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/regmap.h>
  24
  25 /*
  26  * Watchdog selector to timeout in seconds.
  27  *   0: WDT disabled;
  28  *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
  29  */
  30 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
  31 #define DA9063_TWDSCALE_DISABLE         0
  32 #define DA9063_TWDSCALE_MIN             1
  33 #define DA9063_TWDSCALE_MAX             (ARRAY_SIZE(wdt_timeout) - 1)
  34 #define DA9063_WDT_MIN_TIMEOUT          wdt_timeout[DA9063_TWDSCALE_MIN]
  35 #define DA9063_WDT_MAX_TIMEOUT          wdt_timeout[DA9063_TWDSCALE_MAX]
  36 #define DA9063_WDG_TIMEOUT              wdt_timeout[3]
  37 #define DA9063_RESET_PROTECTION_MS      256
  38
  39 struct da9063_watchdog {
  40         struct da9063 *da9063;
  41         struct watchdog_device wdtdev;
  42 };
  43
  44 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
  45 {
  46         unsigned int i;
  47
  48         for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
  49                 if (wdt_timeout[i] >= secs)
  50                         return i;
  51         }
  52
  53         return DA9063_TWDSCALE_MAX;
  54 }
  55
  56 static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
  57 {
  58         return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
  59                                   DA9063_TWDSCALE_MASK, regval);
  60 }
  61
  62 static int da9063_wdt_start(struct watchdog_device *wdd)
  63 {
  64         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  65         unsigned int selector;
  66         int ret;
  67
  68         selector = da9063_wdt_timeout_to_sel(wdt->wdtdev.timeout);
  69         ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
  70         if (ret)
  71                 dev_err(wdt->da9063->dev, "Watchdog failed to start (err = %d)\n",
  72                         ret);
  73
  74         return ret;
  75 }
  76
  77 static int da9063_wdt_stop(struct watchdog_device *wdd)
  78 {
  79         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  80         int ret;
  81
  82         ret = regmap_update_bits(wdt->da9063->regmap, DA9063_REG_CONTROL_D,
  83                                  DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
  84         if (ret)
  85                 dev_alert(wdt->da9063->dev, "Watchdog failed to stop (err = %d)\n",
  86                           ret);
  87
  88         return ret;
  89 }
  90
  91 static int da9063_wdt_ping(struct watchdog_device *wdd)
  92 {
  93         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  94         int ret;
  95
  96         ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
  97                            DA9063_WATCHDOG);
  98         if (ret)
  99                 dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err = %d)\n",
 100                           ret);
 101
 102         return ret;
 103 }
 104
 105 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
 106                                   unsigned int timeout)
 107 {
 108         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
 109         unsigned int selector;
 110         int ret;
 111
 112         selector = da9063_wdt_timeout_to_sel(timeout);
 113         ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
 114         if (ret)
 115                 dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
 116                         ret);
 117         else
 118                 wdd->timeout = wdt_timeout[selector];
 119
 120         return ret;
 121 }
 122
 123 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 124                               void *data)
 125 {
 126         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
 127         int ret;
 128
 129         ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
 130                            DA9063_SHUTDOWN);
 131         if (ret)
 132                 dev_alert(wdt->da9063->dev, "Failed to shutdown (err = %d)\n",
 133                           ret);
 134
 135         return ret;
 136 }
 137
 138 static const struct watchdog_info da9063_watchdog_info = {
 139         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 140         .identity = "DA9063 Watchdog",
 141 };
 142
 143 static const struct watchdog_ops da9063_watchdog_ops = {
 144         .owner = THIS_MODULE,
 145         .start = da9063_wdt_start,
 146         .stop = da9063_wdt_stop,
 147         .ping = da9063_wdt_ping,
 148         .set_timeout = da9063_wdt_set_timeout,
 149         .restart = da9063_wdt_restart,
 150 };
 151
 152 static int da9063_wdt_probe(struct platform_device *pdev)
 153 {
 154         struct da9063 *da9063;
 155         struct da9063_watchdog *wdt;
 156
 157         if (!pdev->dev.parent)
 158                 return -EINVAL;
 159
 160         da9063 = dev_get_drvdata(pdev->dev.parent);
 161         if (!da9063)
 162                 return -EINVAL;
 163
 164         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 165         if (!wdt)
 166                 return -ENOMEM;
 167
 168         wdt->da9063 = da9063;
 169
 170         wdt->wdtdev.info = &da9063_watchdog_info;
 171         wdt->wdtdev.ops = &da9063_watchdog_ops;
 172         wdt->wdtdev.min_timeout = DA9063_WDT_MIN_TIMEOUT;
 173         wdt->wdtdev.max_timeout = DA9063_WDT_MAX_TIMEOUT;
 174         wdt->wdtdev.min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
 175         wdt->wdtdev.timeout = DA9063_WDG_TIMEOUT;
 176         wdt->wdtdev.parent = &pdev->dev;
 177
 178         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 179
 180         watchdog_set_restart_priority(&wdt->wdtdev, 128);
 181
 182         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 183
 184         return devm_watchdog_register_device(&pdev->dev, &wdt->wdtdev);
 185 }
 186
 187 static struct platform_driver da9063_wdt_driver = {
 188         .probe = da9063_wdt_probe,
 189         .driver = {
 190                 .name = DA9063_DRVNAME_WATCHDOG,
 191         },
 192 };
 193 module_platform_driver(da9063_wdt_driver);
 194
 195 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
 196 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
 197 MODULE_LICENSE("GPL");
 198 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);