[RFC] ADV7604: VGA support

[RFC] ADV7604: VGA support

[Jean-Michel Hautbois]

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.

I don't know if you agree with that or if you had something else in
mind when designing it in the first place, I may have missed something
(Lars :) ?).

Thanks,
JM

Re: [RFC] ADV7604: VGA support

[Hans Verkuil]

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.

Regards,

	Hans

> 
> I don't know if you agree with that or if you had something else in
> mind when designing it in the first place, I may have missed something
> (Lars :) ?).
> 
> Thanks,
> JM
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Re: [RFC] ADV7604: VGA support

[Jean-Michel Hautbois]

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 ?

Thanks,
JM

Re: [RFC] ADV7604: VGA support

[Hans Verkuil]

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

Re: [RFC] ADV7604: VGA support

[Jean-Michel Hautbois]

Hi Hans,

2016-01-11 10:15 GMT+01:00 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.

I think it will have to be modified somehow, as those are global
parameters for the chip.
ain_sel is the same whatever the input is. So if you have both RGB and
YCrCb you should be able to define ain_sel for each one.

> 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.

OK.

> 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?

Not to me, but interested :).
JM