watchdog: sp5100_tco: Immediately trigger upon starting.

stable inclusion
from stable-v5.10.181
commit dbcc95bb510e973c874ecacc170bacfad33e0b89
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8GJZJ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dbcc95bb510e973c874ecacc170bacfad33e0b89



--------------------------------

commit 4eda19cc upstream.

The watchdog countdown is supposed to begin when the device file is
opened. Instead, it would begin countdown upon the first write to or
close of the device file. Now, the ping operation is called within the
start operation which ensures the countdown begins. From experimenation,
it does not appear possible to do this with a single write including
both the start bit and the trigger bit. So, it is done as two distinct
writes.

Signed-off-by: Gregory Oakes <gregory.oakes@amd.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230316201312.17538-1-gregory.oakes@amd.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>
(cherry picked from commit aeff4428)