drivers/i2c/busses/i2c-diolan-u2c.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for the Diolan u2c-12 USB-I2C adapter
   4  *
   5  * Copyright (c) 2010-2011 Ericsson AB
   6  *
   7  * Derived from:
   8  *  i2c-tiny-usb.c
   9  *  Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/slab.h>
  17 #include <linux/usb.h>
  18 #include <linux/i2c.h>
  19
  20 #define DRIVER_NAME             "i2c-diolan-u2c"
  21
  22 #define USB_VENDOR_ID_DIOLAN            0x0abf
  23 #define USB_DEVICE_ID_DIOLAN_U2C        0x3370
  24
  25
  26 /* commands via USB, must match command ids in the firmware */
  27 #define CMD_I2C_READ            0x01
  28 #define CMD_I2C_WRITE           0x02
  29 #define CMD_I2C_SCAN            0x03    /* Returns list of detected devices */
  30 #define CMD_I2C_RELEASE_SDA     0x04
  31 #define CMD_I2C_RELEASE_SCL     0x05
  32 #define CMD_I2C_DROP_SDA        0x06
  33 #define CMD_I2C_DROP_SCL        0x07
  34 #define CMD_I2C_READ_SDA        0x08
  35 #define CMD_I2C_READ_SCL        0x09
  36 #define CMD_GET_FW_VERSION      0x0a
  37 #define CMD_GET_SERIAL          0x0b
  38 #define CMD_I2C_START           0x0c
  39 #define CMD_I2C_STOP            0x0d
  40 #define CMD_I2C_REPEATED_START  0x0e
  41 #define CMD_I2C_PUT_BYTE        0x0f
  42 #define CMD_I2C_GET_BYTE        0x10
  43 #define CMD_I2C_PUT_ACK         0x11
  44 #define CMD_I2C_GET_ACK         0x12
  45 #define CMD_I2C_PUT_BYTE_ACK    0x13
  46 #define CMD_I2C_GET_BYTE_ACK    0x14
  47 #define CMD_I2C_SET_SPEED       0x1b
  48 #define CMD_I2C_GET_SPEED       0x1c
  49 #define CMD_I2C_SET_CLK_SYNC    0x24
  50 #define CMD_I2C_GET_CLK_SYNC    0x25
  51 #define CMD_I2C_SET_CLK_SYNC_TO 0x26
  52 #define CMD_I2C_GET_CLK_SYNC_TO 0x27
  53
  54 #define RESP_OK                 0x00
  55 #define RESP_FAILED             0x01
  56 #define RESP_BAD_MEMADDR        0x04
  57 #define RESP_DATA_ERR           0x05
  58 #define RESP_NOT_IMPLEMENTED    0x06
  59 #define RESP_NACK               0x07
  60 #define RESP_TIMEOUT            0x09
  61
  62 #define U2C_I2C_SPEED_FAST      0       /* 400 kHz */
  63 #define U2C_I2C_SPEED_STD       1       /* 100 kHz */
  64 #define U2C_I2C_SPEED_2KHZ      242     /* 2 kHz, minimum speed */
  65 #define U2C_I2C_SPEED(f)        ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
  66
  67 #define U2C_I2C_FREQ_FAST       400000
  68 #define U2C_I2C_FREQ_STD        100000
  69 #define U2C_I2C_FREQ(s)         (1000000 / (2 * (s - 1) + 10))
  70
  71 #define DIOLAN_USB_TIMEOUT      100     /* in ms */
  72 #define DIOLAN_SYNC_TIMEOUT     20      /* in ms */
  73
  74 #define DIOLAN_OUTBUF_LEN       128
  75 #define DIOLAN_FLUSH_LEN        (DIOLAN_OUTBUF_LEN - 4)
  76 #define DIOLAN_INBUF_LEN        256     /* Maximum supported receive length */
  77
  78 /* Structure to hold all of our device specific stuff */
  79 struct i2c_diolan_u2c {
  80         u8 obuffer[DIOLAN_OUTBUF_LEN];  /* output buffer */
  81         u8 ibuffer[DIOLAN_INBUF_LEN];   /* input buffer */
  82         int ep_in, ep_out;              /* Endpoints    */
  83         struct usb_device *usb_dev;     /* the usb device for this device */
  84         struct usb_interface *interface;/* the interface for this device */
  85         struct i2c_adapter adapter;     /* i2c related things */
  86         int olen;                       /* Output buffer length */
  87         int ocount;                     /* Number of enqueued messages */
  88 };
  89
  90 static uint frequency = U2C_I2C_FREQ_STD;       /* I2C clock frequency in Hz */
  91
  92 module_param(frequency, uint, S_IRUGO | S_IWUSR);
  93 MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  94
  95 /* usb layer */
  96
  97 /* Send command to device, and get response. */
  98 static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
  99 {
 100         int ret = 0;
 101         int actual;
 102         int i;
 103
 104         if (!dev->olen || !dev->ocount)
 105                 return -EINVAL;
 106
 107         ret = usb_bulk_msg(dev->usb_dev,
 108                            usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
 109                            dev->obuffer, dev->olen, &actual,
 110                            DIOLAN_USB_TIMEOUT);
 111         if (!ret) {
 112                 for (i = 0; i < dev->ocount; i++) {
 113                         int tmpret;
 114
 115                         tmpret = usb_bulk_msg(dev->usb_dev,
 116                                               usb_rcvbulkpipe(dev->usb_dev,
 117                                                               dev->ep_in),
 118                                               dev->ibuffer,
 119                                               sizeof(dev->ibuffer), &actual,
 120                                               DIOLAN_USB_TIMEOUT);
 121                         /*
 122                          * Stop command processing if a previous command
 123                          * returned an error.
 124                          * Note that we still need to retrieve all messages.
 125                          */
 126                         if (ret < 0)
 127                                 continue;
 128                         ret = tmpret;
 129                         if (ret == 0 && actual > 0) {
 130                                 switch (dev->ibuffer[actual - 1]) {
 131                                 case RESP_NACK:
 132                                         /*
 133                                          * Return ENXIO if NACK was received as
 134                                          * response to the address phase,
 135                                          * EIO otherwise
 136                                          */
 137                                         ret = i == 1 ? -ENXIO : -EIO;
 138                                         break;
 139                                 case RESP_TIMEOUT:
 140                                         ret = -ETIMEDOUT;
 141                                         break;
 142                                 case RESP_OK:
 143                                         /* strip off return code */
 144                                         ret = actual - 1;
 145                                         break;
 146                                 default:
 147                                         ret = -EIO;
 148                                         break;
 149                                 }
 150                         }
 151                 }
 152         }
 153         dev->olen = 0;
 154         dev->ocount = 0;
 155         return ret;
 156 }
 157
 158 static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
 159 {
 160         if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
 161                 return diolan_usb_transfer(dev);
 162         return 0;
 163 }
 164
 165 /* Send command (no data) */
 166 static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
 167 {
 168         dev->obuffer[dev->olen++] = command;
 169         dev->ocount++;
 170         return diolan_write_cmd(dev, flush);
 171 }
 172
 173 /* Send command with one byte of data */
 174 static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
 175                                bool flush)
 176 {
 177         dev->obuffer[dev->olen++] = command;
 178         dev->obuffer[dev->olen++] = data;
 179         dev->ocount++;
 180         return diolan_write_cmd(dev, flush);
 181 }
 182
 183 /* Send command with two bytes of data */
 184 static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
 185                                 u8 d2, bool flush)
 186 {
 187         dev->obuffer[dev->olen++] = command;
 188         dev->obuffer[dev->olen++] = d1;
 189         dev->obuffer[dev->olen++] = d2;
 190         dev->ocount++;
 191         return diolan_write_cmd(dev, flush);
 192 }
 193
 194 /*
 195  * Flush input queue.
 196  * If we don't do this at startup and the controller has queued up
 197  * messages which were not retrieved, it will stop responding
 198  * at some point.
 199  */
 200 static void diolan_flush_input(struct i2c_diolan_u2c *dev)
 201 {
 202         int i;
 203
 204         for (i = 0; i < 10; i++) {
 205                 int actual = 0;
 206                 int ret;
 207
 208                 ret = usb_bulk_msg(dev->usb_dev,
 209                                    usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
 210                                    dev->ibuffer, sizeof(dev->ibuffer), &actual,
 211                                    DIOLAN_USB_TIMEOUT);
 212                 if (ret < 0 || actual == 0)
 213                         break;
 214         }
 215         if (i == 10)
 216                 dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
 217 }
 218
 219 static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 220 {
 221         return diolan_usb_cmd(dev, CMD_I2C_START, false);
 222 }
 223
 224 static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 225 {
 226         return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 227 }
 228
 229 static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 230 {
 231         return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 232 }
 233
 234 static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
 235                                    u8 *byte)
 236 {
 237         int ret;
 238
 239         ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
 240         if (ret > 0)
 241                 *byte = dev->ibuffer[0];
 242         else if (ret == 0)
 243                 ret = -EIO;
 244
 245         return ret;
 246 }
 247
 248 static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
 249 {
 250         return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
 251 }
 252
 253 static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
 254 {
 255         return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
 256 }
 257
 258 /* Enable or disable clock synchronization (stretching) */
 259 static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
 260 {
 261         return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
 262 }
 263
 264 /* Set clock synchronization timeout in ms */
 265 static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
 266 {
 267         int to_val = ms * 10;
 268
 269         return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
 270                                     to_val & 0xff, (to_val >> 8) & 0xff, true);
 271 }
 272
 273 static void diolan_fw_version(struct i2c_diolan_u2c *dev)
 274 {
 275         int ret;
 276
 277         ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
 278         if (ret >= 2)
 279                 dev_info(&dev->interface->dev,
 280                          "Diolan U2C firmware version %u.%u\n",
 281                          (unsigned int)dev->ibuffer[0],
 282                          (unsigned int)dev->ibuffer[1]);
 283 }
 284
 285 static void diolan_get_serial(struct i2c_diolan_u2c *dev)
 286 {
 287         int ret;
 288         u32 serial;
 289
 290         ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
 291         if (ret >= 4) {
 292                 serial = le32_to_cpu(*(u32 *)dev->ibuffer);
 293                 dev_info(&dev->interface->dev,
 294                          "Diolan U2C serial number %u\n", serial);
 295         }
 296 }
 297
 298 static int diolan_init(struct i2c_diolan_u2c *dev)
 299 {
 300         int speed, ret;
 301
 302         if (frequency >= 200000) {
 303                 speed = U2C_I2C_SPEED_FAST;
 304                 frequency = U2C_I2C_FREQ_FAST;
 305         } else if (frequency >= 100000 || frequency == 0) {
 306                 speed = U2C_I2C_SPEED_STD;
 307                 frequency = U2C_I2C_FREQ_STD;
 308         } else {
 309                 speed = U2C_I2C_SPEED(frequency);
 310                 if (speed > U2C_I2C_SPEED_2KHZ)
 311                         speed = U2C_I2C_SPEED_2KHZ;
 312                 frequency = U2C_I2C_FREQ(speed);
 313         }
 314
 315         dev_info(&dev->interface->dev,
 316                  "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
 317                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
 318
 319         diolan_flush_input(dev);
 320         diolan_fw_version(dev);
 321         diolan_get_serial(dev);
 322
 323         /* Set I2C speed */
 324         ret = diolan_set_speed(dev, speed);
 325         if (ret < 0)
 326                 return ret;
 327
 328         /* Configure I2C clock synchronization */
 329         ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
 330         if (ret < 0)
 331                 return ret;
 332
 333         if (speed != U2C_I2C_SPEED_FAST)
 334                 ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
 335
 336         return ret;
 337 }
 338
 339 /* i2c layer */
 340
 341 static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 342                            int num)
 343 {
 344         struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
 345         struct i2c_msg *pmsg;
 346         int i, j;
 347         int ret, sret;
 348
 349         ret = diolan_i2c_start(dev);
 350         if (ret < 0)
 351                 return ret;
 352
 353         for (i = 0; i < num; i++) {
 354                 pmsg = &msgs[i];
 355                 if (i) {
 356                         ret = diolan_i2c_repeated_start(dev);
 357                         if (ret < 0)
 358                                 goto abort;
 359                 }
 360                 ret = diolan_i2c_put_byte_ack(dev,
 361                                               i2c_8bit_addr_from_msg(pmsg));
 362                 if (ret < 0)
 363                         goto abort;
 364                 if (pmsg->flags & I2C_M_RD) {
 365                         for (j = 0; j < pmsg->len; j++) {
 366                                 u8 byte;
 367                                 bool ack = j < pmsg->len - 1;
 368
 369                                 /*
 370                                  * Don't send NACK if this is the first byte
 371                                  * of a SMBUS_BLOCK message.
 372                                  */
 373                                 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
 374                                         ack = true;
 375
 376                                 ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
 377                                 if (ret < 0)
 378                                         goto abort;
 379                                 /*
 380                                  * Adjust count if first received byte is length
 381                                  */
 382                                 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
 383                                         if (byte == 0
 384                                             || byte > I2C_SMBUS_BLOCK_MAX) {
 385                                                 ret = -EPROTO;
 386                                                 goto abort;
 387                                         }
 388                                         pmsg->len += byte;
 389                                 }
 390                                 pmsg->buf[j] = byte;
 391                         }
 392                 } else {
 393                         for (j = 0; j < pmsg->len; j++) {
 394                                 ret = diolan_i2c_put_byte_ack(dev,
 395                                                               pmsg->buf[j]);
 396                                 if (ret < 0)
 397                                         goto abort;
 398                         }
 399                 }
 400         }
 401         ret = num;
 402 abort:
 403         sret = diolan_i2c_stop(dev);
 404         if (sret < 0 && ret >= 0)
 405                 ret = sret;
 406         return ret;
 407 }
 408
 409 /*
 410  * Return list of supported functionality.
 411  */
 412 static u32 diolan_usb_func(struct i2c_adapter *a)
 413 {
 414         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 415                I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 416 }
 417
 418 static const struct i2c_algorithm diolan_usb_algorithm = {
 419         .master_xfer = diolan_usb_xfer,
 420         .functionality = diolan_usb_func,
 421 };
 422
 423 /* device layer */
 424
 425 static const struct usb_device_id diolan_u2c_table[] = {
 426         { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 427         { }
 428 };
 429
 430 MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 431
 432 static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 433 {
 434         usb_put_dev(dev->usb_dev);
 435         kfree(dev);
 436 }
 437
 438 static int diolan_u2c_probe(struct usb_interface *interface,
 439                             const struct usb_device_id *id)
 440 {
 441         struct usb_host_interface *hostif = interface->cur_altsetting;
 442         struct i2c_diolan_u2c *dev;
 443         int ret;
 444
 445         if (hostif->desc.bInterfaceNumber != 0
 446             || hostif->desc.bNumEndpoints < 2)
 447                 return -ENODEV;
 448
 449         /* allocate memory for our device state and initialize it */
 450         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 451         if (dev == NULL) {
 452                 ret = -ENOMEM;
 453                 goto error;
 454         }
 455         dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
 456         dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
 457
 458         dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 459         dev->interface = interface;
 460
 461         /* save our data pointer in this interface device */
 462         usb_set_intfdata(interface, dev);
 463
 464         /* setup i2c adapter description */
 465         dev->adapter.owner = THIS_MODULE;
 466         dev->adapter.class = I2C_CLASS_HWMON;
 467         dev->adapter.algo = &diolan_usb_algorithm;
 468         i2c_set_adapdata(&dev->adapter, dev);
 469         snprintf(dev->adapter.name, sizeof(dev->adapter.name),
 470                  DRIVER_NAME " at bus %03d device %03d",
 471                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
 472
 473         dev->adapter.dev.parent = &dev->interface->dev;
 474
 475         /* initialize diolan i2c interface */
 476         ret = diolan_init(dev);
 477         if (ret < 0) {
 478                 dev_err(&interface->dev, "failed to initialize adapter\n");
 479                 goto error_free;
 480         }
 481
 482         /* and finally attach to i2c layer */
 483         ret = i2c_add_adapter(&dev->adapter);
 484         if (ret < 0)
 485                 goto error_free;
 486
 487         dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
 488
 489         return 0;
 490
 491 error_free:
 492         usb_set_intfdata(interface, NULL);
 493         diolan_u2c_free(dev);
 494 error:
 495         return ret;
 496 }
 497
 498 static void diolan_u2c_disconnect(struct usb_interface *interface)
 499 {
 500         struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
 501
 502         i2c_del_adapter(&dev->adapter);
 503         usb_set_intfdata(interface, NULL);
 504         diolan_u2c_free(dev);
 505
 506         dev_dbg(&interface->dev, "disconnected\n");
 507 }
 508
 509 static struct usb_driver diolan_u2c_driver = {
 510         .name = DRIVER_NAME,
 511         .probe = diolan_u2c_probe,
 512         .disconnect = diolan_u2c_disconnect,
 513         .id_table = diolan_u2c_table,
 514 };
 515
 516 module_usb_driver(diolan_u2c_driver);
 517
 518 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 519 MODULE_DESCRIPTION(DRIVER_NAME " driver");
 520 MODULE_LICENSE("GPL");