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 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 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 = 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