Re: [PATCH 0/3] Suspending i.MX watchdog in WAIT mode

From: Andrej Picej
Date: Thu Oct 20 2022 - 01:22:11 EST


Hi Guenter,

On 19. 10. 22 17:30, Guenter Roeck wrote:
On Wed, Oct 19, 2022 at 01:17:11PM +0200, Andrej Picej wrote:
The i.MX6 watchdog can't be stopped once started. This means that
special hardware suspend needs to be configured when the device enters
low-power modes.
Usually i.MX devices have two bits which deal with this:
- WDZST bit disables the timer in "deeper" low power modes and
- WDW bit disables the timer in "WAIT" mode which corresponds with
Linux's "freeze" low-power mode.

WDZST bit support is already in place since 1a9c5efa576e ("watchdog: imx2_wdt: disable watchdog timer during low power mode").
WDW bit is not common for all imx2-wdt supported devices, therefore use
a new device-tree property "fsl,suspend-in-wait" which suspends the
watchdog in "WAIT" mode.

I think that needs to be validated using the "compatible" property;
it should not be possible to set/accept the new flag for devices
which don't support it.

Ok, I can add that to a v2.

Thanks,
Andrej


Thanks,
Guenter