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 0x1600
  55 #define ZIIRAVE_FIRM_FLASH_MEMORY_END   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 /* Currently writing to flash. Retry Download status in a moment! */
  61 #define ZIIRAVE_FIRM_DOWNLOAD_BUSY      2
  62
  63 /* Wait for ACK timeout in ms */
  64 #define ZIIRAVE_FIRM_WAIT_FOR_ACK_TIMEOUT       50
  65
  66 /* Firmware commands */
  67 #define ZIIRAVE_CMD_DOWNLOAD_START              0x10
  68 #define ZIIRAVE_CMD_DOWNLOAD_END                0x11
  69 #define ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR      0x12
  70 #define ZIIRAVE_CMD_DOWNLOAD_READ_BYTE          0x13
  71 #define ZIIRAVE_CMD_RESET_PROCESSOR             0x0b
  72 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER          0x0c
  73 #define ZIIRAVE_CMD_DOWNLOAD_PACKET             0x0e
  74
  75 #define ZIIRAVE_FW_VERSION_FMT  "02.%02u.%02u"
  76 #define ZIIRAVE_BL_VERSION_FMT  "01.%02u.%02u"
  77
  78 struct ziirave_wdt_rev {
  79         unsigned char major;
  80         unsigned char minor;
  81 };
  82
  83 struct ziirave_wdt_data {
  84         struct mutex sysfs_mutex;
  85         struct watchdog_device wdd;
  86         struct ziirave_wdt_rev bootloader_rev;
  87         struct ziirave_wdt_rev firmware_rev;
  88         int reset_reason;
  89 };
  90
  91 static int wdt_timeout;
  92 module_param(wdt_timeout, int, 0);
  93 MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
  94
  95 static int reset_duration;
  96 module_param(reset_duration, int, 0);
  97 MODULE_PARM_DESC(reset_duration,
  98                  "Watchdog reset pulse duration in milliseconds");
  99
 100 static bool nowayout = WATCHDOG_NOWAYOUT;
 101 module_param(nowayout, bool, 0);
 102 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
 103                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 104
 105 static int ziirave_wdt_revision(struct i2c_client *client,
 106                                 struct ziirave_wdt_rev *rev, u8 command)
 107 {
 108         int ret;
 109
 110         ret = i2c_smbus_read_byte_data(client, command);
 111         if (ret < 0)
 112                 return ret;
 113
 114         rev->major = ret;
 115
 116         ret = i2c_smbus_read_byte_data(client, command + 1);
 117         if (ret < 0)
 118                 return ret;
 119
 120         rev->minor = ret;
 121
 122         return 0;
 123 }
 124
 125 static int ziirave_wdt_set_state(struct watchdog_device *wdd, int state)
 126 {
 127         struct i2c_client *client = to_i2c_client(wdd->parent);
 128
 129         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_STATE, state);
 130 }
 131
 132 static int ziirave_wdt_start(struct watchdog_device *wdd)
 133 {
 134         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_ON);
 135 }
 136
 137 static int ziirave_wdt_stop(struct watchdog_device *wdd)
 138 {
 139         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_OFF);
 140 }
 141
 142 static int ziirave_wdt_ping(struct watchdog_device *wdd)
 143 {
 144         struct i2c_client *client = to_i2c_client(wdd->parent);
 145
 146         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_PING,
 147                                          ZIIRAVE_PING_VALUE);
 148 }
 149
 150 static int ziirave_wdt_set_timeout(struct watchdog_device *wdd,
 151                                    unsigned int timeout)
 152 {
 153         struct i2c_client *client = to_i2c_client(wdd->parent);
 154         int ret;
 155
 156         ret = i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_TIMEOUT, timeout);
 157         if (!ret)
 158                 wdd->timeout = timeout;
 159
 160         return ret;
 161 }
 162
 163 static unsigned int ziirave_wdt_get_timeleft(struct watchdog_device *wdd)
 164 {
 165         struct i2c_client *client = to_i2c_client(wdd->parent);
 166         int ret;
 167
 168         ret = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIME_LEFT);
 169         if (ret < 0)
 170                 ret = 0;
 171
 172         return ret;
 173 }
 174
 175 static int ziirave_firm_wait_for_ack(struct watchdog_device *wdd)
 176 {
 177         struct i2c_client *client = to_i2c_client(wdd->parent);
 178         int ret;
 179         unsigned long timeout;
 180
 181         timeout = jiffies + msecs_to_jiffies(ZIIRAVE_FIRM_WAIT_FOR_ACK_TIMEOUT);
 182         do {
 183                 if (time_after(jiffies, timeout))
 184                         return -ETIMEDOUT;
 185
 186                 usleep_range(5000, 10000);
 187
 188                 ret = i2c_smbus_read_byte(client);
 189                 if (ret < 0) {
 190                         dev_err(&client->dev, "Failed to read byte\n");
 191                         return ret;
 192                 }
 193         } while (ret == ZIIRAVE_FIRM_DOWNLOAD_BUSY);
 194
 195         return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
 196 }
 197
 198 static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u16 addr)
 199 {
 200         struct i2c_client *client = to_i2c_client(wdd->parent);
 201         u8 address[2];
 202
 203         put_unaligned_le16(addr, address);
 204
 205         return i2c_smbus_write_block_data(client,
 206                                           ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
 207                                           sizeof(address), address);
 208 }
 209
 210 static int ziirave_firm_write_block_data(struct watchdog_device *wdd,
 211                                          u8 command, u8 length, const u8 *data,
 212                                          bool wait_for_ack)
 213 {
 214         struct i2c_client *client = to_i2c_client(wdd->parent);
 215         int ret;
 216
 217         ret = i2c_smbus_write_block_data(client, command, length, data);
 218         if (ret) {
 219                 dev_err(&client->dev,
 220                         "Failed to send command 0x%02x: %d\n", command, ret);
 221                 return ret;
 222         }
 223
 224         if (wait_for_ack)
 225                 ret = ziirave_firm_wait_for_ack(wdd);
 226
 227         return ret;
 228 }
 229
 230 static int ziirave_firm_write_byte(struct watchdog_device *wdd, u8 command,
 231                                    u8 byte, bool wait_for_ack)
 232 {
 233         return ziirave_firm_write_block_data(wdd, command, 1, &byte,
 234                                              wait_for_ack);
 235 }
 236
 237 /*
 238  * ziirave_firm_write_pkt() - Build and write a firmware packet
 239  *
 240  * A packet to send to the firmware is composed by following bytes:
 241  *     Length | Addr0 | Addr1 | Data0 .. Data15 | Checksum |
 242  * Where,
 243  *     Length: A data byte containing the length of the data.
 244  *     Addr0: Low byte of the address.
 245  *     Addr1: High byte of the address.
 246  *     Data0 .. Data15: Array of 16 bytes of data.
 247  *     Checksum: Checksum byte to verify data integrity.
 248  */
 249 static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
 250                                     u32 addr, const u8 *data, u8 len)
 251 {
 252         const u16 addr16 = (u16)addr / 2;
 253         struct i2c_client *client = to_i2c_client(wdd->parent);
 254         u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
 255         int ret;
 256
 257         /* Check max data size */
 258         if (len > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
 259                 dev_err(&client->dev, "Firmware packet too long (%d)\n",
 260                         len);
 261                 return -EMSGSIZE;
 262         }
 263
 264         /* Packet length */
 265         packet[0] = len;
 266         /* Packet address */
 267         put_unaligned_le16(addr16, packet + 1);
 268
 269         memcpy(packet + 3, data, len);
 270         memset(packet + 3 + len, 0, ZIIRAVE_FIRM_PKT_DATA_SIZE - len);
 271
 272         /* Packet checksum */
 273         for (i = 0; i < len + 3; i++)
 274                 checksum += packet[i];
 275         packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1] = checksum;
 276
 277         ret = ziirave_firm_write_block_data(wdd, ZIIRAVE_CMD_DOWNLOAD_PACKET,
 278                                             sizeof(packet), packet, true);
 279         if (ret)
 280                 dev_err(&client->dev,
 281                       "Failed to write firmware packet at address 0x%04x: %d\n",
 282                       addr16, ret);
 283
 284         return ret;
 285 }
 286
 287 static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
 288                                   u32 addr, const u8 *data, u8 len)
 289 {
 290         const u8 max_write_len = ZIIRAVE_FIRM_PAGE_SIZE -
 291                 (addr - ALIGN_DOWN(addr, ZIIRAVE_FIRM_PAGE_SIZE));
 292         int ret;
 293
 294         if (len > max_write_len) {
 295                 /*
 296                  * If data crossed page boundary we need to split this
 297                  * write in two
 298                  */
 299                 ret = __ziirave_firm_write_pkt(wdd, addr, data, max_write_len);
 300                 if (ret)
 301                         return ret;
 302
 303                 addr += max_write_len;
 304                 data += max_write_len;
 305                 len  -= max_write_len;
 306         }
 307
 308         return __ziirave_firm_write_pkt(wdd, addr, data, len);
 309 }
 310
 311 static int ziirave_firm_verify(struct watchdog_device *wdd,
 312                                const struct firmware *fw)
 313 {
 314         struct i2c_client *client = to_i2c_client(wdd->parent);
 315         const struct ihex_binrec *rec;
 316         int i, ret;
 317         u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
 318         u16 addr;
 319
 320         for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
 321                 addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1;
 322                 if (addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
 323                     addr > ZIIRAVE_FIRM_FLASH_MEMORY_END)
 324                         continue;
 325
 326                 ret = ziirave_firm_set_read_addr(wdd, addr);
 327                 if (ret) {
 328                         dev_err(&client->dev,
 329                                 "Failed to send SET_READ_ADDR command: %d\n",
 330                                 ret);
 331                         return ret;
 332                 }
 333
 334                 for (i = 0; i < ARRAY_SIZE(data); i++) {
 335                         ret = i2c_smbus_read_byte_data(client,
 336                                                 ZIIRAVE_CMD_DOWNLOAD_READ_BYTE);
 337                         if (ret < 0) {
 338                                 dev_err(&client->dev,
 339                                         "Failed to READ DATA: %d\n", ret);
 340                                 return ret;
 341                         }
 342                         data[i] = ret;
 343                 }
 344
 345                 if (memcmp(data, rec->data, be16_to_cpu(rec->len))) {
 346                         dev_err(&client->dev,
 347                                 "Firmware mismatch at address 0x%04x\n", addr);
 348                         return -EINVAL;
 349                 }
 350         }
 351
 352         return 0;
 353 }
 354
 355 static int ziirave_firm_upload(struct watchdog_device *wdd,
 356                                const struct firmware *fw)
 357 {
 358         struct i2c_client *client = to_i2c_client(wdd->parent);
 359         const struct ihex_binrec *rec;
 360         int ret;
 361
 362         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_JUMP_TO_BOOTLOADER, 1,
 363                                       false);
 364         if (ret) {
 365                 dev_err(&client->dev, "Failed to jump to bootloader\n");
 366                 return ret;
 367         }
 368
 369         msleep(500);
 370
 371         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_DOWNLOAD_START, 1, true);
 372         if (ret) {
 373                 dev_err(&client->dev, "Failed to start download\n");
 374                 return ret;
 375         }
 376
 377         msleep(500);
 378
 379         for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
 380                 ret = ziirave_firm_write_pkt(wdd, be32_to_cpu(rec->addr),
 381                                              rec->data, be16_to_cpu(rec->len));
 382                 if (ret)
 383                         return ret;
 384         }
 385
 386         /*
 387          * Finish firmware download process by sending a zero length
 388          * payload
 389          */
 390         ret = ziirave_firm_write_pkt(wdd, 0, NULL, 0);
 391         if (ret) {
 392                 dev_err(&client->dev, "Failed to send EMPTY packet: %d\n", ret);
 393                 return ret;
 394         }
 395
 396         /* This sleep seems to be required */
 397         msleep(20);
 398
 399         /* Start firmware verification */
 400         ret = ziirave_firm_verify(wdd, fw);
 401         if (ret) {
 402                 dev_err(&client->dev,
 403                         "Failed to verify firmware: %d\n", ret);
 404                 return ret;
 405         }
 406
 407         /* End download operation */
 408         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_DOWNLOAD_END, 1, false);
 409         if (ret) {
 410                 dev_err(&client->dev,
 411                         "Failed to end firmware download: %d\n", ret);
 412                 return ret;
 413         }
 414
 415         /* Reset the processor */
 416         ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_RESET_PROCESSOR, 1,
 417                                       false);
 418         if (ret) {
 419                 dev_err(&client->dev,
 420                         "Failed to reset the watchdog: %d\n", ret);
 421                 return ret;
 422         }
 423
 424         msleep(500);
 425
 426         return 0;
 427 }
 428
 429 static const struct watchdog_info ziirave_wdt_info = {
 430         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 431         .identity = "Zodiac RAVE Watchdog",
 432 };
 433
 434 static const struct watchdog_ops ziirave_wdt_ops = {
 435         .owner          = THIS_MODULE,
 436         .start          = ziirave_wdt_start,
 437         .stop           = ziirave_wdt_stop,
 438         .ping           = ziirave_wdt_ping,
 439         .set_timeout    = ziirave_wdt_set_timeout,
 440         .get_timeleft   = ziirave_wdt_get_timeleft,
 441 };
 442
 443 static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
 444                                            struct device_attribute *attr,
 445                                            char *buf)
 446 {
 447         struct i2c_client *client = to_i2c_client(dev->parent);
 448         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 449         int ret;
 450
 451         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 452         if (ret)
 453                 return ret;
 454
 455         ret = sprintf(buf, ZIIRAVE_FW_VERSION_FMT, w_priv->firmware_rev.major,
 456                       w_priv->firmware_rev.minor);
 457
 458         mutex_unlock(&w_priv->sysfs_mutex);
 459
 460         return ret;
 461 }
 462
 463 static DEVICE_ATTR(firmware_version, S_IRUGO, ziirave_wdt_sysfs_show_firm,
 464                    NULL);
 465
 466 static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
 467                                            struct device_attribute *attr,
 468                                            char *buf)
 469 {
 470         struct i2c_client *client = to_i2c_client(dev->parent);
 471         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 472         int ret;
 473
 474         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 475         if (ret)
 476                 return ret;
 477
 478         ret = sprintf(buf, ZIIRAVE_BL_VERSION_FMT, w_priv->bootloader_rev.major,
 479                       w_priv->bootloader_rev.minor);
 480
 481         mutex_unlock(&w_priv->sysfs_mutex);
 482
 483         return ret;
 484 }
 485
 486 static DEVICE_ATTR(bootloader_version, S_IRUGO, ziirave_wdt_sysfs_show_boot,
 487                    NULL);
 488
 489 static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
 490                                              struct device_attribute *attr,
 491                                              char *buf)
 492 {
 493         struct i2c_client *client = to_i2c_client(dev->parent);
 494         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 495         int ret;
 496
 497         ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 498         if (ret)
 499                 return ret;
 500
 501         ret = sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
 502
 503         mutex_unlock(&w_priv->sysfs_mutex);
 504
 505         return ret;
 506 }
 507
 508 static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
 509                    NULL);
 510
 511 static ssize_t ziirave_wdt_sysfs_store_firm(struct device *dev,
 512                                             struct device_attribute *attr,
 513                                             const char *buf, size_t count)
 514 {
 515         struct i2c_client *client = to_i2c_client(dev->parent);
 516         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 517         const struct firmware *fw;
 518         int err;
 519
 520         err = request_ihex_firmware(&fw, ZIIRAVE_FW_NAME, dev);
 521         if (err) {
 522                 dev_err(&client->dev, "Failed to request ihex firmware\n");
 523                 return err;
 524         }
 525
 526         err = mutex_lock_interruptible(&w_priv->sysfs_mutex);
 527         if (err)
 528                 goto release_firmware;
 529
 530         err = ziirave_firm_upload(&w_priv->wdd, fw);
 531         if (err) {
 532                 dev_err(&client->dev, "The firmware update failed: %d\n", err);
 533                 goto unlock_mutex;
 534         }
 535
 536         /* Update firmware version */
 537         err = ziirave_wdt_revision(client, &w_priv->firmware_rev,
 538                                    ZIIRAVE_WDT_FIRM_VER_MAJOR);
 539         if (err) {
 540                 dev_err(&client->dev, "Failed to read firmware version: %d\n",
 541                         err);
 542                 goto unlock_mutex;
 543         }
 544
 545         dev_info(&client->dev,
 546                  "Firmware updated to version " ZIIRAVE_FW_VERSION_FMT "\n",
 547                  w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
 548
 549         /* Restore the watchdog timeout */
 550         err = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
 551         if (err)
 552                 dev_err(&client->dev, "Failed to set timeout: %d\n", err);
 553
 554 unlock_mutex:
 555         mutex_unlock(&w_priv->sysfs_mutex);
 556
 557 release_firmware:
 558         release_firmware(fw);
 559
 560         return err ? err : count;
 561 }
 562
 563 static DEVICE_ATTR(update_firmware, S_IWUSR, NULL,
 564                    ziirave_wdt_sysfs_store_firm);
 565
 566 static struct attribute *ziirave_wdt_attrs[] = {
 567         &dev_attr_firmware_version.attr,
 568         &dev_attr_bootloader_version.attr,
 569         &dev_attr_reset_reason.attr,
 570         &dev_attr_update_firmware.attr,
 571         NULL
 572 };
 573 ATTRIBUTE_GROUPS(ziirave_wdt);
 574
 575 static int ziirave_wdt_init_duration(struct i2c_client *client)
 576 {
 577         int ret;
 578
 579         if (!reset_duration) {
 580                 /* See if the reset pulse duration is provided in an of_node */
 581                 if (!client->dev.of_node)
 582                         ret = -ENODEV;
 583                 else
 584                         ret = of_property_read_u32(client->dev.of_node,
 585                                                    "reset-duration-ms",
 586                                                    &reset_duration);
 587                 if (ret) {
 588                         dev_info(&client->dev,
 589                                  "Unable to set reset pulse duration, using default\n");
 590                         return 0;
 591                 }
 592         }
 593
 594         if (reset_duration < 1 || reset_duration > 255)
 595                 return -EINVAL;
 596
 597         dev_info(&client->dev, "Setting reset duration to %dms",
 598                  reset_duration);
 599
 600         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_RESET_DURATION,
 601                                          reset_duration);
 602 }
 603
 604 static int ziirave_wdt_probe(struct i2c_client *client,
 605                              const struct i2c_device_id *id)
 606 {
 607         int ret;
 608         struct ziirave_wdt_data *w_priv;
 609         int val;
 610
 611         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 612                 return -ENODEV;
 613
 614         w_priv = devm_kzalloc(&client->dev, sizeof(*w_priv), GFP_KERNEL);
 615         if (!w_priv)
 616                 return -ENOMEM;
 617
 618         mutex_init(&w_priv->sysfs_mutex);
 619
 620         w_priv->wdd.info = &ziirave_wdt_info;
 621         w_priv->wdd.ops = &ziirave_wdt_ops;
 622         w_priv->wdd.min_timeout = ZIIRAVE_TIMEOUT_MIN;
 623         w_priv->wdd.max_timeout = ZIIRAVE_TIMEOUT_MAX;
 624         w_priv->wdd.parent = &client->dev;
 625         w_priv->wdd.groups = ziirave_wdt_groups;
 626
 627         watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
 628
 629         /*
 630          * The default value set in the watchdog should be perfectly valid, so
 631          * pass that in if we haven't provided one via the module parameter or
 632          * of property.
 633          */
 634         if (w_priv->wdd.timeout == 0) {
 635                 val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
 636                 if (val < 0) {
 637                         dev_err(&client->dev, "Failed to read timeout\n");
 638                         return val;
 639                 }
 640
 641                 if (val > ZIIRAVE_TIMEOUT_MAX ||
 642                     val < ZIIRAVE_TIMEOUT_MIN)
 643                         val = ZIIRAVE_TIMEOUT_DEFAULT;
 644
 645                 w_priv->wdd.timeout = val;
 646         }
 647
 648         ret = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
 649         if (ret) {
 650                 dev_err(&client->dev, "Failed to set timeout\n");
 651                 return ret;
 652         }
 653
 654         dev_info(&client->dev, "Timeout set to %ds\n", w_priv->wdd.timeout);
 655
 656         watchdog_set_nowayout(&w_priv->wdd, nowayout);
 657
 658         i2c_set_clientdata(client, w_priv);
 659
 660         /* If in unconfigured state, set to stopped */
 661         val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
 662         if (val < 0) {
 663                 dev_err(&client->dev, "Failed to read state\n");
 664                 return val;
 665         }
 666
 667         if (val == ZIIRAVE_STATE_INITIAL)
 668                 ziirave_wdt_stop(&w_priv->wdd);
 669
 670         ret = ziirave_wdt_init_duration(client);
 671         if (ret) {
 672                 dev_err(&client->dev, "Failed to init duration\n");
 673                 return ret;
 674         }
 675
 676         ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
 677                                    ZIIRAVE_WDT_FIRM_VER_MAJOR);
 678         if (ret) {
 679                 dev_err(&client->dev, "Failed to read firmware version\n");
 680                 return ret;
 681         }
 682
 683         dev_info(&client->dev,
 684                  "Firmware version: " ZIIRAVE_FW_VERSION_FMT "\n",
 685                  w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
 686
 687         ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
 688                                    ZIIRAVE_WDT_BOOT_VER_MAJOR);
 689         if (ret) {
 690                 dev_err(&client->dev, "Failed to read bootloader version\n");
 691                 return ret;
 692         }
 693
 694         dev_info(&client->dev,
 695                  "Bootloader version: " ZIIRAVE_BL_VERSION_FMT "\n",
 696                  w_priv->bootloader_rev.major, w_priv->bootloader_rev.minor);
 697
 698         w_priv->reset_reason = i2c_smbus_read_byte_data(client,
 699                                                 ZIIRAVE_WDT_RESET_REASON);
 700         if (w_priv->reset_reason < 0) {
 701                 dev_err(&client->dev, "Failed to read reset reason\n");
 702                 return w_priv->reset_reason;
 703         }
 704
 705         if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
 706             !ziirave_reasons[w_priv->reset_reason]) {
 707                 dev_err(&client->dev, "Invalid reset reason\n");
 708                 return -ENODEV;
 709         }
 710
 711         ret = watchdog_register_device(&w_priv->wdd);
 712
 713         return ret;
 714 }
 715
 716 static int ziirave_wdt_remove(struct i2c_client *client)
 717 {
 718         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 719
 720         watchdog_unregister_device(&w_priv->wdd);
 721
 722         return 0;
 723 }
 724
 725 static const struct i2c_device_id ziirave_wdt_id[] = {
 726         { "rave-wdt", 0 },
 727         { }
 728 };
 729 MODULE_DEVICE_TABLE(i2c, ziirave_wdt_id);
 730
 731 static const struct of_device_id zrv_wdt_of_match[] = {
 732         { .compatible = "zii,rave-wdt", },
 733         { },
 734 };
 735 MODULE_DEVICE_TABLE(of, zrv_wdt_of_match);
 736
 737 static struct i2c_driver ziirave_wdt_driver = {
 738         .driver = {
 739                 .name = "ziirave_wdt",
 740                 .of_match_table = zrv_wdt_of_match,
 741         },
 742         .probe = ziirave_wdt_probe,
 743         .remove = ziirave_wdt_remove,
 744         .id_table = ziirave_wdt_id,
 745 };
 746
 747 module_i2c_driver(ziirave_wdt_driver);
 748
 749 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk");
 750 MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
 751 MODULE_LICENSE("GPL");