dt-bindings: display: Add Sony Tulip Truly NT35521 panel support

The Sony Tulip Truly NT35521 is a 5.24" 1280x720 DSI panel, which can
be found on Sony Xperia M4 Aqua phone.  The backlight is managed
through DSI link.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210809051008.6172-2-shawn.guo@linaro.org

Documentation/devicetree/bindings/display/panel/sony,tulip-truly-nt35521.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/sony,tulip-truly-nt35521.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sony Tulip Truly NT35521 5.24" 1280x720 MIPI-DSI Panel
+
+maintainers:
+  - Shawn Guo <shawn.guo@linaro.org>
+
+description: |
+  The Sony Tulip Truly NT35521 is a 5.24" 1280x720 MIPI-DSI panel, which
+  can be found no Sony Xperia M4 phone.  The panel backlight is managed
+  through DSI link.
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: sony,tulip-truly-nt35521
+
+  reg: true
+
+  positive5-supply:
+    description: Positive 5V supply
+
+  negative5-supply:
+    description: Negative 5V supply
+
+  reset-gpios: true
+
+  enable-gpios: true
+
+  port: true
+
+required:
+  - compatible
+  - reg
+  - positive5-supply
+  - negative5-supply
+  - reset-gpios
+  - enable-gpios
+  - port
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "sony,tulip-truly-nt35521";
+            reg = <0>;
+            positive5-supply = <&positive5_reg>;
+            negative5-supply = <&negative5_reg>;
+            reset-gpios = <&msmgpio 25 GPIO_ACTIVE_LOW>;
+            enable-gpios = <&msmgpio 10 GPIO_ACTIVE_HIGH>;
+
+            port {
+                panel_in: endpoint {
+                    remote-endpoint = <&dsi0_out>;
+                };
+            };
+        };
+    };
+...