diff mbox series

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

Message ID 20180409105918.20792-3-peda@axentia.se
State Changes Requested, archived
Headers show
Series Add tda998x (HDMI) support to atmel-hlcdc | expand

Commit Message

Peter Rosin April 9, 2018, 10:59 a.m. UTC
Useful for beating cases where an output mode selection heuristic
fails.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 Documentation/devicetree/bindings/display/atmel/hlcdc-dc.txt | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Rob Herring (Arm) April 13, 2018, 5:46 p.m. UTC | #1
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@axentia.se>
> ---
>  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.

Rob
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Peter Rosin April 14, 2018, 1:54 p.m. UTC | #2
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@axentia.se>
>> ---
>>  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
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Rob Herring (Arm) April 16, 2018, 2:22 p.m. UTC | #3
On Sat, Apr 14, 2018 at 8:54 AM, Peter Rosin <peda@axentia.se> wrote:
> 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@axentia.se>
>>> ---
>>>  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?

Ultimately, I'd like it documented in one place. It can stay in
media/video-interfaces.txt for now, but we should probably move it or
portions of it out of media/. I don't have a good suggestion other
than up a level where people will find it easily.

> 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...

I'd say no, it is just the data lines.

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

Not sure, I'd guess not.

Rob
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diff mbox series

Patch

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".
+
 Required children nodes:
  Children nodes are encoding available output ports and their connections
  to external devices using the OF graph reprensentation (see ../graph.txt).