dt-bindings: input: touchscreen: Add Z2 controller

Add bindings for touchscreen controllers attached using the Z2 protocol.
Those are present in most Apple devices.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Link: https://lore.kernel.org/r/20250217-z2-v6-1-c2115d6e5a8f@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/touchscreen/apple,z2-multitouch.yaml

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/apple,z2-multitouch.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple touchscreens attached using the Z2 protocol
+
+maintainers:
+  - Sasha Finkelstein <fnkl.kernel@gmail.com>
+
+description: A series of touschscreen controllers used in Apple products
+
+allOf:
+  - $ref: touchscreen.yaml#
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    enum:
+      - apple,j293-touchbar
+      - apple,j493-touchbar
+
+  interrupts:
+    maxItems: 1
+
+  reset-gpios:
+    maxItems: 1
+
+  firmware-name:
+    maxItems: 1
+
+  apple,z2-cal-blob:
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    maxItems: 4096
+    description:
+      Calibration blob supplied by the bootloader
+
+required:
+  - compatible
+  - interrupts
+  - reset-gpios
+  - firmware-name
+  - touchscreen-size-x
+  - touchscreen-size-y
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        touchscreen@0 {
+            compatible = "apple,j293-touchbar";
+            reg = <0>;
+            spi-max-frequency = <11500000>;
+            reset-gpios = <&pinctrl_ap 139 GPIO_ACTIVE_LOW>;
+            interrupts-extended = <&pinctrl_ap 194 IRQ_TYPE_EDGE_FALLING>;
+            firmware-name = "apple/dfrmtfw-j293.bin";
+            touchscreen-size-x = <23045>;
+            touchscreen-size-y = <640>;
+        };
+    };
+
+...