dt-bindings: display: panel: Convert sitronix,st7701 to DT schema

Convert the sitronix,st7701 panel bindings to DT schema.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200403142453.25307-2-jagan@amarulasolutions.com

Documentation/devicetree/bindings/display/panel/sitronix,st7701.txt

-Sitronix ST7701 based LCD panels
-
-ST7701 designed for small and medium sizes of TFT LCD display, is
-capable of supporting up to 480RGBX864 in resolution. It provides
-several system interfaces like MIPI/RGB/SPI.
-
-Techstar TS8550B is 480x854, 2-lane MIPI DSI LCD panel which has
-inbuilt ST7701 chip.
-
-Required properties:
-- compatible: must be "sitronix,st7701" and one of
-  * "techstar,ts8550b"
-- reset-gpios: a GPIO phandle for the reset pin
-
-Required properties for techstar,ts8550b:
-- reg: DSI virtual channel used by that screen
-- VCC-supply: analog regulator for MIPI circuit
-- IOVCC-supply: I/O system regulator
-
-Optional properties:
-- backlight: phandle for the backlight control.
-
-panel@0 {
-	compatible = "techstar,ts8550b", "sitronix,st7701";
-	reg = <0>;
-	VCC-supply = <&reg_dldo2>;
-	IOVCC-supply = <&reg_dldo2>;
-	reset-gpios = <&pio 3 24 GPIO_ACTIVE_HIGH>; /* LCD-RST: PD24 */
-	backlight = <&backlight>;
-};

Documentation/devicetree/bindings/display/panel/sitronix,st7701.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/sitronix,st7701.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sitronix ST7701 based LCD panels
+
+maintainers:
+  - Jagan Teki <jagan@amarulasolutions.com>
+
+description: |
+  ST7701 designed for small and medium sizes of TFT LCD display, is
+  capable of supporting up to 480RGBX864 in resolution. It provides
+  several system interfaces like MIPI/RGB/SPI.
+
+  Techstar TS8550B is 480x854, 2-lane MIPI DSI LCD panel which has
+  inbuilt ST7701 chip.
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - techstar,ts8550b
+      - const: sitronix,st7701
+
+  reg:
+    description: DSI virtual channel used by that screen
+    maxItems: 1
+
+  VCC-supply:
+    description: analog regulator for MIPI circuit
+
+  IOVCC-supply:
+    description: I/O system regulator
+
+  reset-gpios: true
+
+  backlight: true
+
+required:
+  - compatible
+  - reg
+  - VCC-supply
+  - IOVCC-supply
+  - reset-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "techstar,ts8550b", "sitronix,st7701";
+            reg = <0>;
+            VCC-supply = <&reg_dldo2>;
+            IOVCC-supply = <&reg_dldo2>;
+            reset-gpios = <&pio 3 24 GPIO_ACTIVE_HIGH>; /* LCD-RST: PD24 */
+            backlight = <&backlight>;
+        };
+    };