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Wolfram Sangde6303a2011-09-27 22:35:40 +02001/*
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 */
Wolfram Sangde6303a2011-09-27 22:35:40 +020012#include <linux/kernel.h>
13#include <linux/module.h>
Wolfram Sangde6303a2011-09-27 22:35:40 +020014#include <linux/watchdog.h>
15#include <linux/platform_device.h>
16#include <linux/stmp3xxx_rtc_wdt.h>
17
18#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
19#define STMP3XXX_DEFAULT_TIMEOUT 19
20#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
21
22static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
23module_param(heartbeat, uint, 0);
24MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
25 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
26 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
27
28static int wdt_start(struct watchdog_device *wdd)
29{
30 struct device *dev = watchdog_get_drvdata(wdd);
Jingoo Hanbc8fdfb2013-07-30 19:58:51 +090031 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
Wolfram Sangde6303a2011-09-27 22:35:40 +020032
33 pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
34 return 0;
35}
36
37static int wdt_stop(struct watchdog_device *wdd)
38{
39 struct device *dev = watchdog_get_drvdata(wdd);
Jingoo Hanbc8fdfb2013-07-30 19:58:51 +090040 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
Wolfram Sangde6303a2011-09-27 22:35:40 +020041
42 pdata->wdt_set_timeout(dev->parent, 0);
43 return 0;
44}
45
46static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
47{
48 wdd->timeout = new_timeout;
49 return wdt_start(wdd);
50}
51
52static const struct watchdog_info stmp3xxx_wdt_ident = {
53 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
54 .identity = "STMP3XXX RTC Watchdog",
55};
56
57static const struct watchdog_ops stmp3xxx_wdt_ops = {
58 .owner = THIS_MODULE,
59 .start = wdt_start,
60 .stop = wdt_stop,
61 .set_timeout = wdt_set_timeout,
62};
63
64static struct watchdog_device stmp3xxx_wdd = {
65 .info = &stmp3xxx_wdt_ident,
66 .ops = &stmp3xxx_wdt_ops,
67 .min_timeout = 1,
68 .max_timeout = STMP3XXX_MAX_TIMEOUT,
69 .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
70};
71
72static int stmp3xxx_wdt_probe(struct platform_device *pdev)
73{
74 int ret;
75
76 watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);
77
78 stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
79
80 ret = watchdog_register_device(&stmp3xxx_wdd);
81 if (ret < 0) {
82 dev_err(&pdev->dev, "cannot register watchdog device\n");
83 return ret;
84 }
85
86 dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
87 stmp3xxx_wdd.timeout);
88 return 0;
89}
90
91static int stmp3xxx_wdt_remove(struct platform_device *pdev)
92{
93 watchdog_unregister_device(&stmp3xxx_wdd);
94 return 0;
95}
96
97static struct platform_driver stmp3xxx_wdt_driver = {
98 .driver = {
99 .name = "stmp3xxx_rtc_wdt",
100 },
101 .probe = stmp3xxx_wdt_probe,
102 .remove = stmp3xxx_wdt_remove,
103};
104module_platform_driver(stmp3xxx_wdt_driver);
105
106MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
107MODULE_LICENSE("GPL v2");
108MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");