Re: [RFC PATCH] [media]: of: move graph helpers from drivers/media/v4l2-core to drivers/of

From: Tomi Valkeinen
Date: Sat Mar 08 2014 - 05:58:36 EST


On 07/03/14 19:06, Grant Likely wrote:
> On Thu, 27 Feb 2014 10:36:36 +0200, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
>> On 26/02/14 16:48, Philipp Zabel wrote:
>>
>>>> I would like the document to acknowledge the difference from the
>>>> phandle+args pattern used elsewhere and a description of when it would
>>>> be appropriate to use this instead of a simpler binding.
>>>
>>> Alright. The main point of this binding is that the devices may have
>>> multiple distinct ports that each can be connected to other devices.
>>
>> The other main point with this binding are multiple endpoints per port.
>> So you can have, say, a display controller, with single port, which has
>> two endpoints going to two separate LCD panels.
>>
>> In physical level that would usually mean that the same pins from the
>> display controller are connected to two panels. Most likely this would
>> mean that only one panel can be used at a time, possibly with different
>> settings (say, 16 RGB pins for one panel, 24 RGB pins for the other).
>
> What device is in control in that scenario?

The endpoints in a single port are exclusive, only one can be active at
a time. So the control for the active path would be no different than in
single panel case (for which people have different opinions).

Tomi


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