From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([213.167.242.64]:49522 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727179AbeJERAl (ORCPT ); Fri, 5 Oct 2018 13:00:41 -0400 From: Laurent Pinchart To: jacopo mondi Cc: Niklas =?ISO-8859-1?Q?S=F6derlund?= , Kieran Bingham , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Niklas =?ISO-8859-1?Q?S=F6derlund?= , Rob Herring , devicetree@vger.kernel.org Subject: Re: [PATCH v2 1/5] dt-bindings: adv748x: make data-lanes property mandatory for CSI-2 endpoints Date: Fri, 05 Oct 2018 13:02:53 +0300 Message-ID: <4582789.bxBjXKKKhz@avalon> In-Reply-To: <20181005084945.GL31281@w540> References: <20181004204138.2784-1-niklas.soderlund@ragnatech.se> <18767245.bJLhzbqhM5@avalon> <20181005084945.GL31281@w540> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Jacopo, On Friday, 5 October 2018 11:49:45 EEST jacopo mondi wrote: > On Fri, Oct 05, 2018 at 01:00:47AM +0300, Laurent Pinchart wrote: > > On Friday, 5 October 2018 00:42:17 EEST Laurent Pinchart wrote: > >> On Thursday, 4 October 2018 23:41:34 EEST Niklas S=F6derlund wrote: > >>> From: Niklas S=F6derlund > >>>=20 > >>> The CSI-2 transmitters can use a different number of lanes to transmit > >>> data. Make the data-lanes mandatory for the endpoints describe the > >>=20 > >> s/describe/that describe/ ? > >>=20 > >>> transmitters as no good default can be set to fallback on. > >>>=20 > >>> Signed-off-by: Niklas S=F6derlund > >>> > >>> --- > >>>=20 > >>> Documentation/devicetree/bindings/media/i2c/adv748x.txt | 3 +++ > >>> 1 file changed, 3 insertions(+) > >>>=20 > >>> diff --git a/Documentation/devicetree/bindings/media/i2c/adv748x.txt > >>> b/Documentation/devicetree/bindings/media/i2c/adv748x.txt index > >>> 5dddc95f9cc46084..f9dac01ab795fc28 100644 > >>> --- a/Documentation/devicetree/bindings/media/i2c/adv748x.txt > >>> +++ b/Documentation/devicetree/bindings/media/i2c/adv748x.txt > >>> @@ -50,6 +50,9 @@ are numbered as follows. > >>>=20 > >>> The digital output port nodes must contain at least one endpoint. > >>>=20 > >>> +The endpoints described in TXA and TXB ports must if present contain > >>> +the data-lanes property as described in video-interfaces.txt. > >>> + > >>=20 > >> Would it make sense to merge those two paragraphs, as they refer to the > >> same endpoint ? > >>=20 > >> "The digital output port nodes, when present, shall contain at least o= ne > >> endpoint. Each of those endpoints shall contain the data-lanes property > >> as described in video-interfaces.txt." > >>=20 > >> (DT bindings normally use "shall" instead of "must", but that hasn't > >> really been enforced.) > >>=20 > >> If you want to keep the paragraphs separate, I would recommend using > >> "digital output ports" instead of "TXA and TXB" in the second paragraph > >> for consistency (or the other way around). > >>=20 > >> I'm fine with any of the above option, so please pick your favourite, > >> and add > >>=20 > >> Reviewed-by: Laurent Pinchart > >=20 > > I just realized that TXB only supports a single data lane, so we may wa= nt > > not to have a data-lanes property for TXB. >=20 > Isn't it better to restrict its value to <1> but make it mandatory > anyhow? I understand conceptually that property should not be there, > as it has a single acceptable value, but otherwise we need to traeat > differently the two output ports, in documentation and code. The two ports are different, so I wouldn't be shocked if we handled them=20 differently :-) I believe it would actually reduce the code size (and save = CPU=20 cycles at runtime). > Why not inserting a paragraph with the required endpoint properties > description? >=20 > Eg: >=20 > Required endpoint properties: > - data-lanes: See "video-interfaces.txt" for description. The property > is mandatory for CSI-2 output endpoints and the accepted values > depends on which endpoint the property is applied to: > - TXA: accepted values are <1>, <2>, <4> > - TXB: accepted value is <1> >=20 > >>> Ports are optional if they are not connected to anything at the > >>> hardware level. > >>>=20 > >>> Example: =2D-=20 Regards, Laurent Pinchart