On Fri, Sep 10, 2021 at 08:41:28PM +0200, Paul Kocialkowski wrote:
> The Allwinner A31 MIPI D-PHY block supports both tx and rx directions,
> although each instance of the block is meant to be used in one
> direction only. There will typically be one instance for MIPI DSI and
> one for MIPI CSI-2 (it seems unlikely to ever see a shared instance).
> 
> Describe the direction with a new allwinner,direction property.
> For backwards compatibility, the property is optional and tx mode
> should be assumed by default.
> 
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> ---
>  .../bindings/phy/allwinner,sun6i-a31-mipi-dphy.yaml  | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/allwinner,sun6i-a31-mipi-dphy.yaml b/Documentation/devicetree/bindings/phy/allwinner,sun6i-a31-mipi-dphy.yaml
> index d0b541a461f3..303bbaf3b915 100644
> --- a/Documentation/devicetree/bindings/phy/allwinner,sun6i-a31-mipi-dphy.yaml
> +++ b/Documentation/devicetree/bindings/phy/allwinner,sun6i-a31-mipi-dphy.yaml
> @@ -37,6 +37,18 @@ properties:
>    resets:
>      maxItems: 1
>  
> +  allwinner,direction:
> +    $ref: '/schemas/types.yaml#/definitions/string'
> +    description: |
> +      Direction of the D-PHY:
> +      - "rx" for receiving (e.g. when used with MIPI CSI-2);
> +      - "tx" for transmitting (e.g. when used with MIPI DSI).
> +
> +      When the property is missing, "tx" direction is assumed.

You can provide this using default

> +    oneOf:
> +      - const: tx
> +      - const: rx
> +

enum?

Maxime