[PATCH v2] watchdog: mediatek: acknowledge pretimeout interrupt

[Guenter Roeck]

On Thu, Aug 27, 2026 at 05:26:12PM +0800, Wanming Gao wrote:
> The MediaTek watchdog pretimeout interrupt is level-triggered and does
> not have a separate acknowledge register. The interrupt is cleared by
> changing WDT_MODE_IRQ_LEVEL_EN and then restoring it to its original
> state. Without this transition, the interrupt may remain asserted and
> cause an interrupt storm.
> 
> After changing WDT_MODE_IRQ_LEVEL_EN, wait 70 us before restoring it.
> This is longer than two 32 kHz watchdog clock cycles, allowing the
> level change to propagate across the clock domain.
> 
> WDT_MODE is also updated by the watchdog start, stop, and pretimeout
> operations. Protect its read-modify-write sequences and the complete
> IRQ acknowledge sequence with the watchdog spinlock so that concurrent
> updates cannot overwrite the temporary IRQ level state.
> 
> Signed-off-by: Wanming Gao <wanming.gao at mediatek.com>

Applied.

Thanks,
Guenter