dt-bindings: display: Add Mayqueen Pixpaper e-ink panel

The binding is for the Mayqueen Pixpaper e-ink display panel,
controlled via an SPI interface.

Signed-off-by: LiangCheng Wang <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: Thomas Zimmermann <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

Documentation/devicetree/bindings/display/mayqueen,pixpaper.yaml

···
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/mayqueen,pixpaper.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Mayqueen Pixpaper e-ink display panel
+
+maintainers:
+  - LiangCheng Wang <[e-mail]>
+
+description:
+  The Pixpaper is an e-ink display panel controlled via an SPI interface.
+  The panel has a resolution of 122x250 pixels and requires GPIO pins for
+  reset, busy, and data/command control.
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    const: mayqueen,pixpaper
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 1000000
+    default: 1000000
+
+  reset-gpios:
+    maxItems: 1
+
+  busy-gpios:
+    maxItems: 1
+
+  dc-gpios:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - reset-gpios
+  - busy-gpios
+  - dc-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        display@0 {
+            compatible = "mayqueen,pixpaper";
+            reg = <0>;
+            spi-max-frequency = <1000000>;
+            reset-gpios = <&gpio1 17 GPIO_ACTIVE_HIGH>;
+            busy-gpios = <&gpio1 18 GPIO_ACTIVE_HIGH>;
+            dc-gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
+        };
+    };