2 * Watchdog driver for the wm8350
4 * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
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
11 #include <linux/module.h>
12 #include <linux/moduleparam.h>
13 #include <linux/types.h>
14 #include <linux/kernel.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/mfd/wm8350/core.h>
22 static int nowayout = WATCHDOG_NOWAYOUT;
23 module_param(nowayout, int, 0);
24 MODULE_PARM_DESC(nowayout,
25 "Watchdog cannot be stopped once started (default="
26 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
28 static unsigned long wm8350_wdt_users;
29 static struct miscdevice wm8350_wdt_miscdev;
30 static int wm8350_wdt_expect_close;
31 static DEFINE_MUTEX(wdt_mutex);
34 int time; /* Seconds */
35 u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */
36 } wm8350_wdt_cfgs[] = {
42 static struct wm8350 *get_wm8350(void)
44 return dev_get_drvdata(wm8350_wdt_miscdev.parent);
47 static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value)
52 mutex_lock(&wdt_mutex);
53 wm8350_reg_unlock(wm8350);
55 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
56 reg &= ~WM8350_WDOG_TO_MASK;
58 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
60 wm8350_reg_lock(wm8350);
61 mutex_unlock(&wdt_mutex);
66 static int wm8350_wdt_start(struct wm8350 *wm8350)
71 mutex_lock(&wdt_mutex);
72 wm8350_reg_unlock(wm8350);
74 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
75 reg &= ~WM8350_WDOG_MODE_MASK;
77 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
79 wm8350_reg_lock(wm8350);
80 mutex_unlock(&wdt_mutex);
85 static int wm8350_wdt_stop(struct wm8350 *wm8350)
90 mutex_lock(&wdt_mutex);
91 wm8350_reg_unlock(wm8350);
93 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
94 reg &= ~WM8350_WDOG_MODE_MASK;
95 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
97 wm8350_reg_lock(wm8350);
98 mutex_unlock(&wdt_mutex);
103 static int wm8350_wdt_kick(struct wm8350 *wm8350)
108 mutex_lock(&wdt_mutex);
110 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
111 ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
113 mutex_unlock(&wdt_mutex);
118 static int wm8350_wdt_open(struct inode *inode, struct file *file)
120 struct wm8350 *wm8350 = get_wm8350();
126 if (test_and_set_bit(0, &wm8350_wdt_users))
129 ret = wm8350_wdt_start(wm8350);
133 return nonseekable_open(inode, file);
136 static int wm8350_wdt_release(struct inode *inode, struct file *file)
138 struct wm8350 *wm8350 = get_wm8350();
140 if (wm8350_wdt_expect_close)
141 wm8350_wdt_stop(wm8350);
143 dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n");
144 wm8350_wdt_kick(wm8350);
147 clear_bit(0, &wm8350_wdt_users);
152 static ssize_t wm8350_wdt_write(struct file *file,
153 const char __user *data, size_t count,
156 struct wm8350 *wm8350 = get_wm8350();
160 wm8350_wdt_kick(wm8350);
163 /* In case it was set long ago */
164 wm8350_wdt_expect_close = 0;
166 /* scan to see whether or not we got the magic
168 for (i = 0; i != count; i++) {
170 if (get_user(c, data + i))
173 wm8350_wdt_expect_close = 42;
180 static const struct watchdog_info ident = {
181 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
182 .identity = "WM8350 Watchdog",
185 static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd,
188 struct wm8350 *wm8350 = get_wm8350();
189 int ret = -ENOTTY, time, i;
190 void __user *argp = (void __user *)arg;
191 int __user *p = argp;
195 case WDIOC_GETSUPPORT:
196 ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
199 case WDIOC_GETSTATUS:
200 case WDIOC_GETBOOTSTATUS:
201 ret = put_user(0, p);
204 case WDIOC_SETOPTIONS:
208 if (get_user(options, p))
213 /* Setting both simultaneously means at least one must fail */
214 if (options == WDIOS_DISABLECARD)
215 ret = wm8350_wdt_start(wm8350);
217 if (options == WDIOS_ENABLECARD)
218 ret = wm8350_wdt_stop(wm8350);
222 case WDIOC_KEEPALIVE:
223 ret = wm8350_wdt_kick(wm8350);
226 case WDIOC_SETTIMEOUT:
227 ret = get_user(time, p);
235 wm8350_wdt_stop(wm8350);
239 for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
240 if (wm8350_wdt_cfgs[i].time == time)
242 if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
245 ret = wm8350_wdt_set_timeout(wm8350,
246 wm8350_wdt_cfgs[i].val);
249 case WDIOC_GETTIMEOUT:
250 reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
251 reg &= WM8350_WDOG_TO_MASK;
252 for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
253 if (wm8350_wdt_cfgs[i].val == reg)
255 if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) {
256 dev_warn(wm8350->dev,
257 "Unknown watchdog configuration: %x\n", reg);
260 ret = put_user(wm8350_wdt_cfgs[i].time, p);
267 static const struct file_operations wm8350_wdt_fops = {
268 .owner = THIS_MODULE,
270 .write = wm8350_wdt_write,
271 .unlocked_ioctl = wm8350_wdt_ioctl,
272 .open = wm8350_wdt_open,
273 .release = wm8350_wdt_release,
276 static struct miscdevice wm8350_wdt_miscdev = {
277 .minor = WATCHDOG_MINOR,
279 .fops = &wm8350_wdt_fops,
282 static int __devinit wm8350_wdt_probe(struct platform_device *pdev)
284 struct wm8350 *wm8350 = platform_get_drvdata(pdev);
287 pr_err("No driver data supplied\n");
291 /* Default to 4s timeout */
292 wm8350_wdt_set_timeout(wm8350, 0x05);
294 wm8350_wdt_miscdev.parent = &pdev->dev;
296 return misc_register(&wm8350_wdt_miscdev);
299 static int __devexit wm8350_wdt_remove(struct platform_device *pdev)
301 misc_deregister(&wm8350_wdt_miscdev);
306 static struct platform_driver wm8350_wdt_driver = {
307 .probe = wm8350_wdt_probe,
308 .remove = __devexit_p(wm8350_wdt_remove),
310 .name = "wm8350-wdt",
314 static int __init wm8350_wdt_init(void)
316 return platform_driver_register(&wm8350_wdt_driver);
318 module_init(wm8350_wdt_init);
320 static void __exit wm8350_wdt_exit(void)
322 platform_driver_unregister(&wm8350_wdt_driver);
324 module_exit(wm8350_wdt_exit);
326 MODULE_AUTHOR("Mark Brown");
327 MODULE_DESCRIPTION("WM8350 Watchdog");
328 MODULE_LICENSE("GPL");
329 MODULE_ALIAS("platform:wm8350-wdt");