Re: [PATCH 0/9] Doc/DT: DT bindings for various display components

[Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>]

On 02/28/14 14:47, Philipp Zabel wrote:
> Am Freitag, den 28.02.2014, 13:57 +0100 schrieb Sebastian Hesselbarth:
>> On 02/28/14 13:20, Tomi Valkeinen wrote:
>>> This series is a re-send of
>>> http://article.gmane.org/gmane.linux.drivers.devicetree/61739
>>>
>> ...
>>> Shortly about the display components in the series, in the order of probable
>>> public interest:
>>>
>>> * Analog TV, DVI and HDMI Connectors represent a respective connector on the
>>>     board. They don't do much, but they do mark the end of the video pipeline (from
>>>     the board's pov), and they should also in the future offer ways to handle
>>>     things like the +5V pin on DVI and HDMI connector and HPD pin.
>>>
>>> * MIPI DPI panel and MIPI DSI CM panels represent bindings for simple panels
>>>     using the respective video bus.
>>>
>>> * Sony acx565akm is an SPI controlled panel using flatlink video bus.
>>>
>>> * TFP410 is a DPI to DVI encoder.
>>>
>>> * TPD12S015 is a HDMI companion chip, used on OMAP boards.
>>
>> Tomi,
>>
>> Out of curiosity, will there be DT nodes for pull-up resistors soon,
>> too? ;)
>>
>> Honestly, TPD12S015 is a level shifter, there is nothing in it that
>> would justify a DT node nor a driver.
>>
>> Above you already note, that connector nodes should offer HPD in the
>> future, but I guess the binding should represent that now already.
>> I will be a DT stub anyway, the corresponding video sink driver will
>> have to look it up.
>>
>> Looking through the bindings for DVI and HDMI, I guess HPD gpio is
>> better kept in those nodes. From the relevant (DT) properties DVI and
>> HDMI connectors are in no way different.
>
> I like the idea of adding actual connector nodes to the board device
> trees. A TV encoder driver for example could this way detect from the
> device tree whether it is connected to a VGA, Composite, or S-Video
> connector (or maybe to both Composite and S-Video connectors at the same
> time).

I agree that different connectors help providing a better
user-experienced view of board layout. But I doubt that besides the
differentiation (HDMI, DVI, VGA, SVideo, ...) and the endpoint there
should be anything more in that node.

Sebastian