Re: [PATCH v1 1/3] dt-bindings: display: drop data-mapping from panel-dpi

From: Sam Ravnborg <sam@ravnborg.org>
To: Maxime Ripard <maxime@cerno.tech>
Cc: Rob Herring <robh@kernel.org>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: [PATCH v1 1/3] dt-bindings: display: drop data-mapping from panel-dpi
Date: Tue, 17 Mar 2020 12:22:31 +0100	[thread overview]
Message-ID: <20200317112231.GA7981@ravnborg.org> (raw)
In-Reply-To: <20200317084959.atqs2anx56kamrsy@gilmour.lan>

Hi Maxime.

On Tue, Mar 17, 2020 at 09:49:59AM +0100, Maxime Ripard wrote:
> Hi Sam,
> 
> On Sat, Mar 14, 2020 at 04:30:45PM +0100, Sam Ravnborg wrote:
> > data-mapping may not be the best way to describe the
> > data format used between panels and display interface.
> >
> > Drop it from the panel-dpi binding so we do not start to rely on it.
> > We can then work out how to best describe this mapping and when
> > we know it, we can add it to this binding.
> >
> > Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Cc: Maxime Ripard <mripard@kernel.org>
> > Cc: Rob Herring <robh@kernel.org>
> 
> I can't say whether it's the right decision or not, but if you want to
> go forward with this, you should maintain the backward compatibility,
> so leave the code to deal with this as a fallback solution...

This was all introduced very recently and is for now only present in
drm-misc-next.
The idea was to revert is *before* people started to rely on this new
mapping. So we avoid all the backward compatibility fun.
I had hoped the revert could land before the 5.7 pull, alas that was not
the case.

	Sam

> 
> > ---
> >  .../devicetree/bindings/display/panel/panel-dpi.yaml   | 10 ----------
> >  1 file changed, 10 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml b/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml
> > index f63870384c00..0cd74c8dab42 100644
> > --- a/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml
> > +++ b/Documentation/devicetree/bindings/display/panel/panel-dpi.yaml
> > @@ -21,15 +21,6 @@ properties:
> >        - {}
> >        - const: panel-dpi
> >
> > -  data-mapping:
> > -    enum:
> > -      - rgb24
> > -      - rgb565
> > -      - bgr666
> > -    description: |
> > -      Describes the media format, how the display panel is connected
> > -      to the display interface.
> > -
> 
> And keep that DT property documented too.
> 
> You can express that it's only here for compatibility using the
> deprecated keyword though.
> 
> It doesn't do anything at the moment, but the next spec of the schema
> language uses it, so as soon as the library implements it we'll report
> it.
> 
> Maxime