drm/radeon/rv740: fix backend setup
[linux-2.6.git] / drivers / watchdog / twl4030_wdt.c
1 /*
2  * Copyright (C) Nokia Corporation
3  *
4  * Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19  */
20
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/fs.h>
25 #include <linux/watchdog.h>
26 #include <linux/platform_device.h>
27 #include <linux/miscdevice.h>
28 #include <linux/uaccess.h>
29 #include <linux/i2c/twl4030.h>
30
31 #define TWL4030_WATCHDOG_CFG_REG_OFFS   0x3
32
33 #define TWL4030_WDT_STATE_OPEN          0x1
34 #define TWL4030_WDT_STATE_ACTIVE        0x8
35
36 static struct platform_device *twl4030_wdt_dev;
37
38 struct twl4030_wdt {
39         struct miscdevice       miscdev;
40         int                     timer_margin;
41         unsigned long           state;
42 };
43
44 static int nowayout = WATCHDOG_NOWAYOUT;
45 module_param(nowayout, int, 0);
46 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
47         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
48
49 static int twl4030_wdt_write(unsigned char val)
50 {
51         return twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
52                                         TWL4030_WATCHDOG_CFG_REG_OFFS);
53 }
54
55 static int twl4030_wdt_enable(struct twl4030_wdt *wdt)
56 {
57         return twl4030_wdt_write(wdt->timer_margin + 1);
58 }
59
60 static int twl4030_wdt_disable(struct twl4030_wdt *wdt)
61 {
62         return twl4030_wdt_write(0);
63 }
64
65 static int twl4030_wdt_set_timeout(struct twl4030_wdt *wdt, int timeout)
66 {
67         if (timeout < 0 || timeout > 30) {
68                 dev_warn(wdt->miscdev.parent,
69                         "Timeout can only be in the range [0-30] seconds");
70                 return -EINVAL;
71         }
72         wdt->timer_margin = timeout;
73         return twl4030_wdt_enable(wdt);
74 }
75
76 static ssize_t twl4030_wdt_write_fop(struct file *file,
77                 const char __user *data, size_t len, loff_t *ppos)
78 {
79         struct twl4030_wdt *wdt = file->private_data;
80
81         if (len)
82                 twl4030_wdt_enable(wdt);
83
84         return len;
85 }
86
87 static long twl4030_wdt_ioctl(struct file *file,
88                 unsigned int cmd, unsigned long arg)
89 {
90         void __user *argp = (void __user *)arg;
91         int __user *p = argp;
92         int new_margin;
93         struct twl4030_wdt *wdt = file->private_data;
94
95         static const struct watchdog_info twl4030_wd_ident = {
96                 .identity = "TWL4030 Watchdog",
97                 .options = WDIOF_SETTIMEOUT,
98                 .firmware_version = 0,
99         };
100
101         switch (cmd) {
102         case WDIOC_GETSUPPORT:
103                 return copy_to_user(argp, &twl4030_wd_ident,
104                                 sizeof(twl4030_wd_ident)) ? -EFAULT : 0;
105
106         case WDIOC_GETSTATUS:
107         case WDIOC_GETBOOTSTATUS:
108                 return put_user(0, p);
109
110         case WDIOC_KEEPALIVE:
111                 twl4030_wdt_enable(wdt);
112                 break;
113
114         case WDIOC_SETTIMEOUT:
115                 if (get_user(new_margin, p))
116                         return -EFAULT;
117                 if (twl4030_wdt_set_timeout(wdt, new_margin))
118                         return -EINVAL;
119                 return put_user(wdt->timer_margin, p);
120
121         case WDIOC_GETTIMEOUT:
122                 return put_user(wdt->timer_margin, p);
123
124         default:
125                 return -ENOTTY;
126         }
127
128         return 0;
129 }
130
131 static int twl4030_wdt_open(struct inode *inode, struct file *file)
132 {
133         struct twl4030_wdt *wdt = platform_get_drvdata(twl4030_wdt_dev);
134
135         /* /dev/watchdog can only be opened once */
136         if (test_and_set_bit(0, &wdt->state))
137                 return -EBUSY;
138
139         wdt->state |= TWL4030_WDT_STATE_ACTIVE;
140         file->private_data = (void *) wdt;
141
142         twl4030_wdt_enable(wdt);
143         return nonseekable_open(inode, file);
144 }
145
146 static int twl4030_wdt_release(struct inode *inode, struct file *file)
147 {
148         struct twl4030_wdt *wdt = file->private_data;
149         if (nowayout) {
150                 dev_alert(wdt->miscdev.parent,
151                        "Unexpected close, watchdog still running!\n");
152                 twl4030_wdt_enable(wdt);
153         } else {
154                 if (twl4030_wdt_disable(wdt))
155                         return -EFAULT;
156                 wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
157         }
158
159         clear_bit(0, &wdt->state);
160         return 0;
161 }
162
163 static const struct file_operations twl4030_wdt_fops = {
164         .owner          = THIS_MODULE,
165         .llseek         = no_llseek,
166         .open           = twl4030_wdt_open,
167         .release        = twl4030_wdt_release,
168         .unlocked_ioctl = twl4030_wdt_ioctl,
169         .write          = twl4030_wdt_write_fop,
170 };
171
172 static int __devinit twl4030_wdt_probe(struct platform_device *pdev)
173 {
174         int ret = 0;
175         struct twl4030_wdt *wdt;
176
177         wdt = kzalloc(sizeof(struct twl4030_wdt), GFP_KERNEL);
178         if (!wdt)
179                 return -ENOMEM;
180
181         wdt->state              = 0;
182         wdt->timer_margin       = 30;
183         wdt->miscdev.parent     = &pdev->dev;
184         wdt->miscdev.fops       = &twl4030_wdt_fops;
185         wdt->miscdev.minor      = WATCHDOG_MINOR;
186         wdt->miscdev.name       = "watchdog";
187
188         platform_set_drvdata(pdev, wdt);
189
190         twl4030_wdt_dev = pdev;
191
192         ret = misc_register(&wdt->miscdev);
193         if (ret) {
194                 dev_err(wdt->miscdev.parent,
195                         "Failed to register misc device\n");
196                 platform_set_drvdata(pdev, NULL);
197                 kfree(wdt);
198                 twl4030_wdt_dev = NULL;
199                 return ret;
200         }
201         return 0;
202 }
203
204 static int __devexit twl4030_wdt_remove(struct platform_device *pdev)
205 {
206         struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
207
208         if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
209                 if (twl4030_wdt_disable(wdt))
210                         return -EFAULT;
211
212         wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
213         misc_deregister(&wdt->miscdev);
214
215         platform_set_drvdata(pdev, NULL);
216         kfree(wdt);
217         twl4030_wdt_dev = NULL;
218
219         return 0;
220 }
221
222 #ifdef CONFIG_PM
223 static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
224 {
225         struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
226         if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
227                 return twl4030_wdt_disable(wdt);
228
229         return 0;
230 }
231
232 static int twl4030_wdt_resume(struct platform_device *pdev)
233 {
234         struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
235         if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
236                 return twl4030_wdt_enable(wdt);
237
238         return 0;
239 }
240 #else
241 #define twl4030_wdt_suspend        NULL
242 #define twl4030_wdt_resume         NULL
243 #endif
244
245 static struct platform_driver twl4030_wdt_driver = {
246         .probe          = twl4030_wdt_probe,
247         .remove         = __devexit_p(twl4030_wdt_remove),
248         .suspend        = twl4030_wdt_suspend,
249         .resume         = twl4030_wdt_resume,
250         .driver         = {
251                 .owner  = THIS_MODULE,
252                 .name   = "twl4030_wdt",
253         },
254 };
255
256 static int __devinit twl4030_wdt_init(void)
257 {
258         return platform_driver_register(&twl4030_wdt_driver);
259 }
260 module_init(twl4030_wdt_init);
261
262 static void __devexit twl4030_wdt_exit(void)
263 {
264         platform_driver_unregister(&twl4030_wdt_driver);
265 }
266 module_exit(twl4030_wdt_exit);
267
268 MODULE_AUTHOR("Nokia Corporation");
269 MODULE_LICENSE("GPL");
270 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
271 MODULE_ALIAS("platform:twl4030_wdt");
272