Re: [PATCH v2 2/3] dt-bindings: watchdog: fsl-imx: document suspend in wait mode

[Andrej Picej]

On 26. 10. 22 16:12, Krzysztof Kozlowski wrote:
> On 26/10/2022 02:38, Andrej Picej wrote:
> > On 25. 10. 22 15:48, Krzysztof Kozlowski wrote:
> > > On 25/10/2022 03:25, Andrej Picej wrote:
> > > > Property "fsl,suspend-in-wait" suspends watchdog in "WAIT" mode which
> > > > corresponds to Linux's Suspend-to-Idle S0 mode. If this property is not
> > > > set and the device is put into Suspend-to-Idle mode, the watchdog
> > > > triggers a reset after 128 seconds.
> > > >
> > > > Signed-off-by: Andrej Picej <andrej.picej@xxxxxxxxx>
> > > > Reviewed-by: Fabio Estevam <festevam@xxxxxxxxx>
> > > > ---
> > > > Changes in v2:
> > > >    - add a commit message,
> > > >    - add a list of devices which support this functionality
> > > > ---
> > > >    .../bindings/watchdog/fsl-imx-wdt.yaml        | 22 +++++++++++++++++++
> > > >    1 file changed, 22 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.yaml b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.yaml
> > > > index fb7695515be1..9289de97859b 100644
> > > > --- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.yaml
> > > > +++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.yaml
> > > > @@ -55,6 +55,28 @@ properties:
> > > >          If present, the watchdog device is configured to assert its
> > > >          external reset (WDOG_B) instead of issuing a software reset.
> > > >    
> > > > +  fsl,suspend-in-wait:
> > > > +    $ref: /schemas/types.yaml#/definitions/flag
> > > > +    description: |
> > > > +      If present, the watchdog device is suspended in WAIT mode
> > > > +      (Suspend-to-Idle). Only supported on following devices:
> > > > +        - "fsl,imx25-wdt",
> > >
> > > You need to define such allow/disallow in allOf:if:then, instead. Like
> > > example-schema is doing for foo-supply, just disallow it for some types
> > > or use "if: not: ..."
> >
> > Sorry missed that. So something like that should be added?:
> >
> > > allOf:
> > >    - if:
> > >        not:
> > >          properties:
> > >            compatible:
> > >              contains:
> > >                enum:
> > >                  - fsl,imx25-wdt
> > >                  - fsl,imx35-wdt
> > >                  - fsl,imx50-wdt
> > >                  - fsl,imx51-wdt
> > >                  - fsl,imx53-wdt
> > >                  - fsl,imx6q-wdt
> > >                  - fsl,imx6sl-wdt
> > >                  - fsl,imx6sll-wdt
> > >                  - fsl,imx6sx-wdt
> > >                  - fsl,imx6ul-wdt
> > >                  - fsl,imx7d-wdt
> > >                  - fsl,imx8mm-wdt
> > >                  - fsl,imx8mn-wdt
> > >                  - fsl,imx8mp-wdt
> > >                  - fsl,imx8mq-wdt
> > >                  - fsl,vf610-wdt
>
> Yes.
>
> > >      then:
> > >        properties:
> > >          fsl,suspend-in-wait: false
> >
> > And I'm assuming I can then remove the supported devices list from
> > property description.
>
> Yes.
>
> > Are you fine with this, so we don't have to split the compatible list
> > like Alexander suggested? Basically we have the same list of WDW
> > supported devices in the driver.
>
> I don't know to what you refer.
I'm referring to this comment by Alexander Stein: 
(https://lore.kernel.org/all/13126397.uLZWGnKmhe@steina-w/)

> So the models listed in Documentation/devicetree/bindings/watchdog/fsl-imx-
> wdt.yaml not supporting this feature are
> * fsl,imx21-wdt
> * fsl,imx27-wdt
> * fsl,imx31-wdt
> * fsl,ls1012a-wdt
> * fsl,ls1043a-wdt
> ?
>
> But all models are listed as compatible to fsl,imx21-wdt. So there is 
> something wrong here. IMHO this sounds like the compatible list has to be 
> split and updated. Depending on that this feature can be detected. Maintaining 
> another list seems error prone to me.

Best regards,
Andrej.