Re: [PATCH v1 3/4] dt-bindings: media: add wiring property to video-interfaces

[Rob Herring <robh@kernel.org>]

On Sun, Apr 12, 2020 at 08:20:11PM +0200, Sam Ravnborg wrote:
> The wiring property is used to describe the wiring between
> the connector and the panel. The property can be used when the
> wiring is used to change the mode from for example
> BGR to RGB. The first users are the at91sam9 family where
> such a wiring trick is sometimes used.
> The possilbe values are so far limited to what is required
> by the at91sam9 family, but using "text" allows us to extend
> this in the future.
> 
> There exists similar properties today:
>  - display/tilcdc/tilcdc.txt: blue-and-red-wiring
>  - display/atmel,lcdc.txt: atmel,lcd-wiring-mode
> 
> Neither of the above are defined as endpoint properties.
> 
> The new property "wiring" has a more general name and
> is defined as an endpoint property.
> It will replace atmel,lcd-wiring-mode and may replace
> blue-and-red-wiring.
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Hans Verkuil <hverkuil@xs4all.nl>
> Cc: linux-media@vger.kernel.org
> ---
>  Documentation/devicetree/bindings/media/video-interfaces.txt | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt b/Documentation/devicetree/bindings/media/video-interfaces.txt
> index f884ada0bffc..c3bb87c5c9a9 100644
> --- a/Documentation/devicetree/bindings/media/video-interfaces.txt
> +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt
> @@ -141,6 +141,9 @@ Optional endpoint properties
>  - link-frequencies: Allowed data bus frequencies. For MIPI CSI-2, for
>    instance, this is the actual frequency of the bus, not bits per clock per
>    lane value. An array of 64-bit unsigned integers.
> +- wiring: Wiring of data lines to display.
> +  "straight" - normal wiring.

Don't really need a property to express this...

> +  "red-blue-reversed" - red and blue lines reversed.

For a common property, I think this needs to be looked at in terms of 
formats and some of the format negotiation work Boris was doing.

Rob