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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 | |
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 | |
56 | static int twl4030_wdt_enable(struct twl4030_wdt *wdt) |
57 | { |
58 | return twl4030_wdt_write(wdt->timer_margin + 1); |
59 | } |
60 | |
61 | static int twl4030_wdt_disable(struct twl4030_wdt *wdt) |
62 | { |
63 | return twl4030_wdt_write(0); |
64 | } |
65 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 |
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 | |
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 |
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