dt-bindings: soc: apple: Add Dockchannel and MTP bindings

This adds device tree bindings for the DockChannel,
DockChannel HID and MTP nodes required to enable
internal keyboard/trackpad support on M2 and later
Apple Silicon laptops.

Signed-off-by: Michael Reeves <[email protected]>

Author: IntegralPilot

Documentation/devicetree/bindings/soc/apple/apple,dockchannel.yaml

@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (c) 2025 The Asahi Linux contributors
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/apple/apple,dockchannel.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple DockChannel FIFO
+
+maintainers:
+  - Michael Reeves <[email protected]>
+
+description: |
+  DockChannel is a hardware FIFO and interrupt controller used on Apple SoCs
+  for low-latency communication with co-processors.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: apple,t8112-dockchannel
+      - items:
+          - const: apple,t6020-dockchannel
+          - const: apple,t8112-dockchannel
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 2
+
+  ranges: true
+
+  nonposted-mmio: true
+
+  "#address-cells":
+    const: 2
+
+  "#size-cells":
+    const: 2
+
+patternProperties:
+  "^input@[0-9a-f]+$":
+    $ref: /schemas/input/apple,dockchannel-hid.yaml
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - "#interrupt-cells"
+  - ranges
+  - "#address-cells"
+  - "#size-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/apple-aic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        fifo@2a9b14000 {
+      		compatible = "apple,t6020-dockchannel", "apple,t8112-dockchannel";
+      		reg = <0x2 0xa9b14000 0x0 0x4000>;
+
+      		interrupt-parent = <&aic>;
+      		interrupts = <AIC_IRQ 0 677 IRQ_TYPE_LEVEL_HIGH>;
+
+      		ranges;
+      		#address-cells = <2>;
+      		#size-cells = <2>;
+
+      		interrupt-controller;
+      		#interrupt-cells = <2>;
+        };
+    };