dt-bindings: display: convert sitronix,st7789v to DT Schema

v2:
    - dropped use of spi-slave.yaml (Maxime)
    - added unevaluatedProperties (Maxime)
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408195109.32692-28-sam@ravnborg.org

Documentation/devicetree/bindings/display/panel/sitronix,st7789v.txt

-Sitronix ST7789V RGB panel with SPI control bus
-
-Required properties:
-  - compatible: "sitronix,st7789v"
-  - reg: Chip select of the panel on the SPI bus
-  - reset-gpios: a GPIO phandle for the reset pin
-  - power-supply: phandle of the regulator that provides the supply voltage
-
-Optional properties:
-  - backlight: phandle to the backlight used
-
-The generic bindings for the SPI slaves documented in [1] also applies
-
-The device node can contain one 'port' child node with one child
-'endpoint' node, according to the bindings defined in [2]. This
-node should describe panel's video bus.
-
-[1]: Documentation/devicetree/bindings/spi/spi-bus.txt
-[2]: Documentation/devicetree/bindings/graph.txt
-
-Example:
-
-panel@0 {
-	compatible = "sitronix,st7789v";
-	reg = <0>;
-	reset-gpios = <&pio 6 11 GPIO_ACTIVE_LOW>;
-	backlight = <&pwm_bl>;
-	spi-max-frequency = <100000>;
-	spi-cpol;
-	spi-cpha;
-
-	port {
-		panel_input: endpoint {
-			remote-endpoint = <&tcon0_out_panel>;
-		};
-	};
-};

Documentation/devicetree/bindings/display/panel/sitronix,st7789v.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/sitronix,st7789v.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sitronix ST7789V RGB panel with SPI control bus
+
+description: |
+  The panel must obey the rules for a SPI slave device as specified in
+  spi/spi-controller.yaml
+
+maintainers:
+  - Maxime Ripard <mripard@kernel.org>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: sitronix,st7789v
+
+  reg: true
+  reset-gpios: true
+  power-supply: true
+  backlight: true
+  port: true
+
+required:
+  - compatible
+  - reg
+  - reset-gpios
+  - power-supply
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "sitronix,st7789v";
+            reg = <0>;
+            reset-gpios = <&pio 6 11 GPIO_ACTIVE_LOW>;
+            backlight = <&pwm_bl>;
+            power-supply = <&power>;
+            spi-max-frequency = <100000>;
+            spi-cpol;
+            spi-cpha;
+
+            port {
+                panel_input: endpoint {
+                    remote-endpoint = <&tcon0_out_panel>;
+                };
+            };
+        };
+    };
+
+...