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1 | /* |
2 | * Watchdog driver for the wm8350 | |
3 | * | |
4 | * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/moduleparam.h> | |
13 | #include <linux/types.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/miscdevice.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/watchdog.h> | |
19 | #include <linux/uaccess.h> | |
20 | #include <linux/mfd/wm8350/core.h> | |
21 | ||
22 | static int nowayout = WATCHDOG_NOWAYOUT; | |
23 | module_param(nowayout, int, 0); | |
24 | MODULE_PARM_DESC(nowayout, | |
25 | "Watchdog cannot be stopped once started (default=" | |
26 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
27 | ||
28 | static unsigned long wm8350_wdt_users; | |
29 | static struct miscdevice wm8350_wdt_miscdev; | |
30 | static int wm8350_wdt_expect_close; | |
31 | static DEFINE_MUTEX(wdt_mutex); | |
32 | ||
33 | static struct { | |
34 | int time; /* Seconds */ | |
35 | u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */ | |
36 | } wm8350_wdt_cfgs[] = { | |
37 | { 1, 0x02 }, | |
38 | { 2, 0x04 }, | |
39 | { 4, 0x05 }, | |
40 | }; | |
41 | ||
42 | static struct wm8350 *get_wm8350(void) | |
43 | { | |
44 | return dev_get_drvdata(wm8350_wdt_miscdev.parent); | |
45 | } | |
46 | ||
47 | static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value) | |
48 | { | |
49 | int ret; | |
50 | u16 reg; | |
51 | ||
52 | mutex_lock(&wdt_mutex); | |
53 | wm8350_reg_unlock(wm8350); | |
54 | ||
55 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
56 | reg &= ~WM8350_WDOG_TO_MASK; | |
57 | reg |= value; | |
58 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
59 | ||
60 | wm8350_reg_lock(wm8350); | |
61 | mutex_unlock(&wdt_mutex); | |
62 | ||
63 | return ret; | |
64 | } | |
65 | ||
66 | static int wm8350_wdt_start(struct wm8350 *wm8350) | |
67 | { | |
68 | int ret; | |
69 | u16 reg; | |
70 | ||
71 | mutex_lock(&wdt_mutex); | |
72 | wm8350_reg_unlock(wm8350); | |
73 | ||
74 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
75 | reg &= ~WM8350_WDOG_MODE_MASK; | |
76 | reg |= 0x20; | |
77 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
78 | ||
79 | wm8350_reg_lock(wm8350); | |
80 | mutex_unlock(&wdt_mutex); | |
81 | ||
82 | return ret; | |
83 | } | |
84 | ||
85 | static int wm8350_wdt_stop(struct wm8350 *wm8350) | |
86 | { | |
87 | int ret; | |
88 | u16 reg; | |
89 | ||
90 | mutex_lock(&wdt_mutex); | |
91 | wm8350_reg_unlock(wm8350); | |
92 | ||
93 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
94 | reg &= ~WM8350_WDOG_MODE_MASK; | |
95 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
96 | ||
97 | wm8350_reg_lock(wm8350); | |
98 | mutex_unlock(&wdt_mutex); | |
99 | ||
100 | return ret; | |
101 | } | |
102 | ||
103 | static int wm8350_wdt_kick(struct wm8350 *wm8350) | |
104 | { | |
105 | int ret; | |
106 | u16 reg; | |
107 | ||
108 | mutex_lock(&wdt_mutex); | |
109 | ||
110 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
111 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
112 | ||
113 | mutex_unlock(&wdt_mutex); | |
114 | ||
115 | return ret; | |
116 | } | |
117 | ||
118 | static int wm8350_wdt_open(struct inode *inode, struct file *file) | |
119 | { | |
120 | struct wm8350 *wm8350 = get_wm8350(); | |
121 | int ret; | |
122 | ||
123 | if (!wm8350) | |
124 | return -ENODEV; | |
125 | ||
126 | if (test_and_set_bit(0, &wm8350_wdt_users)) | |
127 | return -EBUSY; | |
128 | ||
129 | ret = wm8350_wdt_start(wm8350); | |
130 | if (ret != 0) | |
131 | return ret; | |
132 | ||
133 | return nonseekable_open(inode, file); | |
134 | } | |
135 | ||
136 | static int wm8350_wdt_release(struct inode *inode, struct file *file) | |
137 | { | |
138 | struct wm8350 *wm8350 = get_wm8350(); | |
139 | ||
140 | if (wm8350_wdt_expect_close) | |
141 | wm8350_wdt_stop(wm8350); | |
142 | else { | |
143 | dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n"); | |
144 | wm8350_wdt_kick(wm8350); | |
145 | } | |
146 | ||
147 | clear_bit(0, &wm8350_wdt_users); | |
148 | ||
149 | return 0; | |
150 | } | |
151 | ||
152 | static ssize_t wm8350_wdt_write(struct file *file, | |
153 | const char __user *data, size_t count, | |
154 | loff_t *ppos) | |
155 | { | |
156 | struct wm8350 *wm8350 = get_wm8350(); | |
157 | size_t i; | |
158 | ||
159 | if (count) { | |
160 | wm8350_wdt_kick(wm8350); | |
161 | ||
162 | if (!nowayout) { | |
163 | /* In case it was set long ago */ | |
164 | wm8350_wdt_expect_close = 0; | |
165 | ||
166 | /* scan to see whether or not we got the magic | |
167 | character */ | |
168 | for (i = 0; i != count; i++) { | |
169 | char c; | |
170 | if (get_user(c, data + i)) | |
171 | return -EFAULT; | |
172 | if (c == 'V') | |
173 | wm8350_wdt_expect_close = 42; | |
174 | } | |
175 | } | |
176 | } | |
177 | return count; | |
178 | } | |
179 | ||
180 | static struct watchdog_info ident = { | |
181 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
182 | .identity = "WM8350 Watchdog", | |
183 | }; | |
184 | ||
185 | static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd, | |
186 | unsigned long arg) | |
187 | { | |
188 | struct wm8350 *wm8350 = get_wm8350(); | |
189 | int ret = -ENOTTY, time, i; | |
190 | void __user *argp = (void __user *)arg; | |
191 | int __user *p = argp; | |
192 | u16 reg; | |
193 | ||
194 | switch (cmd) { | |
195 | case WDIOC_GETSUPPORT: | |
196 | ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
197 | break; | |
198 | ||
199 | case WDIOC_GETSTATUS: | |
200 | case WDIOC_GETBOOTSTATUS: | |
201 | ret = put_user(0, p); | |
202 | break; | |
203 | ||
204 | case WDIOC_SETOPTIONS: | |
205 | { | |
206 | int options; | |
207 | ||
208 | if (get_user(options, p)) | |
209 | return -EFAULT; | |
210 | ||
211 | ret = -EINVAL; | |
212 | ||
213 | /* Setting both simultaneously means at least one must fail */ | |
214 | if (options == WDIOS_DISABLECARD) | |
215 | ret = wm8350_wdt_start(wm8350); | |
216 | ||
217 | if (options == WDIOS_ENABLECARD) | |
218 | ret = wm8350_wdt_stop(wm8350); | |
219 | break; | |
220 | } | |
221 | ||
222 | case WDIOC_KEEPALIVE: | |
223 | ret = wm8350_wdt_kick(wm8350); | |
224 | break; | |
225 | ||
226 | case WDIOC_SETTIMEOUT: | |
227 | ret = get_user(time, p); | |
228 | if (ret) | |
229 | break; | |
230 | ||
231 | if (time == 0) { | |
232 | if (nowayout) | |
233 | ret = -EINVAL; | |
234 | else | |
235 | wm8350_wdt_stop(wm8350); | |
236 | break; | |
237 | } | |
238 | ||
239 | for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++) | |
240 | if (wm8350_wdt_cfgs[i].time == time) | |
241 | break; | |
242 | if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) | |
243 | ret = -EINVAL; | |
244 | else | |
245 | ret = wm8350_wdt_set_timeout(wm8350, | |
246 | wm8350_wdt_cfgs[i].val); | |
247 | break; | |
248 | ||
249 | case WDIOC_GETTIMEOUT: | |
250 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
251 | reg &= WM8350_WDOG_TO_MASK; | |
252 | for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++) | |
253 | if (wm8350_wdt_cfgs[i].val == reg) | |
254 | break; | |
255 | if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) { | |
256 | dev_warn(wm8350->dev, | |
257 | "Unknown watchdog configuration: %x\n", reg); | |
258 | ret = -EINVAL; | |
259 | } else | |
260 | ret = put_user(wm8350_wdt_cfgs[i].time, p); | |
261 | ||
262 | } | |
263 | ||
264 | return ret; | |
265 | } | |
266 | ||
267 | static const struct file_operations wm8350_wdt_fops = { | |
268 | .owner = THIS_MODULE, | |
269 | .llseek = no_llseek, | |
270 | .write = wm8350_wdt_write, | |
271 | .unlocked_ioctl = wm8350_wdt_ioctl, | |
272 | .open = wm8350_wdt_open, | |
273 | .release = wm8350_wdt_release, | |
274 | }; | |
275 | ||
276 | static struct miscdevice wm8350_wdt_miscdev = { | |
277 | .minor = WATCHDOG_MINOR, | |
278 | .name = "watchdog", | |
279 | .fops = &wm8350_wdt_fops, | |
280 | }; | |
281 | ||
b1cf3e99 | 282 | static int __devinit wm8350_wdt_probe(struct platform_device *pdev) |
006948ba MB |
283 | { |
284 | struct wm8350 *wm8350 = platform_get_drvdata(pdev); | |
285 | ||
286 | if (!wm8350) { | |
287 | dev_err(wm8350->dev, "No driver data supplied\n"); | |
288 | return -ENODEV; | |
289 | } | |
290 | ||
291 | /* Default to 4s timeout */ | |
292 | wm8350_wdt_set_timeout(wm8350, 0x05); | |
293 | ||
294 | wm8350_wdt_miscdev.parent = &pdev->dev; | |
295 | ||
296 | return misc_register(&wm8350_wdt_miscdev); | |
297 | } | |
298 | ||
b1cf3e99 | 299 | static int __devexit wm8350_wdt_remove(struct platform_device *pdev) |
006948ba MB |
300 | { |
301 | misc_deregister(&wm8350_wdt_miscdev); | |
302 | ||
303 | return 0; | |
304 | } | |
305 | ||
306 | static struct platform_driver wm8350_wdt_driver = { | |
307 | .probe = wm8350_wdt_probe, | |
b1cf3e99 | 308 | .remove = __devexit_p(wm8350_wdt_remove), |
006948ba MB |
309 | .driver = { |
310 | .name = "wm8350-wdt", | |
311 | }, | |
312 | }; | |
313 | ||
314 | static int __init wm8350_wdt_init(void) | |
315 | { | |
316 | return platform_driver_register(&wm8350_wdt_driver); | |
317 | } | |
318 | module_init(wm8350_wdt_init); | |
319 | ||
320 | static void __exit wm8350_wdt_exit(void) | |
321 | { | |
322 | platform_driver_unregister(&wm8350_wdt_driver); | |
323 | } | |
324 | module_exit(wm8350_wdt_exit); | |
325 | ||
326 | MODULE_AUTHOR("Mark Brown"); | |
327 | MODULE_DESCRIPTION("WM8350 Watchdog"); | |
328 | MODULE_LICENSE("GPL"); | |
329 | MODULE_ALIAS("platform:wm8350-wdt"); |