1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Retu watchdog driver
  4 *
  5 * Copyright (C) 2004, 2005 Nokia Corporation
  6 *
  7 * Based on code written by Amit Kucheria and Michael Buesch.
  8 * Rewritten by Aaro Koskinen.
  9 */
 10
 11#include <linux/devm-helpers.h>
 12#include <linux/slab.h>
 13#include <linux/errno.h>
 14#include <linux/device.h>
 15#include <linux/kernel.h>
 16#include <linux/module.h>
 17#include <linux/mfd/retu.h>
 18#include <linux/watchdog.h>
 19#include <linux/platform_device.h>
 20
 21/* Watchdog timer values in seconds */
 22#define RETU_WDT_MAX_TIMER	63
 23
 24struct retu_wdt_dev {
 25	struct retu_dev		*rdev;
 26	struct device		*dev;
 27	struct delayed_work	ping_work;
 28};
 29
 30/*
 31 * Since Retu watchdog cannot be disabled in hardware, we must kick it
 32 * with a timer until userspace watchdog software takes over. If
 33 * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
 34 */
 35static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
 36{
 37	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
 38	schedule_delayed_work(&wdev->ping_work,
 39			round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
 40}
 41
 42static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
 43{
 44	retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
 45	cancel_delayed_work_sync(&wdev->ping_work);
 46}
 47
 48static void retu_wdt_ping_work(struct work_struct *work)
 49{
 50	struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
 51						struct retu_wdt_dev, ping_work);
 52	retu_wdt_ping_enable(wdev);
 53}
 54
 55static int retu_wdt_start(struct watchdog_device *wdog)
 56{
 57	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 58
 59	retu_wdt_ping_disable(wdev);
 60
 61	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 62}
 63
 64static int retu_wdt_stop(struct watchdog_device *wdog)
 65{
 66	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 67
 68	retu_wdt_ping_enable(wdev);
 69
 70	return 0;
 71}
 72
 73static int retu_wdt_ping(struct watchdog_device *wdog)
 74{
 75	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 76
 77	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 78}
 79
 80static int retu_wdt_set_timeout(struct watchdog_device *wdog,
 81				unsigned int timeout)
 82{
 83	struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 84
 85	wdog->timeout = timeout;
 86	return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
 87}
 88
 89static const struct watchdog_info retu_wdt_info = {
 90	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 91	.identity = "Retu watchdog",
 92};
 93
 94static const struct watchdog_ops retu_wdt_ops = {
 95	.owner		= THIS_MODULE,
 96	.start		= retu_wdt_start,
 97	.stop		= retu_wdt_stop,
 98	.ping		= retu_wdt_ping,
 99	.set_timeout	= retu_wdt_set_timeout,
100};
101
102static int retu_wdt_probe(struct platform_device *pdev)
103{
104	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
105	bool nowayout = WATCHDOG_NOWAYOUT;
106	struct watchdog_device *retu_wdt;
107	struct retu_wdt_dev *wdev;
108	int ret;
109
110	retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
111	if (!retu_wdt)
112		return -ENOMEM;
113
114	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
115	if (!wdev)
116		return -ENOMEM;
117
118	retu_wdt->info		= &retu_wdt_info;
119	retu_wdt->ops		= &retu_wdt_ops;
120	retu_wdt->timeout	= RETU_WDT_MAX_TIMER;
121	retu_wdt->min_timeout	= 0;
122	retu_wdt->max_timeout	= RETU_WDT_MAX_TIMER;
123	retu_wdt->parent	= &pdev->dev;
124
125	watchdog_set_drvdata(retu_wdt, wdev);
126	watchdog_set_nowayout(retu_wdt, nowayout);
127
128	wdev->rdev		= rdev;
129	wdev->dev		= &pdev->dev;
130
131	ret = devm_delayed_work_autocancel(&pdev->dev, &wdev->ping_work,
132					   retu_wdt_ping_work);
133	if (ret)
134		return ret;
135
136	ret = devm_watchdog_register_device(&pdev->dev, retu_wdt);
137	if (ret < 0)
138		return ret;
139
140	if (nowayout)
141		retu_wdt_ping(retu_wdt);
142	else
143		retu_wdt_ping_enable(wdev);
144
145	return 0;
146}
147
148static struct platform_driver retu_wdt_driver = {
149	.probe		= retu_wdt_probe,
150	.driver		= {
151		.name	= "retu-wdt",
152	},
153};
154module_platform_driver(retu_wdt_driver);
155
156MODULE_ALIAS("platform:retu-wdt");
157MODULE_DESCRIPTION("Retu watchdog");
158MODULE_AUTHOR("Amit Kucheria");
159MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
160MODULE_LICENSE("GPL");