ARM: dts: add 'dr_mode' property to hsotg devices for exynos boards
[linux/fpc-iii.git] / drivers / watchdog / ks8695_wdt.c
blobb7ea39b455c86c730f895e1a63ad8d1ee172068f
1 /*
2 * Watchdog driver for Kendin/Micrel KS8695.
4 * (C) 2007 Andrew Victor
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/bitops.h>
14 #include <linux/errno.h>
15 #include <linux/fs.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/miscdevice.h>
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/platform_device.h>
22 #include <linux/types.h>
23 #include <linux/watchdog.h>
24 #include <linux/io.h>
25 #include <linux/uaccess.h>
26 #include <mach/hardware.h>
28 #define KS8695_TMR_OFFSET (0xF0000 + 0xE400)
29 #define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET)
32 * Timer registers
34 #define KS8695_TMCON (0x00) /* Timer Control Register */
35 #define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */
36 #define TMCON_T0EN (1 << 0) /* Timer 0 Enable */
38 /* Timer0 Timeout Counter Register */
39 #define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */
41 #define WDT_DEFAULT_TIME 5 /* seconds */
42 #define WDT_MAX_TIME 171 /* seconds */
44 static int wdt_time = WDT_DEFAULT_TIME;
45 static bool nowayout = WATCHDOG_NOWAYOUT;
47 module_param(wdt_time, int, 0);
48 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
49 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
51 #ifdef CONFIG_WATCHDOG_NOWAYOUT
52 module_param(nowayout, bool, 0);
53 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
54 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
55 #endif
58 static unsigned long ks8695wdt_busy;
59 static DEFINE_SPINLOCK(ks8695_lock);
61 /* ......................................................................... */
64 * Disable the watchdog.
66 static inline void ks8695_wdt_stop(void)
68 unsigned long tmcon;
70 spin_lock(&ks8695_lock);
71 /* disable timer0 */
72 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
73 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
74 spin_unlock(&ks8695_lock);
78 * Enable and reset the watchdog.
80 static inline void ks8695_wdt_start(void)
82 unsigned long tmcon;
83 unsigned long tval = wdt_time * KS8695_CLOCK_RATE;
85 spin_lock(&ks8695_lock);
86 /* disable timer0 */
87 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
88 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
90 /* program timer0 */
91 __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
93 /* re-enable timer0 */
94 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
95 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
96 spin_unlock(&ks8695_lock);
100 * Reload the watchdog timer. (ie, pat the watchdog)
102 static inline void ks8695_wdt_reload(void)
104 unsigned long tmcon;
106 spin_lock(&ks8695_lock);
107 /* disable, then re-enable timer0 */
108 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
109 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
110 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
111 spin_unlock(&ks8695_lock);
115 * Change the watchdog time interval.
117 static int ks8695_wdt_settimeout(int new_time)
120 * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
122 * Since WDV is a 16-bit counter, the maximum period is
123 * 65536 / 0.256 = 256 seconds.
125 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
126 return -EINVAL;
128 /* Set new watchdog time. It will be used when
129 ks8695_wdt_start() is called. */
130 wdt_time = new_time;
131 return 0;
134 /* ......................................................................... */
137 * Watchdog device is opened, and watchdog starts running.
139 static int ks8695_wdt_open(struct inode *inode, struct file *file)
141 if (test_and_set_bit(0, &ks8695wdt_busy))
142 return -EBUSY;
144 ks8695_wdt_start();
145 return nonseekable_open(inode, file);
149 * Close the watchdog device.
150 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
151 * disabled.
153 static int ks8695_wdt_close(struct inode *inode, struct file *file)
155 /* Disable the watchdog when file is closed */
156 if (!nowayout)
157 ks8695_wdt_stop();
158 clear_bit(0, &ks8695wdt_busy);
159 return 0;
162 static const struct watchdog_info ks8695_wdt_info = {
163 .identity = "ks8695 watchdog",
164 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
168 * Handle commands from user-space.
170 static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
171 unsigned long arg)
173 void __user *argp = (void __user *)arg;
174 int __user *p = argp;
175 int new_value;
177 switch (cmd) {
178 case WDIOC_GETSUPPORT:
179 return copy_to_user(argp, &ks8695_wdt_info,
180 sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
181 case WDIOC_GETSTATUS:
182 case WDIOC_GETBOOTSTATUS:
183 return put_user(0, p);
184 case WDIOC_SETOPTIONS:
185 if (get_user(new_value, p))
186 return -EFAULT;
187 if (new_value & WDIOS_DISABLECARD)
188 ks8695_wdt_stop();
189 if (new_value & WDIOS_ENABLECARD)
190 ks8695_wdt_start();
191 return 0;
192 case WDIOC_KEEPALIVE:
193 ks8695_wdt_reload(); /* pat the watchdog */
194 return 0;
195 case WDIOC_SETTIMEOUT:
196 if (get_user(new_value, p))
197 return -EFAULT;
198 if (ks8695_wdt_settimeout(new_value))
199 return -EINVAL;
200 /* Enable new time value */
201 ks8695_wdt_start();
202 /* Return current value */
203 return put_user(wdt_time, p);
204 case WDIOC_GETTIMEOUT:
205 return put_user(wdt_time, p);
206 default:
207 return -ENOTTY;
212 * Pat the watchdog whenever device is written to.
214 static ssize_t ks8695_wdt_write(struct file *file, const char *data,
215 size_t len, loff_t *ppos)
217 ks8695_wdt_reload(); /* pat the watchdog */
218 return len;
221 /* ......................................................................... */
223 static const struct file_operations ks8695wdt_fops = {
224 .owner = THIS_MODULE,
225 .llseek = no_llseek,
226 .unlocked_ioctl = ks8695_wdt_ioctl,
227 .open = ks8695_wdt_open,
228 .release = ks8695_wdt_close,
229 .write = ks8695_wdt_write,
232 static struct miscdevice ks8695wdt_miscdev = {
233 .minor = WATCHDOG_MINOR,
234 .name = "watchdog",
235 .fops = &ks8695wdt_fops,
238 static int ks8695wdt_probe(struct platform_device *pdev)
240 int res;
242 if (ks8695wdt_miscdev.parent)
243 return -EBUSY;
244 ks8695wdt_miscdev.parent = &pdev->dev;
246 res = misc_register(&ks8695wdt_miscdev);
247 if (res)
248 return res;
250 pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n",
251 wdt_time, nowayout ? ", nowayout" : "");
252 return 0;
255 static int ks8695wdt_remove(struct platform_device *pdev)
257 int res;
259 res = misc_deregister(&ks8695wdt_miscdev);
260 if (!res)
261 ks8695wdt_miscdev.parent = NULL;
263 return res;
266 static void ks8695wdt_shutdown(struct platform_device *pdev)
268 ks8695_wdt_stop();
271 #ifdef CONFIG_PM
273 static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
275 ks8695_wdt_stop();
276 return 0;
279 static int ks8695wdt_resume(struct platform_device *pdev)
281 if (ks8695wdt_busy)
282 ks8695_wdt_start();
283 return 0;
286 #else
287 #define ks8695wdt_suspend NULL
288 #define ks8695wdt_resume NULL
289 #endif
291 static struct platform_driver ks8695wdt_driver = {
292 .probe = ks8695wdt_probe,
293 .remove = ks8695wdt_remove,
294 .shutdown = ks8695wdt_shutdown,
295 .suspend = ks8695wdt_suspend,
296 .resume = ks8695wdt_resume,
297 .driver = {
298 .name = "ks8695_wdt",
302 static int __init ks8695_wdt_init(void)
304 /* Check that the heartbeat value is within range;
305 if not reset to the default */
306 if (ks8695_wdt_settimeout(wdt_time)) {
307 ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
308 pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
309 ", using %d\n", wdt_time, WDT_MAX_TIME);
311 return platform_driver_register(&ks8695wdt_driver);
314 static void __exit ks8695_wdt_exit(void)
316 platform_driver_unregister(&ks8695wdt_driver);
319 module_init(ks8695_wdt_init);
320 module_exit(ks8695_wdt_exit);
322 MODULE_AUTHOR("Andrew Victor");
323 MODULE_DESCRIPTION("Watchdog driver for KS8695");
324 MODULE_LICENSE("GPL");
325 MODULE_ALIAS("platform:ks8695_wdt");