1/*
2 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
3 *
4 * Author: Wolfram Sang <kernel@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/kernel.h>
13#include <linux/module.h>
14#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);
31	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
32
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);
40	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
41
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	stmp3xxx_wdd.parent = &pdev->dev;
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 int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
99{
100	struct watchdog_device *wdd = &stmp3xxx_wdd;
101
102	if (watchdog_active(wdd))
103		return wdt_stop(wdd);
104
105	return 0;
106}
107
108static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
109{
110	struct watchdog_device *wdd = &stmp3xxx_wdd;
111
112	if (watchdog_active(wdd))
113		return wdt_start(wdd);
114
115	return 0;
116}
117
118static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
119			 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
120
121static struct platform_driver stmp3xxx_wdt_driver = {
122	.driver = {
123		.name = "stmp3xxx_rtc_wdt",
124		.pm = &stmp3xxx_wdt_pm_ops,
125	},
126	.probe = stmp3xxx_wdt_probe,
127	.remove = stmp3xxx_wdt_remove,
128};
129module_platform_driver(stmp3xxx_wdt_driver);
130
131MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
132MODULE_LICENSE("GPL v2");
133MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
134