From: Gregory Oakes <gregory.oakes@xxxxxxx> commit 4eda19cc8a29cde3580ed73bf11dc73b4e757697 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@xxxxxxx> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230316201312.17538-1-gregory.oakes@xxxxxxx Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx> Cc: Mario Limonciello <mario.limonciello@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/watchdog/sp5100_tco.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/watchdog/sp5100_tco.c +++ b/drivers/watchdog/sp5100_tco.c @@ -115,6 +115,10 @@ static int tco_timer_start(struct watchd val |= SP5100_WDT_START_STOP_BIT; writel(val, SP5100_WDT_CONTROL(tco->tcobase)); + /* This must be a distinct write. */ + val |= SP5100_WDT_TRIGGER_BIT; + writel(val, SP5100_WDT_CONTROL(tco->tcobase)); + return 0; }
