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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
26static int nowayout = WATCHDOG_NOWAYOUT;
27module_param(nowayout, int, 0);
28MODULE_PARM_DESC(nowayout,
29 "Watchdog cannot be stopped once started (default="
30 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
31
32static unsigned long wm831x_wdt_users;
33static struct miscdevice wm831x_wdt_miscdev;
34static int wm831x_wdt_expect_close;
35static DEFINE_MUTEX(wdt_mutex);
36static struct wm831x *wm831x;
37static unsigned int update_gpio;
38static unsigned int update_state;
39
40/* We can't use the sub-second values here but they're included
41 * for completeness. */
42static 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
55static 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
76static 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
97static 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
118static 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
152out:
153 mutex_unlock(&wdt_mutex);
154
155 return ret;
156}
157
158static 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
175static 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
189static 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
216static const struct watchdog_info ident = {
217 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
218 .identity = "WM831x Watchdog",
219};
220
221static 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
302static 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
311static struct miscdevice wm831x_wdt_miscdev = {
312 .minor = WATCHDOG_MINOR,
313 .name = "watchdog",
314 .fops = &wm831x_wdt_fops,
315};
316
317static 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 if (wm831x) {
324 dev_err(&pdev->dev, "wm831x watchdog already registered\n");
325 return -EBUSY;
326 }
327
328 wm831x = dev_get_drvdata(pdev->dev.parent);
329
330 ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
331 if (ret < 0) {
332 dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
333 ret);
334 goto err;
335 }
336 reg = ret;
337
338 if (reg & WM831X_WDOG_DEBUG)
339 dev_warn(wm831x->dev, "Watchdog is paused\n");
340
341 /* Apply any configuration */
342 if (pdev->dev.parent->platform_data) {
343 chip_pdata = pdev->dev.parent->platform_data;
344 pdata = chip_pdata->watchdog;
345 } else {
346 pdata = NULL;
347 }
348
349 if (pdata) {
350 reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
351 WM831X_WDOG_RST_SRC);
352
353 reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
354 reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
355 reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
356
357 if (pdata->update_gpio) {
358 ret = gpio_request(pdata->update_gpio,
359 "Watchdog update");
360 if (ret < 0) {
361 dev_err(wm831x->dev,
362 "Failed to request update GPIO: %d\n",
363 ret);
364 goto err;
365 }
366
367 ret = gpio_direction_output(pdata->update_gpio, 0);
368 if (ret != 0) {
369 dev_err(wm831x->dev,
370 "gpio_direction_output returned: %d\n",
371 ret);
372 goto err_gpio;
373 }
374
375 update_gpio = pdata->update_gpio;
376
377 /* Make sure the watchdog takes hardware updates */
378 reg |= WM831X_WDOG_RST_SRC;
379 }
380
381 ret = wm831x_reg_unlock(wm831x);
382 if (ret == 0) {
383 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
384 wm831x_reg_lock(wm831x);
385 } else {
386 dev_err(wm831x->dev,
387 "Failed to unlock security key: %d\n", ret);
388 goto err_gpio;
389 }
390 }
391
392 wm831x_wdt_miscdev.parent = &pdev->dev;
393
394 ret = misc_register(&wm831x_wdt_miscdev);
395 if (ret != 0) {
396 dev_err(wm831x->dev, "Failed to register miscdev: %d\n", ret);
397 goto err_gpio;
398 }
399
400 return 0;
401
402err_gpio:
403 if (update_gpio) {
404 gpio_free(update_gpio);
405 update_gpio = 0;
406 }
407err:
408 return ret;
409}
410
411static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
412{
413 if (update_gpio) {
414 gpio_free(update_gpio);
415 update_gpio = 0;
416 }
417
418 misc_deregister(&wm831x_wdt_miscdev);
419
420 return 0;
421}
422
423static struct platform_driver wm831x_wdt_driver = {
424 .probe = wm831x_wdt_probe,
425 .remove = __devexit_p(wm831x_wdt_remove),
426 .driver = {
427 .name = "wm831x-watchdog",
428 },
429};
430
431static int __init wm831x_wdt_init(void)
432{
433 return platform_driver_register(&wm831x_wdt_driver);
434}
435module_init(wm831x_wdt_init);
436
437static void __exit wm831x_wdt_exit(void)
438{
439 platform_driver_unregister(&wm831x_wdt_driver);
440}
441module_exit(wm831x_wdt_exit);
442
443MODULE_AUTHOR("Mark Brown");
444MODULE_DESCRIPTION("WM831x Watchdog");
445MODULE_LICENSE("GPL");
446MODULE_ALIAS("platform:wm831x-watchdog");
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Watchdog driver for the wm831x PMICs
4 *
5 * Copyright (C) 2009 Wolfson Microelectronics
6 */
7
8#include <linux/module.h>
9#include <linux/moduleparam.h>
10#include <linux/types.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/platform_device.h>
14#include <linux/watchdog.h>
15#include <linux/uaccess.h>
16#include <linux/gpio.h>
17
18#include <linux/mfd/wm831x/core.h>
19#include <linux/mfd/wm831x/pdata.h>
20#include <linux/mfd/wm831x/watchdog.h>
21
22static bool nowayout = WATCHDOG_NOWAYOUT;
23module_param(nowayout, bool, 0);
24MODULE_PARM_DESC(nowayout,
25 "Watchdog cannot be stopped once started (default="
26 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
27
28struct wm831x_wdt_drvdata {
29 struct watchdog_device wdt;
30 struct wm831x *wm831x;
31 struct mutex lock;
32 int update_gpio;
33 int update_state;
34};
35
36/* We can't use the sub-second values here but they're included
37 * for completeness. */
38static struct {
39 unsigned int time; /* Seconds */
40 u16 val; /* WDOG_TO value */
41} wm831x_wdt_cfgs[] = {
42 { 1, 2 },
43 { 2, 3 },
44 { 4, 4 },
45 { 8, 5 },
46 { 16, 6 },
47 { 32, 7 },
48 { 33, 7 }, /* Actually 32.768s so include both, others round down */
49};
50
51static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
52{
53 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
54 struct wm831x *wm831x = driver_data->wm831x;
55 int ret;
56
57 mutex_lock(&driver_data->lock);
58
59 ret = wm831x_reg_unlock(wm831x);
60 if (ret == 0) {
61 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
62 WM831X_WDOG_ENA, WM831X_WDOG_ENA);
63 wm831x_reg_lock(wm831x);
64 } else {
65 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
66 ret);
67 }
68
69 mutex_unlock(&driver_data->lock);
70
71 return ret;
72}
73
74static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
75{
76 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
77 struct wm831x *wm831x = driver_data->wm831x;
78 int ret;
79
80 mutex_lock(&driver_data->lock);
81
82 ret = wm831x_reg_unlock(wm831x);
83 if (ret == 0) {
84 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
85 WM831X_WDOG_ENA, 0);
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(&driver_data->lock);
93
94 return ret;
95}
96
97static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
98{
99 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
100 struct wm831x *wm831x = driver_data->wm831x;
101 int ret;
102 u16 reg;
103
104 mutex_lock(&driver_data->lock);
105
106 if (driver_data->update_gpio) {
107 gpio_set_value_cansleep(driver_data->update_gpio,
108 driver_data->update_state);
109 driver_data->update_state = !driver_data->update_state;
110 ret = 0;
111 goto out;
112 }
113
114 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
115
116 if (!(reg & WM831X_WDOG_RST_SRC)) {
117 dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
118 ret = -EINVAL;
119 goto out;
120 }
121
122 reg |= WM831X_WDOG_RESET;
123
124 ret = wm831x_reg_unlock(wm831x);
125 if (ret == 0) {
126 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
127 wm831x_reg_lock(wm831x);
128 } else {
129 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
130 ret);
131 }
132
133out:
134 mutex_unlock(&driver_data->lock);
135
136 return ret;
137}
138
139static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
140 unsigned int timeout)
141{
142 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
143 struct wm831x *wm831x = driver_data->wm831x;
144 int ret, i;
145
146 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
147 if (wm831x_wdt_cfgs[i].time == timeout)
148 break;
149 if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
150 return -EINVAL;
151
152 ret = wm831x_reg_unlock(wm831x);
153 if (ret == 0) {
154 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
155 WM831X_WDOG_TO_MASK,
156 wm831x_wdt_cfgs[i].val);
157 wm831x_reg_lock(wm831x);
158 } else {
159 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
160 ret);
161 }
162
163 wdt_dev->timeout = timeout;
164
165 return ret;
166}
167
168static const struct watchdog_info wm831x_wdt_info = {
169 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
170 .identity = "WM831x Watchdog",
171};
172
173static const struct watchdog_ops wm831x_wdt_ops = {
174 .owner = THIS_MODULE,
175 .start = wm831x_wdt_start,
176 .stop = wm831x_wdt_stop,
177 .ping = wm831x_wdt_ping,
178 .set_timeout = wm831x_wdt_set_timeout,
179};
180
181static int wm831x_wdt_probe(struct platform_device *pdev)
182{
183 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
184 struct wm831x_pdata *chip_pdata = dev_get_platdata(pdev->dev.parent);
185 struct wm831x_watchdog_pdata *pdata;
186 struct wm831x_wdt_drvdata *driver_data;
187 struct watchdog_device *wm831x_wdt;
188 int reg, ret, i;
189
190 ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
191 if (ret < 0) {
192 dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
193 ret);
194 return ret;
195 }
196 reg = ret;
197
198 if (reg & WM831X_WDOG_DEBUG)
199 dev_warn(wm831x->dev, "Watchdog is paused\n");
200
201 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
202 GFP_KERNEL);
203 if (!driver_data)
204 return -ENOMEM;
205
206 mutex_init(&driver_data->lock);
207 driver_data->wm831x = wm831x;
208
209 wm831x_wdt = &driver_data->wdt;
210
211 wm831x_wdt->info = &wm831x_wdt_info;
212 wm831x_wdt->ops = &wm831x_wdt_ops;
213 wm831x_wdt->parent = &pdev->dev;
214 watchdog_set_nowayout(wm831x_wdt, nowayout);
215 watchdog_set_drvdata(wm831x_wdt, driver_data);
216
217 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
218 reg &= WM831X_WDOG_TO_MASK;
219 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
220 if (wm831x_wdt_cfgs[i].val == reg)
221 break;
222 if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
223 dev_warn(wm831x->dev,
224 "Unknown watchdog timeout: %x\n", reg);
225 else
226 wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
227
228 /* Apply any configuration */
229 if (chip_pdata)
230 pdata = chip_pdata->watchdog;
231 else
232 pdata = NULL;
233
234 if (pdata) {
235 reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
236 WM831X_WDOG_RST_SRC);
237
238 reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
239 reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
240 reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
241
242 if (pdata->update_gpio) {
243 ret = devm_gpio_request_one(&pdev->dev,
244 pdata->update_gpio,
245 GPIOF_OUT_INIT_LOW,
246 "Watchdog update");
247 if (ret < 0) {
248 dev_err(wm831x->dev,
249 "Failed to request update GPIO: %d\n",
250 ret);
251 return ret;
252 }
253
254 driver_data->update_gpio = pdata->update_gpio;
255
256 /* Make sure the watchdog takes hardware updates */
257 reg |= WM831X_WDOG_RST_SRC;
258 }
259
260 ret = wm831x_reg_unlock(wm831x);
261 if (ret == 0) {
262 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
263 wm831x_reg_lock(wm831x);
264 } else {
265 dev_err(wm831x->dev,
266 "Failed to unlock security key: %d\n", ret);
267 return ret;
268 }
269 }
270
271 ret = devm_watchdog_register_device(&pdev->dev, &driver_data->wdt);
272 if (ret != 0) {
273 dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
274 ret);
275 return ret;
276 }
277
278 return 0;
279}
280
281static struct platform_driver wm831x_wdt_driver = {
282 .probe = wm831x_wdt_probe,
283 .driver = {
284 .name = "wm831x-watchdog",
285 },
286};
287
288module_platform_driver(wm831x_wdt_driver);
289
290MODULE_AUTHOR("Mark Brown");
291MODULE_DESCRIPTION("WM831x Watchdog");
292MODULE_LICENSE("GPL");
293MODULE_ALIAS("platform:wm831x-watchdog");