On 16/06/2023 18:32, 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. > > Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx> > --- > .../devicetree/bindings/display/panel/sitronix,st7789v.yaml | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Documentation/devicetree/bindings/display/panel/sitronix,st7789v.yaml b/Documentation/devicetree/bindings/display/panel/sitronix,st7789v.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 > > + spi-rx-bus-width: > + minimum: 0 > + maximum: 1 0 is already minimum, but I understand you want to emphasize lack of RX. Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> Best regards, Krzysztof