drivers/watchdog/wm8350_wdt.c

   1 /*
   2  * Watchdog driver for the wm8350
   3  *
   4  * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/watchdog.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/mfd/wm8350/core.h>
  21
  22 static bool nowayout = WATCHDOG_NOWAYOUT;
  23 module_param(nowayout, bool, 0);
  24 MODULE_PARM_DESC(nowayout,
  25                  "Watchdog cannot be stopped once started (default="
  26                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  27
  28 static DEFINE_MUTEX(wdt_mutex);
  29
  30 static struct {
  31         unsigned int time;  /* Seconds */
  32         u16 val;            /* To be set in WM8350_SYSTEM_CONTROL_2 */
  33 } wm8350_wdt_cfgs[] = {
  34         { 1, 0x02 },
  35         { 2, 0x04 },
  36         { 4, 0x05 },
  37 };
  38
  39 static int wm8350_wdt_set_timeout(struct watchdog_device *wdt_dev,
  40                                   unsigned int timeout)
  41 {
  42         struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
  43         int ret, i;
  44         u16 reg;
  45
  46         for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
  47                 if (wm8350_wdt_cfgs[i].time == timeout)
  48                         break;
  49         if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
  50                 return -EINVAL;
  51
  52         mutex_lock(&wdt_mutex);
  53         wm8350_reg_unlock(wm8350);
  54
  55         reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
  56         reg &= ~WM8350_WDOG_TO_MASK;
  57         reg |= wm8350_wdt_cfgs[i].val;
  58         ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
  59
  60         wm8350_reg_lock(wm8350);
  61         mutex_unlock(&wdt_mutex);
  62
  63         wdt_dev->timeout = timeout;
  64         return ret;
  65 }
  66
  67 static int wm8350_wdt_start(struct watchdog_device *wdt_dev)
  68 {
  69         struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
  70         int ret;
  71         u16 reg;
  72
  73         mutex_lock(&wdt_mutex);
  74         wm8350_reg_unlock(wm8350);
  75
  76         reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
  77         reg &= ~WM8350_WDOG_MODE_MASK;
  78         reg |= 0x20;
  79         ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
  80
  81         wm8350_reg_lock(wm8350);
  82         mutex_unlock(&wdt_mutex);
  83
  84         return ret;
  85 }
  86
  87 static int wm8350_wdt_stop(struct watchdog_device *wdt_dev)
  88 {
  89         struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
  90         int ret;
  91         u16 reg;
  92
  93         mutex_lock(&wdt_mutex);
  94         wm8350_reg_unlock(wm8350);
  95
  96         reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
  97         reg &= ~WM8350_WDOG_MODE_MASK;
  98         ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
  99
 100         wm8350_reg_lock(wm8350);
 101         mutex_unlock(&wdt_mutex);
 102
 103         return ret;
 104 }
 105
 106 static int wm8350_wdt_ping(struct watchdog_device *wdt_dev)
 107 {
 108         struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
 109         int ret;
 110         u16 reg;
 111
 112         mutex_lock(&wdt_mutex);
 113
 114         reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
 115         ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
 116
 117         mutex_unlock(&wdt_mutex);
 118
 119         return ret;
 120 }
 121
 122 static const struct watchdog_info wm8350_wdt_info = {
 123         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 124         .identity = "WM8350 Watchdog",
 125 };
 126
 127 static const struct watchdog_ops wm8350_wdt_ops = {
 128         .owner = THIS_MODULE,
 129         .start = wm8350_wdt_start,
 130         .stop = wm8350_wdt_stop,
 131         .ping = wm8350_wdt_ping,
 132         .set_timeout = wm8350_wdt_set_timeout,
 133 };
 134
 135 static struct watchdog_device wm8350_wdt = {
 136         .info = &wm8350_wdt_info,
 137         .ops = &wm8350_wdt_ops,
 138         .timeout = 4,
 139         .min_timeout = 1,
 140         .max_timeout = 4,
 141 };
 142
 143 static int wm8350_wdt_probe(struct platform_device *pdev)
 144 {
 145         struct wm8350 *wm8350 = platform_get_drvdata(pdev);
 146
 147         if (!wm8350) {
 148                 pr_err("No driver data supplied\n");
 149                 return -ENODEV;
 150         }
 151
 152         watchdog_set_nowayout(&wm8350_wdt, nowayout);
 153         watchdog_set_drvdata(&wm8350_wdt, wm8350);
 154
 155         /* Default to 4s timeout */
 156         wm8350_wdt_set_timeout(&wm8350_wdt, 4);
 157
 158         return watchdog_register_device(&wm8350_wdt);
 159 }
 160
 161 static int wm8350_wdt_remove(struct platform_device *pdev)
 162 {
 163         watchdog_unregister_device(&wm8350_wdt);
 164         return 0;
 165 }
 166
 167 static struct platform_driver wm8350_wdt_driver = {
 168         .probe = wm8350_wdt_probe,
 169         .remove = wm8350_wdt_remove,
 170         .driver = {
 171                 .name = "wm8350-wdt",
 172         },
 173 };
 174
 175 module_platform_driver(wm8350_wdt_driver);
 176
 177 MODULE_AUTHOR("Mark Brown");
 178 MODULE_DESCRIPTION("WM8350 Watchdog");
 179 MODULE_LICENSE("GPL");
 180 MODULE_ALIAS("platform:wm8350-wdt");