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[linux-3.10.git] / drivers / watchdog / retu_wdt.c
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/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
32 struct 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  */
43 static 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
50 static 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
56 static 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
63 static 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
72 static 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
81 static 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
88 static 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
97 static const struct watchdog_info retu_wdt_info = {
98         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
99         .identity = "Retu watchdog",
100 };
101
102 static 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
110 static 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
154 static 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
165 static struct platform_driver retu_wdt_driver = {
166         .probe          = retu_wdt_probe,
167         .remove         = retu_wdt_remove,
168         .driver         = {
169                 .name   = "retu-wdt",
170         },
171 };
172 module_platform_driver(retu_wdt_driver);
173
174 MODULE_ALIAS("platform:retu-wdt");
175 MODULE_DESCRIPTION("Retu watchdog");
176 MODULE_AUTHOR("Amit Kucheria");
177 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
178 MODULE_LICENSE("GPL");