drivers/watchdog/da9063_wdt.c

   1 /*
   2  * Watchdog driver for DA9063 PMICs.
   3  *
   4  * Copyright(c) 2012 Dialog Semiconductor Ltd.
   5  *
   6  * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/watchdog.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/slab.h>
  20 #include <linux/delay.h>
  21 #include <linux/mfd/da9063/registers.h>
  22 #include <linux/mfd/da9063/core.h>
  23 #include <linux/reboot.h>
  24 #include <linux/regmap.h>
  25
  26 /*
  27  * Watchdog selector to timeout in seconds.
  28  *   0: WDT disabled;
  29  *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
  30  */
  31 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
  32 #define DA9063_TWDSCALE_DISABLE         0
  33 #define DA9063_TWDSCALE_MIN             1
  34 #define DA9063_TWDSCALE_MAX             (ARRAY_SIZE(wdt_timeout) - 1)
  35 #define DA9063_WDT_MIN_TIMEOUT          wdt_timeout[DA9063_TWDSCALE_MIN]
  36 #define DA9063_WDT_MAX_TIMEOUT          wdt_timeout[DA9063_TWDSCALE_MAX]
  37 #define DA9063_WDG_TIMEOUT              wdt_timeout[3]
  38
  39 struct da9063_watchdog {
  40         struct da9063 *da9063;
  41         struct watchdog_device wdtdev;
  42         struct notifier_block restart_handler;
  43 };
  44
  45 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
  46 {
  47         unsigned int i;
  48
  49         for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
  50                 if (wdt_timeout[i] >= secs)
  51                         return i;
  52         }
  53
  54         return DA9063_TWDSCALE_MAX;
  55 }
  56
  57 static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
  58 {
  59         return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
  60                                   DA9063_TWDSCALE_MASK, regval);
  61 }
  62
  63 static int da9063_wdt_start(struct watchdog_device *wdd)
  64 {
  65         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  66         unsigned int selector;
  67         int ret;
  68
  69         selector = da9063_wdt_timeout_to_sel(wdt->wdtdev.timeout);
  70         ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
  71         if (ret)
  72                 dev_err(wdt->da9063->dev, "Watchdog failed to start (err = %d)\n",
  73                         ret);
  74
  75         return ret;
  76 }
  77
  78 static int da9063_wdt_stop(struct watchdog_device *wdd)
  79 {
  80         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  81         int ret;
  82
  83         ret = regmap_update_bits(wdt->da9063->regmap, DA9063_REG_CONTROL_D,
  84                                  DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
  85         if (ret)
  86                 dev_alert(wdt->da9063->dev, "Watchdog failed to stop (err = %d)\n",
  87                           ret);
  88
  89         return ret;
  90 }
  91
  92 static int da9063_wdt_ping(struct watchdog_device *wdd)
  93 {
  94         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  95         int ret;
  96
  97         ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
  98                            DA9063_WATCHDOG);
  99         if (ret)
 100                 dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err = %d)\n",
 101                           ret);
 102
 103         return ret;
 104 }
 105
 106 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
 107                                   unsigned int timeout)
 108 {
 109         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
 110         unsigned int selector;
 111         int ret;
 112
 113         selector = da9063_wdt_timeout_to_sel(timeout);
 114         ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
 115         if (ret)
 116                 dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
 117                         ret);
 118         else
 119                 wdd->timeout = wdt_timeout[selector];
 120
 121         return ret;
 122 }
 123
 124 static int da9063_wdt_restart_handler(struct notifier_block *this,
 125                                       unsigned long mode, void *cmd)
 126 {
 127         struct da9063_watchdog *wdt = container_of(this,
 128                                                    struct da9063_watchdog,
 129                                                    restart_handler);
 130         int ret;
 131
 132         ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
 133                            DA9063_SHUTDOWN);
 134         if (ret)
 135                 dev_alert(wdt->da9063->dev, "Failed to shutdown (err = %d)\n",
 136                           ret);
 137
 138         return NOTIFY_DONE;
 139 }
 140
 141 static const struct watchdog_info da9063_watchdog_info = {
 142         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 143         .identity = "DA9063 Watchdog",
 144 };
 145
 146 static const struct watchdog_ops da9063_watchdog_ops = {
 147         .owner = THIS_MODULE,
 148         .start = da9063_wdt_start,
 149         .stop = da9063_wdt_stop,
 150         .ping = da9063_wdt_ping,
 151         .set_timeout = da9063_wdt_set_timeout,
 152 };
 153
 154 static int da9063_wdt_probe(struct platform_device *pdev)
 155 {
 156         int ret;
 157         struct da9063 *da9063;
 158         struct da9063_watchdog *wdt;
 159
 160         if (!pdev->dev.parent)
 161                 return -EINVAL;
 162
 163         da9063 = dev_get_drvdata(pdev->dev.parent);
 164         if (!da9063)
 165                 return -EINVAL;
 166
 167         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 168         if (!wdt)
 169                 return -ENOMEM;
 170
 171         wdt->da9063 = da9063;
 172
 173         wdt->wdtdev.info = &da9063_watchdog_info;
 174         wdt->wdtdev.ops = &da9063_watchdog_ops;
 175         wdt->wdtdev.min_timeout = DA9063_WDT_MIN_TIMEOUT;
 176         wdt->wdtdev.max_timeout = DA9063_WDT_MAX_TIMEOUT;
 177         wdt->wdtdev.timeout = DA9063_WDG_TIMEOUT;
 178
 179         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 180
 181         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 182         dev_set_drvdata(&pdev->dev, wdt);
 183
 184         ret = watchdog_register_device(&wdt->wdtdev);
 185         if (ret)
 186                 return ret;
 187
 188         wdt->restart_handler.notifier_call = da9063_wdt_restart_handler;
 189         wdt->restart_handler.priority = 128;
 190         ret = register_restart_handler(&wdt->restart_handler);
 191         if (ret)
 192                 dev_err(wdt->da9063->dev,
 193                         "Failed to register restart handler (err = %d)\n", ret);
 194
 195         return 0;
 196 }
 197
 198 static int da9063_wdt_remove(struct platform_device *pdev)
 199 {
 200         struct da9063_watchdog *wdt = dev_get_drvdata(&pdev->dev);
 201
 202         unregister_restart_handler(&wdt->restart_handler);
 203
 204         watchdog_unregister_device(&wdt->wdtdev);
 205
 206         return 0;
 207 }
 208
 209 static struct platform_driver da9063_wdt_driver = {
 210         .probe = da9063_wdt_probe,
 211         .remove = da9063_wdt_remove,
 212         .driver = {
 213                 .name = DA9063_DRVNAME_WATCHDOG,
 214         },
 215 };
 216 module_platform_driver(da9063_wdt_driver);
 217
 218 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
 219 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
 220 MODULE_LICENSE("GPL");
 221 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);