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Aaro Koskinen3d3a6d182012-12-27 22:58:29 +02001/*
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/init.h>
20#include <linux/slab.h>
21#include <linux/errno.h>
22#include <linux/device.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/mfd/retu.h>
26#include <linux/watchdog.h>
27#include <linux/platform_device.h>
28
29/* Watchdog timer values in seconds */
30#define RETU_WDT_MAX_TIMER 63
31
32struct retu_wdt_dev {
33 struct retu_dev *rdev;
34 struct device *dev;
35 struct delayed_work ping_work;
36};
37
38/*
39 * Since Retu watchdog cannot be disabled in hardware, we must kick it
40 * with a timer until userspace watchdog software takes over. If
41 * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
42 */
43static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
44{
45 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
46 schedule_delayed_work(&wdev->ping_work,
47 round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
48}
49
50static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
51{
52 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
53 cancel_delayed_work_sync(&wdev->ping_work);
54}
55
56static void retu_wdt_ping_work(struct work_struct *work)
57{
58 struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
59 struct retu_wdt_dev, ping_work);
60 retu_wdt_ping_enable(wdev);
61}
62
63static int retu_wdt_start(struct watchdog_device *wdog)
64{
65 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
66
67 retu_wdt_ping_disable(wdev);
68
69 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
70}
71
72static int retu_wdt_stop(struct watchdog_device *wdog)
73{
74 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
75
76 retu_wdt_ping_enable(wdev);
77
78 return 0;
79}
80
81static int retu_wdt_ping(struct watchdog_device *wdog)
82{
83 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
84
85 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
86}
87
88static int retu_wdt_set_timeout(struct watchdog_device *wdog,
89 unsigned int timeout)
90{
91 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
92
93 wdog->timeout = timeout;
94 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
95}
96
97static const struct watchdog_info retu_wdt_info = {
98 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
99 .identity = "Retu watchdog",
100};
101
102static const struct watchdog_ops retu_wdt_ops = {
103 .owner = THIS_MODULE,
104 .start = retu_wdt_start,
105 .stop = retu_wdt_stop,
106 .ping = retu_wdt_ping,
107 .set_timeout = retu_wdt_set_timeout,
108};
109
110static int retu_wdt_probe(struct platform_device *pdev)
111{
112 struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
113 bool nowayout = WATCHDOG_NOWAYOUT;
114 struct watchdog_device *retu_wdt;
115 struct retu_wdt_dev *wdev;
116 int ret;
117
118 retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
119 if (!retu_wdt)
120 return -ENOMEM;
121
122 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
123 if (!wdev)
124 return -ENOMEM;
125
126 retu_wdt->info = &retu_wdt_info;
127 retu_wdt->ops = &retu_wdt_ops;
128 retu_wdt->timeout = RETU_WDT_MAX_TIMER;
129 retu_wdt->min_timeout = 0;
130 retu_wdt->max_timeout = RETU_WDT_MAX_TIMER;
131
132 watchdog_set_drvdata(retu_wdt, wdev);
133 watchdog_set_nowayout(retu_wdt, nowayout);
134
135 wdev->rdev = rdev;
136 wdev->dev = &pdev->dev;
137
138 INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
139
140 ret = watchdog_register_device(retu_wdt);
141 if (ret < 0)
142 return ret;
143
144 if (nowayout)
145 retu_wdt_ping(retu_wdt);
146 else
147 retu_wdt_ping_enable(wdev);
148
149 platform_set_drvdata(pdev, retu_wdt);
150
151 return 0;
152}
153
154static int retu_wdt_remove(struct platform_device *pdev)
155{
156 struct watchdog_device *wdog = platform_get_drvdata(pdev);
157 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
158
159 watchdog_unregister_device(wdog);
160 cancel_delayed_work_sync(&wdev->ping_work);
161
162 return 0;
163}
164
165static struct platform_driver retu_wdt_driver = {
166 .probe = retu_wdt_probe,
167 .remove = retu_wdt_remove,
168 .driver = {
169 .name = "retu-wdt",
170 },
171};
172module_platform_driver(retu_wdt_driver);
173
174MODULE_ALIAS("platform:retu-wdt");
175MODULE_DESCRIPTION("Retu watchdog");
176MODULE_AUTHOR("Amit Kucheria");
177MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
178MODULE_LICENSE("GPL");