dt-bindings: interrupt-controller: Convert st,spear3xx-shirq to DT schema

Convert the SPEAr3xx Shared interrupt controller binding to schema
format. It's a straight-forward conversion of the typical interrupt
controller.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Rob Herring (Arm) <[email protected]>

Author: robherring

Documentation/devicetree/bindings/interrupt-controller/st,spear300-shirq.yaml

@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/st,spear300-shirq.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SPEAr3xx Shared IRQ controller
+
+maintainers:
+  - Viresh Kumar <[email protected]>
+  - Shiraz Hashim <[email protected]>
+
+description: |
+  SPEAr3xx architecture includes shared/multiplexed irqs for certain set of
+  devices. The multiplexor provides a single interrupt to parent interrupt
+  controller (VIC) on behalf of a group of devices.
+
+  There can be multiple groups available on SPEAr3xx variants but not exceeding
+  4. The number of devices in a group can differ, further they may share same
+  set of status/mask registers spanning across different bit masks. Also in some
+  cases the group may not have enable or other registers. This makes software
+  little complex.
+
+  A single node in the device tree is used to describe the shared interrupt
+  multiplexer (one node for all groups). A group in the interrupt controller
+  shares config/control registers with other groups. For example, a 32-bit
+  interrupt enable/disable config register can accommodate up to 4 interrupt
+  groups.
+
+properties:
+  compatible:
+    enum:
+      - st,spear300-shirq
+      - st,spear310-shirq
+      - st,spear320-shirq
+
+  reg:
+    maxItems: 1
+
+  '#interrupt-cells':
+    const: 1
+
+  interrupt-controller: true
+
+  interrupts:
+    description: Interrupt specifier array for SHIRQ groups
+    minItems: 1
+    maxItems: 4
+
+required:
+  - compatible
+  - reg
+  - '#interrupt-cells'
+  - interrupt-controller
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    interrupt-controller@b3000000 {
+        compatible = "st,spear320-shirq";
+        reg = <0xb3000000 0x1000>;
+        interrupts = <28 29 30 1>;
+        #interrupt-cells = <1>;
+        interrupt-controller;
+    };