drivers/watchdog/ziirave_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2015 Zodiac Inflight Innovations
   4  *
   5  * Author: Martyn Welch <martyn.welch@collabora.co.uk>
   6  *
   7  * Based on twl4030_wdt.c by Timo Kokkonen <timo.t.kokkonen at nokia.com>:
   8  *
   9  * Copyright (C) Nokia Corporation
  10  */
  11
  12 #include <linux/delay.h>
  13 #include <linux/i2c.h>
  14 #include <linux/ihex.h>
  15 #include <linux/firmware.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19 #include <linux/sysfs.h>
  20 #include <linux/types.h>
  21 #include <linux/version.h>
  22 #include <linux/watchdog.h>
  23
  24 #include <asm/unaligned.h>
  25
  26 #define ZIIRAVE_TIMEOUT_MIN     3
  27 #define ZIIRAVE_TIMEOUT_MAX     255
  28 #define ZIIRAVE_TIMEOUT_DEFAULT 30
  29
  30 #define ZIIRAVE_PING_VALUE      0x0
  31
  32 #define ZIIRAVE_STATE_INITIAL   0x0
  33 #define ZIIRAVE_STATE_OFF       0x1
  34 #define ZIIRAVE_STATE_ON        0x2
  35
  36 #define ZIIRAVE_FW_NAME         "ziirave_wdt.fw"
  37
  38 static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
  39                                   "host request", NULL, "illegal configuration",
  40                                   "illegal instruction", "illegal trap",
  41                                   "unknown"};
  42
  43 #define ZIIRAVE_WDT_FIRM_VER_MAJOR      0x1
  44 #define ZIIRAVE_WDT_BOOT_VER_MAJOR      0x3
  45 #define ZIIRAVE_WDT_RESET_REASON        0x5
  46 #define ZIIRAVE_WDT_STATE               0x6
  47 #define ZIIRAVE_WDT_TIMEOUT             0x7
  48 #define ZIIRAVE_WDT_TIME_LEFT           0x8
  49 #define ZIIRAVE_WDT_PING                0x9
  50 #define ZIIRAVE_WDT_RESET_DURATION      0xa
  51
  52 #define ZIIRAVE_FIRM_PKT_TOTAL_SIZE     20
  53 #define ZIIRAVE_FIRM_PKT_DATA_SIZE      16
  54 #define ZIIRAVE_FIRM_FLASH_MEMORY_START (2 * 0x1600)
  55 #define ZIIRAVE_FIRM_FLASH_MEMORY_END   (2 * 0x2bbf)
  56 #define ZIIRAVE_FIRM_PAGE_SIZE          128
  57
  58 /* Received and ready for next Download packet. */
  59 #define ZIIRAVE_FIRM_DOWNLOAD_ACK       1
  60
  61 /* Firmware commands */
  62 #define ZIIRAVE_CMD_DOWNLOAD_START              0x10
  63 #define ZIIRAVE_CMD_DOWNLOAD_END                0x11
  64 #define ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR      0x12
  65 #define ZIIRAVE_CMD_DOWNLOAD_READ_BYTE          0x13
  66 #define ZIIRAVE_CMD_RESET_PROCESSOR             0x0b
  67 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER          0x0c
  68 #define ZIIRAVE_CMD_DOWNLOAD_PACKET             0x0e
  69
  70 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC    1
  71 #define ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC       1
  72
  73 #define ZIIRAVE_FW_VERSION_FMT  "02.%02u.%02u"
  74 #define ZIIRAVE_BL_VERSION_FMT  "01.%02u.%02u"
  75
  76 struct ziirave_wdt_rev {
  77         unsigned char major;
  78         unsigned char minor;
  79 };
  80
  81 struct ziirave_wdt_data {
  82         struct mutex sysfs_mutex;
  83         struct watchdog_device wdd;
  84         struct ziirave_wdt_rev bootloader_rev;
  85         struct ziirave_wdt_rev firmware_rev;
  86         int reset_reason;
  87 };
  88
  89 static int wdt_timeout;
  90 module_param(wdt_timeout, int, 0);
  91 MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
  92
  93 static int reset_duration;
  94 module_param(reset_duration, int, 0);
  95 MODULE_PARM_DESC(reset_duration,
  96                  "Watchdog reset pulse duration in milliseconds");
  97
  98 static bool nowayout = WATCHDOG_NOWAYOUT;
  99 module_param(nowayout, bool, 0);
 100 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
 101                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 102
 103 static int ziirave_wdt_revision(struct i2c_client *client,
 104                                 struct ziirave_wdt_rev *rev, u8 command)
 105 {
 106         int ret;
 107
 108         ret = i2c_smbus_read_byte_data(client, command);
 109         if (ret < 0)
 110                 return ret;
 111
 112         rev->major = ret;
 113
 114         ret = i2c_smbus_read_byte_data(client, command + 1);
 115         if (ret < 0)
 116                 return ret;
 117
 118         rev->minor = ret;
 119
 120         return 0;
 121 }
 122
 123 static int ziirave_wdt_set_state(struct watchdog_device *wdd, int state)
 124 {
 125         struct i2c_client *client = to_i2c_client(wdd->parent);
 126
 127         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_STATE, state);
 128 }
 129
 130 static int ziirave_wdt_start(struct watchdog_device *wdd)
 131 {
 132         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_ON);
 133 }
 134
 135 static int ziirave_wdt_stop(struct watchdog_device *wdd)
 136 {
 137         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_OFF);
 138 }
 139
 140 static int ziirave_wdt_ping(struct watchdog_device *wdd)
 141 {
 142         struct i2c_client *client = to_i2c_client(wdd->parent);
 143
 144         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_PING,
 145                                          ZIIRAVE_PING_VALUE);
 146 }
 147
 148 static int ziirave_wdt_set_timeout(struct watchdog_device *wdd,
 149                                    unsigned int timeout)
 150 {
 151         struct i2c_client *client = to_i2c_client(wdd->parent);
 152         int ret;
 153
 154         ret = i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_TIMEOUT, timeout);
 155         if (!ret)
 156                 wdd->timeout = timeout;
 157
 158         return ret;
 159 }
 160
 161 static unsigned int ziirave_wdt_get_timeleft(struct watchdog_device *wdd)
 162 {
 163         struct i2c_client *client = to_i2c_client(wdd->parent);
 164         int ret;
 165
 166         ret = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIME_LEFT);
 167         if (ret < 0)
 168                 ret = 0;
 169
 170         return ret;
 171 }
 172
 173 static int ziirave_firm_read_ack(struct watchdog_device *wdd)
 174 {
 175         struct i2c_client *client = to_i2c_client(wdd->parent);
 176         int ret;
 177
 178         ret = i2c_smbus_read_byte(client);
 179         if (ret < 0) {
 180                 dev_err(&client->dev, "Failed to read status byte\n");
 181                 return ret;
 182         }
 183
 184         return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
 185 }
 186
 187 static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u32 addr)
 188 {
 189         struct i2c_client *client = to_i2c_client(wdd->parent);
 190         const u16 addr16 = (u16)addr / 2;
 191         u8 address[2];
 192
 193         put_unaligned_le16(addr16, address);
 194
 195         return i2c_smbus_write_block_data(client,
 196                                           ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
 197                                           sizeof(address), address);
 198 }
 199
 200 static bool ziirave_firm_addr_readonly(u32 addr)
 201 {
 202         return addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
 203                addr > ZIIRAVE_FIRM_FLASH_MEMORY_END;
 204 }
 205
 206 /*
 207  * ziirave_firm_write_pkt() - Build and write a firmware packet
 208  *
 209  * A packet to send to the firmware is composed by following bytes:
 210  *     Length | Addr0 | Addr1 | Data0 .. Data15 | Checksum |
 211  * Where,
 212  *     Length: A data byte containing the length of the data.
 213  *     Addr0: Low byte of the address.
 214  *     Addr1: High byte of the address.
 215  *     Data0 .. Data15: Array of 16 bytes of data.
 216  *     Checksum: Checksum byte to verify data integrity.
 217  */
 218 static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
 219                                     u32 addr, const u8 *data, u8 len)
 220 {
 221         const u16 addr16 = (u16)addr / 2;
 222         struct i2c_client *client = to_i2c_client(wdd->parent);
 223         u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
 224         int ret;
 225
 226         /* Check max data size */
 227         if (len > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
 228                 dev_err(&client->dev, "Firmware packet too long (%d)\n",
 229                         len);
 230                 return -EMSGSIZE;
 231         }
 232
 233         /*
 234          * Ignore packets that are targeting program memory outisde of
 235          * app partition, since they will be ignored by the
 236          * bootloader. At the same time, we need to make sure we'll
 237          * allow zero length packet that will be sent as the last step
 238          * of firmware update
 239          */
 240         if (len && ziirave_firm_addr_readonly(addr))
 241                 return 0;
 242
 243         /* Packet length */
 244         packet[0] = len;
 245         /* Packet address */
 246         put_unaligned_le16(addr16, packet + 1);
 247
 248         memcpy(packet + 3, data, len);
 249         memset(packet + 3 + len, 0, ZIIRAVE_FIRM_PKT_DATA_SIZE - len);
 250
 251         /* Packet checksum */
 252         for (i = 0; i < len + 3; i++)
 253                 checksum += packet[i];
 254         packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1] = checksum;
 255
 256         ret = i2c_smbus_write_block_data(client, ZIIRAVE_CMD_DOWNLOAD_PACKET,
 257                                          sizeof(packet), packet);
 258         if (ret) {
 259                 dev_err(&client->dev,
 260                         "Failed to send DOWNLOAD_PACKET: %d\n", ret);
 261                 return ret;
 262         }
 263
 264         ret = ziirave_firm_read_ack(wdd);
 265         if (ret)
 266                 dev_err(&client->dev,
 267                       "Failed to write firmware packet at address 0x%04x: %d\n",
 268                       addr, ret);
 269
 270         return ret;
 271 }
 272
 273 static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
 274                                   u32 addr, const u8 *data, u8 len)
 275 {
 276         const u8 max_write_len = ZIIRAVE_FIRM_PAGE_SIZE -
 277                 (addr - ALIGN_DOWN(addr, ZIIRAVE_FIRM_PAGE_SIZE));
 278         int ret;
 279
 280         if (len > max_write_len) {
 281                 /*
 282                  * If data crossed page boundary we need to split this
 283                  * write in two
 284                  */
 285                 ret = __ziirave_firm_write_pkt(wdd, addr, data, max_write_len);
 286                 if (ret)
 287                         return ret;
 288
 289                 addr += max_write_len;
 290                 data += max_write_len;
 291                 len  -= max_write_len;
 292         }
 293
 294         return __ziirave_firm_write_pkt(wdd, addr, data, len);
 295 }
 296
 297 static int ziirave_firm_verify(struct watchdog_device *wdd,
 298                                const struct firmware *fw)
 299 {
 300         struct i2c_client *client = to_i2c_client(wdd->parent);
 301         const struct ihex_binrec *rec;
 302         int i, ret;
 303         u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
 304
 305         for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
 306                 const u16 len = be16_to_cpu(rec->len);
 307                 const u32 addr = be32_to_cpu(rec->addr);
 308
 309                 if (ziirave_firm_addr_readonly(addr))
 310                         continue;
 311
 312                 ret = ziirave_firm_set_read_addr(wdd, addr);
 313                 if (ret) {
 314                         dev_err(&client->dev,
 315                                 "Failed to send SET_READ_ADDR command: %d\n",
 316                                 ret);
 317                         return ret;
 318                 }
 319
 320                 for (i = 0; i < len; i++) {
 321                         ret = i2c_smbus_read_byte_data(client,
 322                                                 ZIIRAVE_CMD_DOWNLOAD_READ_BYTE);
 323                         if (ret < 0) {
 324                                 dev_err(&client->dev,
 325                                         "Failed to READ DATA: %d\n", ret);
 326                                 return ret;
 327                         }
 328                         data[i] = ret;
 329                 }
 330
 331                 if (memcmp(data, rec->data, len)) {
 332                         dev_err(&client->dev,
 333                                 "Firmware mismatch at address 0x%04x\n", addr);
 334                         return -EINVAL;
 335                 }
 336         }
 337
 338         return 0;
 339 }
 340
 341 static int ziirave_firm_upload(struct watchdog_device *wdd,
 342                                const struct firmware *fw)
 343 {
 344         struct i2c_client *client = to_i2c_client(wdd->parent);
 345         const struct ihex_binrec *rec;
 346         int ret;
 347
 348         ret = i2c_smbus_write_byte_data(client,
 349                                         ZIIRAVE_CMD_JUMP_TO_BOOTLOADER,
 350                                         ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC);
 351         if (ret) {
 352                 dev_err(&client->dev, "Failed to jump to bootloader\n");
 353                 return ret;
 354         }
 355
 356         msleep(500);
 357
 358         ret = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_START);
 359         if (ret) {
 360                 dev_err(&client->dev, "Failed to start download\n");
 361                 return ret;
 362         }
 363
 364         ret = ziirave_firm_read_ack(wdd);
 365         if (ret) {
 366                 dev_err(&client->dev, "No ACK for start download\n");
 367                 return ret;
 368         }
 369
 370         msleep(500);
 371
 372         for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
 373                 ret = ziirave_firm_write_pkt(wdd, be32_to_cpu(rec->addr),
 374                                              rec->data, be16_to_cpu(rec->len));
 375                 if (ret)
 376                         return ret;
 377         }
 378
 379         /*
 380          * Finish firmware download process by sending a zero length
 381          * payload
 382          */
 383         ret = ziirave_firm_write_pkt(wdd, 0, NULL, 0);
 384         if (ret) {
 385                 dev_err(&client->dev, "Failed to send EMPTY packet: %d\n", ret);
 386                 return ret;
 387         }
 388
 389         /* This sleep seems to be required */
 390         msleep(20);
 391
 392         /* Start firmware verification */
 393         ret = ziirave_firm_verify(wdd, fw);
 394         if (ret) {
 395                 dev_err(&client->dev,
 396                         "Failed to verify firmware: %d\n", ret);
 397                 return ret;
 398         }
 399
 400         /* End download operation */
 401         ret = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_END);
 402         if (ret) {
 403                 dev_err(&client->dev,
 404                         "Failed to end firmware download: %d\n", ret);
 405                 return ret;
 406         }
 407
 408         /* Reset the processor */
 409         ret = i2c_smbus_write_byte_data(client,
 410                                         ZIIRAVE_CMD_RESET_PROCESSOR,
 411                                         ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC);
 412         if (ret) {
 413                 dev_err(&client->dev,
 414                         "Failed to reset the watchdog: %d\n", ret);
 415                 return ret;
 416         }
 417
 418         msleep(500);
 419
 420         return 0;
 421 }
 422
 423 static const struct watchdog_info ziirave_wdt_info = {
 424         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 425         .identity = "RAVE Switch Watchdog",
 426 };
 427
 428 static const struct watchdog_ops ziirave_wdt_ops = {
 429         .owner          = THIS_MODULE,
 430         .start          = ziirave_wdt_start,
 431         .stop           = ziirave_wdt_stop,
 432         .ping           = ziirave_wdt_ping,
 433         .set_timeout    = ziirave_wdt_set_timeout,
 434         .get_timeleft   = ziirave_wdt_get_timeleft,
 435 };
 436
 437 static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
 438                                            struct device_attribute *attr,
 439                                            char *buf)
 440 {
 441         struct i2c_client *client = to_i2c_client(dev->parent);
 442         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 443         int ret;
 444
 445         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 446         if (ret)
 447                 return ret;
 448
 449         ret = sprintf(buf, ZIIRAVE_FW_VERSION_FMT, w_priv->firmware_rev.major,
 450                       w_priv->firmware_rev.minor);
 451
 452         mutex_unlock(&w_priv->sysfs_mutex);
 453
 454         return ret;
 455 }
 456
 457 static DEVICE_ATTR(firmware_version, S_IRUGO, ziirave_wdt_sysfs_show_firm,
 458                    NULL);
 459
 460 static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
 461                                            struct device_attribute *attr,
 462                                            char *buf)
 463 {
 464         struct i2c_client *client = to_i2c_client(dev->parent);
 465         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 466         int ret;
 467
 468         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 469         if (ret)
 470                 return ret;
 471
 472         ret = sprintf(buf, ZIIRAVE_BL_VERSION_FMT, w_priv->bootloader_rev.major,
 473                       w_priv->bootloader_rev.minor);
 474
 475         mutex_unlock(&w_priv->sysfs_mutex);
 476
 477         return ret;
 478 }
 479
 480 static DEVICE_ATTR(bootloader_version, S_IRUGO, ziirave_wdt_sysfs_show_boot,
 481                    NULL);
 482
 483 static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
 484                                              struct device_attribute *attr,
 485                                              char *buf)
 486 {
 487         struct i2c_client *client = to_i2c_client(dev->parent);
 488         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 489         int ret;
 490
 491         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 492         if (ret)
 493                 return ret;
 494
 495         ret = sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
 496
 497         mutex_unlock(&w_priv->sysfs_mutex);
 498
 499         return ret;
 500 }
 501
 502 static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
 503                    NULL);
 504
 505 static ssize_t ziirave_wdt_sysfs_store_firm(struct device *dev,
 506                                             struct device_attribute *attr,
 507                                             const char *buf, size_t count)
 508 {
 509         struct i2c_client *client = to_i2c_client(dev->parent);
 510         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 511         const struct firmware *fw;
 512         int err;
 513
 514         err = request_ihex_firmware(&fw, ZIIRAVE_FW_NAME, dev);
 515         if (err) {
 516                 dev_err(&client->dev, "Failed to request ihex firmware\n");
 517                 return err;
 518         }
 519
 520         err = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 521         if (err)
 522                 goto release_firmware;
 523
 524         err = ziirave_firm_upload(&w_priv->wdd, fw);
 525         if (err) {
 526                 dev_err(&client->dev, "The firmware update failed: %d\n", err);
 527                 goto unlock_mutex;
 528         }
 529
 530         /* Update firmware version */
 531         err = ziirave_wdt_revision(client, &w_priv->firmware_rev,
 532                                    ZIIRAVE_WDT_FIRM_VER_MAJOR);
 533         if (err) {
 534                 dev_err(&client->dev, "Failed to read firmware version: %d\n",
 535                         err);
 536                 goto unlock_mutex;
 537         }
 538
 539         dev_info(&client->dev,
 540                  "Firmware updated to version " ZIIRAVE_FW_VERSION_FMT "\n",
 541                  w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
 542
 543         /* Restore the watchdog timeout */
 544         err = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
 545         if (err)
 546                 dev_err(&client->dev, "Failed to set timeout: %d\n", err);
 547
 548 unlock_mutex:
 549         mutex_unlock(&w_priv->sysfs_mutex);
 550
 551 release_firmware:
 552         release_firmware(fw);
 553
 554         return err ? err : count;
 555 }
 556
 557 static DEVICE_ATTR(update_firmware, S_IWUSR, NULL,
 558                    ziirave_wdt_sysfs_store_firm);
 559
 560 static struct attribute *ziirave_wdt_attrs[] = {
 561         &dev_attr_firmware_version.attr,
 562         &dev_attr_bootloader_version.attr,
 563         &dev_attr_reset_reason.attr,
 564         &dev_attr_update_firmware.attr,
 565         NULL
 566 };
 567 ATTRIBUTE_GROUPS(ziirave_wdt);
 568
 569 static int ziirave_wdt_init_duration(struct i2c_client *client)
 570 {
 571         int ret;
 572
 573         if (!reset_duration) {
 574                 /* See if the reset pulse duration is provided in an of_node */
 575                 if (!client->dev.of_node)
 576                         ret = -ENODEV;
 577                 else
 578                         ret = of_property_read_u32(client->dev.of_node,
 579                                                    "reset-duration-ms",
 580                                                    &reset_duration);
 581                 if (ret) {
 582                         dev_info(&client->dev,
 583                          "No reset pulse duration specified, using default\n");
 584                         return 0;
 585                 }
 586         }
 587
 588         if (reset_duration < 1 || reset_duration > 255)
 589                 return -EINVAL;
 590
 591         dev_info(&client->dev, "Setting reset duration to %dms",
 592                  reset_duration);
 593
 594         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_RESET_DURATION,
 595                                          reset_duration);
 596 }
 597
 598 static int ziirave_wdt_probe(struct i2c_client *client,
 599                              const struct i2c_device_id *id)
 600 {
 601         int ret;
 602         struct ziirave_wdt_data *w_priv;
 603         int val;
 604
 605         if (!i2c_check_functionality(client->adapter,
 606                                      I2C_FUNC_SMBUS_BYTE |
 607                                      I2C_FUNC_SMBUS_BYTE_DATA |
 608                                      I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
 609                 return -ENODEV;
 610
 611         w_priv = devm_kzalloc(&client->dev, sizeof(*w_priv), GFP_KERNEL);
 612         if (!w_priv)
 613                 return -ENOMEM;
 614
 615         mutex_init(&w_priv->sysfs_mutex);
 616
 617         w_priv->wdd.info = &ziirave_wdt_info;
 618         w_priv->wdd.ops = &ziirave_wdt_ops;
 619         w_priv->wdd.min_timeout = ZIIRAVE_TIMEOUT_MIN;
 620         w_priv->wdd.max_timeout = ZIIRAVE_TIMEOUT_MAX;
 621         w_priv->wdd.parent = &client->dev;
 622         w_priv->wdd.groups = ziirave_wdt_groups;
 623
 624         watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
 625
 626         /*
 627          * The default value set in the watchdog should be perfectly valid, so
 628          * pass that in if we haven't provided one via the module parameter or
 629          * of property.
 630          */
 631         if (w_priv->wdd.timeout == 0) {
 632                 val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
 633                 if (val < 0) {
 634                         dev_err(&client->dev, "Failed to read timeout\n");
 635                         return val;
 636                 }
 637
 638                 if (val > ZIIRAVE_TIMEOUT_MAX ||
 639                     val < ZIIRAVE_TIMEOUT_MIN)
 640                         val = ZIIRAVE_TIMEOUT_DEFAULT;
 641
 642                 w_priv->wdd.timeout = val;
 643         }
 644
 645         ret = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
 646         if (ret) {
 647                 dev_err(&client->dev, "Failed to set timeout\n");
 648                 return ret;
 649         }
 650
 651         dev_info(&client->dev, "Timeout set to %ds\n", w_priv->wdd.timeout);
 652
 653         watchdog_set_nowayout(&w_priv->wdd, nowayout);
 654
 655         i2c_set_clientdata(client, w_priv);
 656
 657         /* If in unconfigured state, set to stopped */
 658         val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
 659         if (val < 0) {
 660                 dev_err(&client->dev, "Failed to read state\n");
 661                 return val;
 662         }
 663
 664         if (val == ZIIRAVE_STATE_INITIAL)
 665                 ziirave_wdt_stop(&w_priv->wdd);
 666
 667         ret = ziirave_wdt_init_duration(client);
 668         if (ret) {
 669                 dev_err(&client->dev, "Failed to init duration\n");
 670                 return ret;
 671         }
 672
 673         ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
 674                                    ZIIRAVE_WDT_FIRM_VER_MAJOR);
 675         if (ret) {
 676                 dev_err(&client->dev, "Failed to read firmware version\n");
 677                 return ret;
 678         }
 679
 680         dev_info(&client->dev,
 681                  "Firmware version: " ZIIRAVE_FW_VERSION_FMT "\n",
 682                  w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
 683
 684         ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
 685                                    ZIIRAVE_WDT_BOOT_VER_MAJOR);
 686         if (ret) {
 687                 dev_err(&client->dev, "Failed to read bootloader version\n");
 688                 return ret;
 689         }
 690
 691         dev_info(&client->dev,
 692                  "Bootloader version: " ZIIRAVE_BL_VERSION_FMT "\n",
 693                  w_priv->bootloader_rev.major, w_priv->bootloader_rev.minor);
 694
 695         w_priv->reset_reason = i2c_smbus_read_byte_data(client,
 696                                                 ZIIRAVE_WDT_RESET_REASON);
 697         if (w_priv->reset_reason < 0) {
 698                 dev_err(&client->dev, "Failed to read reset reason\n");
 699                 return w_priv->reset_reason;
 700         }
 701
 702         if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
 703             !ziirave_reasons[w_priv->reset_reason]) {
 704                 dev_err(&client->dev, "Invalid reset reason\n");
 705                 return -ENODEV;
 706         }
 707
 708         ret = watchdog_register_device(&w_priv->wdd);
 709
 710         return ret;
 711 }
 712
 713 static int ziirave_wdt_remove(struct i2c_client *client)
 714 {
 715         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 716
 717         watchdog_unregister_device(&w_priv->wdd);
 718
 719         return 0;
 720 }
 721
 722 static const struct i2c_device_id ziirave_wdt_id[] = {
 723         { "rave-wdt", 0 },
 724         { }
 725 };
 726 MODULE_DEVICE_TABLE(i2c, ziirave_wdt_id);
 727
 728 static const struct of_device_id zrv_wdt_of_match[] = {
 729         { .compatible = "zii,rave-wdt", },
 730         { },
 731 };
 732 MODULE_DEVICE_TABLE(of, zrv_wdt_of_match);
 733
 734 static struct i2c_driver ziirave_wdt_driver = {
 735         .driver = {
 736                 .name = "ziirave_wdt",
 737                 .of_match_table = zrv_wdt_of_match,
 738         },
 739         .probe = ziirave_wdt_probe,
 740         .remove = ziirave_wdt_remove,
 741         .id_table = ziirave_wdt_id,
 742 };
 743
 744 module_i2c_driver(ziirave_wdt_driver);
 745
 746 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk");
 747 MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
 748 MODULE_LICENSE("GPL");