watchdog: add nowayout helpers to Watchdog Timer Driver Kernel API
[deliverable/linux.git] / drivers / watchdog / wm831x_wdt.c
CommitLineData
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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>
00411ee9 15#include <linux/slab.h>
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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
25static int nowayout = WATCHDOG_NOWAYOUT;
26module_param(nowayout, int, 0);
27MODULE_PARM_DESC(nowayout,
28 "Watchdog cannot be stopped once started (default="
29 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
30
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31struct 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};
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38
39/* We can't use the sub-second values here but they're included
40 * for completeness. */
41static struct {
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42 unsigned int time; /* Seconds */
43 u16 val; /* WDOG_TO value */
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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
00411ee9 54static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
502a0106 55{
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56 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
57 struct wm831x *wm831x = driver_data->wm831x;
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58 int ret;
59
00411ee9 60 mutex_lock(&driver_data->lock);
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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
00411ee9 72 mutex_unlock(&driver_data->lock);
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73
74 return ret;
75}
76
00411ee9 77static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
502a0106 78{
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79 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
80 struct wm831x *wm831x = driver_data->wm831x;
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81 int ret;
82
00411ee9 83 mutex_lock(&driver_data->lock);
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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
00411ee9 95 mutex_unlock(&driver_data->lock);
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96
97 return ret;
98}
99
00411ee9 100static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
502a0106 101{
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102 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
103 struct wm831x *wm831x = driver_data->wm831x;
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104 int ret;
105 u16 reg;
106
00411ee9 107 mutex_lock(&driver_data->lock);
502a0106 108
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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;
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113 ret = 0;
114 goto out;
115 }
116
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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
136out:
00411ee9 137 mutex_unlock(&driver_data->lock);
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138
139 return ret;
140}
141
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142static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
143 unsigned int timeout)
502a0106 144{
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145 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
146 struct wm831x *wm831x = driver_data->wm831x;
147 int ret, i;
502a0106 148
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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))
f9849100 153 return -EINVAL;
502a0106 154
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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);
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164 }
165
00411ee9 166 return ret;
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167}
168
00411ee9 169static const struct watchdog_info wm831x_wdt_info = {
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170 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
171 .identity = "WM831x Watchdog",
172};
173
00411ee9 174static const struct watchdog_ops wm831x_wdt_ops = {
502a0106 175 .owner = THIS_MODULE,
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176 .start = wm831x_wdt_start,
177 .stop = wm831x_wdt_stop,
178 .ping = wm831x_wdt_ping,
179 .set_timeout = wm831x_wdt_set_timeout,
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180};
181
182static int __devinit wm831x_wdt_probe(struct platform_device *pdev)
183{
00411ee9 184 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
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185 struct wm831x_pdata *chip_pdata;
186 struct wm831x_watchdog_pdata *pdata;
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187 struct wm831x_wdt_drvdata *driver_data;
188 struct watchdog_device *wm831x_wdt;
189 int reg, ret, i;
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190
191 ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
192 if (ret < 0) {
193 dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
194 ret);
195 goto err;
196 }
197 reg = ret;
198
199 if (reg & WM831X_WDOG_DEBUG)
200 dev_warn(wm831x->dev, "Watchdog is paused\n");
201
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202 driver_data = kzalloc(sizeof(*driver_data), GFP_KERNEL);
203 if (!driver_data) {
204 dev_err(wm831x->dev, "Unable to alloacate watchdog device\n");
205 ret = -ENOMEM;
206 goto err;
207 }
208
209 mutex_init(&driver_data->lock);
210 driver_data->wm831x = wm831x;
211
212 wm831x_wdt = &driver_data->wdt;
213
214 wm831x_wdt->info = &wm831x_wdt_info;
215 wm831x_wdt->ops = &wm831x_wdt_ops;
ff0b3cd4 216 watchdog_set_nowayout(wm831x_wdt, nowayout);
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217 watchdog_set_drvdata(wm831x_wdt, driver_data);
218
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219 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
220 reg &= WM831X_WDOG_TO_MASK;
221 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
222 if (wm831x_wdt_cfgs[i].val == reg)
223 break;
224 if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
225 dev_warn(wm831x->dev,
226 "Unknown watchdog timeout: %x\n", reg);
227 else
228 wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
229
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230 /* Apply any configuration */
231 if (pdev->dev.parent->platform_data) {
232 chip_pdata = pdev->dev.parent->platform_data;
233 pdata = chip_pdata->watchdog;
234 } else {
235 pdata = NULL;
236 }
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 = gpio_request(pdata->update_gpio,
248 "Watchdog update");
249 if (ret < 0) {
250 dev_err(wm831x->dev,
251 "Failed to request update GPIO: %d\n",
252 ret);
00411ee9 253 goto err_alloc;
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254 }
255
256 ret = gpio_direction_output(pdata->update_gpio, 0);
257 if (ret != 0) {
258 dev_err(wm831x->dev,
259 "gpio_direction_output returned: %d\n",
260 ret);
261 goto err_gpio;
262 }
263
00411ee9 264 driver_data->update_gpio = pdata->update_gpio;
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265
266 /* Make sure the watchdog takes hardware updates */
267 reg |= WM831X_WDOG_RST_SRC;
268 }
269
270 ret = wm831x_reg_unlock(wm831x);
271 if (ret == 0) {
272 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
273 wm831x_reg_lock(wm831x);
274 } else {
275 dev_err(wm831x->dev,
276 "Failed to unlock security key: %d\n", ret);
277 goto err_gpio;
278 }
279 }
280
00411ee9 281 ret = watchdog_register_device(&driver_data->wdt);
502a0106 282 if (ret != 0) {
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283 dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
284 ret);
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285 goto err_gpio;
286 }
287
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288 dev_set_drvdata(&pdev->dev, driver_data);
289
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290 return 0;
291
292err_gpio:
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293 if (driver_data->update_gpio)
294 gpio_free(driver_data->update_gpio);
295err_alloc:
296 kfree(driver_data);
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297err:
298 return ret;
299}
300
301static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
302{
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303 struct wm831x_wdt_drvdata *driver_data = dev_get_drvdata(&pdev->dev);
304
305 watchdog_unregister_device(&driver_data->wdt);
502a0106 306
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307 if (driver_data->update_gpio)
308 gpio_free(driver_data->update_gpio);
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309
310 return 0;
311}
312
313static struct platform_driver wm831x_wdt_driver = {
314 .probe = wm831x_wdt_probe,
315 .remove = __devexit_p(wm831x_wdt_remove),
316 .driver = {
317 .name = "wm831x-watchdog",
318 },
319};
320
216f3ad9 321module_platform_driver(wm831x_wdt_driver);
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322
323MODULE_AUTHOR("Mark Brown");
324MODULE_DESCRIPTION("WM831x Watchdog");
325MODULE_LICENSE("GPL");
326MODULE_ALIAS("platform:wm831x-watchdog");
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