dt-bindings: irq: Convert Allwinner NMI Controller to a schema

The Allwinner SoCs have an interrupt controller called NMI supported in
Linux, with a matching Device Tree binding.

Now that we have the DT validation in place, let's convert the device tree
bindings for that controller over to a YAML schemas.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/interrupt-controller/allwinner,sun7i-a20-sc-nmi.yaml

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/allwinner,sun7i-a20-sc-nmi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner A20 Non-Maskable Interrupt Controller Device Tree Bindings
+
+maintainers:
+  - Chen-Yu Tsai <wens@csie.org>
+  - Maxime Ripard <maxime.ripard@bootlin.com>
+
+allOf:
+  - $ref: /schemas/interrupt-controller.yaml#
+
+properties:
+  "#interrupt-cells":
+    const: 2
+    description:
+      The first cell is the IRQ number, the second cell the trigger
+      type as defined in interrupt.txt in this directory.
+
+  compatible:
+    oneOf:
+      - const: allwinner,sun6i-a31-r-intc
+      - const: allwinner,sun6i-a31-sc-nmi
+        deprecated: true
+      - const: allwinner,sun7i-a20-sc-nmi
+      - items:
+        - const: allwinner,sun8i-a83t-r-intc
+        - const: allwinner,sun6i-a31-r-intc
+      - const: allwinner,sun9i-a80-sc-nmi
+      - items:
+        - const: allwinner,sun50i-a64-r-intc
+        - const: allwinner,sun6i-a31-r-intc
+      - items:
+        - const: allwinner,sun50i-h6-r-intc
+        - const: allwinner,sun6i-a31-r-intc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+required:
+  - "#interrupt-cells"
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+
+# FIXME: We should set it, but it would report all the generic
+# properties as additional properties.
+# additionalProperties: false
+
+examples:
+  - |
+    interrupt-controller@1c00030 {
+        compatible = "allwinner,sun7i-a20-sc-nmi";
+        interrupt-controller;
+        #interrupt-cells = <2>;
+        reg = <0x01c00030 0x0c>;
+        interrupt-parent = <&gic>;
+        interrupts = <0 0 4>;
+    };
+
+...