tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
3 *
4 * Author: Wolfram Sang <w.sang@pengutronix.de>
5 *
6 * Copyright (C) 2011-12 Wolfram Sang, Pengutronix
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published by
10 * the Free Software Foundation.
11 */
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/watchdog.h>
16#include <linux/platform_device.h>
17#include <linux/stmp3xxx_rtc_wdt.h>
18
19#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
20#define STMP3XXX_DEFAULT_TIMEOUT 19
21#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
22
23static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
24module_param(heartbeat, uint, 0);
25MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
26 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
27 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
28
29static int wdt_start(struct watchdog_device *wdd)
30{
31 struct device *dev = watchdog_get_drvdata(wdd);
32 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
33
34 pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
35 return 0;
36}
37
38static int wdt_stop(struct watchdog_device *wdd)
39{
40 struct device *dev = watchdog_get_drvdata(wdd);
41 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
42
43 pdata->wdt_set_timeout(dev->parent, 0);
44 return 0;
45}
46
47static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
48{
49 wdd->timeout = new_timeout;
50 return wdt_start(wdd);
51}
52
53static const struct watchdog_info stmp3xxx_wdt_ident = {
54 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
55 .identity = "STMP3XXX RTC Watchdog",
56};
57
58static const struct watchdog_ops stmp3xxx_wdt_ops = {
59 .owner = THIS_MODULE,
60 .start = wdt_start,
61 .stop = wdt_stop,
62 .set_timeout = wdt_set_timeout,
63};
64
65static struct watchdog_device stmp3xxx_wdd = {
66 .info = &stmp3xxx_wdt_ident,
67 .ops = &stmp3xxx_wdt_ops,
68 .min_timeout = 1,
69 .max_timeout = STMP3XXX_MAX_TIMEOUT,
70 .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
71};
72
73static int stmp3xxx_wdt_probe(struct platform_device *pdev)
74{
75 int ret;
76
77 watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);
78
79 stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
80
81 ret = watchdog_register_device(&stmp3xxx_wdd);
82 if (ret < 0) {
83 dev_err(&pdev->dev, "cannot register watchdog device\n");
84 return ret;
85 }
86
87 dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
88 stmp3xxx_wdd.timeout);
89 return 0;
90}
91
92static int stmp3xxx_wdt_remove(struct platform_device *pdev)
93{
94 watchdog_unregister_device(&stmp3xxx_wdd);
95 return 0;
96}
97
98static struct platform_driver stmp3xxx_wdt_driver = {
99 .driver = {
100 .name = "stmp3xxx_rtc_wdt",
101 },
102 .probe = stmp3xxx_wdt_probe,
103 .remove = stmp3xxx_wdt_remove,
104};
105module_platform_driver(stmp3xxx_wdt_driver);
106
107MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
108MODULE_LICENSE("GPL v2");
109MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");