Hi Rob and all,
> -----Original Message-----
> From: Biju Das
> Sent: Monday, August 19, 2024 1:37 PM
> Subject: RE: [PATCH v3 1/4] dt-bindings: display: renesas,rzg2l-du: Document RZ/G2UL DU bindings
>
> Hi Laurent and Rob,
>
> Thanks for the feedback
>
> > -----Original Message-----
> > From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Sent: Tuesday, August 13, 2024 8:39 PM
> > Subject: Re: [PATCH v3 1/4] dt-bindings: display: renesas,rzg2l-du:
> > Document RZ/G2UL DU bindings
> >
> > Hi Rob,
> >
> > On Tue, Aug 13, 2024 at 10:32:20AM -0600, Rob Herring wrote:
> > > On Mon, Aug 05, 2024 at 04:52:35PM +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@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@1 as
> > > > required property for RZ/G2L and RZ/V2L SoCs.
> > > >
> > > > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > > > ---
> > > > v2->v3:
> > > > * Replaced ports->port property for RZ/G2UL as it supports only DPI.
> > > > and retained ports property for RZ/{G2L,V2L} as it supports both DSI
> > > > and DPI output interface.
> > >
> > > Why? Having port and ports is just a needless complication.
> >
> > I agree that making the ports node mandatory, even when the device has
> > a single port, will simplify the bindings. In hindsight we should never have made ports optional,
> but that can't be changed.
> >
> > > > * Added missing blank line before example.
> > > > * Dropped tags from Conor and Geert as there are new changes.
> > > > v1->v2:
> > > > * Updated commit description related to non ABI breakage.
> > > > * Added Ack from Conor.
> > > > ---
> > > > .../bindings/display/renesas,rzg2l-du.yaml | 35 +++++++++++++++++--
> > > > 1 file changed, 32 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..ca01bf26c4c0 100644
> > > > ---
> > > > a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> > > > +++ b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.y
> > > > +++ am
> > > > +++ l
> > > > @@ -18,6 +18,7 @@ properties:
> > > > compatible:
> > > > oneOf:
> > > > - enum:
> > > > + - renesas,r9a07g043u-du # RZ/G2UL
> > > > - renesas,r9a07g044-du # RZ/G2{L,LC}
> > > > - items:
> > > > - enum:
> > > > @@ -60,8 +61,9 @@ properties:
> > > > $ref: /schemas/graph.yaml#/properties/port
> > > > unevaluatedProperties: false
> > > >
> > > > - required:
> > > > - - port@0
> > > > + port:
> > > > + $ref: /schemas/graph.yaml#/properties/port
> > > > + description: Connection to the DU output video port.
> > > >
> > > > unevaluatedProperties: false
> > > >
> > > > @@ -83,11 +85,38 @@ required:
> > > > - clock-names
> > > > - resets
> > > > - power-domains
> > > > - - ports
> > > > - renesas,vsps
> > > >
> > > > additionalProperties: false
> > > >
> > > > +allOf:
> > > > + - if:
> > > > + properties:
> > > > + compatible:
> > > > + contains:
> > > > + const: renesas,r9a07g043u-du
> > > > + then:
> > > > + properties:
> > > > + port:
> > > > + description: DPI
> > >
> > > This is equivalent to 'port@0'. IMO, this case should have a 'port@1'
> > > node so that DPI interface is *always* the same port.
> >
> > That's what Biju did in the previous version, and I recommended to
> > number the ports based on hardware indices, not types. Mapping port
> > numbers to the hardware documentation makes it more consistent for DT
> > writers, makes the logic simpler to understand (in my opinion, based
> > on my experience with the R-Car
> > DU) on the driver side, but most importantly, type-based numbering
> > wouldn't scale as SoCs could have multiple ports of the same type (we've seen that happening with R-
> Car).
>
> OK, I will send bindings based on hardware indices.
I get a warning, if I use ports and port@0 for single port. I don't see this warning if I use ports and port@1
arch/arm64/boot/dts/renesas/r9a07g043u.dtsi:169.9-178.5: Warning (graph_child_address): /soc/display@10890000/ports: graph node has single child node 'port@0', #address-cells/#size-cells are not necessary
Can we fix the dt-schema to getting consistent results for single port usage involving ports?
+ - if:
+ properties:
+ compatible:
+ contains:
+ const: renesas,r9a07g043u-du
+ then:
+ properties:
+ ports:
+ properties:
+ port@0:
+ description: DPI
+
+ required:
+ - port@0
Cheers,
Biju
