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/i2c.h>
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/sysfs.h>
  26 #include <linux/types.h>
  27 #include <linux/version.h>
  28 #include <linux/watchdog.h>
  29
  30 #define ZIIRAVE_TIMEOUT_MIN     3
  31 #define ZIIRAVE_TIMEOUT_MAX     255
  32
  33 #define ZIIRAVE_PING_VALUE      0x0
  34
  35 #define ZIIRAVE_STATE_INITIAL   0x0
  36 #define ZIIRAVE_STATE_OFF       0x1
  37 #define ZIIRAVE_STATE_ON        0x2
  38
  39 static char *ziirave_reasons[] = {"power cycle", "triggered", NULL, NULL,
  40                                   "host request", NULL, "illegal configuration",
  41                                   "illegal instruction", "illegal trap",
  42                                   "unknown"};
  43
  44 #define ZIIRAVE_WDT_FIRM_VER_MAJOR      0x1
  45 #define ZIIRAVE_WDT_BOOT_VER_MAJOR      0x3
  46 #define ZIIRAVE_WDT_RESET_REASON        0x5
  47 #define ZIIRAVE_WDT_STATE               0x6
  48 #define ZIIRAVE_WDT_TIMEOUT             0x7
  49 #define ZIIRAVE_WDT_TIME_LEFT           0x8
  50 #define ZIIRAVE_WDT_PING                0x9
  51 #define ZIIRAVE_WDT_RESET_DURATION      0xa
  52
  53 struct ziirave_wdt_rev {
  54         unsigned char major;
  55         unsigned char minor;
  56 };
  57
  58 struct ziirave_wdt_data {
  59         struct watchdog_device wdd;
  60         struct ziirave_wdt_rev bootloader_rev;
  61         struct ziirave_wdt_rev firmware_rev;
  62         int reset_reason;
  63 };
  64
  65 static int wdt_timeout;
  66 module_param(wdt_timeout, int, 0);
  67 MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
  68
  69 static int reset_duration;
  70 module_param(reset_duration, int, 0);
  71 MODULE_PARM_DESC(reset_duration,
  72                  "Watchdog reset pulse duration in milliseconds");
  73
  74 static bool nowayout = WATCHDOG_NOWAYOUT;
  75 module_param(nowayout, bool, 0);
  76 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
  77                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  78
  79 static int ziirave_wdt_revision(struct i2c_client *client,
  80                                 struct ziirave_wdt_rev *rev, u8 command)
  81 {
  82         int ret;
  83
  84         ret = i2c_smbus_read_byte_data(client, command);
  85         if (ret < 0)
  86                 return ret;
  87
  88         rev->major = ret;
  89
  90         ret = i2c_smbus_read_byte_data(client, command + 1);
  91         if (ret < 0)
  92                 return ret;
  93
  94         rev->minor = ret;
  95
  96         return 0;
  97 }
  98
  99 static int ziirave_wdt_set_state(struct watchdog_device *wdd, int state)
 100 {
 101         struct i2c_client *client = to_i2c_client(wdd->parent);
 102
 103         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_STATE, state);
 104 }
 105
 106 static int ziirave_wdt_start(struct watchdog_device *wdd)
 107 {
 108         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_ON);
 109 }
 110
 111 static int ziirave_wdt_stop(struct watchdog_device *wdd)
 112 {
 113         return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_OFF);
 114 }
 115
 116 static int ziirave_wdt_ping(struct watchdog_device *wdd)
 117 {
 118         struct i2c_client *client = to_i2c_client(wdd->parent);
 119
 120         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_PING,
 121                                          ZIIRAVE_PING_VALUE);
 122 }
 123
 124 static int ziirave_wdt_set_timeout(struct watchdog_device *wdd,
 125                                    unsigned int timeout)
 126 {
 127         struct i2c_client *client = to_i2c_client(wdd->parent);
 128         int ret;
 129
 130         ret = i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_TIMEOUT, timeout);
 131         if (!ret)
 132                 wdd->timeout = timeout;
 133
 134         return ret;
 135 }
 136
 137 static unsigned int ziirave_wdt_get_timeleft(struct watchdog_device *wdd)
 138 {
 139         struct i2c_client *client = to_i2c_client(wdd->parent);
 140         int ret;
 141
 142         ret = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIME_LEFT);
 143         if (ret < 0)
 144                 ret = 0;
 145
 146         return ret;
 147 }
 148
 149 static const struct watchdog_info ziirave_wdt_info = {
 150         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 151         .identity = "Zodiac RAVE Watchdog",
 152 };
 153
 154 static const struct watchdog_ops ziirave_wdt_ops = {
 155         .owner          = THIS_MODULE,
 156         .start          = ziirave_wdt_start,
 157         .stop           = ziirave_wdt_stop,
 158         .ping           = ziirave_wdt_ping,
 159         .set_timeout    = ziirave_wdt_set_timeout,
 160         .get_timeleft   = ziirave_wdt_get_timeleft,
 161 };
 162
 163 static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
 164                                            struct device_attribute *attr,
 165                                            char *buf)
 166 {
 167         struct i2c_client *client = to_i2c_client(dev->parent);
 168         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 169
 170         return sprintf(buf, "02.%02u.%02u", w_priv->firmware_rev.major,
 171                        w_priv->firmware_rev.minor);
 172 }
 173
 174 static DEVICE_ATTR(firmware_version, S_IRUGO, ziirave_wdt_sysfs_show_firm,
 175                    NULL);
 176
 177 static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
 178                                            struct device_attribute *attr,
 179                                            char *buf)
 180 {
 181         struct i2c_client *client = to_i2c_client(dev->parent);
 182         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 183
 184         return sprintf(buf, "01.%02u.%02u", w_priv->bootloader_rev.major,
 185                        w_priv->bootloader_rev.minor);
 186 }
 187
 188 static DEVICE_ATTR(bootloader_version, S_IRUGO, ziirave_wdt_sysfs_show_boot,
 189                    NULL);
 190
 191 static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
 192                                              struct device_attribute *attr,
 193                                              char *buf)
 194 {
 195         struct i2c_client *client = to_i2c_client(dev->parent);
 196         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 197
 198         return sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
 199 }
 200
 201 static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
 202                    NULL);
 203
 204 static struct attribute *ziirave_wdt_attrs[] = {
 205         &dev_attr_firmware_version.attr,
 206         &dev_attr_bootloader_version.attr,
 207         &dev_attr_reset_reason.attr,
 208         NULL
 209 };
 210 ATTRIBUTE_GROUPS(ziirave_wdt);
 211
 212 static int ziirave_wdt_init_duration(struct i2c_client *client)
 213 {
 214         int ret;
 215
 216         if (!reset_duration) {
 217                 /* See if the reset pulse duration is provided in an of_node */
 218                 if (!client->dev.of_node)
 219                         ret = -ENODEV;
 220                 else
 221                         ret = of_property_read_u32(client->dev.of_node,
 222                                                    "reset-duration-ms",
 223                                                    &reset_duration);
 224                 if (ret) {
 225                         dev_info(&client->dev,
 226                                  "Unable to set reset pulse duration, using default\n");
 227                         return 0;
 228                 }
 229         }
 230
 231         if (reset_duration < 1 || reset_duration > 255)
 232                 return -EINVAL;
 233
 234         dev_info(&client->dev, "Setting reset duration to %dms",
 235                  reset_duration);
 236
 237         return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_RESET_DURATION,
 238                                          reset_duration);
 239 }
 240
 241 static int ziirave_wdt_probe(struct i2c_client *client,
 242                              const struct i2c_device_id *id)
 243 {
 244         int ret;
 245         struct ziirave_wdt_data *w_priv;
 246         int val;
 247
 248         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 249                 return -ENODEV;
 250
 251         w_priv = devm_kzalloc(&client->dev, sizeof(*w_priv), GFP_KERNEL);
 252         if (!w_priv)
 253                 return -ENOMEM;
 254
 255         w_priv->wdd.info = &ziirave_wdt_info;
 256         w_priv->wdd.ops = &ziirave_wdt_ops;
 257         w_priv->wdd.min_timeout = ZIIRAVE_TIMEOUT_MIN;
 258         w_priv->wdd.max_timeout = ZIIRAVE_TIMEOUT_MAX;
 259         w_priv->wdd.parent = &client->dev;
 260         w_priv->wdd.groups = ziirave_wdt_groups;
 261
 262         ret = watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
 263         if (ret) {
 264                 dev_info(&client->dev,
 265                          "Unable to select timeout value, using default\n");
 266         }
 267
 268         /*
 269          * The default value set in the watchdog should be perfectly valid, so
 270          * pass that in if we haven't provided one via the module parameter or
 271          * of property.
 272          */
 273         if (w_priv->wdd.timeout == 0) {
 274                 val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
 275                 if (val < 0)
 276                         return val;
 277
 278                 if (val < ZIIRAVE_TIMEOUT_MIN)
 279                         return -ENODEV;
 280
 281                 w_priv->wdd.timeout = val;
 282         } else {
 283                 ret = ziirave_wdt_set_timeout(&w_priv->wdd,
 284                                               w_priv->wdd.timeout);
 285                 if (ret)
 286                         return ret;
 287
 288                 dev_info(&client->dev, "Timeout set to %ds.",
 289                          w_priv->wdd.timeout);
 290         }
 291
 292         watchdog_set_nowayout(&w_priv->wdd, nowayout);
 293
 294         i2c_set_clientdata(client, w_priv);
 295
 296         /* If in unconfigured state, set to stopped */
 297         val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
 298         if (val < 0)
 299                 return val;
 300
 301         if (val == ZIIRAVE_STATE_INITIAL)
 302                 ziirave_wdt_stop(&w_priv->wdd);
 303
 304         ret = ziirave_wdt_init_duration(client);
 305         if (ret)
 306                 return ret;
 307
 308         ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
 309                                    ZIIRAVE_WDT_FIRM_VER_MAJOR);
 310         if (ret)
 311                 return ret;
 312
 313         ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
 314                                    ZIIRAVE_WDT_BOOT_VER_MAJOR);
 315         if (ret)
 316                 return ret;
 317
 318         w_priv->reset_reason = i2c_smbus_read_byte_data(client,
 319                                                 ZIIRAVE_WDT_RESET_REASON);
 320         if (w_priv->reset_reason < 0)
 321                 return w_priv->reset_reason;
 322
 323         if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
 324             !ziirave_reasons[w_priv->reset_reason])
 325                 return -ENODEV;
 326
 327         ret = watchdog_register_device(&w_priv->wdd);
 328
 329         return ret;
 330 }
 331
 332 static int ziirave_wdt_remove(struct i2c_client *client)
 333 {
 334         struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
 335
 336         watchdog_unregister_device(&w_priv->wdd);
 337
 338         return 0;
 339 }
 340
 341 static struct i2c_device_id ziirave_wdt_id[] = {
 342         { "ziirave-wdt", 0 },
 343         { }
 344 };
 345 MODULE_DEVICE_TABLE(i2c, ziirave_wdt_id);
 346
 347 static const struct of_device_id zrv_wdt_of_match[] = {
 348         { .compatible = "zii,rave-wdt", },
 349         { },
 350 };
 351 MODULE_DEVICE_TABLE(of, zrv_wdt_of_match);
 352
 353 static struct i2c_driver ziirave_wdt_driver = {
 354         .driver = {
 355                 .name = "ziirave_wdt",
 356                 .of_match_table = zrv_wdt_of_match,
 357         },
 358         .probe = ziirave_wdt_probe,
 359         .remove = ziirave_wdt_remove,
 360         .id_table = ziirave_wdt_id,
 361 };
 362
 363 module_i2c_driver(ziirave_wdt_driver);
 364
 365 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk");
 366 MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
 367 MODULE_LICENSE("GPL");