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        Sun, 18 Jun 2023 17:37:33 +0000 (UTC)
Date:   Sun, 18 Jun 2023 19:37:32 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Maxime Ripard <maxime@cerno.tech>
Cc:     David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
        Thierry Reding <thierry.reding@gmail.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        dri-devel@lists.freedesktop.org,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Sebastian Reichel <sre@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        devicetree@vger.kernel.org,
        Michael Riesch <michael.riesch@wolfvision.net>
Subject: Re: [PATCH v2 2/6] dt-bindings: display: st7789v: bound the number
 of Rx data lines
Message-ID: <20230618193732.04fc1909@xps-13>
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Hello Maxime,

maxime@cerno.tech wrote on Sun, 18 Jun 2023 16:37:58 +0200:

> Hi,
>=20
> On Fri, Jun 16, 2023 at 06:32:51PM +0200, Miquel Raynal wrote:
> > The ST7789V LCD controller supports regular SPI wiring, as well as no Rx
> > data line at all. The operating system needs to know whether it can read
> > registers from the device or not. Let's detail this specific design
> > possibility by bounding the spi-rx-bus-width property.
> >=20
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---
> >  .../devicetree/bindings/display/panel/sitronix,st7789v.yaml   | 4 ++++
> >  1 file changed, 4 insertions(+)
> >=20
> > diff --git a/Documentation/devicetree/bindings/display/panel/sitronix,s=
t7789v.yaml b/Documentation/devicetree/bindings/display/panel/sitronix,st77=
89v.yaml
> > index 0ccf0487fd8e..a25df7e1df88 100644
> > --- a/Documentation/devicetree/bindings/display/panel/sitronix,st7789v.=
yaml
> > +++ b/Documentation/devicetree/bindings/display/panel/sitronix,st7789v.=
yaml
> > @@ -29,6 +29,10 @@ properties:
> >    spi-cpha: true
> >    spi-cpol: true
> > =20
> > +  spi-rx-bus-width:
> > +    minimum: 0
> > +    maximum: 1
> > + =20
>=20
> It's not clear to me what the default would be?

This binding references spi-peripheral-props.yaml which sets the
default to 1, I believe it is sane to keep it that way?

Thanks,
Miqu=C3=A8l