Re: [PATCH 1/2] dt-bindings: display: panel: Add NewVision NV3051D panel bindings

From: Chris Morgan <macromorgan@hotmail.com>
To: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org, krzysztof.kozlowski+dt@linaro.org,
	airlied@linux.ie, dri-devel@lists.freedesktop.org,
	Chris Morgan <macroalpha82@gmail.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	thierry.reding@gmail.com, sam@ravnborg.org
Subject: Re: [PATCH 1/2] dt-bindings: display: panel: Add NewVision NV3051D panel bindings
Date: Mon, 12 Sep 2022 16:40:11 -0500	[thread overview]
Message-ID: <SN6PR06MB5342A0EE256279CF6E3516D0A5449@SN6PR06MB5342.namprd06.prod.outlook.com> (raw)
In-Reply-To: <20220909014235.GA3737396-robh@kernel.org>

On Thu, Sep 08, 2022 at 08:42:35PM -0500, Rob Herring wrote:
> On Wed, Sep 07, 2022 at 08:35:13AM -0500, Chris Morgan wrote:
> > On Wed, Sep 07, 2022 at 02:53:56PM +0200, Krzysztof Kozlowski wrote:
> > > On 06/09/2022 20:52, Chris Morgan wrote:
> > > > From: Chris Morgan <macromorgan@hotmail.com>
> > > > 
> > > > Add documentation for the NewVision NV3051D panel bindings.
> > > > Note that for the two expected consumers of this panel binding
> > > > the underlying LCD model is unknown.
> > > > 
> > > > Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> > > > ---
> > > >  .../display/panel/newvision,nv3051d.yaml      | 48 +++++++++++++++++++
> > > >  1 file changed, 48 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/display/panel/newvision,nv3051d.yaml
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/display/panel/newvision,nv3051d.yaml b/Documentation/devicetree/bindings/display/panel/newvision,nv3051d.yaml
> > > > new file mode 100644
> > > > index 000000000000..016168d8d7b2
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/display/panel/newvision,nv3051d.yaml
> > > > @@ -0,0 +1,48 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetree.org%2Fschemas%2Fdisplay%2Fpanel%2Fnewvision%2Cnv3051d.yaml%23&amp;data=05%7C01%7C%7Cab7f68ce677846b1638508da920493a4%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637982845610791935%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=6XxrzD1zkl8SYQqV9nkH1WzKfdcy6doNfzan8r228W0%3D&amp;reserved=0
> > > 
> > > You need to document vendor prefix... but the filename does not match
> > > compatible.
> > 
> > Okay, will do that. This is a tricky one because while I know the panel
> > controller IC (a NewVision NV3051D) I don't actually know the LCD panel
> > itself, the vendor is somewhat tight lipped. I do know the product it
> > goes into, so that's why I did what I did with the compatible strings.
> > If that's not correct I guess let me know. I did see for other drivers
> > (such as the NewVision NV3052C) the driver was written for the IC
> > and the panel name was listed differently, hence what I was going for
> > here.
> 
> I think most cases like this targeting a specific LCD driver IC, there's 
> a driver IC compatible as a fallback. 
> 
> (TBC, 'driver' here is not Linux driver, but the h/w chip.)
> 
> Rob

So in this case would my compatible string in the devicetree need to
be something like "anbernic,rg353-panel", "newvision,nv3051d" then?
And the module itself have the compatible string of "newvision,nv3051d"?

My fear is that I write this as a newvision,nv3051d kernel module
and then later on there comes a new panel using the nv3051d that wants
to use this too. Again keeping things confusing I have no LCD panel
part number from the manufacturer for this, and I cannot see anything
on the panel itself denoting what LCD it is.

Thank you for your help. Just wrapping up getting some of my favorite
devices supported in mainline. :-)