Re: [PATCH] dt-bindings: display: bridge: nxp,tda998x: Add missing clocks

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

Hi Geert,

Thank you for the patch.

On Mon, Jan 12, 2026 at 05:02:40PM +0100, Geert Uytterhoeven wrote:
> Some TDA998x variants (e.g. TDA19988) have an OSC_IN pin, to connect
> an external oscillator circuit or clock source.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> This fixes "make dtbs_check":
> 
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874-mipi-2.1.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-cat874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874-idk-2121wr.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
> 
> This patch can be considered v3 of "[PATCH v2 2/3] [RFC] arm64: dts:
> renesas: cat874: Drop bogus clocks property"[1], as the pin is actually
> connected to a clock source on that board.  On BeagleBone Black, it is
> also connected to a clock source, but not described in DT.
> 
> The linux driver does not use this clock directly, but I suspect[2] the
> use of this pin is controlled through the AP_ENA register value, as
> specified in the second cell of the the audio-ports property.
> 
> [1] https://lore.kernel.org/97b949cddd7e30e9c05873800330dccd3483b12b.1663165552.git.geert+renesas@glider.be
> [2] I do not have access to the programming manual.
> ---
>  .../devicetree/bindings/display/bridge/nxp,tda998x.yaml        | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> index 3fce9e698ea1d2dd..1205c8e9de329bbc 100644
> --- a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> @@ -19,6 +19,9 @@ properties:
>    interrupts:
>      maxItems: 1
>  
> +  clocks:
> +    maxItems: 1
> +

I wonder if we should add a compatible string for the variants with a
clock pin, to let drivers manage the clock.

If the clock does not need to be controlled, an alternative would be to
drop the clocks property from
arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts.

>    video-ports:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      default: 0x230145

-- 
Regards,

Laurent Pinchart