1/*
  2 * Retu watchdog driver
  3 *
  4 * Copyright (C) 2004, 2005 Nokia Corporation
  5 *
  6 * Based on code written by Amit Kucheria and Michael Buesch.
  7 * Rewritten by Aaro Koskinen.
  8 *
  9 * This file is subject to the terms and conditions of the GNU General
 10 * Public License. See the file "COPYING" in the main directory of this
 11 * archive for more details.
 12 *
 13 * This program is distributed in the hope that it will be useful,
 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 16 * GNU General Public License for more details.
 17 */
 18
 19#include <linux/slab.h>
 20#include <linux/errno.h>
 21#include <linux/device.h>
 22#include <linux/kernel.h>
 23#include <linux/module.h>
 24#include <linux/mfd/retu.h>
 25#include <linux/watchdog.h>
 26#include <linux/platform_device.h>
 27
 28/* Watchdog timer values in seconds */
 29#define RETU_WDT_MAX_TIMER	63
 30
 31struct retu_wdt_dev {
 32	struct retu_dev		*rdev;
 33	struct device		*dev;
 34	struct delayed_work	ping_work;
 35};
 36
 37/*
 38 * Since Retu watchdog cannot be disabled in hardware, we must kick it
 39 * with a timer until userspace watchdog software takes over. If
 40 * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
 41 */
 42static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
 43{
 44	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
 45	schedule_delayed_work(&wdev->ping_work,
 46			round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
 47}
 48
 49static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
 50{
 51	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
 52	cancel_delayed_work_sync(&wdev->ping_work);
 53}
 54
 55static void retu_wdt_ping_work(struct work_struct *work)
 56{
 57	struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
 58						struct retu_wdt_dev, ping_work);
 59	retu_wdt_ping_enable(wdev);
 60}
 61
 62static int retu_wdt_start(struct watchdog_device *wdog)
 63{
 64	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 65
 66	retu_wdt_ping_disable(wdev);
 67
 68	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 69}
 70
 71static int retu_wdt_stop(struct watchdog_device *wdog)
 72{
 73	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 74
 75	retu_wdt_ping_enable(wdev);
 76
 77	return 0;
 78}
 79
 80static int retu_wdt_ping(struct watchdog_device *wdog)
 81{
 82	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 83
 84	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 85}
 86
 87static int retu_wdt_set_timeout(struct watchdog_device *wdog,
 88				unsigned int timeout)
 89{
 90	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 91
 92	wdog->timeout = timeout;
 93	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 94}
 95
 96static const struct watchdog_info retu_wdt_info = {
 97	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 98	.identity = "Retu watchdog",
 99};
100
101static const struct watchdog_ops retu_wdt_ops = {
102	.owner		= THIS_MODULE,
103	.start		= retu_wdt_start,
104	.stop		= retu_wdt_stop,
105	.ping		= retu_wdt_ping,
106	.set_timeout	= retu_wdt_set_timeout,
107};
108
109static int retu_wdt_probe(struct platform_device *pdev)
110{
111	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
112	bool nowayout = WATCHDOG_NOWAYOUT;
113	struct watchdog_device *retu_wdt;
114	struct retu_wdt_dev *wdev;
115	int ret;
116
117	retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
118	if (!retu_wdt)
119		return -ENOMEM;
120
121	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
122	if (!wdev)
123		return -ENOMEM;
124
125	retu_wdt->info		= &retu_wdt_info;
126	retu_wdt->ops		= &retu_wdt_ops;
127	retu_wdt->timeout	= RETU_WDT_MAX_TIMER;
128	retu_wdt->min_timeout	= 0;
129	retu_wdt->max_timeout	= RETU_WDT_MAX_TIMER;
130
131	watchdog_set_drvdata(retu_wdt, wdev);
132	watchdog_set_nowayout(retu_wdt, nowayout);
133
134	wdev->rdev		= rdev;
135	wdev->dev		= &pdev->dev;
136
137	INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
138
139	ret = watchdog_register_device(retu_wdt);
140	if (ret < 0)
141		return ret;
142
143	if (nowayout)
144		retu_wdt_ping(retu_wdt);
145	else
146		retu_wdt_ping_enable(wdev);
147
148	platform_set_drvdata(pdev, retu_wdt);
149
150	return 0;
151}
152
153static int retu_wdt_remove(struct platform_device *pdev)
154{
155	struct watchdog_device *wdog = platform_get_drvdata(pdev);
156	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
157
158	watchdog_unregister_device(wdog);
159	cancel_delayed_work_sync(&wdev->ping_work);
160
161	return 0;
162}
163
164static struct platform_driver retu_wdt_driver = {
165	.probe		= retu_wdt_probe,
166	.remove		= retu_wdt_remove,
167	.driver		= {
168		.name	= "retu-wdt",
169	},
170};
171module_platform_driver(retu_wdt_driver);
172
173MODULE_ALIAS("platform:retu-wdt");
174MODULE_DESCRIPTION("Retu watchdog");
175MODULE_AUTHOR("Amit Kucheria");
176MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
177MODULE_LICENSE("GPL");