Re: [RFC] ADV7604: VGA support

[Hans Verkuil <hverkuil@xs4all.nl>]

On 01/07/2016 06:20 PM, Jean-Michel Hautbois wrote:
> Hi Hans,
> 
> 2015-10-12 12:22 GMT+02:00 Hans Verkuil <hverkuil@xs4all.nl>:
>> On 10/04/2015 06:17 PM, Jean-Michel Hautbois wrote:
>>> Hi,
>>>
>>> I had another look into the ADV7604 HW manual, and I understand that
>>> in automatic mode, there is 4 AIN_SEL values possible, determining the
>>> connection on AIN pins.
>>> Now, having a look at the current ADV76xx files, I can see that two
>>> pads are there :
>>> ADV7604_PAD_VGA_RGB and ADV7604_PAD_VGA_COMP.
>>>
>>> According to the manual, my understanding is that we should have four
>>> HDMI pads and four analog pads. The latter would be configured as RGB
>>> or component, which allows four analog inputs as described in the HW
>>> manual.
>>
>> When I wrote the driver we only needed one VGA input receiving either RGB
>> or YCbCr. Hence there is only one analog input and two pads. I wouldn't have
>> been able to test the additional analog inputs anyway.
>>
>> I chose to use pads to select between the two modes, but that's something
>> that can be changed (it's not something you can autodetect, unfortunately).
>>
>> If you want to add support for all four analog inputs, then feel free to
>> do so.
> 
> OK, I don't have anything to test the additional inputs either...
> Something else so, the adv7604_state struct constains two fields,
> .ain_sel and .bus_order.
> Should those be parsed from DT (I think so) ? If so, how should it be
> named in the port{} node ?

Do you need to change this from the current default? If not, then I would
leave it as is.

If you do have to change this, then you would indeed have to add it to the DT.
ain_sel is Analog Devices specific, so just check that whatever you propose
is OK for the adv7842 as well.

Regarding bus order: this is probably something that can be more generic. I
have a deja vu feeling that I saw a patch adding support for this recently,
but I can't find it. Does it ring a bell for someone else?

Regards,

	Hans