dt-bindings: display/panel: Add Innolux EJ030NA

Add binding for the Innolux EJ030NA panel, which is a 320x480 3.0" 4:3
24-bit TFT LCD panel with non-square pixels and a delta-RGB 8-bit
interface.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210625121045.81711-1-paul@crapouillou.net

Documentation/devicetree/bindings/display/panel/innolux,ej030na.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/innolux,ej030na.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Innolux EJ030NA 3.0" (320x480 pixels) 24-bit TFT LCD panel
+
+description: |
+  The panel must obey the rules for a SPI slave device as specified in
+  spi/spi-controller.yaml
+
+maintainers:
+  - Paul Cercueil <paul@crapouillou.net>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: innolux,ej030na
+
+  backlight: true
+  port: true
+  power-supply: true
+  reg: true
+  reset-gpios: true
+
+required:
+  - compatible
+  - reg
+  - power-supply
+  - reset-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "innolux,ej030na";
+            reg = <0>;
+
+            spi-max-frequency = <10000000>;
+
+            reset-gpios = <&gpe 4 GPIO_ACTIVE_LOW>;
+            power-supply = <&lcd_power>;
+
+            backlight = <&backlight>;
+
+            port {
+                panel_input: endpoint {
+                    remote-endpoint = <&panel_output>;
+                };
+            };
+        };
+    };