Re: [PATCH 1/2] watchdog: imx2_wdg: Alow ping on suspend

From: Guenter Roeck
Date: Thu Jan 13 2022 - 14:43:17 EST


On 1/13/22 10:55 AM, Stefan Wahren wrote:
Hi,

Am 09.01.22 um 12:41 schrieb Alistair Francis:
The i.MX watchdog cannot be disabled by softwrae once it has been
s/softwrae/software/
enabled. This means that it can't be stopped before suspend.

For systems that enter low power mode this is fine, as the watchdog will
be automatically stopped by hardwrae in low power mode. Not all i.MX
s/hardwrae/hardware/
platforms support low power mode in the mainline kernel. For example the
i.MX7D does not enter low power mode and so will be rebooted 2 minutes
after entering freeze or mem sleep states.

This patch introduces a device tree property "fsl,ping-during-suspend"
that can be used to enable ping on suspend support for these systems.

Introducing vendor specific properties for Linux behavior should be
avoided. The DT should describe just the hardware.

In case i.mx7d is affected, how about enabling this workaround for
compatible fsl,imx7d-wdt? This has the advantage that in case low power
mode will be implemented
<https://elixir.bootlin.com/linux/latest/B/ident/fsl%2Cimx7d-wdt>, we
don't have to care about DTB files.


Agreed.

Guenter