Re: [PATCH v2 17/26] drm: sun4i: Add DT bindings documentation

[Rob Herring]

On Wed, Feb 3, 2016 at 1:59 PM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> Hi Rob,
>
> On Thu, Jan 14, 2016 at 09:15:15PM -0600, Rob Herring wrote:
>> On Thu, Jan 14, 2016 at 04:25:00PM +0100, Maxime Ripard wrote:
>> > The display pipeline of the Allwinner A10 is involving several loosely
>> > coupled components.
>> >
>> > Add a documentation for the bindings.
>> >
>> > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
>> > ---
>> >  .../bindings/display/sunxi/sun4i-drm.txt           | 228 +++++++++++++++++++++

[...]

>> > +Required properties:
>> > +  - compatible: value must be one of:
>> > +    * allwinner,sun5i-a13-display-engine
>> > +  - allwinner,pipelines: list of phandle to the entry points of the
>> > +    pipelines (either to the frontend or backend)
>> > +
>> > +Example:
>> > +
>> > +panel: panel {
>> > +   compatible = "olimex,lcd-olinuxino-43-ts";
>>
>> This should either be a child of what it is attached to or use of-graph.
>
> You had a similar discussion with Thierry last time I sent it, and it
> seemed to settle on keeping that property:
>
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-October/382115.html
>
> Has that changed?

No, I still disagree. We already have 2 ways to describe panels: as a
child node of its controller or with of-graph. We don't need a 3rd way
even if it is simple. The problem with of-graph today is too much of
the parsing is left to the individual drivers. We need to fix that and
make it be handled by common code.

Rob