[PATCH RESEND v4 2/3] dt-bindings: lcdif: Expand the imx6sl/imx6sll fallbacks

[Liu Ying]

On 10/13/2025, Fabio Estevam wrote:
> mx6sl.dtsi and imx6sll.dtsi have the following lcdif entries:
> 
> compatible = "fsl,imx6sl-lcdif", "fsl,imx28-lcdif";
> 
> This causes dt-schema warnings as the current binding only
> allow 'fsl,imx6sx-lcdif' as fallback.
> 
> ['fsl,imx6sl-lcdif', 'fsl,imx28-lcdif'] is too long
> ['fsl,imx6sll-lcdif', 'fsl,imx28-lcdif'] is too long
> 
> The imx6sx-lcdif programming model has more advanced features, such
> as overlay plane and the CRC32 support than the imx28-lcdif IP.

Sorry for the late comment, but the LCDIF chapter in i.MX28 TRM contains
the CRC register too, though I agree that i.MX6SX LCDIF supports overlay
plane while i.MX28 LCDIF doesn't.

> 
> Expand the imx6sl/imx6sll lcdif fallbacks to accept a less specific
> fsl,imx28-lcdif fallback:
> 
> compatible = "fsl,imx6sl-lcdif", "fsl,imx6sx-lcdif", "fsl,imx28-lcdif";

Looking at i.MX6SL TRM, I don't find any register to control overlay plane
in LCDIF chapter, so I don't think i.MX6SL LCDIF supports overlay plane
like i.MX6SX LCDIF does.  So, why not make the DT binding allow
"compatible = "fsl,imx6sl-lcdif", "fsl,imx28-lcdif";" instead?

I'm assuming i.MX6SL LCDIF and i.MX6SLL LCDIF are exactly the same.

> 
> This helps keeping DT compatibility as well as using the more advanced
> lcdif features found on imx6sl and imx6sll.
> 
> Signed-off-by: Fabio Estevam <festevam at gmail.com>
> Acked-by: Rob Herring (Arm) <robh at kernel.org>
> Reviewed-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> Reviewed-by: Frank Li <Frank.Li at nxp.com>
> ---
>  Documentation/devicetree/bindings/display/fsl,lcdif.yaml | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/fsl,lcdif.yaml b/Documentation/devicetree/bindings/display/fsl,lcdif.yaml
> index ce31b873fb95..d665f3241e97 100644
> --- a/Documentation/devicetree/bindings/display/fsl,lcdif.yaml
> +++ b/Documentation/devicetree/bindings/display/fsl,lcdif.yaml
> @@ -23,14 +23,18 @@ properties:
>            - fsl,imx93-lcdif
>        - items:
>            - enum:
> -              - fsl,imx6sl-lcdif
> -              - fsl,imx6sll-lcdif
>                - fsl,imx6ul-lcdif
>                - fsl,imx7d-lcdif
>                - fsl,imx8mm-lcdif
>                - fsl,imx8mn-lcdif
>                - fsl,imx8mq-lcdif
>            - const: fsl,imx6sx-lcdif
> +      - items:
> +          - enum:
> +              - fsl,imx6sl-lcdif
> +              - fsl,imx6sll-lcdif
> +          - const: fsl,imx6sx-lcdif
> +          - const: fsl,imx28-lcdif
>        - items:
>            - enum:
>                - fsl,imx6sx-lcdif


-- 
Regards,
Liu Ying