RE: [PATCH v6 02/11] dt-bindings: pwm: rzg2l-gpt: Document renesas,poegs property

Biju Das <[email protected]>
Newsgroups dev.linux.lists.sashiko-reviews,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-pwm,org.kernel.vger.linux-renesas-soc
Message-ID <TY3PR01MB11346EDD83D9CA3F3252D48F586A22@TY3PR01MB11346.jpnprd01.prod.outlook.com>
Hi Uwe,

> -----Original Message-----
> From: Biju Das <[email protected]>
> Sent: 10 August 2026 09:43
> Subject: Re: [PATCH v6 02/11] dt-bindings: pwm: rzg2l-gpt: Document renesas,poegs property
> 
> Hi Uwe,
> 
> I have clarified the use case with Rob on [1], and he acked on [2] .
> See the details below
> 
> [1]
> https://lore.kernel.org/all/OS0PR01MB5922756F1836AAABFF62C04786049@OS0PR01MB5922.jpnprd01.prod.outlook.co
> m/
> [2] https://lore.kernel.org/all/[email protected]/

Is it ok, if I drop the POEG support as few SoCs such as RZ/T2H and RZ/G3L needs PWM
and this patch series is blocking them. Later I will send patch for POEG.
Please let me know.

Note:
Now, POEG driver exposes a simple char device. Using write we configure it.

Cheers,
Biju

> 
> Cheers,
> Biju
> 
> On Thu, Jul 16, 2026 at 8:50 AM Uwe Kleine-König <[email protected]> wrote:
> >
> > Hello Rob,
> >
> > On Thu, Jun 04, 2026 at 10:06:19AM +0000, [email protected] wrote:
> > > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> > > - [Medium] The `renesas,poegs` property improperly encodes the consumer's channel index as a phandle
> specifier, which is a Devicetree anti-pattern and breaks standard phandle-array parsing semantics.
> > > --
> > >
> > > commit 9d7f9847d3f320fb715022b6159c9c7e869aeedd
> > > Author: Biju Das <[email protected]>
> > >
> > > dt-bindings: pwm: rzg2l-gpt: Document renesas,poegs property
> > >
> > > RZ/G2L GPT IP supports output pin disable function by dead time
> > > error and detecting short-circuits between output pins.
> > > Add documentation for the optional property renesas,poegs to link a
> > > pair of GPT IOs with POEG.
> > >
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/pwm/renesas,rzg2l-gpt.yaml
> > > > b/Documentation/devicetree/bindings/pwm/renesas,rzg2l-gpt.yaml
> > > > --- a/Documentation/devicetree/bindings/pwm/renesas,rzg2l-gpt.yaml
> > > > +++ b/Documentation/devicetree/bindings/pwm/renesas,rzg2l-gpt.yaml
> > >
> > > [ ... ]
> > >
> > > > @@ -245,6 +245,28 @@ properties:
> > > >    resets:
> > > >      maxItems: 1
> > > >
> > > > +  renesas,poegs:
> > > > +    minItems: 1
> > > > +    maxItems: 8
> > > > +    $ref: /schemas/types.yaml#/definitions/phandle-array
> > > > +    items:
> > > > +      items:
> > > > +        - description: phandle to POEG instance that serves the output disable
> > > > +        - enum: [ 0, 1, 2, 3, 4, 5, 6, 7 ]
> > > > +          description: |
> > > > +            An index identifying pair of GPT channels.
> > >
> > > [Severity: Medium]
> > > Does this property correctly follow standard Devicetree phandle semantics?
> > >
> > > By Devicetree specification, phandle arguments in a phandle-array
> > > are defined and interpreted by the target provider node, with their
> > > length dictated by a cell-count property on the provider.
> > >
> > > This definition appears to invert that model by using the specifier
> > > to encode the consumer's (GPT) own channel index rather than a provider argument.
> > >
> > > Additionally, standard OS-agnostic DT parsers might fail to resolve
> > > this because the referenced provider binding
> > > (renesas,rzg2l-poeg.yaml) enforces
> > > additionalProperties: false and natively lacks a #poeg-cells
> > > property to dictate the specifier length.
> > >
> > > Is it possible to redesign this binding so it doesn't encode the
> > > consumer's index into the provider's phandle argument, or at least
> > > ensure the POEG provider specifies a #poeg-cells property?
> >
> > You acked the patch. Is that review concern by Sashiko valid?
> >
> > Best regards
> > Uwe
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