1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
4 *
5 * Author: Wolfram Sang <kernel@pengutronix.de>
6 *
7 * Copyright (C) 2011-12 Wolfram Sang, Pengutronix
8 */
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/watchdog.h>
12#include <linux/platform_device.h>
13#include <linux/stmp3xxx_rtc_wdt.h>
14#include <linux/notifier.h>
15#include <linux/reboot.h>
16
17#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
18#define STMP3XXX_DEFAULT_TIMEOUT 19
19#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
20
21static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
22module_param(heartbeat, uint, 0);
23MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
24 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
25 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
26
27static int wdt_start(struct watchdog_device *wdd)
28{
29 struct device *dev = watchdog_get_drvdata(wdd);
30 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
31
32 pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
33 return 0;
34}
35
36static int wdt_stop(struct watchdog_device *wdd)
37{
38 struct device *dev = watchdog_get_drvdata(wdd);
39 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
40
41 pdata->wdt_set_timeout(dev->parent, 0);
42 return 0;
43}
44
45static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
46{
47 wdd->timeout = new_timeout;
48 return wdt_start(wdd);
49}
50
51static const struct watchdog_info stmp3xxx_wdt_ident = {
52 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
53 .identity = "STMP3XXX RTC Watchdog",
54};
55
56static const struct watchdog_ops stmp3xxx_wdt_ops = {
57 .owner = THIS_MODULE,
58 .start = wdt_start,
59 .stop = wdt_stop,
60 .set_timeout = wdt_set_timeout,
61};
62
63static struct watchdog_device stmp3xxx_wdd = {
64 .info = &stmp3xxx_wdt_ident,
65 .ops = &stmp3xxx_wdt_ops,
66 .min_timeout = 1,
67 .max_timeout = STMP3XXX_MAX_TIMEOUT,
68 .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
69};
70
71static int wdt_notify_sys(struct notifier_block *nb, unsigned long code,
72 void *unused)
73{
74 switch (code) {
75 case SYS_DOWN: /* keep enabled, system might crash while going down */
76 break;
77 case SYS_HALT: /* allow the system to actually halt */
78 case SYS_POWER_OFF:
79 wdt_stop(wdd: &stmp3xxx_wdd);
80 break;
81 }
82
83 return NOTIFY_DONE;
84}
85
86static struct notifier_block wdt_notifier = {
87 .notifier_call = wdt_notify_sys,
88};
89
90static int stmp3xxx_wdt_probe(struct platform_device *pdev)
91{
92 struct device *dev = &pdev->dev;
93 int ret;
94
95 watchdog_set_drvdata(wdd: &stmp3xxx_wdd, data: dev);
96
97 stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
98 stmp3xxx_wdd.parent = dev;
99
100 ret = devm_watchdog_register_device(dev, &stmp3xxx_wdd);
101 if (ret < 0)
102 return ret;
103
104 if (register_reboot_notifier(&wdt_notifier))
105 dev_warn(dev, "cannot register reboot notifier\n");
106
107 dev_info(dev, "initialized watchdog with heartbeat %ds\n",
108 stmp3xxx_wdd.timeout);
109 return 0;
110}
111
112static void stmp3xxx_wdt_remove(struct platform_device *pdev)
113{
114 unregister_reboot_notifier(&wdt_notifier);
115}
116
117static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
118{
119 struct watchdog_device *wdd = &stmp3xxx_wdd;
120
121 if (watchdog_active(wdd))
122 return wdt_stop(wdd);
123
124 return 0;
125}
126
127static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
128{
129 struct watchdog_device *wdd = &stmp3xxx_wdd;
130
131 if (watchdog_active(wdd))
132 return wdt_start(wdd);
133
134 return 0;
135}
136
137static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
138 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
139
140static struct platform_driver stmp3xxx_wdt_driver = {
141 .driver = {
142 .name = "stmp3xxx_rtc_wdt",
143 .pm = &stmp3xxx_wdt_pm_ops,
144 },
145 .probe = stmp3xxx_wdt_probe,
146 .remove = stmp3xxx_wdt_remove,
147};
148module_platform_driver(stmp3xxx_wdt_driver);
149
150MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
151MODULE_LICENSE("GPL v2");
152MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
153

source code of linux/drivers/watchdog/stmp3xxx_rtc_wdt.c