Re: [PATCH v6 10/21] dt-bindings: display: renesas,rzg2l-du: Add support for RZ/G3E SoC

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Apr 08, 2026 at 04:02:14PM +0200, Tommaso Merciai wrote:
> Hi Laurent,
> Thanks for your review.
> 
> On 4/8/26 14:24, Laurent Pinchart wrote:
> > On Wed, Apr 08, 2026 at 12:36:55PM +0200, Tommaso Merciai wrote:
> >> The RZ/G3E SoC has 2 LCD controllers (LCDC), each containing a Frame
> >> Compression Processor (FCPVD), a Video Signal Processor (VSPD), and a
> >> Display Unit (DU).
> >>
> >>   - LCDC0 supports DSI and LVDS (single or dual-channel) outputs.
> >>   - LCDC1 supports DSI, LVDS (single-channel), and RGB outputs.
> >>
> >> Add a new SoC-specific compatible string 'renesas,r9a09g047-du'.
> >>
> >> Extend patternProperties from "^port@[0-1]$" to "^port@[0-3]$" to
> >> allow up to four output ports, and explicitly disable port@2 and port@3
> >> for existing SoCs that do not expose them.
> >>
> >> Describe the four output ports of the RZ/G3E DU:
> >>
> >>   - port@0: DSI (available on both LCDC instances)
> >>   - port@1: DPAD / parallel RGB (LCDC1 only)
> >>   - port@2: LVDS channel 0 (LCDC0 only)
> >>   - port@3: LVDS channel 1 (available on both LCDC instances)
> >>
> >> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> >> ---
> >> v5->v6:
> >>   - Extend patternProperties from "^port@[0-1]$" to "^port@[0-3]$" and
> >>     explicitly disable port@2 and port@3 for existing SoCs that do not expose
> >>     them.
> >>   - Reworked ports numbering + improved/fixed ports descriptions in the
> >>     bindings documentation.
> >>   - Improved commit body.
> >>
> >> v4->v5:
> >>   - Dropped renesas,id property and updated bindings
> >>     accordingly.
> >>
> >> v2->v3:
> >>   - No changes.
> >>
> >> v2->v3:
> >>   - No changes.
> >>
> >> v1->v2:
> >>   - Use single compatible string instead of multiple compatible strings
> >>     for the two DU instances, leveraging a 'renesas,id' property to
> >>     differentiate between DU0 and DU1.
> >>   - Updated commit message accordingly.
> >>
> >>   .../bindings/display/renesas,rzg2l-du.yaml    | 30 ++++++++++++++++++-
> >>   1 file changed, 29 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> >> index 5add3b832eab..32da0b5ec88c 100644
> >> --- a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> >> +++ b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> >> @@ -20,6 +20,7 @@ properties:
> >>         - enum:
> >>             - renesas,r9a07g043u-du # RZ/G2UL
> >>             - renesas,r9a07g044-du # RZ/G2{L,LC}
> >> +          - renesas,r9a09g047-du # RZ/G3E
> >>             - renesas,r9a09g057-du # RZ/V2H(P)
> >>         - items:
> >>             - enum:
> >> @@ -61,7 +62,7 @@ properties:
> >>         model-dependent. Each port shall have a single endpoint.
> >>   
> >>       patternProperties:
> >> -      "^port@[0-1]$":
> >> +      "^port@[0-3]$":
> >>           $ref: /schemas/graph.yaml#/properties/port
> >>           unevaluatedProperties: false
> >>   
> >> @@ -103,6 +104,8 @@ allOf:
> >>               port@0:
> >>                 description: DPI
> >>               port@1: false
> >> +            port@2: false
> >> +            port@3: false
> >>   
> >>             required:
> >>               - port@0
> >> @@ -119,6 +122,8 @@ allOf:
> >>                 description: DSI
> >>               port@1:
> >>                 description: DPI
> >> +            port@2: false
> >> +            port@3: false
> >>   
> >>             required:
> >>               - port@0
> >> @@ -135,9 +140,32 @@ allOf:
> >>               port@0:
> >>                 description: DSI
> >>               port@1: false
> >> +            port@2: false
> >> +            port@3: false
> >>   
> >>             required:
> >>               - port@0
> >> +  - if:
> >> +      properties:
> >> +        compatible:
> >> +          contains:
> >> +            const: renesas,r9a09g047-du
> >> +    then:
> >> +      properties:
> >> +        ports:
> >> +          properties:
> >> +            port@0:
> >> +              description: DSI
> >> +            port@1:
> >> +              description: DPAD
> >> +            port@2:
> >> +              description: LVDS, Channel 0
> >> +            port@3:
> >> +              description: LVDS, Channel 1
> >> +
> >> +          required:
> >> +            - port@0
> >> +            - port@3
> > 
> > Why are ports 1 and 2 not required ?
> 
> About this we had a similar discussion on v5[0]
> We are using the same compatible and:
> 
> - LCDC0 supports DSI and LVDS (single or dual-channel) outputs.
> |
> --> then has:
> 	port@0
> 	port@2
> 	port@3
> 	
> 
>   - LCDC1 supports DSI, LVDS (single-channel), and RGB outputs.
> |
> --> then has:
> 	port@0
> 	port@1
> 	port@3

Ah yes, I forget there are two LCDC instances with different output
configurations.

Something still looks a bit weird to me though. For LCDC1, which
supports a single LVDS channel, you use the port described as the second
LVDS channel. Is there a reason not to use port@2 ?

> Then port@1 is required for DU1 but not for DU0.
> Same port@2 is required for DU0 but not for DU1.
> 
> [0] https://patchwork.kernel.org/project/linux-renesas-soc/patch/ca022fdbba5236c36e0cb3095db4c31e8e0cb1b8.1770996493.git.tommaso.merciai.xr@bp.renesas.com/ 
>
> >>
> >>   examples:
> >>     # RZ/G2L DU

-- 
Regards,

Laurent Pinchart