dt-bindings: display: st7789v: bound the number of Rx data lines

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@bootlin.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Tested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-16-sre@kernel.org

diff --git a/Documentation/devicetree/bindings/display/panel/sitronix,st7789v.yaml b/Documentation/devicetree/bindings/display/panel/sitronix,st7789v.yaml
index 9f4157b02b840ebc6500550b0e3c735a1e0cece1..905c064cd106b8401a60be49a6fa3c5885314a33 100644 (file)
--- 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
+
   dc-gpios:
     maxItems: 1
     description: DCX pin, Display data/command selection pin in parallel interface