Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/watchdog/wm831x_wdt.c

  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 
 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 
 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 
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 
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 
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 = dev_get_platdata(pdev->dev.parent);
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                 ret = -ENOMEM;
208                 goto err;
209         }
210 
211         mutex_init(&driver_data->lock);
212         driver_data->wm831x = wm831x;
213 
214         wm831x_wdt = &driver_data->wdt;
215 
216         wm831x_wdt->info = &wm831x_wdt_info;
217         wm831x_wdt->ops = &wm831x_wdt_ops;
218         watchdog_set_nowayout(wm831x_wdt, nowayout);
219         watchdog_set_drvdata(wm831x_wdt, driver_data);
220 
221         reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
222         reg &= WM831X_WDOG_TO_MASK;
223         for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
224                 if (wm831x_wdt_cfgs[i].val == reg)
225                         break;
226         if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
227                 dev_warn(wm831x->dev,
228                          "Unknown watchdog timeout: %x\n", reg);
229         else
230                 wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
231 
232         /* Apply any configuration */
233         if (chip_pdata)
234                 pdata = chip_pdata->watchdog;
235         else
236                 pdata = NULL;
237 
238         if (pdata) {
239                 reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
240                          WM831X_WDOG_RST_SRC);
241 
242                 reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
243                 reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
244                 reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
245 
246                 if (pdata->update_gpio) {
247                         ret = devm_gpio_request_one(&pdev->dev,
248                                                 pdata->update_gpio,
249                                                 GPIOF_OUT_INIT_LOW,
250                                                 "Watchdog update");
251                         if (ret < 0) {
252                                 dev_err(wm831x->dev,
253                                         "Failed to request update GPIO: %d\n",
254                                         ret);
255                                 goto err;
256                         }
257 
258                         driver_data->update_gpio = pdata->update_gpio;
259 
260                         /* Make sure the watchdog takes hardware updates */
261                         reg |= WM831X_WDOG_RST_SRC;
262                 }
263 
264                 ret = wm831x_reg_unlock(wm831x);
265                 if (ret == 0) {
266                         ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
267                         wm831x_reg_lock(wm831x);
268                 } else {
269                         dev_err(wm831x->dev,
270                                 "Failed to unlock security key: %d\n", ret);
271                         goto err;
272                 }
273         }
274 
275         ret = watchdog_register_device(&driver_data->wdt);
276         if (ret != 0) {
277                 dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
278                         ret);
279                 goto err;
280         }
281 
282         platform_set_drvdata(pdev, driver_data);
283 
284         return 0;
285 
286 err:
287         return ret;
288 }
289 
290 static int wm831x_wdt_remove(struct platform_device *pdev)
291 {
292         struct wm831x_wdt_drvdata *driver_data = platform_get_drvdata(pdev);
293 
294         watchdog_unregister_device(&driver_data->wdt);
295 
296         return 0;
297 }
298 
299 static struct platform_driver wm831x_wdt_driver = {
300         .probe = wm831x_wdt_probe,
301         .remove = wm831x_wdt_remove,
302         .driver = {
303                 .name = "wm831x-watchdog",
304         },
305 };
306 
307 module_platform_driver(wm831x_wdt_driver);
308 
309 MODULE_AUTHOR("Mark Brown");
310 MODULE_DESCRIPTION("WM831x Watchdog");
311 MODULE_LICENSE("GPL");
312 MODULE_ALIAS("platform:wm831x-watchdog");
313 

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