linux watchdog

watchdog_device
watchdog_ops
watchdog_info

static struct class *watchdog_class;
void watchdog_check_min_max_timeout(struct watchdog_device *wdd)

int watchdog_init_timeout(struct watchdog_device *wdd, unsigned int timeout_parm, struct device *dev)


watchdog_ping: ping the watchdog.
watchdog_start: wrapper to start the watchdog.
watchdog_stop: wrapper to stop the watchdog.
watchdog_get_status: wrapper to get the watchdog status.
watchdog_set_timeout: set the watchdog timer timeout
watchdog_get_timeleft: wrapper to get the time left before a reboot
watchdog_ioctl_op: call the watchdog drivers ioctl op if defined

need read the follow files in kernel/deviers/watchdog/ folder:
watchdog_core.c  watchdog_core.h  watchdog_dev.c

watchdog_dev supply file interface to applications and watchdog_core supply interface to specific hardware's driver, the specific watchdog driver need supply the related watchdog_ops something like .start and .stop is must.

watchdog_ping is notify watchdog hardware to delay another timeout to reboot the hardware. in someplace the member .ping and .start of watchdog_ops are same.

need read the follow files in Documents/watchdog/ folder:

watchdog-api.txt      watchdog-kernel-api.txt      wdt.txt