summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/watchdog/wm8350_wdt.c
blob: 4ab4b8347d459b5745da86252c4e27bdd1cb4e8e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
/*
 * Watchdog driver for the wm8350
 *
 * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/mfd/wm8350/core.h>

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
		 "Watchdog cannot be stopped once started (default="
		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static DEFINE_MUTEX(wdt_mutex);

static struct {
	unsigned int time;  /* Seconds */
	u16 val;	    /* To be set in WM8350_SYSTEM_CONTROL_2 */
} wm8350_wdt_cfgs[] = {
	{ 1, 0x02 },
	{ 2, 0x04 },
	{ 4, 0x05 },
};

static int wm8350_wdt_set_timeout(struct watchdog_device *wdt_dev,
				  unsigned int timeout)
{
	struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
	int ret, i;
	u16 reg;

	for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
		if (wm8350_wdt_cfgs[i].time == timeout)
			break;
	if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
		return -EINVAL;

	mutex_lock(&wdt_mutex);
	wm8350_reg_unlock(wm8350);

	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
	reg &= ~WM8350_WDOG_TO_MASK;
	reg |= wm8350_wdt_cfgs[i].val;
	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

	wm8350_reg_lock(wm8350);
	mutex_unlock(&wdt_mutex);

	wdt_dev->timeout = timeout;
	return ret;
}

static int wm8350_wdt_start(struct watchdog_device *wdt_dev)
{
	struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
	int ret;
	u16 reg;

	mutex_lock(&wdt_mutex);
	wm8350_reg_unlock(wm8350);

	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
	reg &= ~WM8350_WDOG_MODE_MASK;
	reg |= 0x20;
	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

	wm8350_reg_lock(wm8350);
	mutex_unlock(&wdt_mutex);

	return ret;
}

static int wm8350_wdt_stop(struct watchdog_device *wdt_dev)
{
	struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
	int ret;
	u16 reg;

	mutex_lock(&wdt_mutex);
	wm8350_reg_unlock(wm8350);

	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
	reg &= ~WM8350_WDOG_MODE_MASK;
	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

	wm8350_reg_lock(wm8350);
	mutex_unlock(&wdt_mutex);

	return ret;
}

static int wm8350_wdt_ping(struct watchdog_device *wdt_dev)
{
	struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
	int ret;
	u16 reg;

	mutex_lock(&wdt_mutex);

	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

	mutex_unlock(&wdt_mutex);

	return ret;
}

static const struct watchdog_info wm8350_wdt_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "WM8350 Watchdog",
};

static const struct watchdog_ops wm8350_wdt_ops = {
	.owner = THIS_MODULE,
	.start = wm8350_wdt_start,
	.stop = wm8350_wdt_stop,
	.ping = wm8350_wdt_ping,
	.set_timeout = wm8350_wdt_set_timeout,
};

static struct watchdog_device wm8350_wdt = {
	.info = &wm8350_wdt_info,
	.ops = &wm8350_wdt_ops,
	.timeout = 4,
	.min_timeout = 1,
	.max_timeout = 4,
};

static int wm8350_wdt_probe(struct platform_device *pdev)
{
	struct wm8350 *wm8350 = platform_get_drvdata(pdev);

	if (!wm8350) {
		pr_err("No driver data supplied\n");
		return -ENODEV;
	}

	watchdog_set_nowayout(&wm8350_wdt, nowayout);
	watchdog_set_drvdata(&wm8350_wdt, wm8350);
	wm8350_wdt.parent = &pdev->dev;

	/* Default to 4s timeout */
	wm8350_wdt_set_timeout(&wm8350_wdt, 4);

	return watchdog_register_device(&wm8350_wdt);
}

static int wm8350_wdt_remove(struct platform_device *pdev)
{
	watchdog_unregister_device(&wm8350_wdt);
	return 0;
}

static struct platform_driver wm8350_wdt_driver = {
	.probe = wm8350_wdt_probe,
	.remove = wm8350_wdt_remove,
	.driver = {
		.name = "wm8350-wdt",
	},
};

module_platform_driver(wm8350_wdt_driver);

MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM8350 Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm8350-wdt");