Root/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
22static bool nowayout = WATCHDOG_NOWAYOUT;
23module_param(nowayout, bool, 0);
24MODULE_PARM_DESC(nowayout,
25         "Watchdog cannot be stopped once started (default="
26         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
27
28static DEFINE_MUTEX(wdt_mutex);
29
30static 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
39static 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
67static 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
87static 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
106static 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
122static const struct watchdog_info wm8350_wdt_info = {
123    .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
124    .identity = "WM8350 Watchdog",
125};
126
127static 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
135static 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
143static int __devinit 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
161static int __devexit wm8350_wdt_remove(struct platform_device *pdev)
162{
163    watchdog_unregister_device(&wm8350_wdt);
164    return 0;
165}
166
167static struct platform_driver wm8350_wdt_driver = {
168    .probe = wm8350_wdt_probe,
169    .remove = __devexit_p(wm8350_wdt_remove),
170    .driver = {
171        .name = "wm8350-wdt",
172    },
173};
174
175module_platform_driver(wm8350_wdt_driver);
176
177MODULE_AUTHOR("Mark Brown");
178MODULE_DESCRIPTION("WM8350 Watchdog");
179MODULE_LICENSE("GPL");
180MODULE_ALIAS("platform:wm8350-wdt");
181

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