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

Guenter Roeck linux at roeck-us.net
Thu Jan 13 11:43:07 PST 2022


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



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