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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 | ||
27c766aa JP |
11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
12 | ||
006948ba MB |
13 | #include <linux/module.h> |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/types.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/miscdevice.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/watchdog.h> | |
21 | #include <linux/uaccess.h> | |
22 | #include <linux/mfd/wm8350/core.h> | |
23 | ||
86a1e189 WVS |
24 | static bool nowayout = WATCHDOG_NOWAYOUT; |
25 | module_param(nowayout, bool, 0); | |
006948ba MB |
26 | MODULE_PARM_DESC(nowayout, |
27 | "Watchdog cannot be stopped once started (default=" | |
28 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
29 | ||
30 | static unsigned long wm8350_wdt_users; | |
31 | static struct miscdevice wm8350_wdt_miscdev; | |
32 | static int wm8350_wdt_expect_close; | |
33 | static DEFINE_MUTEX(wdt_mutex); | |
34 | ||
35 | static struct { | |
36 | int time; /* Seconds */ | |
37 | u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */ | |
38 | } wm8350_wdt_cfgs[] = { | |
39 | { 1, 0x02 }, | |
40 | { 2, 0x04 }, | |
41 | { 4, 0x05 }, | |
42 | }; | |
43 | ||
44 | static struct wm8350 *get_wm8350(void) | |
45 | { | |
46 | return dev_get_drvdata(wm8350_wdt_miscdev.parent); | |
47 | } | |
48 | ||
49 | static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value) | |
50 | { | |
51 | int ret; | |
52 | u16 reg; | |
53 | ||
54 | mutex_lock(&wdt_mutex); | |
55 | wm8350_reg_unlock(wm8350); | |
56 | ||
57 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
58 | reg &= ~WM8350_WDOG_TO_MASK; | |
59 | reg |= value; | |
60 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
61 | ||
62 | wm8350_reg_lock(wm8350); | |
63 | mutex_unlock(&wdt_mutex); | |
64 | ||
65 | return ret; | |
66 | } | |
67 | ||
68 | static int wm8350_wdt_start(struct wm8350 *wm8350) | |
69 | { | |
70 | int ret; | |
71 | u16 reg; | |
72 | ||
73 | mutex_lock(&wdt_mutex); | |
74 | wm8350_reg_unlock(wm8350); | |
75 | ||
76 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
77 | reg &= ~WM8350_WDOG_MODE_MASK; | |
78 | reg |= 0x20; | |
79 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
80 | ||
81 | wm8350_reg_lock(wm8350); | |
82 | mutex_unlock(&wdt_mutex); | |
83 | ||
84 | return ret; | |
85 | } | |
86 | ||
87 | static int wm8350_wdt_stop(struct wm8350 *wm8350) | |
88 | { | |
89 | int ret; | |
90 | u16 reg; | |
91 | ||
92 | mutex_lock(&wdt_mutex); | |
93 | wm8350_reg_unlock(wm8350); | |
94 | ||
95 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
96 | reg &= ~WM8350_WDOG_MODE_MASK; | |
97 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
98 | ||
99 | wm8350_reg_lock(wm8350); | |
100 | mutex_unlock(&wdt_mutex); | |
101 | ||
102 | return ret; | |
103 | } | |
104 | ||
105 | static int wm8350_wdt_kick(struct wm8350 *wm8350) | |
106 | { | |
107 | int ret; | |
108 | u16 reg; | |
109 | ||
110 | mutex_lock(&wdt_mutex); | |
111 | ||
112 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
113 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); | |
114 | ||
115 | mutex_unlock(&wdt_mutex); | |
116 | ||
117 | return ret; | |
118 | } | |
119 | ||
120 | static int wm8350_wdt_open(struct inode *inode, struct file *file) | |
121 | { | |
122 | struct wm8350 *wm8350 = get_wm8350(); | |
123 | int ret; | |
124 | ||
125 | if (!wm8350) | |
126 | return -ENODEV; | |
127 | ||
128 | if (test_and_set_bit(0, &wm8350_wdt_users)) | |
129 | return -EBUSY; | |
130 | ||
131 | ret = wm8350_wdt_start(wm8350); | |
132 | if (ret != 0) | |
133 | return ret; | |
134 | ||
135 | return nonseekable_open(inode, file); | |
136 | } | |
137 | ||
138 | static int wm8350_wdt_release(struct inode *inode, struct file *file) | |
139 | { | |
140 | struct wm8350 *wm8350 = get_wm8350(); | |
141 | ||
142 | if (wm8350_wdt_expect_close) | |
143 | wm8350_wdt_stop(wm8350); | |
144 | else { | |
145 | dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n"); | |
146 | wm8350_wdt_kick(wm8350); | |
147 | } | |
148 | ||
149 | clear_bit(0, &wm8350_wdt_users); | |
150 | ||
151 | return 0; | |
152 | } | |
153 | ||
154 | static ssize_t wm8350_wdt_write(struct file *file, | |
155 | const char __user *data, size_t count, | |
156 | loff_t *ppos) | |
157 | { | |
158 | struct wm8350 *wm8350 = get_wm8350(); | |
159 | size_t i; | |
160 | ||
161 | if (count) { | |
162 | wm8350_wdt_kick(wm8350); | |
163 | ||
164 | if (!nowayout) { | |
165 | /* In case it was set long ago */ | |
166 | wm8350_wdt_expect_close = 0; | |
167 | ||
168 | /* scan to see whether or not we got the magic | |
169 | character */ | |
170 | for (i = 0; i != count; i++) { | |
171 | char c; | |
172 | if (get_user(c, data + i)) | |
173 | return -EFAULT; | |
174 | if (c == 'V') | |
175 | wm8350_wdt_expect_close = 42; | |
176 | } | |
177 | } | |
178 | } | |
179 | return count; | |
180 | } | |
181 | ||
42747d71 | 182 | static const struct watchdog_info ident = { |
006948ba MB |
183 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
184 | .identity = "WM8350 Watchdog", | |
185 | }; | |
186 | ||
187 | static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd, | |
188 | unsigned long arg) | |
189 | { | |
190 | struct wm8350 *wm8350 = get_wm8350(); | |
191 | int ret = -ENOTTY, time, i; | |
192 | void __user *argp = (void __user *)arg; | |
193 | int __user *p = argp; | |
194 | u16 reg; | |
195 | ||
196 | switch (cmd) { | |
197 | case WDIOC_GETSUPPORT: | |
198 | ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
199 | break; | |
200 | ||
201 | case WDIOC_GETSTATUS: | |
202 | case WDIOC_GETBOOTSTATUS: | |
203 | ret = put_user(0, p); | |
204 | break; | |
205 | ||
206 | case WDIOC_SETOPTIONS: | |
207 | { | |
208 | int options; | |
209 | ||
210 | if (get_user(options, p)) | |
211 | return -EFAULT; | |
212 | ||
213 | ret = -EINVAL; | |
214 | ||
215 | /* Setting both simultaneously means at least one must fail */ | |
216 | if (options == WDIOS_DISABLECARD) | |
ebe06e82 | 217 | ret = wm8350_wdt_stop(wm8350); |
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218 | |
219 | if (options == WDIOS_ENABLECARD) | |
ebe06e82 | 220 | ret = wm8350_wdt_start(wm8350); |
006948ba MB |
221 | break; |
222 | } | |
223 | ||
224 | case WDIOC_KEEPALIVE: | |
225 | ret = wm8350_wdt_kick(wm8350); | |
226 | break; | |
227 | ||
228 | case WDIOC_SETTIMEOUT: | |
229 | ret = get_user(time, p); | |
230 | if (ret) | |
231 | break; | |
232 | ||
233 | if (time == 0) { | |
234 | if (nowayout) | |
235 | ret = -EINVAL; | |
236 | else | |
237 | wm8350_wdt_stop(wm8350); | |
238 | break; | |
239 | } | |
240 | ||
241 | for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++) | |
242 | if (wm8350_wdt_cfgs[i].time == time) | |
243 | break; | |
244 | if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) | |
245 | ret = -EINVAL; | |
246 | else | |
247 | ret = wm8350_wdt_set_timeout(wm8350, | |
248 | wm8350_wdt_cfgs[i].val); | |
249 | break; | |
250 | ||
251 | case WDIOC_GETTIMEOUT: | |
252 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); | |
253 | reg &= WM8350_WDOG_TO_MASK; | |
254 | for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++) | |
255 | if (wm8350_wdt_cfgs[i].val == reg) | |
256 | break; | |
257 | if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) { | |
258 | dev_warn(wm8350->dev, | |
259 | "Unknown watchdog configuration: %x\n", reg); | |
260 | ret = -EINVAL; | |
261 | } else | |
262 | ret = put_user(wm8350_wdt_cfgs[i].time, p); | |
263 | ||
264 | } | |
265 | ||
266 | return ret; | |
267 | } | |
268 | ||
269 | static const struct file_operations wm8350_wdt_fops = { | |
270 | .owner = THIS_MODULE, | |
271 | .llseek = no_llseek, | |
272 | .write = wm8350_wdt_write, | |
273 | .unlocked_ioctl = wm8350_wdt_ioctl, | |
274 | .open = wm8350_wdt_open, | |
275 | .release = wm8350_wdt_release, | |
276 | }; | |
277 | ||
278 | static struct miscdevice wm8350_wdt_miscdev = { | |
279 | .minor = WATCHDOG_MINOR, | |
280 | .name = "watchdog", | |
281 | .fops = &wm8350_wdt_fops, | |
282 | }; | |
283 | ||
b1cf3e99 | 284 | static int __devinit wm8350_wdt_probe(struct platform_device *pdev) |
006948ba MB |
285 | { |
286 | struct wm8350 *wm8350 = platform_get_drvdata(pdev); | |
287 | ||
288 | if (!wm8350) { | |
cfca31ce | 289 | pr_err("No driver data supplied\n"); |
006948ba MB |
290 | return -ENODEV; |
291 | } | |
292 | ||
293 | /* Default to 4s timeout */ | |
294 | wm8350_wdt_set_timeout(wm8350, 0x05); | |
295 | ||
296 | wm8350_wdt_miscdev.parent = &pdev->dev; | |
297 | ||
298 | return misc_register(&wm8350_wdt_miscdev); | |
299 | } | |
300 | ||
b1cf3e99 | 301 | static int __devexit wm8350_wdt_remove(struct platform_device *pdev) |
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302 | { |
303 | misc_deregister(&wm8350_wdt_miscdev); | |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | static struct platform_driver wm8350_wdt_driver = { | |
309 | .probe = wm8350_wdt_probe, | |
b1cf3e99 | 310 | .remove = __devexit_p(wm8350_wdt_remove), |
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311 | .driver = { |
312 | .name = "wm8350-wdt", | |
313 | }, | |
314 | }; | |
315 | ||
216f3ad9 | 316 | module_platform_driver(wm8350_wdt_driver); |
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317 | |
318 | MODULE_AUTHOR("Mark Brown"); | |
319 | MODULE_DESCRIPTION("WM8350 Watchdog"); | |
320 | MODULE_LICENSE("GPL"); | |
321 | MODULE_ALIAS("platform:wm8350-wdt"); |