dt-bindings: arm: bcm: raspberrypi,bcm2835-firmware: Add touchscreen child node

Convert Raspberry Pi firmware 7" touchscreen controller device tree
binding to json-schema.

Signed-off-by: Dario Binacchi <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml

···
       - compatible
       - "#pwm-cells"
 
+  touchscreen:
+    type: object
+    $ref: /schemas/input/touchscreen/touchscreen.yaml#
+    additionalProperties: false
+
+    properties:
+      compatible:
+        const: raspberrypi,firmware-ts
+
+      firmware:
+        deprecated: true
+        description: Phandle to RPi's firmware device node.
+
+      touchscreen-size-x: true
+      touchscreen-size-y: true
+      touchscreen-inverted-x: true
+      touchscreen-inverted-y: true
+      touchscreen-swapped-x-y: true
+
+    required:
+      - compatible
+
 required:
   - compatible
   - mboxes
···
         pwm: pwm {
             compatible = "raspberrypi,firmware-poe-pwm";
             #pwm-cells = <2>;
+        };
+
+        ts: touchscreen {
+            compatible = "raspberrypi,firmware-ts";
+            touchscreen-size-x = <800>;
+            touchscreen-size-y = <480>;
         };
     };
 ...

Documentation/devicetree/bindings/input/touchscreen/raspberrypi,firmware-ts.txt

···
-Raspberry Pi firmware based 7" touchscreen
-=====================================
-
-Required properties:
- - compatible: "raspberrypi,firmware-ts"
-
-Optional properties:
- - firmware: Reference to RPi's firmware device node
- - touchscreen-size-x: See touchscreen.txt
- - touchscreen-size-y: See touchscreen.txt
- - touchscreen-inverted-x: See touchscreen.txt
- - touchscreen-inverted-y: See touchscreen.txt
- - touchscreen-swapped-x-y: See touchscreen.txt
-
-Example:
-
-firmware: firmware-rpi {
-	compatible = "raspberrypi,bcm2835-firmware";
-	mboxes = <&mailbox>;
-
-	ts: touchscreen {
-		compatible = "raspberrypi,firmware-ts";
-		touchscreen-size-x = <800>;
-		touchscreen-size-y = <480>;
-	};
-};