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Linux/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");
181 

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