Re: [PATCH 2/5] dt-bindings: display: atmel: add optional output-mode property

[Peter Rosin]

On 2018-04-13 19:46, Rob Herring wrote:
> On Mon, Apr 09, 2018 at 12:59:15PM +0200, Peter Rosin wrote:
>> Useful for beating cases where an output mode selection heuristic
>> fails.
>>
>> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
>> ---
>>  Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt b/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt
>> index 82f2acb3d374..dc478455b883 100644
>> --- a/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt
>> +++ b/Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt
>> @@ -10,6 +10,10 @@ Required properties:
>>   - #address-cells: should be set to 1.
>>   - #size-cells: should be set to 0.
>>  
>> +Optional properties:
>> + - output-mode: override any output mode selection hueristic and force a
>> +   particular output mode. One of "rgb444", "rgb565", "rgb666" and "rgb888".
>> +
> 
> This needs to be generic, not just added to some random display 
> controller binding.
> 
> It also belongs in the port or endpoint node as is done for camera 
> interfaces.

Hmm, should I extend media/video-interfaces.txt with more bus types (or since
I'm targeting parallel interfaces, perhaps the new bus types should be
autodetected from other props?) or should a write a new binding similar to
it?

One question regarding bus-width, should it include hsync/vsync/de/clk?
If yes, how to distinguish rgb565 with all those four from rgb666 with
only de/clk (some panels do not need hsync/vsync)? 20 lines in both
cases...

Or are rgb444/rgb565/rgb666/rgb888 already supported by the media video
interface binding? That's not at all obvious to me.

Cheers,
Peter