Re: [PATCH] media: dt-bindings: media: renesas,csi2: Node port@0 is not mandatory

["Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>]

Hi Laurent and Geert,

On 2021-04-21 12:43:39 +0300, Laurent Pinchart wrote:
> Hi Niklas,
> 
> On Fri, Apr 16, 2021 at 10:05:46AM +0200, Niklas Söderlund wrote:
> > On 2021-04-15 22:09:12 +0300, Laurent Pinchart wrote:
> > > On Tue, Apr 13, 2021 at 05:53:46PM +0200, Niklas Söderlund wrote:
> > > > When converting the binding to use the video-interfaces schemas the node
> > > > port@0 was incorrectly made a mandatory property.
> > > > 
> > > > The port@0 node describes which CSI-2 transmitter the R-Car CSI-2
> > > > receiver is connected too. Not all boards connects all CSI-2 receivers
> > > > to an CSI-2 transmitter.
> > > 
> > > Ports are properties of the device, they should always be there,
> > > regardless of connections. It's the endpoints that describe connections.
> > 
> > I understand what you are saying and if that is the way things are done 
> > I'm fine with it. As this was brought to light by a recent change in the 
> > bindings I wish to understand if this was always the case the bindings 
> > have been wrong all along or not.
> > 
> > I only ask as because if we keep the port@0 mandatory there will be 
> > board files that needs to add empty port@0 nodes as we know they are not 
> > used. And as the media bindings are already quiet large for some Renesas 
> > boards I want to understand this before spewing out a lot of patches 
> > adding empty nodes ;-)
> 
> In my opinion port@0 should be in the SoC .dtsi, not in the board .dts.
> Individual boards can then add endpoints when the CSI-2 receiver is
> connected. Would that make sense for you ?

I think this is a case of pragmatism vs being technically correct, and 
of course 'technically correct' being the best kind of correct ;-)

Any of the two options works for me as long as we fix the DT validation 
errors that currently exists. Laurent seems to prefers keeping the 
port@0 mandatory and adding empty port@0 nodes to dtsi files.

@Geert: Does this work for you?

> 
> > > > Fixes: 066a94e28a23e04c ("media: dt-bindings: media: Use graph and video-interfaces schemas")
> > > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > > > ---
> > > >  Documentation/devicetree/bindings/media/renesas,csi2.yaml | 1 -
> > > >  1 file changed, 1 deletion(-)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/media/renesas,csi2.yaml b/Documentation/devicetree/bindings/media/renesas,csi2.yaml
> > > > index 20396f1be9993461..395484807dd5ed47 100644
> > > > --- a/Documentation/devicetree/bindings/media/renesas,csi2.yaml
> > > > +++ b/Documentation/devicetree/bindings/media/renesas,csi2.yaml
> > > > @@ -78,7 +78,6 @@ properties:
> > > >            modules connected the CSI-2 receiver.
> > > >  
> > > >      required:
> > > > -      - port@0
> > > >        - port@1
> > > >  
> > > >  required:
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Regards,
Niklas Söderlund