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502a0106 MB |
1 | /* |
2 | * Watchdog driver for the wm831x PMICs | |
3 | * | |
4 | * Copyright (C) 2009 Wolfson Microelectronics | |
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/gpio.h> | |
21 | ||
22 | #include <linux/mfd/wm831x/core.h> | |
23 | #include <linux/mfd/wm831x/pdata.h> | |
24 | #include <linux/mfd/wm831x/watchdog.h> | |
25 | ||
26 | static int nowayout = WATCHDOG_NOWAYOUT; | |
27 | module_param(nowayout, int, 0); | |
28 | MODULE_PARM_DESC(nowayout, | |
29 | "Watchdog cannot be stopped once started (default=" | |
30 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
31 | ||
32 | static unsigned long wm831x_wdt_users; | |
33 | static struct miscdevice wm831x_wdt_miscdev; | |
34 | static int wm831x_wdt_expect_close; | |
35 | static DEFINE_MUTEX(wdt_mutex); | |
36 | static struct wm831x *wm831x; | |
37 | static unsigned int update_gpio; | |
38 | static unsigned int update_state; | |
39 | ||
40 | /* We can't use the sub-second values here but they're included | |
41 | * for completeness. */ | |
42 | static struct { | |
43 | int time; /* Seconds */ | |
44 | u16 val; /* WDOG_TO value */ | |
45 | } wm831x_wdt_cfgs[] = { | |
46 | { 1, 2 }, | |
47 | { 2, 3 }, | |
48 | { 4, 4 }, | |
49 | { 8, 5 }, | |
50 | { 16, 6 }, | |
51 | { 32, 7 }, | |
52 | { 33, 7 }, /* Actually 32.768s so include both, others round down */ | |
53 | }; | |
54 | ||
55 | static int wm831x_wdt_set_timeout(struct wm831x *wm831x, u16 value) | |
56 | { | |
57 | int ret; | |
58 | ||
59 | mutex_lock(&wdt_mutex); | |
60 | ||
61 | ret = wm831x_reg_unlock(wm831x); | |
62 | if (ret == 0) { | |
63 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, | |
64 | WM831X_WDOG_TO_MASK, value); | |
65 | wm831x_reg_lock(wm831x); | |
66 | } else { | |
67 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", | |
68 | ret); | |
69 | } | |
70 | ||
71 | mutex_unlock(&wdt_mutex); | |
72 | ||
73 | return ret; | |
74 | } | |
75 | ||
76 | static int wm831x_wdt_start(struct wm831x *wm831x) | |
77 | { | |
78 | int ret; | |
79 | ||
80 | mutex_lock(&wdt_mutex); | |
81 | ||
82 | ret = wm831x_reg_unlock(wm831x); | |
83 | if (ret == 0) { | |
84 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, | |
85 | WM831X_WDOG_ENA, WM831X_WDOG_ENA); | |
86 | wm831x_reg_lock(wm831x); | |
87 | } else { | |
88 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", | |
89 | ret); | |
90 | } | |
91 | ||
92 | mutex_unlock(&wdt_mutex); | |
93 | ||
94 | return ret; | |
95 | } | |
96 | ||
97 | static int wm831x_wdt_stop(struct wm831x *wm831x) | |
98 | { | |
99 | int ret; | |
100 | ||
101 | mutex_lock(&wdt_mutex); | |
102 | ||
103 | ret = wm831x_reg_unlock(wm831x); | |
104 | if (ret == 0) { | |
105 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, | |
106 | WM831X_WDOG_ENA, 0); | |
107 | wm831x_reg_lock(wm831x); | |
108 | } else { | |
109 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", | |
110 | ret); | |
111 | } | |
112 | ||
113 | mutex_unlock(&wdt_mutex); | |
114 | ||
115 | return ret; | |
116 | } | |
117 | ||
118 | static int wm831x_wdt_kick(struct wm831x *wm831x) | |
119 | { | |
120 | int ret; | |
121 | u16 reg; | |
122 | ||
123 | mutex_lock(&wdt_mutex); | |
124 | ||
125 | if (update_gpio) { | |
126 | gpio_set_value_cansleep(update_gpio, update_state); | |
127 | update_state = !update_state; | |
128 | ret = 0; | |
129 | goto out; | |
130 | } | |
131 | ||
132 | ||
133 | reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); | |
134 | ||
135 | if (!(reg & WM831X_WDOG_RST_SRC)) { | |
136 | dev_err(wm831x->dev, "Hardware watchdog update unsupported\n"); | |
137 | ret = -EINVAL; | |
138 | goto out; | |
139 | } | |
140 | ||
141 | reg |= WM831X_WDOG_RESET; | |
142 | ||
143 | ret = wm831x_reg_unlock(wm831x); | |
144 | if (ret == 0) { | |
145 | ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg); | |
146 | wm831x_reg_lock(wm831x); | |
147 | } else { | |
148 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", | |
149 | ret); | |
150 | } | |
151 | ||
152 | out: | |
153 | mutex_unlock(&wdt_mutex); | |
154 | ||
155 | return ret; | |
156 | } | |
157 | ||
158 | static int wm831x_wdt_open(struct inode *inode, struct file *file) | |
159 | { | |
160 | int ret; | |
161 | ||
162 | if (!wm831x) | |
163 | return -ENODEV; | |
164 | ||
165 | if (test_and_set_bit(0, &wm831x_wdt_users)) | |
166 | return -EBUSY; | |
167 | ||
168 | ret = wm831x_wdt_start(wm831x); | |
169 | if (ret != 0) | |
170 | return ret; | |
171 | ||
172 | return nonseekable_open(inode, file); | |
173 | } | |
174 | ||
175 | static int wm831x_wdt_release(struct inode *inode, struct file *file) | |
176 | { | |
177 | if (wm831x_wdt_expect_close) | |
178 | wm831x_wdt_stop(wm831x); | |
179 | else { | |
180 | dev_warn(wm831x->dev, "Watchdog device closed uncleanly\n"); | |
181 | wm831x_wdt_kick(wm831x); | |
182 | } | |
183 | ||
184 | clear_bit(0, &wm831x_wdt_users); | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | static ssize_t wm831x_wdt_write(struct file *file, | |
190 | const char __user *data, size_t count, | |
191 | loff_t *ppos) | |
192 | { | |
193 | size_t i; | |
194 | ||
195 | if (count) { | |
196 | wm831x_wdt_kick(wm831x); | |
197 | ||
198 | if (!nowayout) { | |
199 | /* In case it was set long ago */ | |
200 | wm831x_wdt_expect_close = 0; | |
201 | ||
202 | /* scan to see whether or not we got the magic | |
203 | character */ | |
204 | for (i = 0; i != count; i++) { | |
205 | char c; | |
206 | if (get_user(c, data + i)) | |
207 | return -EFAULT; | |
208 | if (c == 'V') | |
209 | wm831x_wdt_expect_close = 42; | |
210 | } | |
211 | } | |
212 | } | |
213 | return count; | |
214 | } | |
215 | ||
42747d71 | 216 | static const struct watchdog_info ident = { |
502a0106 MB |
217 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
218 | .identity = "WM831x Watchdog", | |
219 | }; | |
220 | ||
221 | static long wm831x_wdt_ioctl(struct file *file, unsigned int cmd, | |
222 | unsigned long arg) | |
223 | { | |
224 | int ret = -ENOTTY, time, i; | |
225 | void __user *argp = (void __user *)arg; | |
226 | int __user *p = argp; | |
227 | u16 reg; | |
228 | ||
229 | switch (cmd) { | |
230 | case WDIOC_GETSUPPORT: | |
231 | ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
232 | break; | |
233 | ||
234 | case WDIOC_GETSTATUS: | |
235 | case WDIOC_GETBOOTSTATUS: | |
236 | ret = put_user(0, p); | |
237 | break; | |
238 | ||
239 | case WDIOC_SETOPTIONS: | |
240 | { | |
241 | int options; | |
242 | ||
243 | if (get_user(options, p)) | |
244 | return -EFAULT; | |
245 | ||
246 | ret = -EINVAL; | |
247 | ||
248 | /* Setting both simultaneously means at least one must fail */ | |
249 | if (options == WDIOS_DISABLECARD) | |
250 | ret = wm831x_wdt_start(wm831x); | |
251 | ||
252 | if (options == WDIOS_ENABLECARD) | |
253 | ret = wm831x_wdt_stop(wm831x); | |
254 | break; | |
255 | } | |
256 | ||
257 | case WDIOC_KEEPALIVE: | |
258 | ret = wm831x_wdt_kick(wm831x); | |
259 | break; | |
260 | ||
261 | case WDIOC_SETTIMEOUT: | |
262 | ret = get_user(time, p); | |
263 | if (ret) | |
264 | break; | |
265 | ||
266 | if (time == 0) { | |
267 | if (nowayout) | |
268 | ret = -EINVAL; | |
269 | else | |
270 | wm831x_wdt_stop(wm831x); | |
271 | break; | |
272 | } | |
273 | ||
274 | for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) | |
275 | if (wm831x_wdt_cfgs[i].time == time) | |
276 | break; | |
277 | if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) | |
278 | ret = -EINVAL; | |
279 | else | |
280 | ret = wm831x_wdt_set_timeout(wm831x, | |
281 | wm831x_wdt_cfgs[i].val); | |
282 | break; | |
283 | ||
284 | case WDIOC_GETTIMEOUT: | |
285 | reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); | |
286 | reg &= WM831X_WDOG_TO_MASK; | |
287 | for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) | |
288 | if (wm831x_wdt_cfgs[i].val == reg) | |
289 | break; | |
290 | if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) { | |
291 | dev_warn(wm831x->dev, | |
292 | "Unknown watchdog configuration: %x\n", reg); | |
293 | ret = -EINVAL; | |
294 | } else | |
295 | ret = put_user(wm831x_wdt_cfgs[i].time, p); | |
296 | ||
297 | } | |
298 | ||
299 | return ret; | |
300 | } | |
301 | ||
302 | static const struct file_operations wm831x_wdt_fops = { | |
303 | .owner = THIS_MODULE, | |
304 | .llseek = no_llseek, | |
305 | .write = wm831x_wdt_write, | |
306 | .unlocked_ioctl = wm831x_wdt_ioctl, | |
307 | .open = wm831x_wdt_open, | |
308 | .release = wm831x_wdt_release, | |
309 | }; | |
310 | ||
311 | static struct miscdevice wm831x_wdt_miscdev = { | |
312 | .minor = WATCHDOG_MINOR, | |
313 | .name = "watchdog", | |
314 | .fops = &wm831x_wdt_fops, | |
315 | }; | |
316 | ||
317 | static int __devinit wm831x_wdt_probe(struct platform_device *pdev) | |
318 | { | |
319 | struct wm831x_pdata *chip_pdata; | |
320 | struct wm831x_watchdog_pdata *pdata; | |
321 | int reg, ret; | |
322 | ||
323 | wm831x = dev_get_drvdata(pdev->dev.parent); | |
324 | ||
325 | ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG); | |
326 | if (ret < 0) { | |
327 | dev_err(wm831x->dev, "Failed to read watchdog status: %d\n", | |
328 | ret); | |
329 | goto err; | |
330 | } | |
331 | reg = ret; | |
332 | ||
333 | if (reg & WM831X_WDOG_DEBUG) | |
334 | dev_warn(wm831x->dev, "Watchdog is paused\n"); | |
335 | ||
336 | /* Apply any configuration */ | |
337 | if (pdev->dev.parent->platform_data) { | |
338 | chip_pdata = pdev->dev.parent->platform_data; | |
339 | pdata = chip_pdata->watchdog; | |
340 | } else { | |
341 | pdata = NULL; | |
342 | } | |
343 | ||
344 | if (pdata) { | |
345 | reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK | | |
346 | WM831X_WDOG_RST_SRC); | |
347 | ||
348 | reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT; | |
349 | reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT; | |
350 | reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT; | |
351 | ||
352 | if (pdata->update_gpio) { | |
353 | ret = gpio_request(pdata->update_gpio, | |
354 | "Watchdog update"); | |
355 | if (ret < 0) { | |
356 | dev_err(wm831x->dev, | |
357 | "Failed to request update GPIO: %d\n", | |
358 | ret); | |
359 | goto err; | |
360 | } | |
361 | ||
362 | ret = gpio_direction_output(pdata->update_gpio, 0); | |
363 | if (ret != 0) { | |
364 | dev_err(wm831x->dev, | |
365 | "gpio_direction_output returned: %d\n", | |
366 | ret); | |
367 | goto err_gpio; | |
368 | } | |
369 | ||
370 | update_gpio = pdata->update_gpio; | |
371 | ||
372 | /* Make sure the watchdog takes hardware updates */ | |
373 | reg |= WM831X_WDOG_RST_SRC; | |
374 | } | |
375 | ||
376 | ret = wm831x_reg_unlock(wm831x); | |
377 | if (ret == 0) { | |
378 | ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg); | |
379 | wm831x_reg_lock(wm831x); | |
380 | } else { | |
381 | dev_err(wm831x->dev, | |
382 | "Failed to unlock security key: %d\n", ret); | |
383 | goto err_gpio; | |
384 | } | |
385 | } | |
386 | ||
387 | wm831x_wdt_miscdev.parent = &pdev->dev; | |
388 | ||
389 | ret = misc_register(&wm831x_wdt_miscdev); | |
390 | if (ret != 0) { | |
391 | dev_err(wm831x->dev, "Failed to register miscdev: %d\n", ret); | |
392 | goto err_gpio; | |
393 | } | |
394 | ||
395 | return 0; | |
396 | ||
397 | err_gpio: | |
398 | if (update_gpio) { | |
399 | gpio_free(update_gpio); | |
400 | update_gpio = 0; | |
401 | } | |
402 | err: | |
403 | return ret; | |
404 | } | |
405 | ||
406 | static int __devexit wm831x_wdt_remove(struct platform_device *pdev) | |
407 | { | |
408 | if (update_gpio) { | |
409 | gpio_free(update_gpio); | |
410 | update_gpio = 0; | |
411 | } | |
412 | ||
413 | misc_deregister(&wm831x_wdt_miscdev); | |
414 | ||
415 | return 0; | |
416 | } | |
417 | ||
418 | static struct platform_driver wm831x_wdt_driver = { | |
419 | .probe = wm831x_wdt_probe, | |
420 | .remove = __devexit_p(wm831x_wdt_remove), | |
421 | .driver = { | |
422 | .name = "wm831x-watchdog", | |
423 | }, | |
424 | }; | |
425 | ||
426 | static int __init wm831x_wdt_init(void) | |
427 | { | |
428 | return platform_driver_register(&wm831x_wdt_driver); | |
429 | } | |
430 | module_init(wm831x_wdt_init); | |
431 | ||
432 | static void __exit wm831x_wdt_exit(void) | |
433 | { | |
434 | platform_driver_unregister(&wm831x_wdt_driver); | |
435 | } | |
436 | module_exit(wm831x_wdt_exit); | |
437 | ||
438 | MODULE_AUTHOR("Mark Brown"); | |
439 | MODULE_DESCRIPTION("WM831x Watchdog"); | |
440 | MODULE_LICENSE("GPL"); | |
441 | MODULE_ALIAS("platform:wm831x-watchdog"); |