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/slab.h>
16 #include <linux/platform_device.h>
17 #include <linux/watchdog.h>
18 #include <linux/uaccess.h>
19 #include <linux/gpio.h>
20
21 #include <linux/mfd/wm831x/core.h>
22 #include <linux/mfd/wm831x/pdata.h>
23 #include <linux/mfd/wm831x/watchdog.h>
24
25 static bool nowayout = WATCHDOG_NOWAYOUT;
26 module_param(nowayout, bool, 0);
27 MODULE_PARM_DESC(nowayout,
28 "Watchdog cannot be stopped once started (default="
29 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
30
31 struct wm831x_wdt_drvdata {
32 struct watchdog_device wdt;
33 struct wm831x *wm831x;
34 struct mutex lock;
35 int update_gpio;
36 int update_state;
37 };
38
39 /* We can't use the sub-second values here but they're included
40 * for completeness. */
41 static struct {
42 unsigned int time; /* Seconds */
43 u16 val; /* WDOG_TO value */
44 } wm831x_wdt_cfgs[] = {
45 { 1, 2 },
46 { 2, 3 },
47 { 4, 4 },
48 { 8, 5 },
49 { 16, 6 },
50 { 32, 7 },
51 { 33, 7 }, /* Actually 32.768s so include both, others round down */
52 };
53
wm831x_wdt_start(struct watchdog_device * wdt_dev)54 static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
55 {
56 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
57 struct wm831x *wm831x = driver_data->wm831x;
58 int ret;
59
60 mutex_lock(&driver_data->lock);
61
62 ret = wm831x_reg_unlock(wm831x);
63 if (ret == 0) {
64 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
65 WM831X_WDOG_ENA, WM831X_WDOG_ENA);
66 wm831x_reg_lock(wm831x);
67 } else {
68 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
69 ret);
70 }
71
72 mutex_unlock(&driver_data->lock);
73
74 return ret;
75 }
76
wm831x_wdt_stop(struct watchdog_device * wdt_dev)77 static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
78 {
79 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
80 struct wm831x *wm831x = driver_data->wm831x;
81 int ret;
82
83 mutex_lock(&driver_data->lock);
84
85 ret = wm831x_reg_unlock(wm831x);
86 if (ret == 0) {
87 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
88 WM831X_WDOG_ENA, 0);
89 wm831x_reg_lock(wm831x);
90 } else {
91 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
92 ret);
93 }
94
95 mutex_unlock(&driver_data->lock);
96
97 return ret;
98 }
99
wm831x_wdt_ping(struct watchdog_device * wdt_dev)100 static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
101 {
102 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
103 struct wm831x *wm831x = driver_data->wm831x;
104 int ret;
105 u16 reg;
106
107 mutex_lock(&driver_data->lock);
108
109 if (driver_data->update_gpio) {
110 gpio_set_value_cansleep(driver_data->update_gpio,
111 driver_data->update_state);
112 driver_data->update_state = !driver_data->update_state;
113 ret = 0;
114 goto out;
115 }
116
117 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
118
119 if (!(reg & WM831X_WDOG_RST_SRC)) {
120 dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
121 ret = -EINVAL;
122 goto out;
123 }
124
125 reg |= WM831X_WDOG_RESET;
126
127 ret = wm831x_reg_unlock(wm831x);
128 if (ret == 0) {
129 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
130 wm831x_reg_lock(wm831x);
131 } else {
132 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
133 ret);
134 }
135
136 out:
137 mutex_unlock(&driver_data->lock);
138
139 return ret;
140 }
141
wm831x_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)142 static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
143 unsigned int timeout)
144 {
145 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
146 struct wm831x *wm831x = driver_data->wm831x;
147 int ret, i;
148
149 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
150 if (wm831x_wdt_cfgs[i].time == timeout)
151 break;
152 if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
153 return -EINVAL;
154
155 ret = wm831x_reg_unlock(wm831x);
156 if (ret == 0) {
157 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
158 WM831X_WDOG_TO_MASK,
159 wm831x_wdt_cfgs[i].val);
160 wm831x_reg_lock(wm831x);
161 } else {
162 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
163 ret);
164 }
165
166 wdt_dev->timeout = timeout;
167
168 return ret;
169 }
170
171 static const struct watchdog_info wm831x_wdt_info = {
172 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
173 .identity = "WM831x Watchdog",
174 };
175
176 static const struct watchdog_ops wm831x_wdt_ops = {
177 .owner = THIS_MODULE,
178 .start = wm831x_wdt_start,
179 .stop = wm831x_wdt_stop,
180 .ping = wm831x_wdt_ping,
181 .set_timeout = wm831x_wdt_set_timeout,
182 };
183
wm831x_wdt_probe(struct platform_device * pdev)184 static int wm831x_wdt_probe(struct platform_device *pdev)
185 {
186 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
187 struct wm831x_pdata *chip_pdata;
188 struct wm831x_watchdog_pdata *pdata;
189 struct wm831x_wdt_drvdata *driver_data;
190 struct watchdog_device *wm831x_wdt;
191 int reg, ret, i;
192
193 ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
194 if (ret < 0) {
195 dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
196 ret);
197 goto err;
198 }
199 reg = ret;
200
201 if (reg & WM831X_WDOG_DEBUG)
202 dev_warn(wm831x->dev, "Watchdog is paused\n");
203
204 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
205 GFP_KERNEL);
206 if (!driver_data) {
207 dev_err(wm831x->dev, "Unable to alloacate watchdog device\n");
208 ret = -ENOMEM;
209 goto err;
210 }
211
212 mutex_init(&driver_data->lock);
213 driver_data->wm831x = wm831x;
214
215 wm831x_wdt = &driver_data->wdt;
216
217 wm831x_wdt->info = &wm831x_wdt_info;
218 wm831x_wdt->ops = &wm831x_wdt_ops;
219 watchdog_set_nowayout(wm831x_wdt, nowayout);
220 watchdog_set_drvdata(wm831x_wdt, driver_data);
221
222 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
223 reg &= WM831X_WDOG_TO_MASK;
224 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
225 if (wm831x_wdt_cfgs[i].val == reg)
226 break;
227 if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
228 dev_warn(wm831x->dev,
229 "Unknown watchdog timeout: %x\n", reg);
230 else
231 wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
232
233 /* Apply any configuration */
234 if (pdev->dev.parent->platform_data) {
235 chip_pdata = pdev->dev.parent->platform_data;
236 pdata = chip_pdata->watchdog;
237 } else {
238 pdata = NULL;
239 }
240
241 if (pdata) {
242 reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
243 WM831X_WDOG_RST_SRC);
244
245 reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
246 reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
247 reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
248
249 if (pdata->update_gpio) {
250 ret = gpio_request_one(pdata->update_gpio,
251 GPIOF_DIR_OUT | GPIOF_INIT_LOW,
252 "Watchdog update");
253 if (ret < 0) {
254 dev_err(wm831x->dev,
255 "Failed to request update GPIO: %d\n",
256 ret);
257 goto err;
258 }
259
260 driver_data->update_gpio = pdata->update_gpio;
261
262 /* Make sure the watchdog takes hardware updates */
263 reg |= WM831X_WDOG_RST_SRC;
264 }
265
266 ret = wm831x_reg_unlock(wm831x);
267 if (ret == 0) {
268 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
269 wm831x_reg_lock(wm831x);
270 } else {
271 dev_err(wm831x->dev,
272 "Failed to unlock security key: %d\n", ret);
273 goto err_gpio;
274 }
275 }
276
277 ret = watchdog_register_device(&driver_data->wdt);
278 if (ret != 0) {
279 dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
280 ret);
281 goto err_gpio;
282 }
283
284 dev_set_drvdata(&pdev->dev, driver_data);
285
286 return 0;
287
288 err_gpio:
289 if (driver_data->update_gpio)
290 gpio_free(driver_data->update_gpio);
291 err:
292 return ret;
293 }
294
wm831x_wdt_remove(struct platform_device * pdev)295 static int wm831x_wdt_remove(struct platform_device *pdev)
296 {
297 struct wm831x_wdt_drvdata *driver_data = dev_get_drvdata(&pdev->dev);
298
299 watchdog_unregister_device(&driver_data->wdt);
300
301 if (driver_data->update_gpio)
302 gpio_free(driver_data->update_gpio);
303
304 return 0;
305 }
306
307 static struct platform_driver wm831x_wdt_driver = {
308 .probe = wm831x_wdt_probe,
309 .remove = wm831x_wdt_remove,
310 .driver = {
311 .name = "wm831x-watchdog",
312 },
313 };
314
315 module_platform_driver(wm831x_wdt_driver);
316
317 MODULE_AUTHOR("Mark Brown");
318 MODULE_DESCRIPTION("WM831x Watchdog");
319 MODULE_LICENSE("GPL");
320 MODULE_ALIAS("platform:wm831x-watchdog");
321