On 06/09/2017 05:31 PM, Rob Herring wrote:
> On Fri, Jun 9, 2017 at 9:11 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
>> On 09/06/17 16:07, Rob Herring wrote:
>>> On Wed, Jun 07, 2017 at 04:46:14PM +0200, Hans Verkuil wrote:
>>>> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>>>>
>>>> Needed for boards that wire the CEC pin in such a way that it
>>>> is unavailable when the HPD is low.
>>>>
>>>> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>>>> Cc: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
>>>> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
>>>> Cc: devicetree@xxxxxxxxxxxxxxx
>>>> ---
>>>> Documentation/devicetree/bindings/media/s5p-cec.txt | 6 ++++++
>>>> 1 file changed, 6 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/media/s5p-cec.txt b/Documentation/devicetree/bindings/media/s5p-cec.txt
>>>> index 4bb08d9d940b..261af4d1a791 100644
>>>> --- a/Documentation/devicetree/bindings/media/s5p-cec.txt
>>>> +++ b/Documentation/devicetree/bindings/media/s5p-cec.txt
>>>> @@ -17,6 +17,12 @@ Required properties:
>>>> - samsung,syscon-phandle - phandle to the PMU system controller
>>>> - hdmi-phandle - phandle to the HDMI controller
>>>>
>>>> +Optional:
>>>> + - needs-hpd : if present the CEC support is only available when the HPD
>>>> + is high. Some boards only let the CEC pin through if the HPD is high, for
>>>> + example if there is a level converter that uses the HPD to power up
>>>> + or down.
>>>
>>> Seems like something common. Can you document in a common location?
>>
>> Should we do the same with hdmi-phandle? It is also used by CEC drivers to find
>> the HDMI driver.
>
> Yes.
>
>> Currently only used by s5p-cec and stih-cec, but there will be more.
>>
>> I guess this would be a sensible place to document this:
>>
>> Documentation/devicetree/bindings/media/cec.txt
>
> Sounds good. You can do this as a follow-up to this patch if you want.
> For this one:
>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
>
Sorry, I have what might be a stupid question: should I update the s5p-cec.txt
to refer to the cec.txt bindings file for the hdmi-phandle and needs-hpd instead
of describing it here? It seems pointless to do that for the hdmi-phandle, but
it might make more sense for the needs-hpd property.
E.g.:
- needs-hpd: CEC support is only present if HPD is high. See cec.txt for more
details.
Proposed text for cec.txt:
-------------------------------------------------
Common bindings for HDMI CEC adapters
- hdmi-phandle: phandle to the HDMI controller.
- needs-hpd: if present the CEC support is only available when the HPD
is high. Some boards only let the CEC pin through if the HPD is high, for
example if there is a level converter that uses the HPD to power up
or down.
-------------------------------------------------
Regards,
Hans
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