[PATCH] dt-bindings: simplefb: Document naming scheme for pre-populated simplefb nodes

Grant Likely grant.likely at linaro.org
Fri Nov 14 01:12:59 PST 2014

On Fri, Nov 14, 2014 at 9:02 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> Since we advice to use pre-populated simeplfb nodes in dt files, where the
> firmware then only needs to fill in the mode info + address and enable it,
> we should also specify how these pre-populated nodes should be named so
> that the firmware can find and enable the right one.
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
>  Documentation/devicetree/bindings/video/simple-framebuffer.txt | 7 +++++++
>  1 file changed, 7 insertions(+)
> diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt
> index c548f33..01dc948 100644
> --- a/Documentation/devicetree/bindings/video/simple-framebuffer.txt
> +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt
> @@ -29,6 +29,13 @@ enable them. This way if e.g. later on support for more display clocks get
>  added, the simplefb nodes will already contain this info and the firmware
>  does not need to be updated.
> +If pre-filled framebuffer nodes are used, they should be named
> +"framebuffer#-<output>", e.g. "framebuffer0-hdmi". The output should be
> +included in the name since different outputs typically require different
> +clocks and the clocks are part of the pre-populated nodes. The firmware must
> +rename the nodes to the standard "framebuffer@<address>" using the runtime
> +chosen address when enabling the nodes.

-<output> should be optional, an only used when there are multiple options.

Something we've not talked about is how to handle a framebuffer that
has been set up with mirrored displays. Does that case matter?


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