1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Watchdog driver for the wm8350
4 *
5 * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/platform_device.h>
15 #include <linux/watchdog.h>
16 #include <linux/uaccess.h>
17 #include <linux/mfd/wm8350/core.h>
18
19 static bool nowayout = WATCHDOG_NOWAYOUT;
20 module_param(nowayout, bool, 0);
21 MODULE_PARM_DESC(nowayout,
22 "Watchdog cannot be stopped once started (default="
23 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
24
25 static DEFINE_MUTEX(wdt_mutex);
26
27 static struct {
28 unsigned int time; /* Seconds */
29 u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */
30 } wm8350_wdt_cfgs[] = {
31 { 1, 0x02 },
32 { 2, 0x04 },
33 { 4, 0x05 },
34 };
35
wm8350_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)36 static int wm8350_wdt_set_timeout(struct watchdog_device *wdt_dev,
37 unsigned int timeout)
38 {
39 struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
40 int ret, i;
41 u16 reg;
42
43 for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
44 if (wm8350_wdt_cfgs[i].time == timeout)
45 break;
46 if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
47 return -EINVAL;
48
49 mutex_lock(&wdt_mutex);
50 wm8350_reg_unlock(wm8350);
51
52 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
53 reg &= ~WM8350_WDOG_TO_MASK;
54 reg |= wm8350_wdt_cfgs[i].val;
55 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
56
57 wm8350_reg_lock(wm8350);
58 mutex_unlock(&wdt_mutex);
59
60 wdt_dev->timeout = timeout;
61 return ret;
62 }
63
wm8350_wdt_start(struct watchdog_device * wdt_dev)64 static int wm8350_wdt_start(struct watchdog_device *wdt_dev)
65 {
66 struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
67 int ret;
68 u16 reg;
69
70 mutex_lock(&wdt_mutex);
71 wm8350_reg_unlock(wm8350);
72
73 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
74 reg &= ~WM8350_WDOG_MODE_MASK;
75 reg |= 0x20;
76 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
77
78 wm8350_reg_lock(wm8350);
79 mutex_unlock(&wdt_mutex);
80
81 return ret;
82 }
83
wm8350_wdt_stop(struct watchdog_device * wdt_dev)84 static int wm8350_wdt_stop(struct watchdog_device *wdt_dev)
85 {
86 struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
87 int ret;
88 u16 reg;
89
90 mutex_lock(&wdt_mutex);
91 wm8350_reg_unlock(wm8350);
92
93 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
94 reg &= ~WM8350_WDOG_MODE_MASK;
95 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
96
97 wm8350_reg_lock(wm8350);
98 mutex_unlock(&wdt_mutex);
99
100 return ret;
101 }
102
wm8350_wdt_ping(struct watchdog_device * wdt_dev)103 static int wm8350_wdt_ping(struct watchdog_device *wdt_dev)
104 {
105 struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
106 int ret;
107 u16 reg;
108
109 mutex_lock(&wdt_mutex);
110
111 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
112 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
113
114 mutex_unlock(&wdt_mutex);
115
116 return ret;
117 }
118
119 static const struct watchdog_info wm8350_wdt_info = {
120 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
121 .identity = "WM8350 Watchdog",
122 };
123
124 static const struct watchdog_ops wm8350_wdt_ops = {
125 .owner = THIS_MODULE,
126 .start = wm8350_wdt_start,
127 .stop = wm8350_wdt_stop,
128 .ping = wm8350_wdt_ping,
129 .set_timeout = wm8350_wdt_set_timeout,
130 };
131
132 static struct watchdog_device wm8350_wdt = {
133 .info = &wm8350_wdt_info,
134 .ops = &wm8350_wdt_ops,
135 .timeout = 4,
136 .min_timeout = 1,
137 .max_timeout = 4,
138 };
139
wm8350_wdt_probe(struct platform_device * pdev)140 static int wm8350_wdt_probe(struct platform_device *pdev)
141 {
142 struct wm8350 *wm8350 = platform_get_drvdata(pdev);
143
144 if (!wm8350) {
145 pr_err("No driver data supplied\n");
146 return -ENODEV;
147 }
148
149 watchdog_set_nowayout(&wm8350_wdt, nowayout);
150 watchdog_set_drvdata(&wm8350_wdt, wm8350);
151 wm8350_wdt.parent = &pdev->dev;
152
153 /* Default to 4s timeout */
154 wm8350_wdt_set_timeout(&wm8350_wdt, 4);
155
156 return devm_watchdog_register_device(&pdev->dev, &wm8350_wdt);
157 }
158
159 static struct platform_driver wm8350_wdt_driver = {
160 .probe = wm8350_wdt_probe,
161 .driver = {
162 .name = "wm8350-wdt",
163 },
164 };
165
166 module_platform_driver(wm8350_wdt_driver);
167
168 MODULE_AUTHOR("Mark Brown");
169 MODULE_DESCRIPTION("WM8350 Watchdog");
170 MODULE_LICENSE("GPL");
171 MODULE_ALIAS("platform:wm8350-wdt");
172