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
19static bool nowayout = WATCHDOG_NOWAYOUT;
20module_param(nowayout, bool, 0);
21MODULE_PARM_DESC(nowayout,
22		 "Watchdog cannot be stopped once started (default="
23		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
24
25static DEFINE_MUTEX(wdt_mutex);
26
27static 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
36static 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
64static 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
84static 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
103static 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
119static const struct watchdog_info wm8350_wdt_info = {
120	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
121	.identity = "WM8350 Watchdog",
122};
123
124static 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
132static 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
140static 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
159static struct platform_driver wm8350_wdt_driver = {
160	.probe = wm8350_wdt_probe,
161	.driver = {
162		.name = "wm8350-wdt",
163	},
164};
165
166module_platform_driver(wm8350_wdt_driver);
167
168MODULE_AUTHOR("Mark Brown");
169MODULE_DESCRIPTION("WM8350 Watchdog");
170MODULE_LICENSE("GPL");
171MODULE_ALIAS("platform:wm8350-wdt");
172