[PATCH v2 3/9] dt-bindings: display: renesas,rzg2l-du: Document RZ/G2UL DU bindings

[Biju Das]

Hi Laurent Pinchart,

Thanks for the feedback.

> -----Original Message-----
> From: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Sent: Wednesday, July 31, 2024 2:47 PM
> Subject: Re: [PATCH v2 3/9] dt-bindings: display: renesas,rzg2l-du: Document RZ/G2UL DU bindings
> 
> Hi Biju,
> 
> On Mon, Jul 29, 2024 at 09:05:59AM +0000, Biju Das wrote:
> > On Saturday, July 27, 2024 1:50 AM, Laurent Pinchart wrote:
> > > On Tue, Jul 09, 2024 at 02:51:41PM +0100, Biju Das wrote:
> > > > Document DU found in RZ/G2UL SoC. The DU block is identical to
> > > > RZ/G2L SoC, but has only DPI interface.
> > > >
> > > > While at it, add missing required property port at 1 for RZ/G2L and
> > > > RZ/V2L SoCs. Currently there is no user for the DPI interface and
> > > > hence there won't be any ABI breakage for adding port at 1 as
> > > > required property for RZ/G2L and RZ/V2L SoCs.
> > > >
> > > > Signed-off-by: Biju Das <biju.das.jz at bp.renesas.com>
> > > > Acked-by: Conor Dooley <conor.dooley at microchip.com>
> > > > ---
> > > > v1->v2:
> > > >  * Updated commit description related to non ABI breakage.
> > > >  * Added Ack from Conor.
> > > > ---
> > > >  .../bindings/display/renesas,rzg2l-du.yaml    | 32 +++++++++++++++++--
> > > >  1 file changed, 29 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> > > > b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> > > > index 08e5b9478051..c0fec282fa45 100644
> > > > ---
> > > > a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> > > > +++ b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.y
> > > > +++ aml
> > > > @@ -18,6 +18,7 @@ properties:
> > > >    compatible:
> > > >      oneOf:
> > > >        - enum:
> > > > +          - renesas,r9a07g043u-du # RZ/G2UL
> > > >            - renesas,r9a07g044-du # RZ/G2{L,LC}
> > > >        - items:
> > > >            - enum:
> > > > @@ -60,9 +61,6 @@ properties:
> > > >          $ref: /schemas/graph.yaml#/properties/port
> > > >          unevaluatedProperties: false
> > > >
> > > > -    required:
> > > > -      - port at 0
> > > > -
> > > >      unevaluatedProperties: false
> > > >
> > > >    renesas,vsps:
> > > > @@ -88,6 +86,34 @@ required:
> > > >
> > > >  additionalProperties: false
> > > >
> > > > +allOf:
> > > > +  - if:
> > > > +      properties:
> > > > +        compatible:
> > > > +          contains:
> > > > +            const: renesas,r9a07g043u-du
> > > > +    then:
> > > > +      properties:
> > > > +        ports:
> > > > +          properties:
> > > > +            port at 0: false
> > > > +            port at 1:
> > > > +              description: DPI
> > > > +
> > > > +          required:
> > > > +            - port at 1
> > >
> > > Why do you use port at 1 for the DPI output here, and not port at 0 ?
> >
> > Currently the output is based on port number and port = 1 corresponds to DPI. See [1].
> >
> > For consistency, I documented bindings for RZ/G2L family DU's similar to RZ/G2{H,M,N,E} DU [2].
> >
> > So please let me know, are you ok with this?
> 
> I won't insist strongly, but I don't think that using the port number to indicate the output type is
> the best idea. In the R-Car DU driver at least, that wouldn't have scaled. We have multiple outputs of
> the same type on some SoCs. Furthemore, the same DU hardware channel number (i.e.
> the offset of the registers specific to that channel in the DU register
> space) is not the same across SoCs for the same output type. I recommend numbering the ports based on
> the hardware number of the output (the exact meaning of this is specific to your device, I haven't
> checked what it means for RZ/G2L), not on the output type.

OK, will update the bindings to use port for RZ/G2UL and Ports for RZ/{G2L, V2L} as it has multiple DU outputs.
From the driver will remove using port number to indicate the output type.

-                       if (rcdu->info->routes[i].port == ep.port) {
-                               output = i;
+                       if (i == rcdu->info->routes[i].du_output) {
+                               output = rcdu->info->routes[i].du_output;
Cheers,
Biju

> 
> > [1]
> > https://elixir.bootlin.com/linux/v6.10.2/source/drivers/gpu/drm/renesa
> > s/rz-du/rzg2l_du_kms.c#L187
> >
> > [2]
> > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tr
> > ee/Documentation/devicetree/bindings/display/renesas,du.yaml?h=next-20
> > 240729#n546
> >
> > > > +    else:
> > > > +      properties:
> > > > +        ports:
> > > > +          properties:
> > > > +            port at 0:
> > > > +              description: DSI
> > > > +            port at 1:
> > > > +              description: DPI
> > > > +
> > > > +          required:
> > > > +            - port at 0
> > > > +            - port at 1
> > >
> > > You're missing a blank line here.
> >
> > OK, will fix this'
> 
> --
> Regards,
> 
> Laurent Pinchart