs_gpios)
 588                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 589
 590         /* Drivers may modify this initial i/o setup, but will
 591          * normally rely on the device being setup.  Devices
 592          * using SPI_CS_HIGH can't coexist well otherwise...
 593          */
 594         status = spi_setup(spi);
 595         if (status < 0) {
 596                 dev_err(dev, "can't setup %s, status %d\n",
 597                                 dev_name(&spi->dev), status);
 598                 goto done;
 599         }
 600
 601         /* Device may be bound to an active driver when this returns */
 602         status = device_add(&spi->dev);
 603         if (status < 0)
 604                 dev_err(dev, "can't add %s, status %d\n",
 605                                 dev_name(&spi->dev), status);
 606         else
 607                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 608
 609 done:
 610         mutex_unlock(&spi_add_lock);
 611         return status;
 612 }
 613 EXPORT_SYMBOL_GPL(spi_add_device);
 614
 615 /**
 616  * spi_new_device - instantiate one new SPI device
 617  * @ctlr: Controller to which device is connected
 618  * @chip: Describes the SPI device
 619  * Context: can sleep
 620  *
 621  * On typical mainboards, this is purely internal; and it's not needed
 622  * after board init creates the hard-wired devices.  Some development
 623  * platforms may not be able to use spi_register_board_info though, and
 624  * this is exported so that for example a USB or parport based adapter
 625  * driver could add devices (which it would learn about out-of-band).
 626  *
 627  * Return: the new device, or NULL.
 628  */
 629 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 630                                   struct spi_board_info *chip)
 631 {
 632         struct spi_device       *proxy;
 633         int                     status;
 634
 635         /* NOTE:  caller did any chip->bus_num checks necessary.
 636          *
 637          * Also, unless we change the return value convention to use
 638          * error-or-pointer (not NULL-or-pointer), troubleshootability
 639          * suggests syslogged diagnostics are best here (ugh).
 640          */
 641
 642         proxy = spi_alloc_device(ctlr);
 643         if (!proxy)
 644                 return NULL;
 645
 646         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 647
 648         proxy->chip_select = chip->chip_select;
 649         proxy->max_speed_hz = chip->max_speed_hz;
 650         proxy->mode = chip->mode;
 651         proxy->irq = chip->irq;
 652         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 653         proxy->dev.platform_data = (void *) chip->platform_data;
 654         proxy->controller_data = chip->controller_data;
 655         proxy->controller_state = NULL;
 656
 657         if (chip->properties) {
 658                 status = device_add_properties(&proxy->dev, chip->properties);
 659                 if (status) {
 660                         dev_err(&ctlr->dev,
 661                                 "failed to add properties to '%s': %d\n",
 662                                 chip->modalias, status);
 663                         goto err_dev_put;
 664                 }
 665         }
 666
 667         status = spi_add_device(proxy);
 668         if (status < 0)
 669                 goto err_remove_props;
 670
 671         return proxy;
 672
 673 err_remove_props:
 674         if (chip->properties)
 675                 device_remove_properties(&proxy->dev);
 676 err_dev_put:
 677         spi_dev_put(proxy);
 678         return NULL;
 679 }
 680 EXPORT_SYMBOL_GPL(spi_new_device);
 681
 682 /**
 683  * spi_unregister_device - unregister a single SPI device
 684  * @spi: spi_device to unregister
 685  *
 686  * Start making the passed SPI device vanish. Normally this would be handled
 687  * by spi_unregister_controller().
 688  */
 689 void spi_unregister_device(struct spi_device *spi)
 690 {
 691         if (!spi)
 692                 return;
 693
 694         if (spi->dev.of_node) {
 695                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 696                 of_node_put(spi->dev.of_node);
 697         }
 698         if (ACPI_COMPANION(&spi->dev))
 699                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 700         device_unregister(&spi->dev);
 701 }
 702 EXPORT_SYMBOL_GPL(spi_unregister_device);
 703
 704 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 705                                               struct spi_board_info *bi)
 706 {
 707         struct spi_device *dev;
 708
 709         if (ctlr->bus_num != bi->bus_num)
 710                 return;
 711
 712         dev = spi_new_device(ctlr, bi);
 713         if (!dev)
 714                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 715                         bi->modalias);
 716 }
 717
 718 /**
 719  * spi_register_board_info - register SPI devices for a given board
 720  * @info: array of chip descriptors
 721  * @n: how many descriptors are provided
 722  * Context: can sleep
 723  *
 724  * Board-specific early init code calls this (probably during arch_initcall)
 725  * with segments of the SPI device table.  Any device nodes are created later,
 726  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 727  * this table of devices forever, so that reloading a controller driver will
 728  * not make Linux forget about these hard-wired devices.
 729  *
 730  * Other code can also call this, e.g. a particular add-on board might provide
 731  * SPI devices through its expansion connector, so code initializing that board
 732  * would naturally declare its SPI devices.
 733  *
 734  * The board info passed can safely be __initdata ... but be careful of
 735  * any embedded pointers (platform_data, etc), they're copied as-is.
 736  * Device properties are deep-copied though.
 737  *
 738  * Return: zero on success, else a negative error code.
 739  */
 740 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 741 {
 742         struct boardinfo *bi;
 743         int i;
 744
 745         if (!n)
 746                 return 0;
 747
 748         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 749         if (!bi)
 750                 return -ENOMEM;
 751
 752         for (i = 0; i < n; i++, bi++, info++) {
 753                 struct spi_controller *ctlr;
 754
 755                 memcpy(&bi->board_info, info, sizeof(*info));
 756                 if (info->properties) {
 757                         bi->board_info.properties =
 758                                         property_entries_dup(info->properties);
 759                         if (IS_ERR(bi->board_info.properties))
 760                                 return PTR_ERR(bi->board_info.properties);
 761                 }
 762
 763                 mutex_lock(&board_lock);
 764                 list_add_tail(&bi->list, &board_list);
 765                 list_for_each_entry(ctlr, &spi_controller_list, list)
 766                         spi_match_controller_to_boardinfo(ctlr,
 767                                                           &bi->board_info);
 768                 mutex_unlock(&board_lock);
 769         }
 770
 771         return 0;
 772 }
 773
 774 /*-------------------------------------------------------------------------*/
 775
 776 static void spi_set_cs(struct spi_device *spi, bool enable)
 777 {
 778         if (spi->mode & SPI_CS_HIGH)
 779                 enable = !enable;
 780
 781         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 782                 /*
 783                  * Honour the SPI_NO_CS flag and invert the enable line, as
 784                  * active low is default for SPI. Execution paths that handle
 785                  * polarity inversion in gpiolib (such as device tree) will
 786                  * enforce active high using the SPI_CS_HIGH resulting in a
 787                  * double inversion through the code above.
 788                  */
 789                 if (!(spi->mode & SPI_NO_CS)) {
 790                         if (spi->cs_gpiod)
 791                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 792                                                          !enable);
 793                         else
 794                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 795                 }
 796                 /* Some SPI masters need both GPIO CS & slave_select */
 797                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 798                     spi->controller->set_cs)
 799                         spi->controller->set_cs(spi, !enable);
 800         } else if (spi->controller->set_cs) {
 801                 spi->controller->set_cs(spi, !enable);
 802         }
 803 }
 804
 805 #ifdef CONFIG_HAS_DMA
 806 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 807                 struct sg_table *sgt, void *buf, size_t len,
 808                 enum dma_data_direction dir)
 809 {
 810         const bool vmalloced_buf = is_vmalloc_addr(buf);
 811         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 812 #ifdef CONFIG_HIGHMEM
 813         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 814                                 (unsigned long)buf < (PKMAP_BASE +
 815                                         (LAST_PKMAP * PAGE_SIZE)));
 816 #else
 817         const bool kmap_buf = false;
 818 #endif
 819         int desc_len;
 820         int sgs;
 821         struct page *vm_page;
 822         struct scatterlist *sg;
 823         void *sg_buf;
 824         size_t min;
 825         int i, ret;
 826
 827         if (vmalloced_buf || kmap_buf) {
 828                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 829                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 830         } else if (virt_addr_valid(buf)) {
 831                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 832                 sgs = DIV_ROUND_UP(len, desc_len);
 833         } else {
 834                 return -EINVAL;
 835         }
 836
 837         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 838         if (ret != 0)
 839                 return ret;
 840
 841         sg = &sgt->sgl[0];
 842         for (i = 0; i < sgs; i++) {
 843
 844                 if (vmalloced_buf || kmap_buf) {
 845                         /*
 846                          * Next scatterlist entry size is the minimum between
 847                          * the desc_len and the remaining buffer length that
 848                          * fits in a page.
 849                          */
 850                         min = min_t(size_t, desc_len,
 851                                     min_t(size_t, len,
 852                                           PAGE_SIZE - offset_in_page(buf)));
 853                         if (vmalloced_buf)
 854                                 vm_page = vmalloc_to_page(buf);
 855                         else
 856                                 vm_page = kmap_to_page(buf);
 857                         if (!vm_page) {
 858                                 sg_free_table(sgt);
 859                                 return -ENOMEM;
 860                         }
 861                         sg_set_page(sg, vm_page,
 862                                     min, offset_in_page(buf));
 863                 } else {
 864                         min = min_t(size_t, len, desc_len);
 865                         sg_buf = buf;
 866                         sg_set_buf(sg, sg_buf, min);
 867                 }
 868
 869                 buf += min;
 870                 len -= min;
 871                 sg = sg_next(sg);
 872         }
 873
 874         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 875         if (!ret)
 876                 ret = -ENOMEM;
 877         if (ret < 0) {
 878                 sg_free_table(sgt);
 879                 return ret;
 880         }
 881
 882         sgt->nents = ret;
 883
 884         return 0;
 885 }
 886
 887 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 888                    struct sg_table *sgt, enum dma_data_direction dir)
 889 {
 890         if (sgt->orig_nents) {
 891                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 892                 sg_free_table(sgt);
 893         }
 894 }
 895
 896 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 897 {
 898         struct device *tx_dev, *rx_dev;
 899         struct spi_transfer *xfer;
 900         int ret;
 901
 902         if (!ctlr->can_dma)
 903                 return 0;
 904
 905         if (ctlr->dma_tx)
 906                 tx_dev = ctlr->dma_tx->device->dev;
 907         else
 908                 tx_dev = ctlr->dev.parent;
 909
 910         if (ctlr->dma_rx)
 911                 rx_dev = ctlr->dma_rx->device->dev;
 912         else
 913                 rx_dev = ctlr->dev.parent;
 914
 915         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 916                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 917                         continue;
 918
 919                 if (xfer->tx_buf != NULL) {
 920                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 921                                           (void *)xfer->tx_buf, xfer->len,
 922                                           DMA_TO_DEVICE);
 923                         if (ret != 0)
 924                                 return ret;
 925                 }
 926
 927                 if (xfer->rx_buf != NULL) {
 928                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 929                                           xfer->rx_buf, xfer->len,
 930                                           DMA_FROM_DEVICE);
 931                         if (ret != 0) {
 932                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 933                                               DMA_TO_DEVICE);
 934                                 return ret;
 935                         }
 936                 }
 937         }
 938
 939         ctlr->cur_msg_mapped = true;
 940
 941         return 0;
 942 }
 943
 944 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 945 {
 946         struct spi_transfer *xfer;
 947         struct device *tx_dev, *rx_dev;
 948
 949         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 950                 return 0;
 951
 952         if (ctlr->dma_tx)
 953                 tx_dev = ctlr->dma_tx->device->dev;
 954         else
 955                 tx_dev = ctlr->dev.parent;
 956
 957         if (ctlr->dma_rx)
 958                 rx_dev = ctlr->dma_rx->device->dev;
 959         else
 960                 rx_dev = ctlr->dev.parent;
 961
 962         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 963                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 964                         continue;
 965
 966                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 967                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 968         }
 969
 970         return 0;
 971 }
 972 #else /* !CONFIG_HAS_DMA */
 973 static inline int __spi_map_msg(struct spi_controller *ctlr,
 974                                 struct spi_message *msg)
 975 {
 976         return 0;
 977 }
 978
 979 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 980                                   struct spi_message *msg)
 981 {
 982         return 0;
 983 }
 984 #endif /* !CONFIG_HAS_DMA */
 985
 986 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 987                                 struct spi_message *msg)
 988 {
 989         struct spi_transfer *xfer;
 990
 991         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 992                 /*
 993                  * Restore the original value of tx_buf or rx_buf if they are
 994                  * NULL.
 995                  */
 996                 if (xfer->tx_buf == ctlr->dummy_tx)
 997                         xfer->tx_buf = NULL;
 998                 if (xfer->rx_buf == ctlr->dummy_rx)
 999                         xfer->rx_buf = NULL;
1000         }
1001
1002         return __spi_unmap_msg(ctlr, msg);
1003 }
1004
1005 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1006 {
1007         struct spi_transfer *xfer;
1008         void *tmp;
1009         unsigned int max_tx, max_rx;
1010
1011         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
1012                 max_tx = 0;
1013                 max_rx = 0;
1014
1015                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1016                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1017                             !xfer->tx_buf)
1018                                 max_tx = max(xfer->len, max_tx);
1019                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1020                             !xfer->rx_buf)
1021                                 max_rx = max(xfer->len, max_rx);
1022                 }
1023
1024                 if (max_tx) {
1025                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1026                                        GFP_KERNEL | GFP_DMA);
1027                         if (!tmp)
1028                                 return -ENOMEM;
1029                         ctlr->dummy_tx = tmp;
1030                         memset(tmp, 0, max_tx);
1031                 }
1032
1033                 if (max_rx) {
1034                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1035                                        GFP_KERNEL | GFP_DMA);
1036                         if (!tmp)
1037                                 return -ENOMEM;
1038                         ctlr->dummy_rx = tmp;
1039                 }
1040
1041                 if (max_tx || max_rx) {
1042                         list_for_each_entry(xfer, &msg->transfers,
1043                                             transfer_list) {
1044                                 if (!xfer->len)
1045                                         continue;
1046                                 if (!xfer->tx_buf)
1047                                         xfer->tx_buf = ctlr->dummy_tx;
1048                                 if (!xfer->rx_buf)
1049                                         xfer->rx_buf = ctlr->dummy_rx;
1050                         }
1051                 }
1052         }
1053
1054         return __spi_map_msg(ctlr, msg);
1055 }
1056
1057 static int spi_transfer_wait(struct spi_controller *ctlr,
1058                              struct spi_message *msg,
1059                              struct spi_transfer *xfer)
1060 {
1061         struct spi_statistics *statm = &ctlr->statistics;
1062         struct spi_statistics *stats = &msg->spi->statistics;
1063         unsigned long long ms = 1;
1064
1065         if (spi_controller_is_slave(ctlr)) {
1066                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1067                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1068                         return -EINTR;
1069                 }
1070         } else {
1071                 ms = 8LL * 1000LL * xfer->len;
1072                 do_div(ms, xfer->speed_hz);
1073                 ms += ms + 200; /* some tolerance */
1074
1075                 if (ms > UINT_MAX)
1076                         ms = UINT_MAX;
1077
1078                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1079                                                  msecs_to_jiffies(ms));
1080
1081                 if (ms == 0) {
1082                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1083                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1084                         dev_err(&msg->spi->dev,
1085                                 "SPI transfer timed out\n");
1086                         return -ETIMEDOUT;
1087                 }
1088         }
1089
1090         return 0;
1091 }
1092
1093 static void _spi_transfer_delay_ns(u32 ns)
1094 {
1095         if (!ns)
1096                 return;
1097         if (ns <= 1000) {
1098                 ndelay(ns);
1099         } else {
1100                 u32 us = DIV_ROUND_UP(ns, 1000);
1101
1102                 if (us <= 10)
1103                         udelay(us);
1104                 else
1105                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1106         }
1107 }
1108
1109 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1110                                           struct spi_transfer *xfer)
1111 {
1112         u32 delay = xfer->cs_change_delay;
1113         u32 unit = xfer->cs_change_delay_unit;
1114         u32 hz;
1115
1116         /* return early on "fast" mode - for everything but USECS */
1117         if (!delay && unit != SPI_DELAY_UNIT_USECS)
1118                 return;
1119
1120         switch (unit) {
1121         case SPI_DELAY_UNIT_USECS:
1122                 /* for compatibility use default of 10us */
1123                 if (!delay)
1124                         delay = 10000;
1125                 else
1126                         delay *= 1000;
1127                 break;
1128         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1129                 break;
1130         case SPI_DELAY_UNIT_SCK:
1131                 /* if there is no effective speed know, then approximate
1132                  * by underestimating with half the requested hz
1133                  */
1134                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1135                 delay *= DIV_ROUND_UP(1000000000, hz);
1136                 break;
1137         default:
1138                 dev_err_once(&msg->spi->dev,
1139                              "Use of unsupported delay unit %i, using default of 10us\n",
1140                              xfer->cs_change_delay_unit);
1141                 delay = 10000;
1142         }
1143         /* now sleep for the requested amount of time */
1144         _spi_transfer_delay_ns(delay);
1145 }
1146
1147 /*
1148  * spi_transfer_one_message - Default implementation of transfer_one_message()
1149  *
1150  * This is a standard implementation of transfer_one_message() for
1151  * drivers which implement a transfer_one() operation.  It provides
1152  * standard handling of delays and chip select management.
1153  */
1154 static int spi_transfer_one_message(struct spi_controller *ctlr,
1155                                     struct spi_message *msg)
1156 {
1157         struct spi_transfer *xfer;
1158         bool keep_cs = false;
1159         int ret = 0;
1160         struct spi_statistics *statm = &ctlr->statistics;
1161         struct spi_statistics *stats = &msg->spi->statistics;
1162
1163         spi_set_cs(msg->spi, true);
1164
1165         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1166         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1167
1168         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1169                 trace_spi_transfer_start(msg, xfer);
1170
1171                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1172                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1173
1174                 if (!ctlr->ptp_sts_supported) {
1175                         xfer->ptp_sts_word_pre = 0;
1176                         ptp_read_system_prets(xfer->ptp_sts);
1177                 }
1178
1179                 if (xfer->tx_buf || xfer->rx_buf) {
1180                         reinit_completion(&ctlr->xfer_completion);
1181
1182                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1183                         if (ret < 0) {
1184                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1185                                                                errors);
1186                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1187                                                                errors);
1188                                 dev_err(&msg->spi->dev,
1189                                         "SPI transfer failed: %d\n", ret);
1190                                 goto out;
1191                         }
1192
1193                         if (ret > 0) {
1194                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1195                                 if (ret < 0)
1196                                         msg->status = ret;
1197                         }
1198                 } else {
1199                         if (xfer->len)
1200                                 dev_err(&msg->spi->dev,
1201                                         "Bufferless transfer has length %u\n",
1202                                         xfer->len);
1203                 }
1204
1205                 if (!ctlr->ptp_sts_supported) {
1206                         ptp_read_system_postts(xfer->ptp_sts);
1207                         xfer->ptp_sts_word_post = xfer->len;
1208                 }
1209
1210                 trace_spi_transfer_stop(msg, xfer);
1211
1212                 if (msg->status != -EINPROGRESS)
1213                         goto out;
1214
1215                 if (xfer->delay_usecs)
1216                         _spi_transfer_delay_ns(xfer->delay_usecs * 1000);
1217
1218                 if (xfer->cs_change) {
1219                         if (list_is_last(&xfer->transfer_list,
1220                                          &msg->transfers)) {
1221                                 keep_cs = true;
1222                         } else {
1223                                 spi_set_cs(msg->spi, false);
1224                                 _spi_transfer_cs_change_delay(msg, xfer);
1225                                 spi_set_cs(msg->spi, true);
1226                         }
1227                 }
1228
1229                 msg->actual_length += xfer->len;
1230         }
1231
1232 out:
1233         if (ret != 0 || !keep_cs)
1234                 spi_set_cs(msg->spi, false);
1235
1236         if (msg->status == -EINPROGRESS)
1237                 msg->status = ret;
1238
1239         if (msg->status && ctlr->handle_err)
1240                 ctlr->handle_err(ctlr, msg);
1241
1242         spi_res_release(ctlr, msg);
1243
1244         spi_finalize_current_message(ctlr);
1245
1246         return ret;
1247 }
1248
1249 /**
1250  * spi_finalize_current_transfer - report completion of a transfer
1251  * @ctlr: the controller reporting completion
1252  *
1253  * Called by SPI drivers using the core transfer_one_message()
1254  * implementation to notify it that the current interrupt driven
1255  * transfer has finished and the next one may be scheduled.
1256  */
1257 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1258 {
1259         complete(&ctlr->xfer_completion);
1260 }
1261 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1262
1263 /**
1264  * __spi_pump_messages - function which processes spi message queue
1265  * @ctlr: controller to process queue for
1266  * @in_kthread: true if we are in the context of the message pump thread
1267  *
1268  * This function checks if there is any spi message in the queue that
1269  * needs processing and if so call out to the driver to initialize hardware
1270  * and transfer each message.
1271  *
1272  * Note that it is called both from the kthread itself and also from
1273  * inside spi_sync(); the queue extraction handling at the top of the
1274  * function should deal with this safely.
1275  */
1276 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1277 {
1278         struct spi_transfer *xfer;
1279         struct spi_message *msg;
1280         bool was_busy = false;
1281         unsigned long flags;
1282         int ret;
1283
1284         /* Lock queue */
1285         spin_lock_irqsave(&ctlr->queue_lock, flags);
1286
1287         /* Make sure we are not already running a message */
1288         if (ctlr->cur_msg) {
1289                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1290                 return;
1291         }
1292
1293         /* If another context is idling the device then defer */
1294         if (ctlr->idling) {
1295                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1296                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1297                 return;
1298         }
1299
1300         /* Check if the queue is idle */
1301         if (list_empty(&ctlr->queue) || !ctlr->running) {
1302                 if (!ctlr->busy) {
1303                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1304                         return;
1305                 }
1306
1307                 /* Only do teardown in the thread */
1308                 if (!in_kthread) {
1309                         kthread_queue_work(&ctlr->kworker,
1310                                            &ctlr->pump_messages);
1311                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1312                         return;
1313                 }
1314
1315                 ctlr->busy = false;
1316                 ctlr->idling = true;
1317                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1318
1319                 kfree(ctlr->dummy_rx);
1320                 ctlr->dummy_rx = NULL;
1321                 kfree(ctlr->dummy_tx);
1322                 ctlr->dummy_tx = NULL;
1323                 if (ctlr->unprepare_transfer_hardware &&
1324                     ctlr->unprepare_transfer_hardware(ctlr))
1325                         dev_err(&ctlr->dev,
1326                                 "failed to unprepare transfer hardware\n");
1327                 if (ctlr->auto_runtime_pm) {
1328                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1329                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1330                 }
1331                 trace_spi_controller_idle(ctlr);
1332
1333                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1334                 ctlr->idling = false;
1335                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1336                 return;
1337         }
1338
1339         /* Extract head of queue */
1340         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1341         ctlr->cur_msg = msg;
1342
1343         list_del_init(&msg->queue);
1344         if (ctlr->busy)
1345                 was_busy = true;
1346         else
1347                 ctlr->busy = true;
1348         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1349
1350         mutex_lock(&ctlr->io_mutex);
1351
1352         if (!was_busy && ctlr->auto_runtime_pm) {
1353                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1354                 if (ret < 0) {
1355                         pm_runtime_put_noidle(ctlr->dev.parent);
1356                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1357                                 ret);
1358                         mutex_unlock(&ctlr->io_mutex);
1359                         return;
1360                 }
1361         }
1362
1363         if (!was_busy)
1364                 trace_spi_controller_busy(ctlr);
1365
1366         if (!was_busy && ctlr->prepare_transfer_hardware) {
1367                 ret = ctlr->prepare_transfer_hardware(ctlr);
1368                 if (ret) {
1369                         dev_err(&ctlr->dev,
1370                                 "failed to prepare transfer hardware: %d\n",
1371                                 ret);
1372
1373                         if (ctlr->auto_runtime_pm)
1374                                 pm_runtime_put(ctlr->dev.parent);
1375
1376                         msg->status = ret;
1377                         spi_finalize_current_message(ctlr);
1378
1379                         mutex_unlock(&ctlr->io_mutex);
1380                         return;
1381                 }
1382         }
1383
1384         trace_spi_message_start(msg);
1385
1386         if (ctlr->prepare_message) {
1387                 ret = ctlr->prepare_message(ctlr, msg);
1388                 if (ret) {
1389                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1390                                 ret);
1391                         msg->status = ret;
1392                         spi_finalize_current_message(ctlr);
1393                         goto out;
1394                 }
1395                 ctlr->cur_msg_prepared = true;
1396         }
1397
1398         ret = spi_map_msg(ctlr, msg);
1399         if (ret) {
1400                 msg->status = ret;
1401                 spi_finalize_current_message(ctlr);
1402                 goto out;
1403         }
1404
1405         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1406                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1407                         xfer->ptp_sts_word_pre = 0;
1408                         ptp_read_system_prets(xfer->ptp_sts);
1409                 }
1410         }
1411
1412         ret = ctlr->transfer_one_message(ctlr, msg);
1413         if (ret) {
1414                 dev_err(&ctlr->dev,
1415                         "failed to transfer one message from queue\n");
1416                 goto out;
1417         }
1418
1419 out:
1420         mutex_unlock(&ctlr->io_mutex);
1421
1422         /* Prod the scheduler in case transfer_one() was busy waiting */
1423         if (!ret)
1424                 cond_resched();
1425 }
1426
1427 /**
1428  * spi_pump_messages - kthread work function which processes spi message queue
1429  * @work: pointer to kthread work struct contained in the controller struct
1430  */
1431 static void spi_pump_messages(struct kthread_work *work)
1432 {
1433         struct spi_controller *ctlr =
1434                 container_of(work, struct spi_controller, pump_messages);
1435
1436         __spi_pump_messages(ctlr, true);
1437 }
1438
1439 /**
1440  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1441  *                          TX timestamp for the requested byte from the SPI
1442  *                          transfer. The frequency with which this function
1443  *                          must be called (once per word, once for the whole
1444  *                          transfer, once per batch of words etc) is arbitrary
1445  *                          as long as the @tx buffer offset is greater than or
1446  *                          equal to the requested byte at the time of the
1447  *                          call. The timestamp is only taken once, at the
1448  *                          first such call. It is assumed that the driver
1449  *                          advances its @tx buffer pointer monotonically.
1450  * @ctlr: Pointer to the spi_controller structure of the driver
1451  * @xfer: Pointer to the transfer being timestamped
1452  * @tx: Pointer to the current word within the xfer->tx_buf that the driver is
1453  *      preparing to transmit right now.
1454  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1455  *            transfer, for less jitter in time measurement. Only compatible
1456  *            with PIO drivers. If true, must follow up with
1457  *            spi_take_timestamp_post or otherwise system will crash.
1458  *            WARNING: for fully predictable results, the CPU frequency must
1459  *            also be under control (governor).
1460  */
1461 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1462                             struct spi_transfer *xfer,
1463                             const void *tx, bool irqs_off)
1464 {
1465         u8 bytes_per_word = DIV_ROUND_UP(xfer->bits_per_word, 8);
1466
1467         if (!xfer->ptp_sts)
1468                 return;
1469
1470         if (xfer->timestamped_pre)
1471                 return;
1472
1473         if (tx < (xfer->tx_buf + xfer->ptp_sts_word_pre * bytes_per_word))
1474                 return;
1475
1476         /* Capture the resolution of the timestamp */
1477         xfer->ptp_sts_word_pre = (tx - xfer->tx_buf) / bytes_per_word;
1478
1479         xfer->timestamped_pre = true;
1480
1481         if (irqs_off) {
1482                 local_irq_save(ctlr->irq_flags);
1483                 preempt_disable();
1484         }
1485
1486         ptp_read_system_prets(xfer->ptp_sts);
1487 }
1488 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1489
1490 /**
1491  * spi_take_timestamp_post - helper for drivers to collect the end of the
1492  *                           TX timestamp for the requested byte from the SPI
1493  *                           transfer. Can be called with an arbitrary
1494  *                           frequency: only the first call where @tx exceeds
1495  *                           or is equal to the requested word will be
1496  *                           timestamped.
1497  * @ctlr: Pointer to the spi_controller structure of the driver
1498  * @xfer: Pointer to the transfer being timestamped
1499  * @tx: Pointer to the current word within the xfer->tx_buf that the driver has
1500  *      just transmitted.
1501  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1502  */
1503 void spi_take_timestamp_post(struct spi_controller *ctlr,
1504                              struct spi_transfer *xfer,
1505                              const void *tx, bool irqs_off)
1506 {
1507         u8 bytes_per_word = DIV_ROUND_UP(xfer->bits_per_word, 8);
1508
1509         if (!xfer->ptp_sts)
1510                 return;
1511
1512         if (xfer->timestamped_post)
1513                 return;
1514
1515         if (tx < (xfer->tx_buf + xfer->ptp_sts_word_post * bytes_per_word))
1516                 return;
1517
1518         ptp_read_system_postts(xfer->ptp_sts);
1519
1520         if (irqs_off) {
1521                 local_irq_restore(ctlr->irq_flags);
1522                 preempt_enable();
1523         }
1524
1525         /* Capture the resolution of the timestamp */
1526         xfer->ptp_sts_word_post = (tx - xfer->tx_buf) / bytes_per_word;
1527
1528         xfer->timestamped_post = true;
1529 }
1530 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1531
1532 /**
1533  * spi_set_thread_rt - set the controller to pump at realtime priority
1534  * @ctlr: controller to boost priority of
1535  *
1536  * This can be called because the controller requested realtime priority
1537  * (by setting the ->rt value before calling spi_register_controller()) or
1538  * because a device on the bus said that its transfers needed realtime
1539  * priority.
1540  *
1541  * NOTE: at the moment if any device on a bus says it needs realtime then
1542  * the thread will be at realtime priority for all transfers on that
1543  * controller.  If this eventually becomes a problem we may see if we can
1544  * find a way to boost the priority only temporarily during relevant
1545  * transfers.
1546  */
1547 static void spi_set_thread_rt(struct spi_controller *ctlr)
1548 {
1549         struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
1550
1551         dev_info(&ctlr->dev,
1552                 "will run message pump with realtime priority\n");
1553         sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1554 }
1555
1556 static int spi_init_queue(struct spi_controller *ctlr)
1557 {
1558         ctlr->running = false;
1559         ctlr->busy = false;
1560
1561         kthread_init_worker(&ctlr->kworker);
1562         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1563                                          "%s", dev_name(&ctlr->dev));
1564         if (IS_ERR(ctlr->kworker_task)) {
1565                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1566                 return PTR_ERR(ctlr->kworker_task);
1567         }
1568         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1569
1570         /*
1571          * Controller config will indicate if this controller should run the
1572          * message pump with high (realtime) priority to reduce the transfer
1573          * latency on the bus by minimising the delay between a transfer
1574          * request and the scheduling of the message pump thread. Without this
1575          * setting the message pump thread will remain at default priority.
1576          */
1577         if (ctlr->rt)
1578                 spi_set_thread_rt(ctlr);
1579
1580         return 0;
1581 }
1582
1583 /**
1584  * spi_get_next_queued_message() - called by driver to check for queued
1585  * messages
1586  * @ctlr: the controller to check for queued messages
1587  *
1588  * If there are more messages in the queue, the next message is returned from
1589  * this call.
1590  *
1591  * Return: the next message in the queue, else NULL if the queue is empty.
1592  */
1593 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1594 {
1595         struct spi_message *next;
1596         unsigned long flags;
1597
1598         /* get a pointer to the next message, if any */
1599         spin_lock_irqsave(&ctlr->queue_lock, flags);
1600         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1601                                         queue);
1602         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1603
1604         return next;
1605 }
1606 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1607
1608 /**
1609  * spi_finalize_current_message() - the current message is complete
1610  * @ctlr: the controller to return the message to
1611  *
1612  * Called by the driver to notify the core that the message in the front of the
1613  * queue is complete and can be removed from the queue.
1614  */
1615 void spi_finalize_current_message(struct spi_controller *ctlr)
1616 {
1617         struct spi_transfer *xfer;
1618         struct spi_message *mesg;
1619         unsigned long flags;
1620         int ret;
1621
1622         spin_lock_irqsave(&ctlr->queue_lock, flags);
1623         mesg = ctlr->cur_msg;
1624         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1625
1626         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1627                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1628                         ptp_read_system_postts(xfer->ptp_sts);
1629                         xfer->ptp_sts_word_post = xfer->len;
1630                 }
1631         }
1632
1633         spi_unmap_msg(ctlr, mesg);
1634
1635         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1636                 ret = ctlr->unprepare_message(ctlr, mesg);
1637                 if (ret) {
1638                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1639                                 ret);
1640                 }
1641         }
1642
1643         spin_lock_irqsave(&ctlr->queue_lock, flags);
1644         ctlr->cur_msg = NULL;
1645         ctlr->cur_msg_prepared = false;
1646         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1647         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1648
1649         trace_spi_message_done(mesg);
1650
1651         mesg->state = NULL;
1652         if (mesg->complete)
1653                 mesg->complete(mesg->context);
1654 }
1655 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1656
1657 static int spi_start_queue(struct spi_controller *ctlr)
1658 {
1659         unsigned long flags;
1660
1661         spin_lock_irqsave(&ctlr->queue_lock, flags);
1662
1663         if (ctlr->running || ctlr->busy) {
1664                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1665                 return -EBUSY;
1666         }
1667
1668         ctlr->running = true;
1669         ctlr->cur_msg = NULL;
1670         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1671
1672         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1673
1674         return 0;
1675 }
1676
1677 static int spi_stop_queue(struct spi_controller *ctlr)
1678 {
1679         unsigned long flags;
1680         unsigned limit = 500;
1681         int ret = 0;
1682
1683         spin_lock_irqsave(&ctlr->queue_lock, flags);
1684
1685         /*
1686          * This is a bit lame, but is optimized for the common execution path.
1687          * A wait_queue on the ctlr->busy could be used, but then the common
1688          * execution path (pump_messages) would be required to call wake_up or
1689          * friends on every SPI message. Do this instead.
1690          */
1691         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1692                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1693                 usleep_range(10000, 11000);
1694                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1695         }
1696
1697         if (!list_empty(&ctlr->queue) || ctlr->busy)
1698                 ret = -EBUSY;
1699         else
1700                 ctlr->running = false;
1701
1702         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1703
1704         if (ret) {
1705                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1706                 return ret;
1707         }
1708         return ret;
1709 }
1710
1711 static int spi_destroy_queue(struct spi_controller *ctlr)
1712 {
1713         int ret;
1714
1715         ret = spi_stop_queue(ctlr);
1716
1717         /*
1718          * kthread_flush_worker will block until all work is done.
1719          * If the reason that stop_queue timed out is that the work will never
1720          * finish, then it does no good to call flush/stop thread, so
1721          * return anyway.
1722          */
1723         if (ret) {
1724                 dev_err(&ctlr->dev, "problem destroying queue\n");
1725                 return ret;
1726         }
1727
1728         kthread_flush_worker(&ctlr->kworker);
1729         kthread_stop(ctlr->kworker_task);
1730
1731         return 0;
1732 }
1733
1734 static int __spi_queued_transfer(struct spi_device *spi,
1735                                  struct spi_message *msg,
1736                                  bool need_pump)
1737 {
1738         struct spi_controller *ctlr = spi->controller;
1739         unsigned long flags;
1740
1741         spin_lock_irqsave(&ctlr->queue_lock, flags);
1742
1743         if (!ctlr->running) {
1744                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1745                 return -ESHUTDOWN;
1746         }
1747         msg->actual_length = 0;
1748         msg->status = -EINPROGRESS;
1749
1750         list_add_tail(&msg->queue, &ctlr->queue);
1751         if (!ctlr->busy && need_pump)
1752                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1753
1754         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1755         return 0;
1756 }
1757
1758 /**
1759  * spi_queued_transfer - transfer function for queued transfers
1760  * @spi: spi device which is requesting transfer
1761  * @msg: spi message which is to handled is queued to driver queue
1762  *
1763  * Return: zero on success, else a negative error code.
1764  */
1765 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1766 {
1767         return __spi_queued_transfer(spi, msg, true);
1768 }
1769
1770 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1771 {
1772         int ret;
1773
1774         ctlr->transfer = spi_queued_transfer;
1775         if (!ctlr->transfer_one_message)
1776                 ctlr->transfer_one_message = spi_transfer_one_message;
1777
1778         /* Initialize and start queue */
1779         ret = spi_init_queue(ctlr);
1780         if (ret) {
1781                 dev_err(&ctlr->dev, "problem initializing queue\n");
1782                 goto err_init_queue;
1783         }
1784         ctlr->queued = true;
1785         ret = spi_start_queue(ctlr);
1786         if (ret) {
1787                 dev_err(&ctlr->dev, "problem starting queue\n");
1788                 goto err_start_queue;
1789         }
1790
1791         return 0;
1792
1793 err_start_queue:
1794         spi_destroy_queue(ctlr);
1795 err_init_queue:
1796         return ret;
1797 }
1798
1799 /**
1800  * spi_flush_queue - Send all pending messages in the queue from the callers'
1801  *                   context
1802  * @ctlr: controller to process queue for
1803  *
1804  * This should be used when one wants to ensure all pending messages have been
1805  * sent before doing something. Is used by the spi-mem code to make sure SPI
1806  * memory operations do not preempt regular SPI transfers that have been queued
1807  * before the spi-mem operation.
1808  */
1809 void spi_flush_queue(struct spi_controller *ctlr)
1810 {
1811         if (ctlr->transfer == spi_queued_transfer)
1812                 __spi_pump_messages(ctlr, false);
1813 }
1814
1815 /*-------------------------------------------------------------------------*/
1816
1817 #if defined(CONFIG_OF)
1818 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1819                            struct device_node *nc)
1820 {
1821         u32 value;
1822         int rc;
1823
1824         /* Mode (clock phase/polarity/etc.) */
1825         if (of_property_read_bool(nc, "spi-cpha"))
1826                 spi->mode |= SPI_CPHA;
1827         if (of_property_read_bool(nc, "spi-cpol"))
1828                 spi->mode |= SPI_CPOL;
1829         if (of_property_read_bool(nc, "spi-3wire"))
1830                 spi->mode |= SPI_3WIRE;
1831         if (of_property_read_bool(nc, "spi-lsb-first"))
1832                 spi->mode |= SPI_LSB_FIRST;
1833
1834         /*
1835          * For descriptors associated with the device, polarity inversion is
1836          * handled in the gpiolib, so all chip selects are "active high" in
1837          * the logical sense, the gpiolib will invert the line if need be.
1838          */
1839         if (ctlr->use_gpio_descriptors)
1840                 spi->mode |= SPI_CS_HIGH;
1841         else if (of_property_read_bool(nc, "spi-cs-high"))
1842                 spi->mode |= SPI_CS_HIGH;
1843
1844         /* Device DUAL/QUAD mode */
1845         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1846                 switch (value) {
1847                 case 1:
1848                         break;
1849                 case 2:
1850                         spi->mode |= SPI_TX_DUAL;
1851                         break;
1852                 case 4:
1853                         spi->mode |= SPI_TX_QUAD;
1854                         break;
1855                 case 8:
1856                         spi->mode |= SPI_TX_OCTAL;
1857                         break;
1858                 default:
1859                         dev_warn(&ctlr->dev,
1860                                 "spi-tx-bus-width %d not supported\n",
1861                                 value);
1862                         break;
1863                 }
1864         }
1865
1866         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1867                 switch (value) {
1868                 case 1:
1869                         break;
1870                 case 2:
1871                         spi->mode |= SPI_RX_DUAL;
1872                         break;
1873                 case 4:
1874                         spi->mode |= SPI_RX_QUAD;
1875                         break;
1876                 case 8:
1877                         spi->mode |= SPI_RX_OCTAL;
1878                         break;
1879                 default:
1880                         dev_warn(&ctlr->dev,
1881                                 "spi-rx-bus-width %d not supported\n",
1882                                 value);
1883                         break;
1884                 }
1885         }
1886
1887         if (spi_controller_is_slave(ctlr)) {
1888                 if (!of_node_name_eq(nc, "slave")) {
1889                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1890                                 nc);
1891                         return -EINVAL;
1892                 }
1893                 return 0;
1894         }
1895
1896         /* Device address */
1897         rc = of_property_read_u32(nc, "reg", &value);
1898         if (rc) {
1899                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1900                         nc, rc);
1901                 return rc;
1902         }
1903         spi->chip_select = value;
1904
1905         /* Device speed */
1906         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1907         if (rc) {
1908                 dev_err(&ctlr->dev,
1909                         "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1910                 return rc;
1911         }
1912         spi->max_speed_hz = value;
1913
1914         return 0;
1915 }
1916
1917 static struct spi_device *
1918 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1919 {
1920         struct spi_device *spi;
1921         int rc;
1922
1923         /* Alloc an spi_device */
1924         spi = spi_alloc_device(ctlr);
1925         if (!spi) {
1926                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1927                 rc = -ENOMEM;
1928                 goto err_out;
1929         }
1930
1931         /* Select device driver */
1932         rc = of_modalias_node(nc, spi->modalias,
1933                                 sizeof(spi->modalias));
1934         if (rc < 0) {
1935                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1936                 goto err_out;
1937         }
1938
1939         rc = of_spi_parse_dt(ctlr, spi, nc);
1940         if (rc)
1941                 goto err_out;
1942
1943         /* Store a pointer to the node in the device structure */
1944         of_node_get(nc);
1945         spi->dev.of_node = nc;
1946
1947         /* Register the new device */
1948         rc = spi_add_device(spi);
1949         if (rc) {
1950                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1951                 goto err_of_node_put;
1952         }
1953
1954         return spi;
1955
1956 err_of_node_put:
1957         of_node_put(nc);
1958 err_out:
1959         spi_dev_put(spi);
1960         return ERR_PTR(rc);
1961 }
1962
1963 /**
1964  * of_register_spi_devices() - Register child devices onto the SPI bus
1965  * @ctlr:       Pointer to spi_controller device
1966  *
1967  * Registers an spi_device for each child node of controller node which
1968  * represents a valid SPI slave.
1969  */
1970 static void of_register_spi_devices(struct spi_controller *ctlr)
1971 {
1972         struct spi_device *spi;
1973         struct device_node *nc;
1974
1975         if (!ctlr->dev.of_node)
1976                 return;
1977
1978         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1979                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1980                         continue;
1981                 spi = of_register_spi_device(ctlr, nc);
1982                 if (IS_ERR(spi)) {
1983                         dev_warn(&ctlr->dev,
1984                                  "Failed to create SPI device for %pOF\n", nc);
1985                         of_node_clear_flag(nc, OF_POPULATED);
1986                 }
1987         }
1988 }
1989 #else
1990 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1991 #endif
1992
1993 #ifdef CONFIG_ACPI
1994 struct acpi_spi_lookup {
1995         struct spi_controller   *ctlr;
1996         u32                     max_speed_hz;
1997         u32                     mode;
1998         int                     irq;
1999         u8                      bits_per_word;
2000         u8                      chip_select;
2001 };
2002
2003 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2004                                             struct acpi_spi_lookup *lookup)
2005 {
2006         const union acpi_object *obj;
2007
2008         if (!x86_apple_machine)
2009                 return;
2010
2011         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2012             && obj->buffer.length >= 4)
2013                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2014
2015         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2016             && obj->buffer.length == 8)
2017                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2018
2019         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2020             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2021                 lookup->mode |= SPI_LSB_FIRST;
2022
2023         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2024             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2025                 lookup->mode |= SPI_CPOL;
2026
2027         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2028             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2029                 lookup->mode |= SPI_CPHA;
2030 }
2031
2032 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2033 {
2034         struct acpi_spi_lookup *lookup = data;
2035         struct spi_controller *ctlr = lookup->ctlr;
2036
2037         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2038                 struct acpi_resource_spi_serialbus *sb;
2039                 acpi_handle parent_handle;
2040                 acpi_status status;
2041
2042                 sb = &ares->data.spi_serial_bus;
2043                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2044
2045                         status = acpi_get_handle(NULL,
2046                                                  sb->resource_source.string_ptr,
2047                                                  &parent_handle);
2048
2049                         if (ACPI_FAILURE(status) ||
2050                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2051                                 return -ENODEV;
2052
2053                         /*
2054                          * ACPI DeviceSelection numbering is handled by the
2055                          * host controller driver in Windows and can vary
2056                          * from driver to driver. In Linux we always expect
2057                          * 0 .. max - 1 so we need to ask the driver to
2058                          * translate between the two schemes.
2059                          */
2060                         if (ctlr->fw_translate_cs) {
2061                                 int cs = ctlr->fw_translate_cs(ctlr,
2062                                                 sb->device_selection);
2063                                 if (cs < 0)
2064                                         return cs;
2065                                 lookup->chip_select = cs;
2066                         } else {
2067                                 lookup->chip_select = sb->device_selection;
2068                         }
2069
2070                         lookup->max_speed_hz = sb->connection_speed;
2071
2072                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2073                                 lookup->mode |= SPI_CPHA;
2074                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2075                                 lookup->mode |= SPI_CPOL;
2076                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2077                                 lookup->mode |= SPI_CS_HIGH;
2078                 }
2079         } else if (lookup->irq < 0) {
2080                 struct resource r;
2081
2082                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2083                         lookup->irq = r.start;
2084         }
2085
2086         /* Always tell the ACPI core to skip this resource */
2087         return 1;
2088 }
2089
2090 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2091                                             struct acpi_device *adev)
2092 {
2093         acpi_handle parent_handle = NULL;
2094         struct list_head resource_list;
2095         struct acpi_spi_lookup lookup = {};
2096         struct spi_device *spi;
2097         int ret;
2098
2099         if (acpi_bus_get_status(adev) || !adev->status.present ||
2100             acpi_device_enumerated(adev))
2101                 return AE_OK;
2102
2103         lookup.ctlr             = ctlr;
2104         lookup.irq              = -1;
2105
2106         INIT_LIST_HEAD(&resource_list);
2107         ret = acpi_dev_get_resources(adev, &resource_list,
2108                                      acpi_spi_add_resource, &lookup);
2109         acpi_dev_free_resource_list(&resource_list);
2110
2111         if (ret < 0)
2112                 /* found SPI in _CRS but it points to another controller */
2113                 return AE_OK;
2114
2115         if (!lookup.max_speed_hz &&
2116             !ACPI_FAILURE(acpi_get_parent(adev->handle, &parent_handle)) &&
2117             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2118                 /* Apple does not use _CRS but nested devices for SPI slaves */
2119                 acpi_spi_parse_apple_properties(adev, &lookup);
2120         }
2121
2122         if (!lookup.max_speed_hz)
2123                 return AE_OK;
2124
2125         spi = spi_alloc_device(ctlr);
2126         if (!spi) {
2127                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2128                         dev_name(&adev->dev));
2129                 return AE_NO_MEMORY;
2130         }
2131
2132         ACPI_COMPANION_SET(&spi->dev, adev);
2133         spi->max_speed_hz       = lookup.max_speed_hz;
2134         spi->mode               = lookup.mode;
2135         spi->irq                = lookup.irq;
2136         spi->bits_per_word      = lookup.bits_per_word;
2137         spi->chip_select        = lookup.chip_select;
2138
2139         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2140                           sizeof(spi->modalias));
2141
2142         if (spi->irq < 0)
2143                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2144
2145         acpi_device_set_enumerated(adev);
2146
2147         adev->power.flags.ignore_parent = true;
2148         if (spi_add_device(spi)) {
2149                 adev->power.flags.ignore_parent = false;
2150                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2151                         dev_name(&adev->dev));
2152                 spi_dev_put(spi);
2153         }
2154
2155         return AE_OK;
2156 }
2157
2158 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2159                                        void *data, void **return_value)
2160 {
2161         struct spi_controller *ctlr = data;
2162         struct acpi_device *adev;
2163
2164         if (acpi_bus_get_device(handle, &adev))
2165                 return AE_OK;
2166
2167         return acpi_register_spi_device(ctlr, adev);
2168 }
2169
2170 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2171
2172 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2173 {
2174         acpi_status status;
2175         acpi_handle handle;
2176
2177         handle = ACPI_HANDLE(ctlr->dev.parent);
2178         if (!handle)
2179                 return;
2180
2181         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2182                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2183                                      acpi_spi_add_device, NULL, ctlr, NULL);
2184         if (ACPI_FAILURE(status))
2185                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2186 }
2187 #else
2188 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2189 #endif /* CONFIG_ACPI */
2190
2191 static void spi_controller_release(struct device *dev)
2192 {
2193         struct spi_controller *ctlr;
2194
2195         ctlr = container_of(dev, struct spi_controller, dev);
2196         kfree(ctlr);
2197 }
2198
2199 static struct class spi_master_class = {
2200         .name           = "spi_master",
2201         .owner          = THIS_MODULE,
2202         .dev_release    = spi_controller_release,
2203         .dev_groups     = spi_master_groups,
2204 };
2205
2206 #ifdef CONFIG_SPI_SLAVE
2207 /**
2208  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2209  *                   controller
2210  * @spi: device used for the current transfer
2211  */
2212 int spi_slave_abort(struct spi_device *spi)
2213 {
2214         struct spi_controller *ctlr = spi->controller;
2215
2216         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2217                 return ctlr->slave_abort(ctlr);
2218
2219         return -ENOTSUPP;
2220 }
2221 EXPORT_SYMBOL_GPL(spi_slave_abort);
2222
2223 static int match_true(struct device *dev, void *data)
2224 {
2225         return 1;
2226 }
2227
2228 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2229                           char *buf)
2230 {
2231         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2232                                                    dev);
2233         struct device *child;
2234
2235         child = device_find_child(&ctlr->dev, NULL, match_true);
2236         return sprintf(buf, "%s\n",
2237                        child ? to_spi_device(child)->modalias : NULL);
2238 }
2239
2240 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2241                            const char *buf, size_t count)
2242 {
2243         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2244                                                    dev);
2245         struct spi_device *spi;
2246         struct device *child;
2247         char name[32];
2248         int rc;
2249
2250         rc = sscanf(buf, "%31s", name);
2251         if (rc != 1 || !name[0])
2252                 return -EINVAL;
2253
2254         child = device_find_child(&ctlr->dev, NULL, match_true);
2255         if (child) {
2256                 /* Remove registered slave */
2257                 device_unregister(child);
2258                 put_device(child);
2259         }
2260
2261         if (strcmp(name, "(null)")) {
2262                 /* Register new slave */
2263                 spi = spi_alloc_device(ctlr);
2264                 if (!spi)
2265                         return -ENOMEM;
2266
2267                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2268
2269                 rc = spi_add_device(spi);
2270                 if (rc) {
2271                         spi_dev_put(spi);
2272                         return rc;
2273                 }
2274         }
2275
2276         return count;
2277 }
2278
2279 static DEVICE_ATTR_RW(slave);
2280
2281 static struct attribute *spi_slave_attrs[] = {
2282         &dev_attr_slave.attr,
2283         NULL,
2284 };
2285
2286 static const struct attribute_group spi_slave_group = {
2287         .attrs = spi_slave_attrs,
2288 };
2289
2290 static const struct attribute_group *spi_slave_groups[] = {
2291         &spi_controller_statistics_group,
2292         &spi_slave_group,
2293         NULL,
2294 };
2295
2296 static struct class spi_slave_class = {
2297         .name           = "spi_slave",
2298         .owner          = THIS_MODULE,
2299         .dev_release    = spi_controller_release,
2300         .dev_groups     = spi_slave_groups,
2301 };
2302 #else
2303 extern struct class spi_slave_class;    /* dummy */
2304 #endif
2305
2306 /**
2307  * __spi_alloc_controller - allocate an SPI master or slave controller
2308  * @dev: the controller, possibly using the platform_bus
2309  * @size: how much zeroed driver-private data to allocate; the pointer to this
2310  *      memory is in the driver_data field of the returned device, accessible
2311  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2312  *      drivers granting DMA access to portions of their private data need to
2313  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2314  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2315  *      slave (true) controller
2316  * Context: can sleep
2317  *
2318  * This call is used only by SPI controller drivers, which are the
2319  * only ones directly touching chip registers.  It's how they allocate
2320  * an spi_controller structure, prior to calling spi_register_controller().
2321  *
2322  * This must be called from context that can sleep.
2323  *
2324  * The caller is responsible for assigning the bus number and initializing the
2325  * controller's methods before calling spi_register_controller(); and (after
2326  * errors adding the device) calling spi_controller_put() to prevent a memory
2327  * leak.
2328  *
2329  * Return: the SPI controller structure on success, else NULL.
2330  */
2331 struct spi_controller *__spi_alloc_controller(struct device *dev,
2332                                               unsigned int size, bool slave)
2333 {
2334         struct spi_controller   *ctlr;
2335         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2336
2337         if (!dev)
2338                 return NULL;
2339
2340         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2341         if (!ctlr)
2342                 return NULL;
2343
2344         device_initialize(&ctlr->dev);
2345         ctlr->bus_num = -1;
2346         ctlr->num_chipselect = 1;
2347         ctlr->slave = slave;
2348         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2349                 ctlr->dev.class = &spi_slave_class;
2350         else
2351                 ctlr->dev.class = &spi_master_class;
2352         ctlr->dev.parent = dev;
2353         pm_suspend_ignore_children(&ctlr->dev, true);
2354         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2355
2356         return ctlr;
2357 }
2358 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2359
2360 #ifdef CONFIG_OF
2361 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2362 {
2363         int nb, i, *cs;
2364         struct device_node *np = ctlr->dev.of_node;
2365
2366         if (!np)
2367                 return 0;
2368
2369         nb = of_gpio_named_count(np, "cs-gpios");
2370         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2371
2372         /* Return error only for an incorrectly formed cs-gpios property */
2373         if (nb == 0 || nb == -ENOENT)
2374                 return 0;
2375         else if (nb < 0)
2376                 return nb;
2377
2378         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2379                           GFP_KERNEL);
2380         ctlr->cs_gpios = cs;
2381
2382         if (!ctlr->cs_gpios)
2383                 return -ENOMEM;
2384
2385         for (i = 0; i < ctlr->num_chipselect; i++)
2386                 cs[i] = -ENOENT;
2387
2388         for (i = 0; i < nb; i++)
2389                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2390
2391         return 0;
2392 }
2393 #else
2394 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2395 {
2396         return 0;
2397 }
2398 #endif
2399
2400 /**
2401  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2402  * @ctlr: The SPI master to grab GPIO descriptors for
2403  */
2404 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2405 {
2406         int nb, i;
2407         struct gpio_desc **cs;
2408         struct device *dev = &ctlr->dev;
2409
2410         nb = gpiod_count(dev, "cs");
2411         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2412
2413         /* No GPIOs at all is fine, else return the error */
2414         if (nb == 0 || nb == -ENOENT)
2415                 return 0;
2416         else if (nb < 0)
2417                 return nb;
2418
2419         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2420                           GFP_KERNEL);
2421         if (!cs)
2422                 return -ENOMEM;
2423         ctlr->cs_gpiods = cs;
2424
2425         for (i = 0; i < nb; i++) {
2426                 /*
2427                  * Most chipselects are active low, the inverted
2428                  * semantics are handled by special quirks in gpiolib,
2429                  * so initializing them GPIOD_OUT_LOW here means
2430                  * "unasserted", in most cases this will drive the physical
2431                  * line high.
2432                  */
2433                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2434                                                       GPIOD_OUT_LOW);
2435                 if (IS_ERR(cs[i]))
2436                         return PTR_ERR(cs[i]);
2437
2438                 if (cs[i]) {
2439                         /*
2440                          * If we find a CS GPIO, name it after the device and
2441                          * chip select line.
2442                          */
2443                         char *gpioname;
2444
2445                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2446                                                   dev_name(dev), i);
2447                         if (!gpioname)
2448                                 return -ENOMEM;
2449                         gpiod_set_consumer_name(cs[i], gpioname);
2450                 }
2451         }
2452
2453         return 0;
2454 }
2455
2456 static int spi_controller_check_ops(struct spi_controller *ctlr)
2457 {
2458         /*
2459          * The controller may implement only the high-level SPI-memory like
2460          * operations if it does not support regular SPI transfers, and this is
2461          * valid use case.
2462          * If ->mem_ops is NULL, we request that at least one of the
2463          * ->transfer_xxx() method be implemented.
2464          */
2465         if (ctlr->mem_ops) {
2466                 if (!ctlr->mem_ops->exec_op)
2467                         return -EINVAL;
2468         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2469                    !ctlr->transfer_one_message) {
2470                 return -EINVAL;
2471         }
2472
2473         return 0;
2474 }
2475
2476 /**
2477  * spi_register_controller - register SPI master or slave controller
2478  * @ctlr: initialized master, originally from spi_alloc_master() or
2479  *      spi_alloc_slave()
2480  * Context: can sleep
2481  *
2482  * SPI controllers connect to their drivers using some non-SPI bus,
2483  * such as the platform bus.  The final stage of probe() in that code
2484  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2485  *
2486  * SPI controllers use board specific (often SOC specific) bus numbers,
2487  * and board-specific addressing for SPI devices combines those numbers
2488  * with chip select numbers.  Since SPI does not directly support dynamic
2489  * device identification, boards need configuration tables telling which
2490  * chip is at which address.
2491  *
2492  * This must be called from context that can sleep.  It returns zero on
2493  * success, else a negative error code (dropping the controller's refcount).
2494  * After a successful return, the caller is responsible for calling
2495  * spi_unregister_controller().
2496  *
2497  * Return: zero on success, else a negative error code.
2498  */
2499 int spi_register_controller(struct spi_controller *ctlr)
2500 {
2501         struct device           *dev = ctlr->dev.parent;
2502         struct boardinfo        *bi;
2503         int                     status;
2504         int                     id, first_dynamic;
2505
2506         if (!dev)
2507                 return -ENODEV;
2508
2509         /*
2510          * Make sure all necessary hooks are implemented before registering
2511          * the SPI controller.
2512          */
2513         status = spi_controller_check_ops(ctlr);
2514         if (status)
2515                 return status;
2516
2517         if (ctlr->bus_num >= 0) {
2518                 /* devices with a fixed bus num must check-in with the num */
2519                 mutex_lock(&board_lock);
2520                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2521                         ctlr->bus_num + 1, GFP_KERNEL);
2522                 mutex_unlock(&board_lock);
2523                 if (WARN(id < 0, "couldn't get idr"))
2524                         return id == -ENOSPC ? -EBUSY : id;
2525                 ctlr->bus_num = id;
2526         } else if (ctlr->dev.of_node) {
2527                 /* allocate dynamic bus number using Linux idr */
2528                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2529                 if (id >= 0) {
2530                         ctlr->bus_num = id;
2531                         mutex_lock(&board_lock);
2532                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2533                                        ctlr->bus_num + 1, GFP_KERNEL);
2534                         mutex_unlock(&board_lock);
2535                         if (WARN(id < 0, "couldn't get idr"))
2536                                 return id == -ENOSPC ? -EBUSY : id;
2537                 }
2538         }
2539         if (ctlr->bus_num < 0) {
2540                 first_dynamic = of_alias_get_highest_id("spi");
2541                 if (first_dynamic < 0)
2542                         first_dynamic = 0;
2543                 else
2544                         first_dynamic++;
2545
2546                 mutex_lock(&board_lock);
2547                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2548                                0, GFP_KERNEL);
2549                 mutex_unlock(&board_lock);
2550                 if (WARN(id < 0, "couldn't get idr"))
2551                         return id;
2552                 ctlr->bus_num = id;
2553         }
2554         INIT_LIST_HEAD(&ctlr->queue);
2555         spin_lock_init(&ctlr->queue_lock);
2556         spin_lock_init(&ctlr->bus_lock_spinlock);
2557         mutex_init(&ctlr->bus_lock_mutex);
2558         mutex_init(&ctlr->io_mutex);
2559         ctlr->bus_lock_flag = 0;
2560         init_completion(&ctlr->xfer_completion);
2561         if (!ctlr->max_dma_len)
2562                 ctlr->max_dma_len = INT_MAX;
2563
2564         /* register the device, then userspace will see it.
2565          * registration fails if the bus ID is in use.
2566          */
2567         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2568
2569         if (!spi_controller_is_slave(ctlr)) {
2570                 if (ctlr->use_gpio_descriptors) {
2571                         status = spi_get_gpio_descs(ctlr);
2572                         if (status)
2573                                 return status;
2574                         /*
2575                          * A controller using GPIO descriptors always
2576                          * supports SPI_CS_HIGH if need be.
2577                          */
2578                         ctlr->mode_bits |= SPI_CS_HIGH;
2579                 } else {
2580                         /* Legacy code path for GPIOs from DT */
2581                         status = of_spi_get_gpio_numbers(ctlr);
2582                         if (status)
2583                                 return status;
2584                 }
2585         }
2586
2587         /*
2588          * Even if it's just one always-selected device, there must
2589          * be at least one chipselect.
2590          */
2591         if (!ctlr->num_chipselect)
2592                 return -EINVAL;
2593
2594         status = device_add(&ctlr->dev);
2595         if (status < 0) {
2596                 /* free bus id */
2597                 mutex_lock(&board_lock);
2598                 idr_remove(&spi_master_idr, ctlr->bus_num);
2599                 mutex_unlock(&board_lock);
2600                 goto done;
2601         }
2602         dev_dbg(dev, "registered %s %s\n",
2603                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2604                         dev_name(&ctlr->dev));
2605
2606         /*
2607          * If we're using a queued driver, start the queue. Note that we don't
2608          * need the queueing logic if the driver is only supporting high-level
2609          * memory operations.
2610          */
2611         if (ctlr->transfer) {
2612                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2613         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2614                 status = spi_controller_initialize_queue(ctlr);
2615                 if (status) {
2616                         device_del(&ctlr->dev);
2617                         /* free bus id */
2618                         mutex_lock(&board_lock);
2619                         idr_remove(&spi_master_idr, ctlr->bus_num);
2620                         mutex_unlock(&board_lock);
2621                         goto done;
2622                 }
2623         }
2624         /* add statistics */
2625         spin_lock_init(&ctlr->statistics.lock);
2626
2627         mutex_lock(&board_lock);
2628         list_add_tail(&ctlr->list, &spi_controller_list);
2629         list_for_each_entry(bi, &board_list, list)
2630                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2631         mutex_unlock(&board_lock);
2632
2633         /* Register devices from the device tree and ACPI */
2634         of_register_spi_devices(ctlr);
2635         acpi_register_spi_devices(ctlr);
2636 done:
2637         return status;
2638 }
2639 EXPORT_SYMBOL_GPL(spi_register_controller);
2640
2641 static void devm_spi_unregister(struct device *dev, void *res)
2642 {
2643         spi_unregister_controller(*(struct spi_controller **)res);
2644 }
2645
2646 /**
2647  * devm_spi_register_controller - register managed SPI master or slave
2648  *      controller
2649  * @dev:    device managing SPI controller
2650  * @ctlr: initialized controller, originally from spi_alloc_master() or
2651  *      spi_alloc_slave()
2652  * Context: can sleep
2653  *
2654  * Register a SPI device as with spi_register_controller() which will
2655  * automatically be unregistered and freed.
2656  *
2657  * Return: zero on success, else a negative error code.
2658  */
2659 int devm_spi_register_controller(struct device *dev,
2660                                  struct spi_controller *ctlr)
2661 {
2662         struct spi_controller **ptr;
2663         int ret;
2664
2665         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2666         if (!ptr)
2667                 return -ENOMEM;
2668
2669         ret = spi_register_controller(ctlr);
2670         if (!ret) {
2671                 *ptr = ctlr;
2672                 devres_add(dev, ptr);
2673         } else {
2674                 devres_free(ptr);
2675         }
2676
2677         return ret;
2678 }
2679 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2680
2681 static int __unregister(struct device *dev, void *null)
2682 {
2683         spi_unregister_device(to_spi_device(dev));
2684         return 0;
2685 }
2686
2687 /**
2688  * spi_unregister_controller - unregister SPI master or slave controller
2689  * @ctlr: the controller being unregistered
2690  * Context: can sleep
2691  *
2692  * This call is used only by SPI controller drivers, which are the
2693  * only ones directly touching chip registers.
2694  *
2695  * This must be called from context that can sleep.
2696  *
2697  * Note that this function also drops a reference to the controller.
2698  */
2699 void spi_unregister_controller(struct spi_controller *ctlr)
2700 {
2701         struct spi_controller *found;
2702         int id = ctlr->bus_num;
2703
2704         /* First make sure that this controller was ever added */
2705         mutex_lock(&board_lock);
2706         found = idr_find(&spi_master_idr, id);
2707         mutex_unlock(&board_lock);
2708         if (ctlr->queued) {
2709                 if (spi_destroy_queue(ctlr))
2710                         dev_err(&ctlr->dev, "queue remove failed\n");
2711         }
2712         mutex_lock(&board_lock);
2713         list_del(&ctlr->list);
2714         mutex_unlock(&board_lock);
2715
2716         device_for_each_child(&ctlr->dev, NULL, __unregister);
2717         device_unregister(&ctlr->dev);
2718         /* free bus id */
2719         mutex_lock(&board_lock);
2720         if (found == ctlr)
2721                 idr_remove(&spi_master_idr, id);
2722         mutex_unlock(&board_lock);
2723 }
2724 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2725
2726 int spi_controller_suspend(struct spi_controller *ctlr)
2727 {
2728         int ret;
2729
2730         /* Basically no-ops for non-queued controllers */
2731         if (!ctlr->queued)
2732                 return 0;
2733
2734         ret = spi_stop_queue(ctlr);
2735         if (ret)
2736                 dev_err(&ctlr->dev, "queue stop failed\n");
2737
2738         return ret;
2739 }
2740 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2741
2742 int spi_controller_resume(struct spi_controller *ctlr)
2743 {
2744         int ret;
2745
2746         if (!ctlr->queued)
2747                 return 0;
2748
2749         ret = spi_start_queue(ctlr);
2750         if (ret)
2751                 dev_err(&ctlr->dev, "queue restart failed\n");
2752
2753         return ret;
2754 }
2755 EXPORT_SYMBOL_GPL(spi_controller_resume);
2756
2757 static int __spi_controller_match(struct device *dev, const void *data)
2758 {
2759         struct spi_controller *ctlr;
2760         const u16 *bus_num = data;
2761
2762         ctlr = container_of(dev, struct spi_controller, dev);
2763         return ctlr->bus_num == *bus_num;
2764 }
2765
2766 /**
2767  * spi_busnum_to_master - look up master associated with bus_num
2768  * @bus_num: the master's bus number
2769  * Context: can sleep
2770  *
2771  * This call may be used with devices that are registered after
2772  * arch init time.  It returns a refcounted pointer to the relevant
2773  * spi_controller (which the caller must release), or NULL if there is
2774  * no such master registered.
2775  *
2776  * Return: the SPI master structure on success, else NULL.
2777  */
2778 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2779 {
2780         struct device           *dev;
2781         struct spi_controller   *ctlr = NULL;
2782
2783         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2784                                 __spi_controller_match);
2785         if (dev)
2786                 ctlr = container_of(dev, struct spi_controller, dev);
2787         /* reference got in class_find_device */
2788         return ctlr;
2789 }
2790 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2791
2792 /*-------------------------------------------------------------------------*/
2793
2794 /* Core methods for SPI resource management */
2795
2796 /**
2797  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2798  *                 during the processing of a spi_message while using
2799  *                 spi_transfer_one
2800  * @spi:     the spi device for which we allocate memory
2801  * @release: the release code to execute for this resource
2802  * @size:    size to alloc and return
2803  * @gfp:     GFP allocation flags
2804  *
2805  * Return: the pointer to the allocated data
2806  *
2807  * This may get enhanced in the future to allocate from a memory pool
2808  * of the @spi_device or @spi_controller to avoid repeated allocations.
2809  */
2810 void *spi_res_alloc(struct spi_device *spi,
2811                     spi_res_release_t release,
2812                     size_t size, gfp_t gfp)
2813 {
2814         struct spi_res *sres;
2815
2816         sres = kzalloc(sizeof(*sres) + size, gfp);
2817         if (!sres)
2818                 return NULL;
2819
2820         INIT_LIST_HEAD(&sres->entry);
2821         sres->release = release;
2822
2823         return sres->data;
2824 }
2825 EXPORT_SYMBOL_GPL(spi_res_alloc);
2826
2827 /**
2828  * spi_res_free - free an spi resource
2829  * @res: pointer to the custom data of a resource
2830  *
2831  */
2832 void spi_res_free(void *res)
2833 {
2834         struct spi_res *sres = container_of(res, struct spi_res, data);
2835
2836         if (!res)
2837                 return;
2838
2839         WARN_ON(!list_empty(&sres->entry));
2840         kfree(sres);
2841 }
2842 EXPORT_SYMBOL_GPL(spi_res_free);
2843
2844 /**
2845  * spi_res_add - add a spi_res to the spi_message
2846  * @message: the spi message
2847  * @res:     the spi_resource
2848  */
2849 void spi_res_add(struct spi_message *message, void *res)
2850 {
2851         struct spi_res *sres = container_of(res, struct spi_res, data);
2852
2853         WARN_ON(!list_empty(&sres->entry));
2854         list_add_tail(&sres->entry, &message->resources);
2855 }
2856 EXPORT_SYMBOL_GPL(spi_res_add);
2857
2858 /**
2859  * spi_res_release - release all spi resources for this message
2860  * @ctlr:  the @spi_controller
2861  * @message: the @spi_message
2862  */
2863 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2864 {
2865         struct spi_res *res, *tmp;
2866
2867         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
2868                 if (res->release)
2869                         res->release(ctlr, message, res->data);
2870
2871                 list_del(&res->entry);
2872
2873                 kfree(res);
2874         }
2875 }
2876 EXPORT_SYMBOL_GPL(spi_res_release);
2877
2878 /*-------------------------------------------------------------------------*/
2879
2880 /* Core methods for spi_message alterations */
2881
2882 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2883                                             struct spi_message *msg,
2884                                             void *res)
2885 {
2886         struct spi_replaced_transfers *rxfer = res;
2887         size_t i;
2888
2889         /* call extra callback if requested */
2890         if (rxfer->release)
2891                 rxfer->release(ctlr, msg, res);
2892
2893         /* insert replaced transfers back into the message */
2894         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2895
2896         /* remove the formerly inserted entries */
2897         for (i = 0; i < rxfer->inserted; i++)
2898                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2899 }
2900
2901 /**
2902  * spi_replace_transfers - replace transfers with several transfers
2903  *                         and register change with spi_message.resources
2904  * @msg:           the spi_message we work upon
2905  * @xfer_first:    the first spi_transfer we want to replace
2906  * @remove:        number of transfers to remove
2907  * @insert:        the number of transfers we want to insert instead
2908  * @release:       extra release code necessary in some circumstances
2909  * @extradatasize: extra data to allocate (with alignment guarantees
2910  *                 of struct @spi_transfer)
2911  * @gfp:           gfp flags
2912  *
2913  * Returns: pointer to @spi_replaced_transfers,
2914  *          PTR_ERR(...) in case of errors.
2915  */
2916 struct spi_replaced_transfers *spi_replace_transfers(
2917         struct spi_message *msg,
2918         struct spi_transfer *xfer_first,
2919         size_t remove,
2920         size_t insert,
2921         spi_replaced_release_t release,
2922         size_t extradatasize,
2923         gfp_t gfp)
2924 {
2925         struct spi_replaced_transfers *rxfer;
2926         struct spi_transfer *xfer;
2927         size_t i;
2928
2929         /* allocate the structure using spi_res */
2930         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2931                               struct_size(rxfer, inserted_transfers, insert)
2932                               + extradatasize,
2933                               gfp);
2934         if (!rxfer)
2935                 return ERR_PTR(-ENOMEM);
2936
2937         /* the release code to invoke before running the generic release */
2938         rxfer->release = release;
2939
2940         /* assign extradata */
2941         if (extradatasize)
2942                 rxfer->extradata =
2943                         &rxfer->inserted_transfers[insert];
2944
2945         /* init the replaced_transfers list */
2946         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2947
2948         /* assign the list_entry after which we should reinsert
2949          * the @replaced_transfers - it may be spi_message.messages!
2950          */
2951         rxfer->replaced_after = xfer_first->transfer_list.prev;
2952
2953         /* remove the requested number of transfers */
2954         for (i = 0; i < remove; i++) {
2955                 /* if the entry after replaced_after it is msg->transfers
2956                  * then we have been requested to remove more transfers
2957                  * than are in the list
2958                  */
2959                 if (rxfer->replaced_after->next == &msg->transfers) {
2960                         dev_err(&msg->spi->dev,
2961                                 "requested to remove more spi_transfers than are available\n");
2962                         /* insert replaced transfers back into the message */
2963                         list_splice(&rxfer->replaced_transfers,
2964                                     rxfer->replaced_after);
2965
2966                         /* free the spi_replace_transfer structure */
2967                         spi_res_free(rxfer);
2968
2969                         /* and return with an error */
2970                         return ERR_PTR(-EINVAL);
2971                 }
2972
2973                 /* remove the entry after replaced_after from list of
2974                  * transfers and add it to list of replaced_transfers
2975                  */
2976                 list_move_tail(rxfer->replaced_after->next,
2977                                &rxfer->replaced_transfers);
2978         }
2979
2980         /* create copy of the given xfer with identical settings
2981          * based on the first transfer to get removed
2982          */
2983         for (i = 0; i < insert; i++) {
2984                 /* we need to run in reverse order */
2985                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2986
2987                 /* copy all spi_transfer data */
2988                 memcpy(xfer, xfer_first, sizeof(*xfer));
2989
2990                 /* add to list */
2991                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2992
2993                 /* clear cs_change and delay_usecs for all but the last */
2994                 if (i) {
2995                         xfer->cs_change = false;
2996                         xfer->delay_usecs = 0;
2997                 }
2998         }
2999
3000         /* set up inserted */
3001         rxfer->inserted = insert;
3002
3003         /* and register it with spi_res/spi_message */
3004         spi_res_add(msg, rxfer);
3005
3006         return rxfer;
3007 }
3008 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3009
3010 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3011                                         struct spi_message *msg,
3012                                         struct spi_transfer **xferp,
3013                                         size_t maxsize,
3014                                         gfp_t gfp)
3015 {
3016         struct spi_transfer *xfer = *xferp, *xfers;
3017         struct spi_replaced_transfers *srt;
3018         size_t offset;
3019         size_t count, i;
3020
3021         /* calculate how many we have to replace */
3022         count = DIV_ROUND_UP(xfer->len, maxsize);
3023
3024         /* create replacement */
3025         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3026         if (IS_ERR(srt))
3027                 return PTR_ERR(srt);
3028         xfers = srt->inserted_transfers;
3029
3030         /* now handle each of those newly inserted spi_transfers
3031          * note that the replacements spi_transfers all are preset
3032          * to the same values as *xferp, so tx_buf, rx_buf and len
3033          * are all identical (as well as most others)
3034          * so we just have to fix up len and the pointers.
3035          *
3036          * this also includes support for the depreciated
3037          * spi_message.is_dma_mapped interface
3038          */
3039
3040         /* the first transfer just needs the length modified, so we
3041          * run it outside the loop
3042          */
3043         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3044
3045         /* all the others need rx_buf/tx_buf also set */
3046         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3047                 /* update rx_buf, tx_buf and dma */
3048                 if (xfers[i].rx_buf)
3049                         xfers[i].rx_buf += offset;
3050                 if (xfers[i].rx_dma)
3051                         xfers[i].rx_dma += offset;
3052                 if (xfers[i].tx_buf)
3053                         xfers[i].tx_buf += offset;
3054                 if (xfers[i].tx_dma)
3055                         xfers[i].tx_dma += offset;
3056
3057                 /* update length */
3058                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3059         }
3060
3061         /* we set up xferp to the last entry we have inserted,
3062          * so that we skip those already split transfers
3063          */
3064         *xferp = &xfers[count - 1];
3065
3066         /* increment statistics counters */
3067         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3068                                        transfers_split_maxsize);
3069         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3070                                        transfers_split_maxsize);
3071
3072         return 0;
3073 }
3074
3075 /**
3076  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
3077  *                              when an individual transfer exceeds a
3078  *                              certain size
3079  * @ctlr:    the @spi_controller for this transfer
3080  * @msg:   the @spi_message to transform
3081  * @maxsize:  the maximum when to apply this
3082  * @gfp: GFP allocation flags
3083  *
3084  * Return: status of transformation
3085  */
3086 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3087                                 struct spi_message *msg,
3088                                 size_t maxsize,
3089                                 gfp_t gfp)
3090 {
3091         struct spi_transfer *xfer;
3092         int ret;
3093
3094         /* iterate over the transfer_list,
3095          * but note that xfer is advanced to the last transfer inserted
3096          * to avoid checking sizes again unnecessarily (also xfer does
3097          * potentiall belong to a different list by the time the
3098          * replacement has happened
3099          */
3100         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3101                 if (xfer->len > maxsize) {
3102                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3103                                                            maxsize, gfp);
3104                         if (ret)
3105                                 return ret;
3106                 }
3107         }
3108
3109         return 0;
3110 }
3111 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3112
3113 /*-------------------------------------------------------------------------*/
3114
3115 /* Core methods for SPI controller protocol drivers.  Some of the
3116  * other core methods are currently defined as inline functions.
3117  */
3118
3119 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3120                                         u8 bits_per_word)
3121 {
3122         if (ctlr->bits_per_word_mask) {
3123                 /* Only 32 bits fit in the mask */
3124                 if (bits_per_word > 32)
3125                         return -EINVAL;
3126                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3127                         return -EINVAL;
3128         }
3129
3130         return 0;
3131 }
3132
3133 /**
3134  * spi_setup - setup SPI mode and clock rate
3135  * @spi: the device whose settings are being modified
3136  * Context: can sleep, and no requests are queued to the device
3137  *
3138  * SPI protocol drivers may need to update the transfer mode if the
3139  * device doesn't work with its default.  They may likewise need
3140  * to update clock rates or word sizes from initial values.  This function
3141  * changes those settings, and must be called from a context that can sleep.
3142  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3143  * effect the next time the device is selected and data is transferred to
3144  * or from it.  When this function returns, the spi device is deselected.
3145  *
3146  * Note that this call will fail if the protocol driver specifies an option
3147  * that the underlying controller or its driver does not support.  For
3148  * example, not all hardware supports wire transfers using nine bit words,
3149  * LSB-first wire encoding, or active-high chipselects.
3150  *
3151  * Return: zero on success, else a negative error code.
3152  */
3153 int spi_setup(struct spi_device *spi)
3154 {
3155         unsigned        bad_bits, ugly_bits;
3156         int             status;
3157
3158         /* check mode to prevent that DUAL and QUAD set at the same time
3159          */
3160         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
3161                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
3162                 dev_err(&spi->dev,
3163                 "setup: can not select dual and quad at the same time\n");
3164                 return -EINVAL;
3165         }
3166         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3167          */
3168         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3169                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3170                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3171                 return -EINVAL;
3172         /* help drivers fail *cleanly* when they need options
3173          * that aren't supported with their current controller
3174          * SPI_CS_WORD has a fallback software implementation,
3175          * so it is ignored here.
3176          */
3177         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3178         /* nothing prevents from working with active-high CS in case if it
3179          * is driven by GPIO.
3180          */
3181         if (gpio_is_valid(spi->cs_gpio))
3182                 bad_bits &= ~SPI_CS_HIGH;
3183         ugly_bits = bad_bits &
3184                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3185                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3186         if (ugly_bits) {
3187                 dev_warn(&spi->dev,
3188                          "setup: ignoring unsupported mode bits %x\n",
3189                          ugly_bits);
3190                 spi->mode &= ~ugly_bits;
3191                 bad_bits &= ~ugly_bits;
3192         }
3193         if (bad_bits) {
3194                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3195                         bad_bits);
3196                 return -EINVAL;
3197         }
3198
3199         if (!spi->bits_per_word)
3200                 spi->bits_per_word = 8;
3201
3202         status = __spi_validate_bits_per_word(spi->controller,
3203                                               spi->bits_per_word);
3204         if (status)
3205                 return status;
3206
3207         if (!spi->max_speed_hz)
3208                 spi->max_speed_hz = spi->controller->max_speed_hz;
3209
3210         if (spi->controller->setup)
3211                 status = spi->controller->setup(spi);
3212
3213         spi_set_cs(spi, false);
3214
3215         if (spi->rt && !spi->controller->rt) {
3216                 spi->controller->rt = true;
3217                 spi_set_thread_rt(spi->controller);
3218         }
3219
3220         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3221                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3222                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3223                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3224                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3225                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3226                         spi->bits_per_word, spi->max_speed_hz,
3227                         status);
3228
3229         return status;
3230 }
3231 EXPORT_SYMBOL_GPL(spi_setup);
3232
3233 /**
3234  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3235  * @spi: the device that requires specific CS timing configuration
3236  * @setup: CS setup time in terms of clock count
3237  * @hold: CS hold time in terms of clock count
3238  * @inactive_dly: CS inactive delay between transfers in terms of clock count
3239  */
3240 void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
3241                        u8 inactive_dly)
3242 {
3243         if (spi->controller->set_cs_timing)
3244                 spi->controller->set_cs_timing(spi, setup, hold, inactive_dly);
3245 }
3246 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3247
3248 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3249 {
3250         struct spi_controller *ctlr = spi->controller;
3251         struct spi_transfer *xfer;
3252         int w_size;
3253
3254         if (list_empty(&message->transfers))
3255                 return -EINVAL;
3256
3257         /* If an SPI controller does not support toggling the CS line on each
3258          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3259          * for the CS line, we can emulate the CS-per-word hardware function by
3260          * splitting transfers into one-word transfers and ensuring that
3261          * cs_change is set for each transfer.
3262          */
3263         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3264                                           spi->cs_gpiod ||
3265                                           gpio_is_valid(spi->cs_gpio))) {
3266                 size_t maxsize;
3267                 int ret;
3268
3269                 maxsize = (spi->bits_per_word + 7) / 8;
3270
3271                 /* spi_split_transfers_maxsize() requires message->spi */
3272                 message->spi = spi;
3273
3274                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3275                                                   GFP_KERNEL);
3276                 if (ret)
3277                         return ret;
3278
3279                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3280                         /* don't change cs_change on the last entry in the list */
3281                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3282                                 break;
3283                         xfer->cs_change = 1;
3284                 }
3285         }
3286
3287         /* Half-duplex links include original MicroWire, and ones with
3288          * only one data pin like SPI_3WIRE (switches direction) or where
3289          * either MOSI or MISO is missing.  They can also be caused by
3290          * software limitations.
3291          */
3292         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3293             (spi->mode & SPI_3WIRE)) {
3294                 unsigned flags = ctlr->flags;
3295
3296                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3297                         if (xfer->rx_buf && xfer->tx_buf)
3298                                 return -EINVAL;
3299                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3300                                 return -EINVAL;
3301                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3302                                 return -EINVAL;
3303                 }
3304         }
3305
3306         /**
3307          * Set transfer bits_per_word and max speed as spi device default if
3308          * it is not set for this transfer.
3309          * Set transfer tx_nbits and rx_nbits as single transfer default
3310          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3311          * Ensure transfer word_delay is at least as long as that required by
3312          * device itself.
3313          */
3314         message->frame_length = 0;
3315         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3316                 xfer->effective_speed_hz = 0;
3317                 message->frame_length += xfer->len;
3318                 if (!xfer->bits_per_word)
3319                         xfer->bits_per_word = spi->bits_per_word;
3320
3321                 if (!xfer->speed_hz)
3322                         xfer->speed_hz = spi->max_speed_hz;
3323
3324                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3325                         xfer->speed_hz = ctlr->max_speed_hz;
3326
3327                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3328                         return -EINVAL;
3329
3330                 /*
3331                  * SPI transfer length should be multiple of SPI word size
3332                  * where SPI word size should be power-of-two multiple
3333                  */
3334                 if (xfer->bits_per_word <= 8)
3335                         w_size = 1;
3336                 else if (xfer->bits_per_word <= 16)
3337                         w_size = 2;
3338                 else
3339                         w_size = 4;
3340
3341                 /* No partial transfers accepted */
3342                 if (xfer->len % w_size)
3343                         return -EINVAL;
3344
3345                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3346                     xfer->speed_hz < ctlr->min_speed_hz)
3347                         return -EINVAL;
3348
3349                 if (xfer->tx_buf && !xfer->tx_nbits)
3350                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3351                 if (xfer->rx_buf && !xfer->rx_nbits)
3352                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3353                 /* check transfer tx/rx_nbits:
3354                  * 1. check the value matches one of single, dual and quad
3355                  * 2. check tx/rx_nbits match the mode in spi_device
3356                  */
3357                 if (xfer->tx_buf) {
3358                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3359                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3360                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3361                                 return -EINVAL;
3362                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3363                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3364                                 return -EINVAL;
3365                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3366                                 !(spi->mode & SPI_TX_QUAD))
3367                                 return -EINVAL;
3368                 }
3369                 /* check transfer rx_nbits */
3370                 if (xfer->rx_buf) {
3371                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3372                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3373                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3374                                 return -EINVAL;
3375                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3376                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3377                                 return -EINVAL;
3378                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3379                                 !(spi->mode & SPI_RX_QUAD))
3380                                 return -EINVAL;
3381                 }
3382
3383                 if (xfer->word_delay_usecs < spi->word_delay_usecs)
3384                         xfer->word_delay_usecs = spi->word_delay_usecs;
3385         }
3386
3387         message->status = -EINPROGRESS;
3388
3389         return 0;
3390 }
3391
3392 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3393 {
3394         struct spi_controller *ctlr = spi->controller;
3395         struct spi_transfer *xfer;
3396
3397         /*
3398          * Some controllers do not support doing regular SPI transfers. Return
3399          * ENOTSUPP when this is the case.
3400          */
3401         if (!ctlr->transfer)
3402                 return -ENOTSUPP;
3403
3404         message->spi = spi;
3405
3406         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3407         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3408
3409         trace_spi_message_submit(message);
3410
3411         if (!ctlr->ptp_sts_supported) {
3412                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3413                         xfer->ptp_sts_word_pre = 0;
3414                         ptp_read_system_prets(xfer->ptp_sts);
3415                 }
3416         }
3417
3418         return ctlr->transfer(spi, message);
3419 }
3420
3421 /**
3422  * spi_async - asynchronous SPI transfer
3423  * @spi: device with which data will be exchanged
3424  * @message: describes the data transfers, including completion callback
3425  * Context: any (irqs may be blocked, etc)
3426  *
3427  * This call may be used in_irq and other contexts which can't sleep,
3428  * as well as from task contexts which can sleep.
3429  *
3430  * The completion callback is invoked in a context which can't sleep.
3431  * Before that invocation, the value of message->status is undefined.
3432  * When the callback is issued, message->status holds either zero (to
3433  * indicate complete success) or a negative error code.  After that
3434  * callback returns, the driver which issued the transfer request may
3435  * deallocate the associated memory; it's no longer in use by any SPI
3436  * core or controller driver code.
3437  *
3438  * Note that although all messages to a spi_device are handled in
3439  * FIFO order, messages may go to different devices in other orders.
3440  * Some device might be higher priority, or have various "hard" access
3441  * time requirements, for example.
3442  *
3443  * On detection of any fault during the transfer, processing of
3444  * the entire message is aborted, and the device is deselected.
3445  * Until returning from the associated message completion callback,
3446  * no other spi_message queued to that device will be processed.
3447  * (This rule applies equally to all the synchronous transfer calls,
3448  * which are wrappers around this core asynchronous primitive.)
3449  *
3450  * Return: zero on success, else a negative error code.
3451  */
3452 int spi_async(struct spi_device *spi, struct spi_message *message)
3453 {
3454         struct spi_controller *ctlr = spi->controller;
3455         int ret;
3456         unsigned long flags;
3457
3458         ret = __spi_validate(spi, message);
3459         if (ret != 0)
3460                 return ret;
3461
3462         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3463
3464         if (ctlr->bus_lock_flag)
3465                 ret = -EBUSY;
3466         else
3467                 ret = __spi_async(spi, message);
3468
3469         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3470
3471         return ret;
3472 }
3473 EXPORT_SYMBOL_GPL(spi_async);
3474
3475 /**
3476  * spi_async_locked - version of spi_async with exclusive bus usage
3477  * @spi: device with which data will be exchanged
3478  * @message: describes the data transfers, including completion callback
3479  * Context: any (irqs may be blocked, etc)
3480  *
3481  * This call may be used in_irq and other contexts which can't sleep,
3482  * as well as from task contexts which can sleep.
3483  *
3484  * The completion callback is invoked in a context which can't sleep.
3485  * Before that invocation, the value of message->status is undefined.
3486  * When the callback is issued, message->status holds either zero (to
3487  * indicate complete success) or a negative error code.  After that
3488  * callback returns, the driver which issued the transfer request may
3489  * deallocate the associated memory; it's no longer in use by any SPI
3490  * core or controller driver code.
3491  *
3492  * Note that although all messages to a spi_device are handled in
3493  * FIFO order, messages may go to different devices in other orders.
3494  * Some device might be higher priority, or have various "hard" access
3495  * time requirements, for example.
3496  *
3497  * On detection of any fault during the transfer, processing of
3498  * the entire message is aborted, and the device is deselected.
3499  * Until returning from the associated message completion callback,
3500  * no other spi_message queued to that device will be processed.
3501  * (This rule applies equally to all the synchronous transfer calls,
3502  * which are wrappers around this core asynchronous primitive.)
3503  *
3504  * Return: zero on success, else a negative error code.
3505  */
3506 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3507 {
3508         struct spi_controller *ctlr = spi->controller;
3509         int ret;
3510         unsigned long flags;
3511
3512         ret = __spi_validate(spi, message);
3513         if (ret != 0)
3514                 return ret;
3515
3516         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3517
3518         ret = __spi_async(spi, message);
3519
3520         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3521
3522         return ret;
3523
3524 }
3525 EXPORT_SYMBOL_GPL(spi_async_locked);
3526
3527 /*-------------------------------------------------------------------------*/
3528
3529 /* Utility methods for SPI protocol drivers, layered on
3530  * top of the core.  Some other utility methods are defined as
3531  * inline functions.
3532  */
3533
3534 static void spi_complete(void *arg)
3535 {
3536         complete(arg);
3537 }
3538
3539 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3540 {
3541         DECLARE_COMPLETION_ONSTACK(done);
3542         int status;
3543         struct spi_controller *ctlr = spi->controller;
3544         unsigned long flags;
3545
3546         status = __spi_validate(spi, message);
3547         if (status != 0)
3548                 return status;
3549
3550         message->complete = spi_complete;
3551         message->context = &done;
3552         message->spi = spi;
3553
3554         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3555         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3556
3557         /* If we're not using the legacy transfer method then we will
3558          * try to transfer in the calling context so special case.
3559          * This code would be less tricky if we could remove the
3560          * support for driver implemented message queues.
3561          */
3562         if (ctlr->transfer == spi_queued_transfer) {
3563                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3564
3565                 trace_spi_message_submit(message);
3566
3567                 status = __spi_queued_transfer(spi, message, false);
3568
3569                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3570         } else {
3571                 status = spi_async_locked(spi, message);
3572         }
3573
3574         if (status == 0) {
3575                 /* Push out the messages in the calling context if we
3576                  * can.
3577                  */
3578                 if (ctlr->transfer == spi_queued_transfer) {
3579                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3580                                                        spi_sync_immediate);
3581                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3582                                                        spi_sync_immediate);
3583                         __spi_pump_messages(ctlr, false);
3584                 }
3585
3586                 wait_for_completion(&done);
3587                 status = message->status;
3588         }
3589         message->context = NULL;
3590         return status;
3591 }
3592
3593 /**
3594  * spi_sync - blocking/synchronous SPI data transfers
3595  * @spi: device with which data will be exchanged
3596  * @message: describes the data transfers
3597  * Context: can sleep
3598  *
3599  * This call may only be used from a context that may sleep.  The sleep
3600  * is non-interruptible, and has no timeout.  Low-overhead controller
3601  * drivers may DMA directly into and out of the message buffers.
3602  *
3603  * Note that the SPI device's chip select is active during the message,
3604  * and then is normally disabled between messages.  Drivers for some
3605  * frequently-used devices may want to minimize costs of selecting a chip,
3606  * by leaving it selected in anticipation that the next message will go
3607  * to the same chip.  (That may increase power usage.)
3608  *
3609  * Also, the caller is guaranteeing that the memory associated with the
3610  * message will not be freed before this call returns.
3611  *
3612  * Return: zero on success, else a negative error code.
3613  */
3614 int spi_sync(struct spi_device *spi, struct spi_message *message)
3615 {
3616         int ret;
3617
3618         mutex_lock(&spi->controller->bus_lock_mutex);
3619         ret = __spi_sync(spi, message);
3620         mutex_unlock(&spi->controller->bus_lock_mutex);
3621
3622         return ret;
3623 }
3624 EXPORT_SYMBOL_GPL(spi_sync);
3625
3626 /**
3627  * spi_sync_locked - version of spi_sync with exclusive bus usage
3628  * @spi: device with which data will be exchanged
3629  * @message: describes the data transfers
3630  * Context: can sleep
3631  *
3632  * This call may only be used from a context that may sleep.  The sleep
3633  * is non-interruptible, and has no timeout.  Low-overhead controller
3634  * drivers may DMA directly into and out of the message buffers.
3635  *
3636  * This call should be used by drivers that require exclusive access to the
3637  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3638  * be released by a spi_bus_unlock call when the exclusive access is over.
3639  *
3640  * Return: zero on success, else a negative error code.
3641  */
3642 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3643 {
3644         return __spi_sync(spi, message);
3645 }
3646 EXPORT_SYMBOL_GPL(spi_sync_locked);
3647
3648 /**
3649  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3650  * @ctlr: SPI bus master that should be locked for exclusive bus access
3651  * Context: can sleep
3652  *
3653  * This call may only be used from a context that may sleep.  The sleep
3654  * is non-interruptible, and has no timeout.
3655  *
3656  * This call should be used by drivers that require exclusive access to the
3657  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3658  * exclusive access is over. Data transfer must be done by spi_sync_locked
3659  * and spi_async_locked calls when the SPI bus lock is held.
3660  *
3661  * Return: always zero.
3662  */
3663 int spi_bus_lock(struct spi_controller *ctlr)
3664 {
3665         unsigned long flags;
3666
3667         mutex_lock(&ctlr->bus_lock_mutex);
3668
3669         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3670         ctlr->bus_lock_flag = 1;
3671         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3672
3673         /* mutex remains locked until spi_bus_unlock is called */
3674
3675         return 0;
3676 }
3677 EXPORT_SYMBOL_GPL(spi_bus_lock);
3678
3679 /**
3680  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3681  * @ctlr: SPI bus master that was locked for exclusive bus access
3682  * Context: can sleep
3683  *
3684  * This call may only be used from a context that may sleep.  The sleep
3685  * is non-interruptible, and has no timeout.
3686  *
3687  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3688  * call.
3689  *
3690  * Return: always zero.
3691  */
3692 int spi_bus_unlock(struct spi_controller *ctlr)
3693 {
3694         ctlr->bus_lock_flag = 0;
3695
3696         mutex_unlock(&ctlr->bus_lock_mutex);
3697
3698         return 0;
3699 }
3700 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3701
3702 /* portable code must never pass more than 32 bytes */
3703 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3704
3705 static u8       *buf;
3706
3707 /**
3708  * spi_write_then_read - SPI synchronous write followed by read
3709  * @spi: device with which data will be exchanged
3710  * @txbuf: data to be written (need not be dma-safe)
3711  * @n_tx: size of txbuf, in bytes
3712  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3713  * @n_rx: size of rxbuf, in bytes
3714  * Context: can sleep
3715  *
3716  * This performs a half duplex MicroWire style transaction with the
3717  * device, sending txbuf and then reading rxbuf.  The return value
3718  * is zero for success, else a negative errno status code.
3719  * This call may only be used from a context that may sleep.
3720  *
3721  * Parameters to this routine are always copied using a small buffer;
3722  * portable code should never use this for more than 32 bytes.
3723  * Performance-sensitive or bulk transfer code should instead use
3724  * spi_{async,sync}() calls with dma-safe buffers.
3725  *
3726  * Return: zero on success, else a negative error code.
3727  */
3728 int spi_write_then_read(struct spi_device *spi,
3729                 const void *txbuf, unsigned n_tx,
3730                 void *rxbuf, unsigned n_rx)
3731 {
3732         static DEFINE_MUTEX(lock);
3733
3734         int                     status;
3735         struct spi_message      message;
3736         struct spi_transfer     x[2];
3737         u8                      *local_buf;
3738
3739         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3740          * copying here, (as a pure convenience thing), but we can
3741          * keep heap costs out of the hot path unless someone else is
3742          * using the pre-allocated buffer or the transfer is too large.
3743          */
3744         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3745                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3746                                     GFP_KERNEL | GFP_DMA);
3747                 if (!local_buf)
3748                         return -ENOMEM;
3749         } else {
3750                 local_buf = buf;
3751         }
3752
3753         spi_message_init(&message);
3754         memset(x, 0, sizeof(x));
3755         if (n_tx) {
3756                 x[0].len = n_tx;
3757                 spi_message_add_tail(&x[0], &message);
3758         }
3759         if (n_rx) {
3760                 x[1].len = n_rx;
3761                 spi_message_add_tail(&x[1], &message);
3762         }
3763
3764         memcpy(local_buf, txbuf, n_tx);
3765         x[0].tx_buf = local_buf;
3766         x[1].rx_buf = local_buf + n_tx;
3767
3768         /* do the i/o */
3769         status = spi_sync(spi, &message);
3770         if (status == 0)
3771                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3772
3773         if (x[0].tx_buf == buf)
3774                 mutex_unlock(&lock);
3775         else
3776                 kfree(local_buf);
3777
3778         return status;
3779 }
3780 EXPORT_SYMBOL_GPL(spi_write_then_read);
3781
3782 /*-------------------------------------------------------------------------*/
3783
3784 #if IS_ENABLED(CONFIG_OF)
3785 /* must call put_device() when done with returned spi_device device */
3786 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3787 {
3788         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
3789
3790         return dev ? to_spi_device(dev) : NULL;
3791 }
3792 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3793 #endif /* IS_ENABLED(CONFIG_OF) */
3794
3795 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3796 /* the spi controllers are not using spi_bus, so we find it with another way */
3797 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3798 {
3799         struct device *dev;
3800
3801         dev = class_find_device_by_of_node(&spi_master_class, node);
3802         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3803                 dev = class_find_device_by_of_node(&spi_slave_class, node);
3804         if (!dev)
3805                 return NULL;
3806
3807         /* reference got in class_find_device */
3808         return container_of(dev, struct spi_controller, dev);
3809 }
3810
3811 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3812                          void *arg)
3813 {
3814         struct of_reconfig_data *rd = arg;
3815         struct spi_controller *ctlr;
3816         struct spi_device *spi;
3817
3818         switch (of_reconfig_get_state_change(action, arg)) {
3819         case OF_RECONFIG_CHANGE_ADD:
3820                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3821                 if (ctlr == NULL)
3822                         return NOTIFY_OK;       /* not for us */
3823
3824                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3825                         put_device(&ctlr->dev);
3826                         return NOTIFY_OK;
3827                 }
3828
3829                 spi = of_register_spi_device(ctlr, rd->dn);
3830                 put_device(&ctlr->dev);
3831
3832                 if (IS_ERR(spi)) {
3833                         pr_err("%s: failed to create for '%pOF'\n",
3834                                         __func__, rd->dn);
3835                         of_node_clear_flag(rd->dn, OF_POPULATED);
3836                         return notifier_from_errno(PTR_ERR(spi));
3837                 }
3838                 break;
3839
3840         case OF_RECONFIG_CHANGE_REMOVE:
3841                 /* already depopulated? */
3842                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3843                         return NOTIFY_OK;
3844
3845                 /* find our device by node */
3846                 spi = of_find_spi_device_by_node(rd->dn);
3847                 if (spi == NULL)
3848                         return NOTIFY_OK;       /* no? not meant for us */
3849
3850                 /* unregister takes one ref away */
3851                 spi_unregister_device(spi);
3852
3853                 /* and put the reference of the find */
3854                 put_device(&spi->dev);
3855                 break;
3856         }
3857
3858         return NOTIFY_OK;
3859 }
3860
3861 static struct notifier_block spi_of_notifier = {
3862         .notifier_call = of_spi_notify,
3863 };
3864 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3865 extern struct notifier_block spi_of_notifier;
3866 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3867
3868 #if IS_ENABLED(CONFIG_ACPI)
3869 static int spi_acpi_controller_match(struct device *dev, const void *data)
3870 {
3871         return ACPI_COMPANION(dev->parent) == data;
3872 }
3873
3874 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3875 {
3876         struct device *dev;
3877
3878         dev = class_find_device(&spi_master_class, NULL, adev,
3879                                 spi_acpi_controller_match);
3880         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3881                 dev = class_find_device(&spi_slave_class, NULL, adev,
3882                                         spi_acpi_controller_match);
3883         if (!dev)
3884                 return NULL;
3885
3886         return container_of(dev, struct spi_controller, dev);
3887 }
3888
3889 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3890 {
3891         struct device *dev;
3892
3893         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
3894         return dev ? to_spi_device(dev) : NULL;
3895 }
3896
3897 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3898                            void *arg)
3899 {
3900         struct acpi_device *adev = arg;
3901         struct spi_controller *ctlr;
3902         struct spi_device *spi;
3903
3904         switch (value) {
3905         case ACPI_RECONFIG_DEVICE_ADD:
3906                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3907                 if (!ctlr)
3908                         break;
3909
3910                 acpi_register_spi_device(ctlr, adev);
3911                 put_device(&ctlr->dev);
3912                 break;
3913         case ACPI_RECONFIG_DEVICE_REMOVE:
3914                 if (!acpi_device_enumerated(adev))
3915                         break;
3916
3917                 spi = acpi_spi_find_device_by_adev(adev);
3918                 if (!spi)
3919                         break;
3920
3921                 spi_unregister_device(spi);
3922                 put_device(&spi->dev);
3923                 break;
3924         }
3925
3926         return NOTIFY_OK;
3927 }
3928
3929 static struct notifier_block spi_acpi_notifier = {
3930         .notifier_call = acpi_spi_notify,
3931 };
3932 #else
3933 extern struct notifier_block spi_acpi_notifier;
3934 #endif
3935
3936 static int __init spi_init(void)
3937 {
3938         int     status;
3939
3940         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3941         if (!buf) {
3942                 status = -ENOMEM;
3943                 goto err0;
3944         }
3945
3946         status = bus_register(&spi_bus_type);
3947         if (status < 0)
3948                 goto err1;
3949
3950         status = class_register(&spi_master_class);
3951         if (status < 0)
3952                 goto err2;
3953
3954         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3955                 status = class_register(&spi_slave_class);
3956                 if (status < 0)
3957                         goto err3;
3958         }
3959
3960         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3961                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3962         if (IS_ENABLED(CONFIG_ACPI))
3963                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3964
3965         return 0;
3966
3967 err3:
3968         class_unregister(&spi_master_class);
3969 err2:
3970         bus_unregister(&spi_bus_type);
3971 err1:
3972         kfree(buf);
3973         buf = NULL;
3974 err0:
3975         return status;
3976 }
3977
3978 /* board_info is normally registered in arch_initcall(),
3979  * but even essential drivers wait till later
3980  *
3981  * REVISIT only boardinfo really needs static linking. the rest (device and
3982  * driver registration) _could_ be dynamically linked (modular) ... costs
3983  * include needing to have boardinfo data structures be much more public.
3984  */
3985 postcore_initcall(spi_init);