From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Verkuil Subject: Re: [PATCH 7/9] dt-bindings: media/s5p-cec.txt: document needs-hpd property Date: Fri, 9 Jun 2017 17:55:33 +0200 Message-ID: <8e6ed9b6-5b4b-8650-2c92-47a593e73d94@cisco.com> References: <20170607144616.15247-1-hverkuil@xs4all.nl> <20170607144616.15247-8-hverkuil@xs4all.nl> <20170609140719.o2qzty6eyez66oxy@rob-hp-laptop> <2fa55431-bef2-9340-4ce8-e06f9648e109@xs4all.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-media-owner@vger.kernel.org To: Rob Herring , Hans Verkuil Cc: "linux-media@vger.kernel.org" , Hans Verkuil , Krzysztof Kozlowski , dri-devel , "devicetree@vger.kernel.org" List-Id: devicetree@vger.kernel.org On 06/09/2017 05:31 PM, Rob Herring wrote: > On Fri, Jun 9, 2017 at 9:11 AM, Hans Verkuil 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 >>>> >>>> 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 >>>> Cc: Krzysztof Kozlowski >>>> Cc: Andrzej Hajda >>>> Cc: devicetree@vger.kernel.org >>>> --- >>>> 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 > 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