dt-bindings: display: Add Apple pre-DCP display controller

Add bindings for a secondary display controller present on certain
Apple laptops.

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://patchwork.freedesktop.org/patch/msgid/20250224-adpdrm-v8-1-cccf96710f0f@gmail.com
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>

Documentation/devicetree/bindings/display/apple,h7-display-pipe.yaml

@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/apple,h7-display-pipe.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple pre-DCP display controller
+
+maintainers:
+  - Sasha Finkelstein <fnkl.kernel@gmail.com>
+
+description:
+  A secondary display controller used to drive the "touchbar" on
+  certain Apple laptops.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - apple,t8112-display-pipe
+          - apple,t8103-display-pipe
+      - const: apple,h7-display-pipe
+
+  reg:
+    items:
+      - description: Primary register block, controls planes and blending
+      - description:
+          Contains other configuration registers like interrupt
+          and FIFO control
+
+  reg-names:
+    items:
+      - const: be
+      - const: fe
+
+  power-domains:
+    description:
+      Phandles to pmgr entries that are needed for this controller to turn on.
+      Aside from that, their specific functions are unknown
+    maxItems: 2
+
+  interrupts:
+    items:
+      - description: Unknown function
+      - description: Primary interrupt. Vsync events are reported via it
+
+  interrupt-names:
+    items:
+      - const: be
+      - const: fe
+
+  iommus:
+    maxItems: 1
+
+  port:
+    $ref: /schemas/graph.yaml#/properties/port
+    description: Output port. Always connected to apple,h7-display-pipe-mipi
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - port
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/apple-aic.h>
+    display-pipe@28200000 {
+        compatible = "apple,t8103-display-pipe", "apple,h7-display-pipe";
+        reg = <0x28200000 0xc000>,
+              <0x28400000 0x4000>;
+        reg-names = "be", "fe";
+        power-domains = <&ps_dispdfr_fe>, <&ps_dispdfr_be>;
+        interrupt-parent = <&aic>;
+        interrupts = <AIC_IRQ 502 IRQ_TYPE_LEVEL_HIGH>,
+                     <AIC_IRQ 506 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "be", "fe";
+        iommus = <&displaydfr_dart 0>;
+
+        port {
+            dfr_adp_out_mipi: endpoint {
+                remote-endpoint = <&dfr_mipi_in_adp>;
+            };
+        };
+    };
+...