drivers/watchdog/sbc60xxwdt.c

1 // SPDX-License-Identifier: GPL-2.0-or-later
3  *	60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
8  *	any of this software. This material is provided "AS-IS" in
13  *           12/4 - 2000      [Initial revision]
14  *           25/4 - 2000      Added /dev/watchdog support
15  *           09/5 - 2001      [smj@oro.net] fixed fop_write to "return 1"
17  *           12/4 - 2002      [rob@osinvestor.com] eliminate fop_read
28  *           09/8 - 2003      [wim@iguana.be] cleanup of trailing spaces
39  *  *)  The driver will ping the watchdog by itself, because this
50 #include <linux/timer.h>
53 #include <linux/watchdog.h>
67  * You must set these - The driver cannot probe for the settings
79  * The 60xx board can use watchdog timeout values from one second
81  * the watchdog every ~250ms we should be safe.
89  * char to /dev/watchdog every 30 seconds.
100 	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
106 	"Watchdog cannot be stopped once started (default="
110 static DEFINE_TIMER(timer, wdt_timer_ping);
127 		/* Re-set the timer interval */  in wdt_timer_ping()
128 		mod_timer(&timer, jiffies + WDT_INTERVAL);  in wdt_timer_ping()
130 		pr_warn("Heartbeat lost! Will not ping the watchdog\n");  in wdt_timer_ping()
141 	/* Start the timer */  in wdt_startup()
142 	mod_timer(&timer, jiffies + WDT_INTERVAL);  in wdt_startup()
143 	pr_info("Watchdog timer is now enabled\n");  in wdt_startup()
148 	/* Stop the timer */  in wdt_turnoff()
149 	del_timer_sync(&timer);  in wdt_turnoff()
151 	pr_info("Watchdog timer is now disabled...\n");  in wdt_turnoff()
161  * /dev/watchdog handling
167 	/* See if we got the magic character 'V' and reload the timer */  in fop_write()
181 					return -EFAULT;  in fop_write()
198 		return -EBUSY;  in fop_open()
213 		del_timer(&timer);  in fop_close()
234 		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;  in fop_ioctl()
240 		int new_options, retval = -EINVAL;  in fop_ioctl()
242 			return -EFAULT;  in fop_ioctl()
260 			return -EFAULT;  in fop_ioctl()
263 			return -EINVAL;  in fop_ioctl()
272 		return -ENOTTY;  in fop_ioctl()
287 	.name = "watchdog",
327 	int rc = -EBUSY;  in sbc60xxwdt_init()
337 		rc = -EIO;  in sbc60xxwdt_init()
341 	/* We cannot reserve 0x45 - the kernel already has! */  in sbc60xxwdt_init()
345 			rc = -EIO;  in sbc60xxwdt_init()
382 MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");