Hi Laurent, Jacopo Thanks for your comments. On 2018-10-05 13:02:53 +0300, Laurent Pinchart wrote: > 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 Söderlund wrote: > > >>> From: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> > > >>> > > >>> The CSI-2 transmitters can use a different number of lanes to transmit > > >>> data. Make the data-lanes mandatory for the endpoints describe the > > >> > > >> s/describe/that describe/ ? > > >> > > >>> transmitters as no good default can be set to fallback on. > > >>> > > >>> Signed-off-by: Niklas Söderlund > > >>> <niklas.soderlund+renesas@xxxxxxxxxxxx> > > >>> --- > > >>> > > >>> Documentation/devicetree/bindings/media/i2c/adv748x.txt | 3 +++ > > >>> 1 file changed, 3 insertions(+) > > >>> > > >>> 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. > > >>> > > >>> The digital output port nodes must contain at least one endpoint. > > >>> > > >>> +The endpoints described in TXA and TXB ports must if present contain > > >>> +the data-lanes property as described in video-interfaces.txt. > > >>> + > > >> > > >> Would it make sense to merge those two paragraphs, as they refer to the > > >> same endpoint ? > > >> > > >> "The digital output port nodes, when present, shall contain at least one > > >> endpoint. Each of those endpoints shall contain the data-lanes property > > >> as described in video-interfaces.txt." > > >> > > >> (DT bindings normally use "shall" instead of "must", but that hasn't > > >> really been enforced.) > > >> > > >> 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). > > >> > > >> I'm fine with any of the above option, so please pick your favourite, > > >> and add > > >> > > >> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > > > > > I just realized that TXB only supports a single data lane, so we may want > > > not to have a data-lanes property for TXB. > > > > 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 > differently :-) I believe it would actually reduce the code size (and save CPU > cycles at runtime). I'm leaning towards Jacopo on this that I think it's more clear to treat the two the same. I also think it adheres to the notion that DT shall describe hardware which I think this adds value. Also I only have datasheets for adv7482 so I can't be sure other adv748x don't support more then one lane on TXB. I do not feel strongly about this so I'm open to treating them differently. I might keep it as is for v3 if no one screams to loud :-) > > > Why not inserting a paragraph with the required endpoint properties > > description? > > > > Eg: > > > > 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> > > > > >>> Ports are optional if they are not connected to anything at the > > >>> hardware level. > > >>> > > >>> Example: > > -- > Regards, > > Laurent Pinchart > > > -- Regards, Niklas Söderlund
