USB: usbsevseg: fix max length
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / watchdog / wm831x_wdt.c
blobe789a47db41f4dc1c618efaba3c8e189851c42bb
1 /*
2 * Watchdog driver for the wm831x PMICs
4 * Copyright (C) 2009 Wolfson Microelectronics
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 */
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>
21 #include <linux/mfd/wm831x/core.h>
22 #include <linux/mfd/wm831x/pdata.h>
23 #include <linux/mfd/wm831x/watchdog.h>
25 static int nowayout = WATCHDOG_NOWAYOUT;
26 module_param(nowayout, int, 0);
27 MODULE_PARM_DESC(nowayout,
28 "Watchdog cannot be stopped once started (default="
29 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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;
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 */
54 static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
56 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
57 struct wm831x *wm831x = driver_data->wm831x;
58 int ret;
60 mutex_lock(&driver_data->lock);
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);
72 mutex_unlock(&driver_data->lock);
74 return ret;
77 static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
79 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
80 struct wm831x *wm831x = driver_data->wm831x;
81 int ret;
83 mutex_lock(&driver_data->lock);
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);
95 mutex_unlock(&driver_data->lock);
97 return ret;
100 static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
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;
107 mutex_lock(&driver_data->lock);
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;
117 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
119 if (!(reg & WM831X_WDOG_RST_SRC)) {
120 dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
121 ret = -EINVAL;
122 goto out;
125 reg |= WM831X_WDOG_RESET;
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);
136 out:
137 mutex_unlock(&driver_data->lock);
139 return ret;
142 static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
143 unsigned int timeout)
145 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
146 struct wm831x *wm831x = driver_data->wm831x;
147 int ret, i;
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;
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);
166 return ret;
169 static const struct watchdog_info wm831x_wdt_info = {
170 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
171 .identity = "WM831x Watchdog",
174 static const struct watchdog_ops wm831x_wdt_ops = {
175 .owner = THIS_MODULE,
176 .start = wm831x_wdt_start,
177 .stop = wm831x_wdt_stop,
178 .ping = wm831x_wdt_ping,
179 .set_timeout = wm831x_wdt_set_timeout,
182 static int __devinit wm831x_wdt_probe(struct platform_device *pdev)
184 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
185 struct wm831x_pdata *chip_pdata;
186 struct wm831x_watchdog_pdata *pdata;
187 struct wm831x_wdt_drvdata *driver_data;
188 struct watchdog_device *wm831x_wdt;
189 int reg, ret, i;
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;
197 reg = ret;
199 if (reg & WM831X_WDOG_DEBUG)
200 dev_warn(wm831x->dev, "Watchdog is paused\n");
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;
209 mutex_init(&driver_data->lock);
210 driver_data->wm831x = wm831x;
212 wm831x_wdt = &driver_data->wdt;
214 wm831x_wdt->info = &wm831x_wdt_info;
215 wm831x_wdt->ops = &wm831x_wdt_ops;
216 watchdog_set_drvdata(wm831x_wdt, driver_data);
218 if (nowayout)
219 wm831x_wdt->status |= WDOG_NO_WAY_OUT;
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;
232 /* Apply any configuration */
233 if (pdev->dev.parent->platform_data) {
234 chip_pdata = pdev->dev.parent->platform_data;
235 pdata = chip_pdata->watchdog;
236 } else {
237 pdata = NULL;
240 if (pdata) {
241 reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
242 WM831X_WDOG_RST_SRC);
244 reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
245 reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
246 reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
248 if (pdata->update_gpio) {
249 ret = gpio_request(pdata->update_gpio,
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_alloc;
258 ret = gpio_direction_output(pdata->update_gpio, 0);
259 if (ret != 0) {
260 dev_err(wm831x->dev,
261 "gpio_direction_output returned: %d\n",
262 ret);
263 goto err_gpio;
266 driver_data->update_gpio = pdata->update_gpio;
268 /* Make sure the watchdog takes hardware updates */
269 reg |= WM831X_WDOG_RST_SRC;
272 ret = wm831x_reg_unlock(wm831x);
273 if (ret == 0) {
274 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
275 wm831x_reg_lock(wm831x);
276 } else {
277 dev_err(wm831x->dev,
278 "Failed to unlock security key: %d\n", ret);
279 goto err_gpio;
283 ret = watchdog_register_device(&driver_data->wdt);
284 if (ret != 0) {
285 dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
286 ret);
287 goto err_gpio;
290 dev_set_drvdata(&pdev->dev, driver_data);
292 return 0;
294 err_gpio:
295 if (driver_data->update_gpio)
296 gpio_free(driver_data->update_gpio);
297 err_alloc:
298 kfree(driver_data);
299 err:
300 return ret;
303 static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
305 struct wm831x_wdt_drvdata *driver_data = dev_get_drvdata(&pdev->dev);
307 watchdog_unregister_device(&driver_data->wdt);
309 if (driver_data->update_gpio)
310 gpio_free(driver_data->update_gpio);
312 return 0;
315 static struct platform_driver wm831x_wdt_driver = {
316 .probe = wm831x_wdt_probe,
317 .remove = __devexit_p(wm831x_wdt_remove),
318 .driver = {
319 .name = "wm831x-watchdog",
323 static int __init wm831x_wdt_init(void)
325 return platform_driver_register(&wm831x_wdt_driver);
327 module_init(wm831x_wdt_init);
329 static void __exit wm831x_wdt_exit(void)
331 platform_driver_unregister(&wm831x_wdt_driver);
333 module_exit(wm831x_wdt_exit);
335 MODULE_AUTHOR("Mark Brown");
336 MODULE_DESCRIPTION("WM831x Watchdog");
337 MODULE_LICENSE("GPL");
338 MODULE_ALIAS("platform:wm831x-watchdog");