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/miscdevice.h>
16#include <linux/watchdog.h>
17#include <linux/platform_device.h>
18#include <linux/stmp3xxx_rtc_wdt.h>
19
20#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
21#define STMP3XXX_DEFAULT_TIMEOUT 19
22#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
23
24static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
25module_param(heartbeat, uint, 0);
26MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
27 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
28 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
29
30static int wdt_start(struct watchdog_device *wdd)
31{
32 struct device *dev = watchdog_get_drvdata(wdd);
33 struct stmp3xxx_wdt_pdata *pdata = dev->platform_data;
34
35 pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
36 return 0;
37}
38
39static int wdt_stop(struct watchdog_device *wdd)
40{
41 struct device *dev = watchdog_get_drvdata(wdd);
42 struct stmp3xxx_wdt_pdata *pdata = dev->platform_data;
43
44 pdata->wdt_set_timeout(dev->parent, 0);
45 return 0;
46}
47
48static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
49{
50 wdd->timeout = new_timeout;
51 return wdt_start(wdd);
52}
53
54static const struct watchdog_info stmp3xxx_wdt_ident = {
55 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
56 .identity = "STMP3XXX RTC Watchdog",
57};
58
59static const struct watchdog_ops stmp3xxx_wdt_ops = {
60 .owner = THIS_MODULE,
61 .start = wdt_start,
62 .stop = wdt_stop,
63 .set_timeout = wdt_set_timeout,
64};
65
66static struct watchdog_device stmp3xxx_wdd = {
67 .info = &stmp3xxx_wdt_ident,
68 .ops = &stmp3xxx_wdt_ops,
69 .min_timeout = 1,
70 .max_timeout = STMP3XXX_MAX_TIMEOUT,
71 .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
72};
73
74static int stmp3xxx_wdt_probe(struct platform_device *pdev)
75{
76 int ret;
77
78 watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);
79
80 stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
81
82 ret = watchdog_register_device(&stmp3xxx_wdd);
83 if (ret < 0) {
84 dev_err(&pdev->dev, "cannot register watchdog device\n");
85 return ret;
86 }
87
88 dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
89 stmp3xxx_wdd.timeout);
90 return 0;
91}
92
93static int stmp3xxx_wdt_remove(struct platform_device *pdev)
94{
95 watchdog_unregister_device(&stmp3xxx_wdd);
96 return 0;
97}
98
99static struct platform_driver stmp3xxx_wdt_driver = {
100 .driver = {
101 .name = "stmp3xxx_rtc_wdt",
102 },
103 .probe = stmp3xxx_wdt_probe,
104 .remove = stmp3xxx_wdt_remove,
105};
106module_platform_driver(stmp3xxx_wdt_driver);
107
108MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
109MODULE_LICENSE("GPL v2");
110MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
111MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);