1 // SPDX-License-Identifier: GPL-2.0-or-later
3  *	Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
12 #include <linux/watchdog.h>
36 		"Watchdog timeout in seconds. (0 < timeout < 18000, default="
42 		"Watchdog cannot be stopped once started (default="
46  *	ali_start	-	start watchdog countdown
48  *	Starts the timer running providing the timer has a counter
67  *	ali_stop	-	stop the timer countdown
69  *	Stop the ALi watchdog countdown
87  *	ali_keepalive	-	send a keepalive to the watchdog
89  *	Send a keepalive to the timer (actually we restart the timer).
98  *	ali_settimer	-	compute the timer reload value
107 		return -EINVAL;  in ali_settimer()
115 		return -EINVAL;  in ali_settimer()
122  *	/dev/watchdog handling
126  *	ali_write	-	writes to ALi watchdog
132  *	Handle a write to the ALi watchdog. Writing to the file pings
133  *	the watchdog and resets it. Writing the magic 'V' sequence allows
134  *	the next close to turn off the watchdog.
140 	/* See if we got the magic character 'V' and reload the timer */  in ali_write()
154 					return -EFAULT;  in ali_write()
160 		/* someone wrote to us, we should reload the timer */  in ali_write()
167  *	ali_ioctl	-	handle watchdog ioctls
172  *	Handle the watchdog ioctls supported by the ALi driver. Really
185 		.identity =		"ALi M1535 WatchDog Timer",  in ali_ioctl()
190 		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;  in ali_ioctl()
197 		int new_options, retval = -EINVAL;  in ali_ioctl()
200 			return -EFAULT;  in ali_ioctl()
218 			return -EFAULT;  in ali_ioctl()
220 			return -EINVAL;  in ali_ioctl()
227 		return -ENOTTY;  in ali_ioctl()
232  *	ali_open	-	handle open of ali watchdog
236  *	Open the ALi watchdog device. Ensure only one person opens it
237  *	at a time. Also start the watchdog running.
242 	/* /dev/watchdog can only be opened once */  in ali_open()
244 		return -EBUSY;  in ali_open()
252  *	ali_release	-	close an ALi watchdog
256  *	Close the ALi watchdog device. Actual shutdown of the timer
263 	 *      Shut off the timer.  in ali_release()
268 		pr_crit("Unexpected close, not stopping watchdog!\n");  in ali_release()
277  *	ali_notify_sys	-	System down notifier
308  *	ali_find_watchdog	-	find a 1535 and 7101
311  *	watchdog device. This may be overtight but it is better to be safe
324 		return -ENODEV;  in ali_find_watchdog()
330 		return -ENODEV;  in ali_find_watchdog()
334 		return -EIO;  in ali_find_watchdog()
340 	 *	Initialize the timer bits  in ali_find_watchdog()
344 	/* Timer bits */  in ali_find_watchdog()
371 	.name =		"watchdog",
380  *	watchdog_init	-	module initialiser
382  *	Scan for a suitable watchdog and if so initialize it. Return an error
390 	/* Check whether or not the hardware watchdog is there */  in watchdog_init()
392 		return -ENODEV;  in watchdog_init()
402 	/* Calculate the watchdog's timeout */  in watchdog_init()
429  *	watchdog_exit	-	module de-initialiser
431  *	Called while unloading a successfully installed watchdog module.
436 	/* Stop the timer before we leave */  in watchdog_exit()
449 MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");