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/slab.h>
24 #include <linux/kernel.h>
25 #include <linux/fs.h>
26 #include <linux/watchdog.h>
27 #include <linux/platform_device.h>
28 #include <linux/miscdevice.h>
29 #include <linux/uaccess.h>
30 #include <linux/i2c/twl.h>
31
32 #define TWL4030_WATCHDOG_CFG_REG_OFFS 0x3
33
34 #define TWL4030_WDT_STATE_OPEN 0x1
35 #define TWL4030_WDT_STATE_ACTIVE 0x8
36
37 static struct platform_device *twl4030_wdt_dev;
38
39 struct twl4030_wdt {
40 struct miscdevice miscdev;
41 int timer_margin;
42 unsigned long state;
43 };
44
45 static bool nowayout = WATCHDOG_NOWAYOUT;
46 module_param(nowayout, bool, 0);
47 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
48 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
49
twl4030_wdt_write(unsigned char val)50 static int twl4030_wdt_write(unsigned char val)
51 {
52 return twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
53 TWL4030_WATCHDOG_CFG_REG_OFFS);
54 }
55
twl4030_wdt_enable(struct twl4030_wdt * wdt)56 static int twl4030_wdt_enable(struct twl4030_wdt *wdt)
57 {
58 return twl4030_wdt_write(wdt->timer_margin + 1);
59 }
60
twl4030_wdt_disable(struct twl4030_wdt * wdt)61 static int twl4030_wdt_disable(struct twl4030_wdt *wdt)
62 {
63 return twl4030_wdt_write(0);
64 }
65
twl4030_wdt_set_timeout(struct twl4030_wdt * wdt,int timeout)66 static int twl4030_wdt_set_timeout(struct twl4030_wdt *wdt, int timeout)
67 {
68 if (timeout < 0 || timeout > 30) {
69 dev_warn(wdt->miscdev.parent,
70 "Timeout can only be in the range [0-30] seconds");
71 return -EINVAL;
72 }
73 wdt->timer_margin = timeout;
74 return twl4030_wdt_enable(wdt);
75 }
76
twl4030_wdt_write_fop(struct file * file,const char __user * data,size_t len,loff_t * ppos)77 static ssize_t twl4030_wdt_write_fop(struct file *file,
78 const char __user *data, size_t len, loff_t *ppos)
79 {
80 struct twl4030_wdt *wdt = file->private_data;
81
82 if (len)
83 twl4030_wdt_enable(wdt);
84
85 return len;
86 }
87
twl4030_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)88 static long twl4030_wdt_ioctl(struct file *file,
89 unsigned int cmd, unsigned long arg)
90 {
91 void __user *argp = (void __user *)arg;
92 int __user *p = argp;
93 int new_margin;
94 struct twl4030_wdt *wdt = file->private_data;
95
96 static const struct watchdog_info twl4030_wd_ident = {
97 .identity = "TWL4030 Watchdog",
98 .options = WDIOF_SETTIMEOUT,
99 .firmware_version = 0,
100 };
101
102 switch (cmd) {
103 case WDIOC_GETSUPPORT:
104 return copy_to_user(argp, &twl4030_wd_ident,
105 sizeof(twl4030_wd_ident)) ? -EFAULT : 0;
106
107 case WDIOC_GETSTATUS:
108 case WDIOC_GETBOOTSTATUS:
109 return put_user(0, p);
110
111 case WDIOC_KEEPALIVE:
112 twl4030_wdt_enable(wdt);
113 break;
114
115 case WDIOC_SETTIMEOUT:
116 if (get_user(new_margin, p))
117 return -EFAULT;
118 if (twl4030_wdt_set_timeout(wdt, new_margin))
119 return -EINVAL;
120 return put_user(wdt->timer_margin, p);
121
122 case WDIOC_GETTIMEOUT:
123 return put_user(wdt->timer_margin, p);
124
125 default:
126 return -ENOTTY;
127 }
128
129 return 0;
130 }
131
twl4030_wdt_open(struct inode * inode,struct file * file)132 static int twl4030_wdt_open(struct inode *inode, struct file *file)
133 {
134 struct twl4030_wdt *wdt = platform_get_drvdata(twl4030_wdt_dev);
135
136 /* /dev/watchdog can only be opened once */
137 if (test_and_set_bit(0, &wdt->state))
138 return -EBUSY;
139
140 wdt->state |= TWL4030_WDT_STATE_ACTIVE;
141 file->private_data = (void *) wdt;
142
143 twl4030_wdt_enable(wdt);
144 return nonseekable_open(inode, file);
145 }
146
twl4030_wdt_release(struct inode * inode,struct file * file)147 static int twl4030_wdt_release(struct inode *inode, struct file *file)
148 {
149 struct twl4030_wdt *wdt = file->private_data;
150 if (nowayout) {
151 dev_alert(wdt->miscdev.parent,
152 "Unexpected close, watchdog still running!\n");
153 twl4030_wdt_enable(wdt);
154 } else {
155 if (twl4030_wdt_disable(wdt))
156 return -EFAULT;
157 wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
158 }
159
160 clear_bit(0, &wdt->state);
161 return 0;
162 }
163
164 static const struct file_operations twl4030_wdt_fops = {
165 .owner = THIS_MODULE,
166 .llseek = no_llseek,
167 .open = twl4030_wdt_open,
168 .release = twl4030_wdt_release,
169 .unlocked_ioctl = twl4030_wdt_ioctl,
170 .write = twl4030_wdt_write_fop,
171 };
172
twl4030_wdt_probe(struct platform_device * pdev)173 static int __devinit twl4030_wdt_probe(struct platform_device *pdev)
174 {
175 int ret = 0;
176 struct twl4030_wdt *wdt;
177
178 wdt = kzalloc(sizeof(struct twl4030_wdt), GFP_KERNEL);
179 if (!wdt)
180 return -ENOMEM;
181
182 wdt->state = 0;
183 wdt->timer_margin = 30;
184 wdt->miscdev.parent = &pdev->dev;
185 wdt->miscdev.fops = &twl4030_wdt_fops;
186 wdt->miscdev.minor = WATCHDOG_MINOR;
187 wdt->miscdev.name = "watchdog";
188
189 platform_set_drvdata(pdev, wdt);
190
191 twl4030_wdt_dev = pdev;
192
193 twl4030_wdt_disable(wdt);
194
195 ret = misc_register(&wdt->miscdev);
196 if (ret) {
197 dev_err(wdt->miscdev.parent,
198 "Failed to register misc device\n");
199 platform_set_drvdata(pdev, NULL);
200 kfree(wdt);
201 twl4030_wdt_dev = NULL;
202 return ret;
203 }
204 return 0;
205 }
206
twl4030_wdt_remove(struct platform_device * pdev)207 static int __devexit twl4030_wdt_remove(struct platform_device *pdev)
208 {
209 struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
210
211 if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
212 if (twl4030_wdt_disable(wdt))
213 return -EFAULT;
214
215 wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
216 misc_deregister(&wdt->miscdev);
217
218 platform_set_drvdata(pdev, NULL);
219 kfree(wdt);
220 twl4030_wdt_dev = NULL;
221
222 return 0;
223 }
224
225 #ifdef CONFIG_PM
twl4030_wdt_suspend(struct platform_device * pdev,pm_message_t state)226 static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
227 {
228 struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
229 if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
230 return twl4030_wdt_disable(wdt);
231
232 return 0;
233 }
234
twl4030_wdt_resume(struct platform_device * pdev)235 static int twl4030_wdt_resume(struct platform_device *pdev)
236 {
237 struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
238 if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
239 return twl4030_wdt_enable(wdt);
240
241 return 0;
242 }
243 #else
244 #define twl4030_wdt_suspend NULL
245 #define twl4030_wdt_resume NULL
246 #endif
247
248 static struct platform_driver twl4030_wdt_driver = {
249 .probe = twl4030_wdt_probe,
250 .remove = __devexit_p(twl4030_wdt_remove),
251 .suspend = twl4030_wdt_suspend,
252 .resume = twl4030_wdt_resume,
253 .driver = {
254 .owner = THIS_MODULE,
255 .name = "twl4030_wdt",
256 },
257 };
258
259 module_platform_driver(twl4030_wdt_driver);
260
261 MODULE_AUTHOR("Nokia Corporation");
262 MODULE_LICENSE("GPL");
263 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
264 MODULE_ALIAS("platform:twl4030_wdt");
265
266