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
  38 struct da9063_watchdog {
  39         struct da9063 *da9063;
  40         struct watchdog_device wdtdev;
  41 };
  42
  43 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
  44 {
  45         unsigned int i;
  46
  47         for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
  48                 if (wdt_timeout[i] >= secs)
  49                         return i;
  50         }
  51
  52         return DA9063_TWDSCALE_MAX;
  53 }
  54
  55 static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
  56 {
  57         return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
  58                                   DA9063_TWDSCALE_MASK, regval);
  59 }
  60
  61 static int da9063_wdt_start(struct watchdog_device *wdd)
  62 {
  63         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  64         unsigned int selector;
  65         int ret;
  66
  67         selector = da9063_wdt_timeout_to_sel(wdt->wdtdev.timeout);
  68         ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
  69         if (ret)
  70                 dev_err(wdt->da9063->dev, "Watchdog failed to start (err = %d)\n",
  71                         ret);
  72
  73         return ret;
  74 }
  75
  76 static int da9063_wdt_stop(struct watchdog_device *wdd)
  77 {
  78         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  79         int ret;
  80
  81         ret = regmap_update_bits(wdt->da9063->regmap, DA9063_REG_CONTROL_D,
  82                                  DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
  83         if (ret)
  84                 dev_alert(wdt->da9063->dev, "Watchdog failed to stop (err = %d)\n",
  85                           ret);
  86
  87         return ret;
  88 }
  89
  90 static int da9063_wdt_ping(struct watchdog_device *wdd)
  91 {
  92         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
  93         int ret;
  94
  95         ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
  96                            DA9063_WATCHDOG);
  97         if (ret)
  98                 dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err = %d)\n",
  99                           ret);
 100
 101         return ret;
 102 }
 103
 104 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
 105                                   unsigned int timeout)
 106 {
 107         struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
 108         unsigned int selector;
 109         int ret;
 110
 111         selector = da9063_wdt_timeout_to_sel(timeout);
 112         ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
 113         if (ret)
 114                 dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
 115                         ret);
 116         else
 117                 wdd->timeout = wdt_timeout[selector];
 118
 119         return ret;
 120 }
 121
 122 static const struct watchdog_info da9063_watchdog_info = {
 123         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 124         .identity = "DA9063 Watchdog",
 125 };
 126
 127 static const struct watchdog_ops da9063_watchdog_ops = {
 128         .owner = THIS_MODULE,
 129         .start = da9063_wdt_start,
 130         .stop = da9063_wdt_stop,
 131         .ping = da9063_wdt_ping,
 132         .set_timeout = da9063_wdt_set_timeout,
 133 };
 134
 135 static int da9063_wdt_probe(struct platform_device *pdev)
 136 {
 137         int ret;
 138         struct da9063 *da9063;
 139         struct da9063_watchdog *wdt;
 140
 141         if (!pdev->dev.parent)
 142                 return -EINVAL;
 143
 144         da9063 = dev_get_drvdata(pdev->dev.parent);
 145         if (!da9063)
 146                 return -EINVAL;
 147
 148         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 149         if (!wdt)
 150                 return -ENOMEM;
 151
 152         wdt->da9063 = da9063;
 153
 154         wdt->wdtdev.info = &da9063_watchdog_info;
 155         wdt->wdtdev.ops = &da9063_watchdog_ops;
 156         wdt->wdtdev.min_timeout = DA9063_WDT_MIN_TIMEOUT;
 157         wdt->wdtdev.max_timeout = DA9063_WDT_MAX_TIMEOUT;
 158         wdt->wdtdev.timeout = DA9063_WDG_TIMEOUT;
 159
 160         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 161
 162         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 163         dev_set_drvdata(&pdev->dev, wdt);
 164
 165         ret = watchdog_register_device(&wdt->wdtdev);
 166
 167         return ret;
 168 }
 169
 170 static int da9063_wdt_remove(struct platform_device *pdev)
 171 {
 172         struct da9063_watchdog *wdt = dev_get_drvdata(&pdev->dev);
 173
 174         watchdog_unregister_device(&wdt->wdtdev);
 175
 176         return 0;
 177 }
 178
 179 static struct platform_driver da9063_wdt_driver = {
 180         .probe = da9063_wdt_probe,
 181         .remove = da9063_wdt_remove,
 182         .driver = {
 183                 .name = DA9063_DRVNAME_WATCHDOG,
 184         },
 185 };
 186 module_platform_driver(da9063_wdt_driver);
 187
 188 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
 189 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
 190 MODULE_LICENSE("GPL");
 191 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);