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

[Rob Herring]

On Sat, Apr 14, 2018 at 8:54 AM, Peter Rosin  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 
>>> ---
>>>  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

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

[Rob Herring]

On Sat, Apr 14, 2018 at 8:54 AM, Peter Rosin  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 
>>> ---
>>>  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

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 
>> ---
>>  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

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 
>> ---
>>  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

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

[Rob Herring]

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 
> ---
>  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

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

[Rob Herring]

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 
> ---
>  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