Re: [PATCH 2/3] dt-bindings: display: sitronix,st7920: Add DT schema

[Conor Dooley]

On Wed, Aug 06, 2025 at 02:48:10PM +0200, Iker Pedrosa wrote:
> Add binding for Sitronix ST7920 display.
> 
> Signed-off-by: Iker Pedrosa <ikerpedro...@gmail.com>
> ---
>  .../bindings/display/sitronix,st7920.yaml          | 55 
> ++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/sitronix,st7920.yaml 
> b/Documentation/devicetree/bindings/display/sitronix,st7920.yaml
> new file mode 100644
> index 
> 0000000000000000000000000000000000000000..caee85f98c6d242dfab73729210f8c34b23a3a99
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/sitronix,st7920.yaml
> @@ -0,0 +1,55 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/sitronix,st7920.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Sitronix ST7920 LCD Display Controllers
> +
> +maintainers:
> +  - Iker Pedrosa <ikerpedro...@gmail.com>
> +
> +description: |
> +  The Sitronix ST7920 is a controller for monochrome dot-matrix graphical 
> LCDs,
> +  most commonly used for 128x64 pixel displays.
> +  This binding supports connecting the display via a standard SPI bus.
> +
> +properties:
> +  compatible:
> +    const: sitronix,st7920
> +
> +  reg:
> +    description: The chip-select number for the device on the SPI bus.
> +    maxItems: 1
> +
> +  spi-max-frequency:
> +    description: Maximum SPI clock frequency in Hz.
> +    maximum: 600000
> +
> +  spi-cs-high:
> +    type: boolean
> +    description: Indicates the chip select is active high.

Don't redefine this, it's defined in spi-peripheral-props.yaml:
  spi-cs-high:
    $ref: /schemas/types.yaml#/definitions/flag
    description:
      The device requires the chip select active high.

spi-max-frequency's type comes from there, so you need it for that too.


> +
> +required:
> +  - compatible
> +  - reg
> +  - spi-max-frequency
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    // Example: ST7920 connected to an SPI bus
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    spi0 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        display@0 {
> +            compatible = "sitronix,st7920";
> +            reg = <0>; // Chip select 0
> +            spi-max-frequency = <600000>;
> +            spi-cs-high;
> +        };
> +    };
> 
> -- 
> 2.50.1
> 

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