drivers/i2c/i2c-core-acpi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Linux I2C core ACPI support code
   4  *
   5  * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
   6  */
   7
   8 #include <linux/acpi.h>
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/i2c.h>
  12 #include <linux/list.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15
  16 #include "i2c-core.h"
  17
  18 struct i2c_acpi_handler_data {
  19         struct acpi_connection_info info;
  20         struct i2c_adapter *adapter;
  21 };
  22
  23 struct gsb_buffer {
  24         u8      status;
  25         u8      len;
  26         union {
  27                 u16     wdata;
  28                 u8      bdata;
  29                 u8      data[0];
  30         };
  31 } __packed;
  32
  33 struct i2c_acpi_lookup {
  34         struct i2c_board_info *info;
  35         acpi_handle adapter_handle;
  36         acpi_handle device_handle;
  37         acpi_handle search_handle;
  38         int n;
  39         int index;
  40         u32 speed;
  41         u32 min_speed;
  42 };
  43
  44 /**
  45  * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches
  46  * @ares:       ACPI resource
  47  * @i2c:        Pointer to I2cSerialBus resource will be returned here
  48  *
  49  * Checks if the given ACPI resource is of type I2cSerialBus.
  50  * In this case, returns a pointer to it to the caller.
  51  *
  52  * Returns true if resource type is of I2cSerialBus, otherwise false.
  53  */
  54 bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
  55                                struct acpi_resource_i2c_serialbus **i2c)
  56 {
  57         struct acpi_resource_i2c_serialbus *sb;
  58
  59         if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
  60                 return false;
  61
  62         sb = &ares->data.i2c_serial_bus;
  63         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
  64                 return false;
  65
  66         *i2c = sb;
  67         return true;
  68 }
  69 EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
  70
  71 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
  72 {
  73         struct i2c_acpi_lookup *lookup = data;
  74         struct i2c_board_info *info = lookup->info;
  75         struct acpi_resource_i2c_serialbus *sb;
  76         acpi_status status;
  77
  78         if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
  79                 return 1;
  80
  81         if (lookup->index != -1 && lookup->n++ != lookup->index)
  82                 return 1;
  83
  84         status = acpi_get_handle(lookup->device_handle,
  85                                  sb->resource_source.string_ptr,
  86                                  &lookup->adapter_handle);
  87         if (ACPI_FAILURE(status))
  88                 return 1;
  89
  90         info->addr = sb->slave_address;
  91         lookup->speed = sb->connection_speed;
  92         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
  93                 info->flags |= I2C_CLIENT_TEN;
  94
  95         return 1;
  96 }
  97
  98 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
  99         /*
 100          * ACPI video acpi_devices, which are handled by the acpi-video driver
 101          * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
 102          */
 103         { ACPI_VIDEO_HID, 0 },
 104         {}
 105 };
 106
 107 static int i2c_acpi_do_lookup(struct acpi_device *adev,
 108                               struct i2c_acpi_lookup *lookup)
 109 {
 110         struct i2c_board_info *info = lookup->info;
 111         struct list_head resource_list;
 112         int ret;
 113
 114         if (acpi_bus_get_status(adev) || !adev->status.present)
 115                 return -EINVAL;
 116
 117         if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
 118                 return -ENODEV;
 119
 120         memset(info, 0, sizeof(*info));
 121         lookup->device_handle = acpi_device_handle(adev);
 122
 123         /* Look up for I2cSerialBus resource */
 124         INIT_LIST_HEAD(&resource_list);
 125         ret = acpi_dev_get_resources(adev, &resource_list,
 126                                      i2c_acpi_fill_info, lookup);
 127         acpi_dev_free_resource_list(&resource_list);
 128
 129         if (ret < 0 || !info->addr)
 130                 return -EINVAL;
 131
 132         return 0;
 133 }
 134
 135 static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
 136 {
 137         int *irq = data;
 138         struct resource r;
 139
 140         if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r))
 141                 *irq = i2c_dev_irq_from_resources(&r, 1);
 142
 143         return 1; /* No need to add resource to the list */
 144 }
 145
 146 /**
 147  * i2c_acpi_get_irq - get device IRQ number from ACPI
 148  * @client: Pointer to the I2C client device
 149  *
 150  * Find the IRQ number used by a specific client device.
 151  *
 152  * Return: The IRQ number or an error code.
 153  */
 154 int i2c_acpi_get_irq(struct i2c_client *client)
 155 {
 156         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 157         struct list_head resource_list;
 158         int irq = -ENOENT;
 159         int ret;
 160
 161         INIT_LIST_HEAD(&resource_list);
 162
 163         ret = acpi_dev_get_resources(adev, &resource_list,
 164                                      i2c_acpi_add_resource, &irq);
 165         if (ret < 0)
 166                 return ret;
 167
 168         acpi_dev_free_resource_list(&resource_list);
 169
 170         if (irq == -ENOENT)
 171                 irq = acpi_dev_gpio_irq_get(adev, 0);
 172
 173         return irq;
 174 }
 175
 176 static int i2c_acpi_get_info(struct acpi_device *adev,
 177                              struct i2c_board_info *info,
 178                              struct i2c_adapter *adapter,
 179                              acpi_handle *adapter_handle)
 180 {
 181         struct i2c_acpi_lookup lookup;
 182         int ret;
 183
 184         memset(&lookup, 0, sizeof(lookup));
 185         lookup.info = info;
 186         lookup.index = -1;
 187
 188         if (acpi_device_enumerated(adev))
 189                 return -EINVAL;
 190
 191         ret = i2c_acpi_do_lookup(adev, &lookup);
 192         if (ret)
 193                 return ret;
 194
 195         if (adapter) {
 196                 /* The adapter must match the one in I2cSerialBus() connector */
 197                 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
 198                         return -ENODEV;
 199         } else {
 200                 struct acpi_device *adapter_adev;
 201
 202                 /* The adapter must be present */
 203                 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
 204                         return -ENODEV;
 205                 if (acpi_bus_get_status(adapter_adev) ||
 206                     !adapter_adev->status.present)
 207                         return -ENODEV;
 208         }
 209
 210         info->fwnode = acpi_fwnode_handle(adev);
 211         if (adapter_handle)
 212                 *adapter_handle = lookup.adapter_handle;
 213
 214         acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
 215                           sizeof(info->type));
 216
 217         return 0;
 218 }
 219
 220 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
 221                                      struct acpi_device *adev,
 222                                      struct i2c_board_info *info)
 223 {
 224         adev->power.flags.ignore_parent = true;
 225         acpi_device_set_enumerated(adev);
 226
 227         if (!i2c_new_device(adapter, info)) {
 228                 adev->power.flags.ignore_parent = false;
 229                 dev_err(&adapter->dev,
 230                         "failed to add I2C device %s from ACPI\n",
 231                         dev_name(&adev->dev));
 232         }
 233 }
 234
 235 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
 236                                        void *data, void **return_value)
 237 {
 238         struct i2c_adapter *adapter = data;
 239         struct acpi_device *adev;
 240         struct i2c_board_info info;
 241
 242         if (acpi_bus_get_device(handle, &adev))
 243                 return AE_OK;
 244
 245         if (i2c_acpi_get_info(adev, &info, adapter, NULL))
 246                 return AE_OK;
 247
 248         i2c_acpi_register_device(adapter, adev, &info);
 249
 250         return AE_OK;
 251 }
 252
 253 #define I2C_ACPI_MAX_SCAN_DEPTH 32
 254
 255 /**
 256  * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
 257  * @adap: pointer to adapter
 258  *
 259  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
 260  * namespace. When a device is found it will be added to the Linux device
 261  * model and bound to the corresponding ACPI handle.
 262  */
 263 void i2c_acpi_register_devices(struct i2c_adapter *adap)
 264 {
 265         acpi_status status;
 266
 267         if (!has_acpi_companion(&adap->dev))
 268                 return;
 269
 270         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 271                                      I2C_ACPI_MAX_SCAN_DEPTH,
 272                                      i2c_acpi_add_device, NULL,
 273                                      adap, NULL);
 274         if (ACPI_FAILURE(status))
 275                 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 276 }
 277
 278 const struct acpi_device_id *
 279 i2c_acpi_match_device(const struct acpi_device_id *matches,
 280                       struct i2c_client *client)
 281 {
 282         if (!(client && matches))
 283                 return NULL;
 284
 285         return acpi_match_device(matches, &client->dev);
 286 }
 287
 288 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
 289                                            void *data, void **return_value)
 290 {
 291         struct i2c_acpi_lookup *lookup = data;
 292         struct acpi_device *adev;
 293
 294         if (acpi_bus_get_device(handle, &adev))
 295                 return AE_OK;
 296
 297         if (i2c_acpi_do_lookup(adev, lookup))
 298                 return AE_OK;
 299
 300         if (lookup->search_handle != lookup->adapter_handle)
 301                 return AE_OK;
 302
 303         if (lookup->speed <= lookup->min_speed)
 304                 lookup->min_speed = lookup->speed;
 305
 306         return AE_OK;
 307 }
 308
 309 /**
 310  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
 311  * @dev: The device owning the bus
 312  *
 313  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
 314  * devices connected to this bus and use the speed of slowest device.
 315  *
 316  * Returns the speed in Hz or zero
 317  */
 318 u32 i2c_acpi_find_bus_speed(struct device *dev)
 319 {
 320         struct i2c_acpi_lookup lookup;
 321         struct i2c_board_info dummy;
 322         acpi_status status;
 323
 324         if (!has_acpi_companion(dev))
 325                 return 0;
 326
 327         memset(&lookup, 0, sizeof(lookup));
 328         lookup.search_handle = ACPI_HANDLE(dev);
 329         lookup.min_speed = UINT_MAX;
 330         lookup.info = &dummy;
 331         lookup.index = -1;
 332
 333         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 334                                      I2C_ACPI_MAX_SCAN_DEPTH,
 335                                      i2c_acpi_lookup_speed, NULL,
 336                                      &lookup, NULL);
 337
 338         if (ACPI_FAILURE(status)) {
 339                 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
 340                 return 0;
 341         }
 342
 343         return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
 344 }
 345 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
 346
 347 static int i2c_acpi_find_match_adapter(struct device *dev, const void *data)
 348 {
 349         struct i2c_adapter *adapter = i2c_verify_adapter(dev);
 350
 351         if (!adapter)
 352                 return 0;
 353
 354         return ACPI_HANDLE(dev) == (acpi_handle)data;
 355 }
 356
 357 static int i2c_acpi_find_match_device(struct device *dev, const void *data)
 358 {
 359         return ACPI_COMPANION(dev) == data;
 360 }
 361
 362 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
 363 {
 364         struct device *dev;
 365
 366         dev = bus_find_device(&i2c_bus_type, NULL, handle,
 367                               i2c_acpi_find_match_adapter);
 368         return dev ? i2c_verify_adapter(dev) : NULL;
 369 }
 370 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
 371
 372 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
 373 {
 374         struct device *dev;
 375
 376         dev = bus_find_device(&i2c_bus_type, NULL, adev,
 377                               i2c_acpi_find_match_device);
 378         return dev ? i2c_verify_client(dev) : NULL;
 379 }
 380
 381 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
 382                            void *arg)
 383 {
 384         struct acpi_device *adev = arg;
 385         struct i2c_board_info info;
 386         acpi_handle adapter_handle;
 387         struct i2c_adapter *adapter;
 388         struct i2c_client *client;
 389
 390         switch (value) {
 391         case ACPI_RECONFIG_DEVICE_ADD:
 392                 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
 393                         break;
 394
 395                 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
 396                 if (!adapter)
 397                         break;
 398
 399                 i2c_acpi_register_device(adapter, adev, &info);
 400                 break;
 401         case ACPI_RECONFIG_DEVICE_REMOVE:
 402                 if (!acpi_device_enumerated(adev))
 403                         break;
 404
 405                 client = i2c_acpi_find_client_by_adev(adev);
 406                 if (!client)
 407                         break;
 408
 409                 i2c_unregister_device(client);
 410                 put_device(&client->dev);
 411                 break;
 412         }
 413
 414         return NOTIFY_OK;
 415 }
 416
 417 struct notifier_block i2c_acpi_notifier = {
 418         .notifier_call = i2c_acpi_notify,
 419 };
 420
 421 /**
 422  * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
 423  * @dev:     Device owning the ACPI resources to get the client from
 424  * @index:   Index of ACPI resource to get
 425  * @info:    describes the I2C device; note this is modified (addr gets set)
 426  * Context: can sleep
 427  *
 428  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
 429  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
 430  * resources, in that case this function can be used to create an i2c-client
 431  * for other I2cSerialBus resources in the Current Resource Settings table.
 432  *
 433  * Also see i2c_new_device, which this function calls to create the i2c-client.
 434  *
 435  * Returns a pointer to the new i2c-client, or error pointer in case of failure.
 436  * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
 437  */
 438 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 439                                        struct i2c_board_info *info)
 440 {
 441         struct i2c_acpi_lookup lookup;
 442         struct i2c_adapter *adapter;
 443         struct i2c_client *client;
 444         struct acpi_device *adev;
 445         LIST_HEAD(resource_list);
 446         int ret;
 447
 448         adev = ACPI_COMPANION(dev);
 449         if (!adev)
 450                 return ERR_PTR(-EINVAL);
 451
 452         memset(&lookup, 0, sizeof(lookup));
 453         lookup.info = info;
 454         lookup.device_handle = acpi_device_handle(adev);
 455         lookup.index = index;
 456
 457         ret = acpi_dev_get_resources(adev, &resource_list,
 458                                      i2c_acpi_fill_info, &lookup);
 459         if (ret < 0)
 460                 return ERR_PTR(ret);
 461
 462         acpi_dev_free_resource_list(&resource_list);
 463
 464         if (!info->addr)
 465                 return ERR_PTR(-EADDRNOTAVAIL);
 466
 467         adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
 468         if (!adapter)
 469                 return ERR_PTR(-EPROBE_DEFER);
 470
 471         client = i2c_new_device(adapter, info);
 472         if (!client)
 473                 return ERR_PTR(-ENODEV);
 474
 475         return client;
 476 }
 477 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 478
 479 #ifdef CONFIG_ACPI_I2C_OPREGION
 480 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 481                 u8 cmd, u8 *data, u8 data_len)
 482 {
 483
 484         struct i2c_msg msgs[2];
 485         int ret;
 486         u8 *buffer;
 487
 488         buffer = kzalloc(data_len, GFP_KERNEL);
 489         if (!buffer)
 490                 return AE_NO_MEMORY;
 491
 492         msgs[0].addr = client->addr;
 493         msgs[0].flags = client->flags;
 494         msgs[0].len = 1;
 495         msgs[0].buf = &cmd;
 496
 497         msgs[1].addr = client->addr;
 498         msgs[1].flags = client->flags | I2C_M_RD;
 499         msgs[1].len = data_len;
 500         msgs[1].buf = buffer;
 501
 502         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 503         if (ret < 0) {
 504                 /* Getting a NACK is unfortunately normal with some DSTDs */
 505                 if (ret == -EREMOTEIO)
 506                         dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
 507                                 data_len, client->addr, cmd, ret);
 508                 else
 509                         dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
 510                                 data_len, client->addr, cmd, ret);
 511         /* 2 transfers must have completed successfully */
 512         } else if (ret == 2) {
 513                 memcpy(data, buffer, data_len);
 514                 ret = 0;
 515         } else {
 516                 ret = -EIO;
 517         }
 518
 519         kfree(buffer);
 520         return ret;
 521 }
 522
 523 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
 524                 u8 cmd, u8 *data, u8 data_len)
 525 {
 526
 527         struct i2c_msg msgs[1];
 528         u8 *buffer;
 529         int ret = AE_OK;
 530
 531         buffer = kzalloc(data_len + 1, GFP_KERNEL);
 532         if (!buffer)
 533                 return AE_NO_MEMORY;
 534
 535         buffer[0] = cmd;
 536         memcpy(buffer + 1, data, data_len);
 537
 538         msgs[0].addr = client->addr;
 539         msgs[0].flags = client->flags;
 540         msgs[0].len = data_len + 1;
 541         msgs[0].buf = buffer;
 542
 543         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 544
 545         kfree(buffer);
 546
 547         if (ret < 0) {
 548                 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
 549                 return ret;
 550         }
 551
 552         /* 1 transfer must have completed successfully */
 553         return (ret == 1) ? 0 : -EIO;
 554 }
 555
 556 static acpi_status
 557 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
 558                         u32 bits, u64 *value64,
 559                         void *handler_context, void *region_context)
 560 {
 561         struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
 562         struct i2c_acpi_handler_data *data = handler_context;
 563         struct acpi_connection_info *info = &data->info;
 564         struct acpi_resource_i2c_serialbus *sb;
 565         struct i2c_adapter *adapter = data->adapter;
 566         struct i2c_client *client;
 567         struct acpi_resource *ares;
 568         u32 accessor_type = function >> 16;
 569         u8 action = function & ACPI_IO_MASK;
 570         acpi_status ret;
 571         int status;
 572
 573         ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
 574         if (ACPI_FAILURE(ret))
 575                 return ret;
 576
 577         client = kzalloc(sizeof(*client), GFP_KERNEL);
 578         if (!client) {
 579                 ret = AE_NO_MEMORY;
 580                 goto err;
 581         }
 582
 583         if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
 584                 ret = AE_BAD_PARAMETER;
 585                 goto err;
 586         }
 587
 588         client->adapter = adapter;
 589         client->addr = sb->slave_address;
 590
 591         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
 592                 client->flags |= I2C_CLIENT_TEN;
 593
 594         switch (accessor_type) {
 595         case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
 596                 if (action == ACPI_READ) {
 597                         status = i2c_smbus_read_byte(client);
 598                         if (status >= 0) {
 599                                 gsb->bdata = status;
 600                                 status = 0;
 601                         }
 602                 } else {
 603                         status = i2c_smbus_write_byte(client, gsb->bdata);
 604                 }
 605                 break;
 606
 607         case ACPI_GSB_ACCESS_ATTRIB_BYTE:
 608                 if (action == ACPI_READ) {
 609                         status = i2c_smbus_read_byte_data(client, command);
 610                         if (status >= 0) {
 611                                 gsb->bdata = status;
 612                                 status = 0;
 613                         }
 614                 } else {
 615                         status = i2c_smbus_write_byte_data(client, command,
 616                                         gsb->bdata);
 617                 }
 618                 break;
 619
 620         case ACPI_GSB_ACCESS_ATTRIB_WORD:
 621                 if (action == ACPI_READ) {
 622                         status = i2c_smbus_read_word_data(client, command);
 623                         if (status >= 0) {
 624                                 gsb->wdata = status;
 625                                 status = 0;
 626                         }
 627                 } else {
 628                         status = i2c_smbus_write_word_data(client, command,
 629                                         gsb->wdata);
 630                 }
 631                 break;
 632
 633         case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
 634                 if (action == ACPI_READ) {
 635                         status = i2c_smbus_read_block_data(client, command,
 636                                         gsb->data);
 637                         if (status >= 0) {
 638                                 gsb->len = status;
 639                                 status = 0;
 640                         }
 641                 } else {
 642                         status = i2c_smbus_write_block_data(client, command,
 643                                         gsb->len, gsb->data);
 644                 }
 645                 break;
 646
 647         case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
 648                 if (action == ACPI_READ) {
 649                         status = acpi_gsb_i2c_read_bytes(client, command,
 650                                         gsb->data, info->access_length);
 651                 } else {
 652                         status = acpi_gsb_i2c_write_bytes(client, command,
 653                                         gsb->data, info->access_length);
 654                 }
 655                 break;
 656
 657         default:
 658                 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
 659                          accessor_type, client->addr);
 660                 ret = AE_BAD_PARAMETER;
 661                 goto err;
 662         }
 663
 664         gsb->status = status;
 665
 666  err:
 667         kfree(client);
 668         ACPI_FREE(ares);
 669         return ret;
 670 }
 671
 672
 673 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
 674 {
 675         acpi_handle handle;
 676         struct i2c_acpi_handler_data *data;
 677         acpi_status status;
 678
 679         if (!adapter->dev.parent)
 680                 return -ENODEV;
 681
 682         handle = ACPI_HANDLE(adapter->dev.parent);
 683
 684         if (!handle)
 685                 return -ENODEV;
 686
 687         data = kzalloc(sizeof(struct i2c_acpi_handler_data),
 688                             GFP_KERNEL);
 689         if (!data)
 690                 return -ENOMEM;
 691
 692         data->adapter = adapter;
 693         status = acpi_bus_attach_private_data(handle, (void *)data);
 694         if (ACPI_FAILURE(status)) {
 695                 kfree(data);
 696                 return -ENOMEM;
 697         }
 698
 699         status = acpi_install_address_space_handler(handle,
 700                                 ACPI_ADR_SPACE_GSBUS,
 701                                 &i2c_acpi_space_handler,
 702                                 NULL,
 703                                 data);
 704         if (ACPI_FAILURE(status)) {
 705                 dev_err(&adapter->dev, "Error installing i2c space handler\n");
 706                 acpi_bus_detach_private_data(handle);
 707                 kfree(data);
 708                 return -ENOMEM;
 709         }
 710
 711         acpi_walk_dep_device_list(handle);
 712         return 0;
 713 }
 714
 715 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
 716 {
 717         acpi_handle handle;
 718         struct i2c_acpi_handler_data *data;
 719         acpi_status status;
 720
 721         if (!adapter->dev.parent)
 722                 return;
 723
 724         handle = ACPI_HANDLE(adapter->dev.parent);
 725
 726         if (!handle)
 727                 return;
 728
 729         acpi_remove_address_space_handler(handle,
 730                                 ACPI_ADR_SPACE_GSBUS,
 731                                 &i2c_acpi_space_handler);
 732
 733         status = acpi_bus_get_private_data(handle, (void **)&data);
 734         if (ACPI_SUCCESS(status))
 735                 kfree(data);
 736
 737         acpi_bus_detach_private_data(handle);
 738 }
 739 #endif /* CONFIG_ACPI_I2C_OPREGION */