On Mon, 23 Apr 2018 09:22:55 +0200
Peter Rosin <peda@xxxxxxxxxx> wrote:
> With bus-type/bus-width properties in the endpoint nodes, the video-
> interface of the connection can be specified for cases where the
> heuristic fails to select the correct output mode. This can happen
> e.g. if not all RGB pins are routed on the PCB; the driver has no
> way of knowing this, and needs to be told explicitly.
>
> This is critical for the devices that have the "conflicting output
> formats" issue (SAM9N12, SAM9X5, SAMA5D3), since the most significant
> RGB bits move around depending on the selected output mode. For
> devices that do not have the "conflicting output formats" issue
> (SAMA5D2, SAMA5D4), this is completely irrelevant.
>
> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
Acked-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
> ---
> .../devicetree/bindings/display/atmel/hlcdc-dc.txt | 26 ++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt b/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt
> index 82f2acb3d374..9de434a8f523 100644
> --- a/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt
> +++ b/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt
> @@ -15,6 +15,14 @@ Required children nodes:
> to external devices using the OF graph reprensentation (see ../graph.txt).
> At least one port node is required.
>
> +Optional properties in grandchild nodes:
> + Any endpoint grandchild node may specify a desired video interface
> + according to ../../media/video-interfaces.txt, specifically
> + - bus-type: must be <0>.
> + - bus-width: recognized values are <12>, <16>, <18> and <24>, and
> + override any output mode selection heuristic, forcing "rgb444",
> + "rgb565", "rgb666" and "rgb888" respectively.
> +
> Example:
>
> hlcdc: hlcdc@f0030000 {
> @@ -50,3 +58,21 @@ Example:
> #pwm-cells = <3>;
> };
> };
> +
> +
> +Example 2: With a video interface override to force rgb565; as above
> +but with these changes/additions:
> +
> + &hlcdc {
> + hlcdc-display-controller {
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_lcd_base &pinctrl_lcd_rgb565>;
> +
> + port@0 {
> + hlcdc_panel_output: endpoint@0 {
> + bus-type = <0>;
> + bus-width = <16>;
> + };
> + };
> + };
> + };
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