Re: [PATCH v7 2/2] dt-bindings: input: Goodix SPI HID Touchscreen

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Wed, Sep 25, 2024 at 12:40:56PM -0500, Rob Herring wrote:
> On Tue, Sep 10, 2024 at 5:41 PM Rob Herring <robh@kernel.org> wrote:
> >
> > On Fri, Sep 6, 2024 at 3:28 PM Rob Herring <robh@kernel.org> wrote:
> > >
> > > On Tue, Aug 13, 2024 at 9:45 PM Charles Wang <charles.goodix@gmail.com> wrote:
> > > >
> > > > The Goodix GT7986U touch controller report touch data according to the
> > > > HID protocol through the SPI bus. However, it is incompatible with
> > > > Microsoft's HID-over-SPI protocol.
> > > >
> > > > Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> > > > Signed-off-by: Charles Wang <charles.goodix@gmail.com>
> > > > ---
> > > >  .../bindings/input/goodix,gt7986u.yaml        | 71 +++++++++++++++++++
> > > >  1 file changed, 71 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/input/goodix,gt7986u.yaml
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/input/goodix,gt7986u.yaml b/Documentation/devicetree/bindings/input/goodix,gt7986u.yaml
> > > > new file mode 100644
> > > > index 000000000..a7d42a5d6
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/input/goodix,gt7986u.yaml
> > > > @@ -0,0 +1,71 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/input/goodix,gt7986u.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: GOODIX GT7986U SPI HID Touchscreen
> > > > +
> > > > +maintainers:
> > > > +  - Charles Wang <charles.goodix@gmail.com>
> > > > +
> > > > +description: Supports the Goodix GT7986U touchscreen.
> > > > +  This touch controller reports data packaged according to the HID protocol,
> > > > +  but is incompatible with Microsoft's HID-over-SPI protocol.
> > > > +
> > > > +allOf:
> > > > +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> > > > +
> > > > +properties:
> > > > +  compatible:
> > > > +    enum:
> > > > +      - goodix,gt7986u
> > >
> > > This is already documented in goodix,gt7375p.yaml. Now linux-next has warnings:
> > >
> > > /builds/robherring/linux-dt/Documentation/devicetree/bindings/input/goodix,gt7986u.example.dtb:
> > > touchscreen@0: compatible: 'oneOf' conditional failed, one must be
> > > fixed:
> > >         ['goodix,gt7986u'] is too short
> > >         'goodix,gt7375p' was expected
> > >         from schema $id:
> > > http://devicetree.org/schemas/input/goodix,gt7375p.yaml#
> > > /builds/robherring/linux-dt/Documentation/devicetree/bindings/input/goodix,gt7986u.example.dtb:
> > > touchscreen@0: reg:0:0: 0 is not one of [93, 20]
> > >         from schema $id:
> > > http://devicetree.org/schemas/input/goodix,gt7375p.yaml#
> > > /builds/robherring/linux-dt/Documentation/devicetree/bindings/input/goodix,gt7986u.example.dtb:
> > > touchscreen@0: 'vdd-supply' is a required property
> > >         from schema $id:
> > > http://devicetree.org/schemas/input/goodix,gt7375p.yaml#
> > > /builds/robherring/linux-dt/Documentation/devicetree/bindings/input/goodix,gt7986u.example.dtb:
> > > touchscreen@0: 'goodix,hid-report-addr', 'spi-max-frequency' do not
> > > match any of the regexes: 'pinctrl-[0-9]+'
> > >         from schema $id:
> > > http://devicetree.org/schemas/input/goodix,gt7375p.yaml#
> > >
> > > Please sort this out and send a fix.
> >
> > I should add that it is intermittent whether you see this error or
> > not. The tools select a single schema based on the compatible string
> > and it is undefined which of the 2 schemas you will get.
> 
> Still an issue and no response. Please fix or revert the series.

I see that Krzysztof sent a revert, but what a proper fix would be?
Apparently Goodix is using the same product ID gt7986u for both I2C and
SPI parts, and covering them in one binding is not really easy (well, I
guess it is possible with a big ugly "if"). Do we just slap "-spi"
suffix on the compatible, so it becomes "goodix,gt7986u-spi" and go on
on our merry way? Is there a better option for such products that
support multiple interfaces/transports?

Thanks.

-- 
Dmitry