drivers/watchdog/ziirave_wdt.c

   1 /*
   2  * Copyright (C) 2015 Zodiac Inflight Innovations
   3  *
   4  * Author: Martyn Welch <martyn.welch@collabora.co.uk>
   5  *
   6  * Based on twl4030_wdt.c by Timo Kokkonen <timo.t.kokkonen at nokia.com>:
   7  *
   8  * Copyright (C) Nokia Corporation
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #include <linux/delay.h>
  22 #include <linux/i2c.h>
  23 #include <linux/ihex.h>
  24 #include <linux/firmware.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/slab.h>
  28 #include <linux/sysfs.h>
  29 #include <linux/types.h>
  30 #include <linux/version.h>
  31 #include <linux/watchdog.h>
  32
  33 #define ZIIRAVE_TIMEOUT_MIN     3
  34 #define ZIIRAVE_TIMEOUT_MAX     255
  35
  36 #define ZIIRAVE_PING_VALUE      0x0
  37
  38 #define ZIIRAVE_STATE_INITIAL   0x0
  39 #define ZIIRAVE_STATE_OFF       0x1
  40 #define ZIIRAVE_STATE_ON        0x2
  41
  42 #define ZIIRAVE_FW_NAME         "ziirave_wdt.fw"
  43
  44 static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
  45                                   "host request", NULL, "illegal configuration",
  46                                   "illegal instruction", "illegal trap",
  47                                   "unknown"};
  48
  49 #define ZIIRAVE_WDT_FIRM_VER_MAJOR      0x1
  50 #define ZIIRAVE_WDT_BOOT_VER_MAJOR      0x3
  51 #define ZIIRAVE_WDT_RESET_REASON        0x5
  52 #define ZIIRAVE_WDT_STATE               0x6
  53 #define ZIIRAVE_WDT_TIMEOUT             0x7
  54 #define ZIIRAVE_WDT_TIME_LEFT           0x8
  55 #define ZIIRAVE_WDT_PING                0x9
  56 #define ZIIRAVE_WDT_RESET_DURATION      0xa
  57
  58 #define ZIIRAVE_FIRM_PKT_TOTAL_SIZE     20
  59 #define ZIIRAVE_FIRM_PKT_DATA_SIZE      16
  60 #define ZIIRAVE_FIRM_FLASH_MEMORY_START 0x1600
  61 #define ZIIRAVE_FIRM_FLASH_MEMORY_END   0x2bbf
  62
  63 /* Received and ready for next Download packet. */
  64 #define ZIIRAVE_FIRM_DOWNLOAD_ACK       1
  65 /* Currently writing to flash. Retry Download status in a moment! */
  66 #define ZIIRAVE_FIRM_DOWNLOAD_BUSY      2
  67
  68 /* Wait for ACK timeout in ms */
  69 #define ZIIRAVE_FIRM_WAIT_FOR_ACK_TIMEOUT       50
  70
  71 /* Firmware commands */
  72 #define ZIIRAVE_CMD_DOWNLOAD_START              0x10
  73 #define ZIIRAVE_CMD_DOWNLOAD_END                0x11
  74 #define ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR      0x12
  75 #define ZIIRAVE_CMD_DOWNLOAD_READ_BYTE          0x13
  76 #define ZIIRAVE_CMD_RESET_PROCESSOR             0x0b
  77 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER          0x0c
  78 #define ZIIRAVE_CMD_DOWNLOAD_PACKET             0x0e
  79
  80 struct ziirave_wdt_rev {
  81         unsigned char major;
  82         unsigned char minor;
  83 };
  84
  85 struct ziirave_wdt_data {
  86         struct mutex sysfs_mutex;
  87         struct watchdog_device wdd;
  88         struct ziirave_wdt_rev bootloader_rev;
  89         struct ziirave_wdt_rev firmware_rev;
  90         int reset_reason;
  91 };
  92
  93 static int wdt_timeout;
  94 module_param(wdt_timeout, int, 0);
  95 MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
  96
  97 static int reset_duration;
  98 module_param(reset_duration, int, 0);
  99 MODULE_PARM_DESC(reset_duration,
 100                  "Watchdog reset pulse duration in milliseconds");
 101
 102 static bool nowayout = WATCHDOG_NOWAYOUT;
 103 module_param(nowayout, bool, 0);
 104 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
 105                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 106
 107 static int ziirave_wdt_revision(struct i2c_client *client,
 108                                 struct ziirave_wdt_rev *rev, u8 command)
 109 {
 110         int ret;
 111
 112         ret = i2c_smbus_read_byte_data(client, command);
 113         if (ret < 0)
 114                 return ret;
 115
 116         rev->major = ret;
 117
 118         ret = i2c_smbus_read_byte_data(client, command + 1);
 119         if (ret < 0)
 120                 return ret;
 121
 122         rev->minor = ret;
 123
 124         return 0;
 125 }
 126
 127 static int ziirave_wdt_set_state(struct watchdog_device *wdd, int state)
 128 {
 129         struct i2c_client *client = to_i2c_client(wdd->parent);
 130
 131         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_STATE, state);
 132 }
 133
 134 static int ziirave_wdt_start(struct watchdog_device *wdd)
 135 {
 136         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_ON);
 137 }
 138
 139 static int ziirave_wdt_stop(struct watchdog_device *wdd)
 140 {
 141         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_OFF);
 142 }
 143
 144 static int ziirave_wdt_ping(struct watchdog_device *wdd)
 145 {
 146         struct i2c_client *client = to_i2c_client(wdd->parent);
 147
 148         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_PING,
 149                                          ZIIRAVE_PING_VALUE);
 150 }
 151
 152 static int ziirave_wdt_set_timeout(struct watchdog_device *wdd,
 153                                    unsigned int timeout)
 154 {
 155         struct i2c_client *client = to_i2c_client(wdd->parent);
 156         int ret;
 157
 158         ret = i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_TIMEOUT, timeout);
 159         if (!ret)
 160                 wdd->timeout = timeout;
 161
 162         return ret;
 163 }
 164
 165 static unsigned int ziirave_wdt_get_timeleft(struct watchdog_device *wdd)
 166 {
 167         struct i2c_client *client = to_i2c_client(wdd->parent);
 168         int ret;
 169
 170         ret = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIME_LEFT);
 171         if (ret < 0)
 172                 ret = 0;
 173
 174         return ret;
 175 }
 176
 177 static int ziirave_firm_wait_for_ack(struct watchdog_device *wdd)
 178 {
 179         struct i2c_client *client = to_i2c_client(wdd->parent);
 180         int ret;
 181         unsigned long timeout;
 182
 183         timeout = jiffies + msecs_to_jiffies(ZIIRAVE_FIRM_WAIT_FOR_ACK_TIMEOUT);
 184         do {
 185                 if (time_after(jiffies, timeout))
 186                         return -ETIMEDOUT;
 187
 188                 usleep_range(5000, 10000);
 189
 190                 ret = i2c_smbus_read_byte(client);
 191                 if (ret < 0) {
 192                         dev_err(&client->dev, "Failed to read byte\n");
 193                         return ret;
 194                 }
 195         } while (ret == ZIIRAVE_FIRM_DOWNLOAD_BUSY);
 196
 197         return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
 198 }
 199
 200 static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u16 addr)
 201 {
 202         struct i2c_client *client = to_i2c_client(wdd->parent);
 203         u8 address[2];
 204
 205         address[0] = addr & 0xff;
 206         address[1] = (addr >> 8) & 0xff;
 207
 208         return i2c_smbus_write_block_data(client,
 209                                           ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
 210                                           ARRAY_SIZE(address), address);
 211 }
 212
 213 static int ziirave_firm_write_block_data(struct watchdog_device *wdd,
 214                                          u8 command, u8 length, const u8 *data,
 215                                          bool wait_for_ack)
 216 {
 217         struct i2c_client *client = to_i2c_client(wdd->parent);
 218         int ret;
 219
 220         ret = i2c_smbus_write_block_data(client, command, length, data);
 221         if (ret) {
 222                 dev_err(&client->dev,
 223                         "Failed to send command 0x%02x: %d\n", command, ret);
 224                 return ret;
 225         }
 226
 227         if (wait_for_ack)
 228                 ret = ziirave_firm_wait_for_ack(wdd);
 229
 230         return ret;
 231 }
 232
 233 static int ziirave_firm_write_byte(struct watchdog_device *wdd, u8 command,
 234                                    u8 byte, bool wait_for_ack)
 235 {
 236         return ziirave_firm_write_block_data(wdd, command, 1, &byte,
 237                                              wait_for_ack);
 238 }
 239
 240 /*
 241  * ziirave_firm_write_pkt() - Build and write a firmware packet
 242  *
 243  * A packet to send to the firmware is composed by following bytes:
 244  *     Length | Addr0 | Addr1 | Data0 .. Data15 | Checksum |
 245  * Where,
 246  *     Length: A data byte containing the length of the data.
 247  *     Addr0: Low byte of the address.
 248  *     Addr1: High byte of the address.
 249  *     Data0 .. Data15: Array of 16 bytes of data.
 250  *     Checksum: Checksum byte to verify data integrity.
 251  */
 252 static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
 253                                   const struct ihex_binrec *rec)
 254 {
 255         struct i2c_client *client = to_i2c_client(wdd->parent);
 256         u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
 257         int ret;
 258         u16 addr;
 259
 260         memset(packet, 0, ARRAY_SIZE(packet));
 261
 262         /* Packet length */
 263         packet[0] = (u8)be16_to_cpu(rec->len);
 264         /* Packet address */
 265         addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1;
 266         packet[1] = addr & 0xff;
 267         packet[2] = (addr & 0xff00) >> 8;
 268
 269         /* Packet data */
 270         if (be16_to_cpu(rec->len) > ZIIRAVE_FIRM_PKT_DATA_SIZE)
 271                 return -EMSGSIZE;
 272         memcpy(packet + 3, rec->data, be16_to_cpu(rec->len));
 273
 274         /* Packet checksum */
 275         for (i = 0; i < ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1; i++)
 276                 checksum += packet[i];
 277         packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1] = checksum;
 278
 279         ret = ziirave_firm_write_block_data(wdd, ZIIRAVE_CMD_DOWNLOAD_PACKET,
 280                                             ARRAY_SIZE(packet), packet, true);
 281         if (ret)
 282                 dev_err(&client->dev,
 283                       "Failed to write firmware packet at address 0x%04x: %d\n",
 284                       addr, ret);
 285
 286         return ret;
 287 }
 288
 289 static int ziirave_firm_verify(struct watchdog_device *wdd,
 290                                const struct firmware *fw)
 291 {
 292         struct i2c_client *client = to_i2c_client(wdd->parent);
 293         const struct ihex_binrec *rec;
 294         int i, ret;
 295         u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
 296         u16 addr;
 297
 298         for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
 299                 /* Zero length marks end of records */
 300                 if (!be16_to_cpu(rec->len))
 301                         break;
 302
 303                 addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1;
 304                 if (addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
 305                     addr > ZIIRAVE_FIRM_FLASH_MEMORY_END)
 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 < ARRAY_SIZE(data); 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, be16_to_cpu(rec->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         int ret, words_till_page_break;
 342         const struct ihex_binrec *rec;
 343         struct ihex_binrec *rec_new;
 344
 345         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_JUMP_TO_BOOTLOADER, 1,
 346                                       false);
 347         if (ret)
 348                 return ret;
 349
 350         msleep(500);
 351
 352         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_DOWNLOAD_START, 1, true);
 353         if (ret)
 354                 return ret;
 355
 356         msleep(500);
 357
 358         for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
 359                 /* Zero length marks end of records */
 360                 if (!be16_to_cpu(rec->len))
 361                         break;
 362
 363                 /* Check max data size */
 364                 if (be16_to_cpu(rec->len) > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
 365                         dev_err(&client->dev, "Firmware packet too long (%d)\n",
 366                                 be16_to_cpu(rec->len));
 367                         return -EMSGSIZE;
 368                 }
 369
 370                 /* Calculate words till page break */
 371                 words_till_page_break = (64 - ((be32_to_cpu(rec->addr) >> 1) &
 372                                          0x3f));
 373                 if ((be16_to_cpu(rec->len) >> 1) > words_till_page_break) {
 374                         /*
 375                          * Data in passes page boundary, so we need to split in
 376                          * two blocks of data. Create a packet with the first
 377                          * block of data.
 378                          */
 379                         rec_new = kzalloc(sizeof(struct ihex_binrec) +
 380                                           (words_till_page_break << 1),
 381                                           GFP_KERNEL);
 382                         if (!rec_new)
 383                                 return -ENOMEM;
 384
 385                         rec_new->len = cpu_to_be16(words_till_page_break << 1);
 386                         rec_new->addr = rec->addr;
 387                         memcpy(rec_new->data, rec->data,
 388                                be16_to_cpu(rec_new->len));
 389
 390                         ret = ziirave_firm_write_pkt(wdd, rec_new);
 391                         kfree(rec_new);
 392                         if (ret)
 393                                 return ret;
 394
 395                         /* Create a packet with the second block of data */
 396                         rec_new = kzalloc(sizeof(struct ihex_binrec) +
 397                                           be16_to_cpu(rec->len) -
 398                                           (words_till_page_break << 1),
 399                                           GFP_KERNEL);
 400                         if (!rec_new)
 401                                 return -ENOMEM;
 402
 403                         /* Remaining bytes */
 404                         rec_new->len = rec->len -
 405                                        cpu_to_be16(words_till_page_break << 1);
 406
 407                         rec_new->addr = cpu_to_be32(be32_to_cpu(rec->addr) +
 408                                         (words_till_page_break << 1));
 409
 410                         memcpy(rec_new->data,
 411                                rec->data + (words_till_page_break << 1),
 412                                be16_to_cpu(rec_new->len));
 413
 414                         ret = ziirave_firm_write_pkt(wdd, rec_new);
 415                         kfree(rec_new);
 416                         if (ret)
 417                                 return ret;
 418                 } else {
 419                         ret = ziirave_firm_write_pkt(wdd, rec);
 420                         if (ret)
 421                                 return ret;
 422                 }
 423         }
 424
 425         /* For end of download, the length field will be set to 0 */
 426         rec_new = kzalloc(sizeof(struct ihex_binrec) + 1, GFP_KERNEL);
 427         if (!rec_new)
 428                 return -ENOMEM;
 429
 430         ret = ziirave_firm_write_pkt(wdd, rec_new);
 431         kfree(rec_new);
 432         if (ret) {
 433                 dev_err(&client->dev, "Failed to send EMPTY packet: %d\n", ret);
 434                 return ret;
 435         }
 436
 437         /* This sleep seems to be required */
 438         msleep(20);
 439
 440         /* Start firmware verification */
 441         ret = ziirave_firm_verify(wdd, fw);
 442         if (ret) {
 443                 dev_err(&client->dev,
 444                         "Failed to verify firmware: %d\n", ret);
 445                 return ret;
 446         }
 447
 448         /* End download operation */
 449         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_DOWNLOAD_END, 1, false);
 450         if (ret)
 451                 return ret;
 452
 453         /* Reset the processor */
 454         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_RESET_PROCESSOR, 1,
 455                                       false);
 456         if (ret)
 457                 return ret;
 458
 459         msleep(500);
 460
 461         return 0;
 462 }
 463
 464 static const struct watchdog_info ziirave_wdt_info = {
 465         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 466         .identity = "Zodiac RAVE Watchdog",
 467 };
 468
 469 static const struct watchdog_ops ziirave_wdt_ops = {
 470         .owner          = THIS_MODULE,
 471         .start          = ziirave_wdt_start,
 472         .stop           = ziirave_wdt_stop,
 473         .ping           = ziirave_wdt_ping,
 474         .set_timeout    = ziirave_wdt_set_timeout,
 475         .get_timeleft   = ziirave_wdt_get_timeleft,
 476 };
 477
 478 static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
 479                                            struct device_attribute *attr,
 480                                            char *buf)
 481 {
 482         struct i2c_client *client = to_i2c_client(dev->parent);
 483         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 484         int ret;
 485
 486         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 487         if (ret)
 488                 return ret;
 489
 490         ret = sprintf(buf, "02.%02u.%02u", w_priv->firmware_rev.major,
 491                       w_priv->firmware_rev.minor);
 492
 493         mutex_unlock(&w_priv->sysfs_mutex);
 494
 495         return ret;
 496 }
 497
 498 static DEVICE_ATTR(firmware_version, S_IRUGO, ziirave_wdt_sysfs_show_firm,
 499                    NULL);
 500
 501 static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
 502                                            struct device_attribute *attr,
 503                                            char *buf)
 504 {
 505         struct i2c_client *client = to_i2c_client(dev->parent);
 506         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 507         int ret;
 508
 509         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 510         if (ret)
 511                 return ret;
 512
 513         ret = sprintf(buf, "01.%02u.%02u", w_priv->bootloader_rev.major,
 514                       w_priv->bootloader_rev.minor);
 515
 516         mutex_unlock(&w_priv->sysfs_mutex);
 517
 518         return ret;
 519 }
 520
 521 static DEVICE_ATTR(bootloader_version, S_IRUGO, ziirave_wdt_sysfs_show_boot,
 522                    NULL);
 523
 524 static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
 525                                              struct device_attribute *attr,
 526                                              char *buf)
 527 {
 528         struct i2c_client *client = to_i2c_client(dev->parent);
 529         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 530         int ret;
 531
 532         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 533         if (ret)
 534                 return ret;
 535
 536         ret = sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
 537
 538         mutex_unlock(&w_priv->sysfs_mutex);
 539
 540         return ret;
 541 }
 542
 543 static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
 544                    NULL);
 545
 546 static ssize_t ziirave_wdt_sysfs_store_firm(struct device *dev,
 547                                             struct device_attribute *attr,
 548                                             const char *buf, size_t count)
 549 {
 550         struct i2c_client *client = to_i2c_client(dev->parent);
 551         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 552         const struct firmware *fw;
 553         int err;
 554
 555         err = request_ihex_firmware(&fw, ZIIRAVE_FW_NAME, dev);
 556         if (err) {
 557                 dev_err(&client->dev, "Failed to request ihex firmware\n");
 558                 return err;
 559         }
 560
 561         err = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 562         if (err)
 563                 goto release_firmware;
 564
 565         err = ziirave_firm_upload(&w_priv->wdd, fw);
 566         if (err) {
 567                 dev_err(&client->dev, "The firmware update failed: %d\n", err);
 568                 goto unlock_mutex;
 569         }
 570
 571         /* Update firmware version */
 572         err = ziirave_wdt_revision(client, &w_priv->firmware_rev,
 573                                    ZIIRAVE_WDT_FIRM_VER_MAJOR);
 574         if (err) {
 575                 dev_err(&client->dev, "Failed to read firmware version: %d\n",
 576                         err);
 577                 goto unlock_mutex;
 578         }
 579
 580         dev_info(&client->dev, "Firmware updated to version 02.%02u.%02u\n",
 581                  w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
 582
 583         /* Restore the watchdog timeout */
 584         err = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
 585         if (err)
 586                 dev_err(&client->dev, "Failed to set timeout: %d\n", err);
 587
 588 unlock_mutex:
 589         mutex_unlock(&w_priv->sysfs_mutex);
 590
 591 release_firmware:
 592         release_firmware(fw);
 593
 594         return err ? err : count;
 595 }
 596
 597 static DEVICE_ATTR(update_firmware, S_IWUSR, NULL,
 598                    ziirave_wdt_sysfs_store_firm);
 599
 600 static struct attribute *ziirave_wdt_attrs[] = {
 601         &dev_attr_firmware_version.attr,
 602         &dev_attr_bootloader_version.attr,
 603         &dev_attr_reset_reason.attr,
 604         &dev_attr_update_firmware.attr,
 605         NULL
 606 };
 607 ATTRIBUTE_GROUPS(ziirave_wdt);
 608
 609 static int ziirave_wdt_init_duration(struct i2c_client *client)
 610 {
 611         int ret;
 612
 613         if (!reset_duration) {
 614                 /* See if the reset pulse duration is provided in an of_node */
 615                 if (!client->dev.of_node)
 616                         ret = -ENODEV;
 617                 else
 618                         ret = of_property_read_u32(client->dev.of_node,
 619                                                    "reset-duration-ms",
 620                                                    &reset_duration);
 621                 if (ret) {
 622                         dev_info(&client->dev,
 623                                  "Unable to set reset pulse duration, using default\n");
 624                         return 0;
 625                 }
 626         }
 627
 628         if (reset_duration < 1 || reset_duration > 255)
 629                 return -EINVAL;
 630
 631         dev_info(&client->dev, "Setting reset duration to %dms",
 632                  reset_duration);
 633
 634         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_RESET_DURATION,
 635                                          reset_duration);
 636 }
 637
 638 static int ziirave_wdt_probe(struct i2c_client *client,
 639                              const struct i2c_device_id *id)
 640 {
 641         int ret;
 642         struct ziirave_wdt_data *w_priv;
 643         int val;
 644
 645         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 646                 return -ENODEV;
 647
 648         w_priv = devm_kzalloc(&client->dev, sizeof(*w_priv), GFP_KERNEL);
 649         if (!w_priv)
 650                 return -ENOMEM;
 651
 652         mutex_init(&w_priv->sysfs_mutex);
 653
 654         w_priv->wdd.info = &ziirave_wdt_info;
 655         w_priv->wdd.ops = &ziirave_wdt_ops;
 656         w_priv->wdd.min_timeout = ZIIRAVE_TIMEOUT_MIN;
 657         w_priv->wdd.max_timeout = ZIIRAVE_TIMEOUT_MAX;
 658         w_priv->wdd.parent = &client->dev;
 659         w_priv->wdd.groups = ziirave_wdt_groups;
 660
 661         ret = watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
 662         if (ret) {
 663                 dev_info(&client->dev,
 664                          "Unable to select timeout value, using default\n");
 665         }
 666
 667         /*
 668          * The default value set in the watchdog should be perfectly valid, so
 669          * pass that in if we haven't provided one via the module parameter or
 670          * of property.
 671          */
 672         if (w_priv->wdd.timeout == 0) {
 673                 val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
 674                 if (val < 0)
 675                         return val;
 676
 677                 if (val < ZIIRAVE_TIMEOUT_MIN)
 678                         return -ENODEV;
 679
 680                 w_priv->wdd.timeout = val;
 681         } else {
 682                 ret = ziirave_wdt_set_timeout(&w_priv->wdd,
 683                                               w_priv->wdd.timeout);
 684                 if (ret)
 685                         return ret;
 686
 687                 dev_info(&client->dev, "Timeout set to %ds.",
 688                          w_priv->wdd.timeout);
 689         }
 690
 691         watchdog_set_nowayout(&w_priv->wdd, nowayout);
 692
 693         i2c_set_clientdata(client, w_priv);
 694
 695         /* If in unconfigured state, set to stopped */
 696         val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
 697         if (val < 0)
 698                 return val;
 699
 700         if (val == ZIIRAVE_STATE_INITIAL)
 701                 ziirave_wdt_stop(&w_priv->wdd);
 702
 703         ret = ziirave_wdt_init_duration(client);
 704         if (ret)
 705                 return ret;
 706
 707         ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
 708                                    ZIIRAVE_WDT_FIRM_VER_MAJOR);
 709         if (ret)
 710                 return ret;
 711
 712         ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
 713                                    ZIIRAVE_WDT_BOOT_VER_MAJOR);
 714         if (ret)
 715                 return ret;
 716
 717         w_priv->reset_reason = i2c_smbus_read_byte_data(client,
 718                                                 ZIIRAVE_WDT_RESET_REASON);
 719         if (w_priv->reset_reason < 0)
 720                 return w_priv->reset_reason;
 721
 722         if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
 723             !ziirave_reasons[w_priv->reset_reason])
 724                 return -ENODEV;
 725
 726         ret = watchdog_register_device(&w_priv->wdd);
 727
 728         return ret;
 729 }
 730
 731 static int ziirave_wdt_remove(struct i2c_client *client)
 732 {
 733         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 734
 735         watchdog_unregister_device(&w_priv->wdd);
 736
 737         return 0;
 738 }
 739
 740 static struct i2c_device_id ziirave_wdt_id[] = {
 741         { "rave-wdt", 0 },
 742         { }
 743 };
 744 MODULE_DEVICE_TABLE(i2c, ziirave_wdt_id);
 745
 746 static const struct of_device_id zrv_wdt_of_match[] = {
 747         { .compatible = "zii,rave-wdt", },
 748         { },
 749 };
 750 MODULE_DEVICE_TABLE(of, zrv_wdt_of_match);
 751
 752 static struct i2c_driver ziirave_wdt_driver = {
 753         .driver = {
 754                 .name = "ziirave_wdt",
 755                 .of_match_table = zrv_wdt_of_match,
 756         },
 757         .probe = ziirave_wdt_probe,
 758         .remove = ziirave_wdt_remove,
 759         .id_table = ziirave_wdt_id,
 760 };
 761
 762 module_i2c_driver(ziirave_wdt_driver);
 763
 764 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk");
 765 MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
 766 MODULE_LICENSE("GPL");