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