dt-bindings: interrupt-controller: Add T-HEAD C900 ACLINT SSWI device

Sophgo SG2044 has a new version of T-HEAD C920, which implement a fully
featured T-HEAD ACLINT device. This ACLINT device contains a SSWI device to
support fast S-mode IPI.

Add necessary compatible string for the T-HEAD ACLINT SSWI device.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/all/20241031060859.722258-2-inochiama@gmail.com
Link: https://www.xrvm.com/product/xuantie/C920

Documentation/devicetree/bindings/interrupt-controller/thead,c900-aclint-sswi.yaml

@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/thead,c900-aclint-sswi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-HEAD C900 ACLINT Supervisor-level Software Interrupt Device
+
+maintainers:
+  - Inochi Amaoto <inochiama@outlook.com>
+
+description:
+  The SSWI device is a part of the THEAD ACLINT device. It provides
+  supervisor-level IPI functionality for a set of HARTs on a THEAD
+  platform. It provides a register to set an IPI (SETSSIP) for each
+  HART connected to the SSWI device.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - sophgo,sg2044-aclint-sswi
+      - const: thead,c900-aclint-sswi
+
+  reg:
+    maxItems: 1
+
+  "#interrupt-cells":
+    const: 0
+
+  interrupt-controller: true
+
+  interrupts-extended:
+    minItems: 1
+    maxItems: 4095
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - "#interrupt-cells"
+  - interrupt-controller
+  - interrupts-extended
+
+examples:
+  - |
+    interrupt-controller@94000000 {
+      compatible = "sophgo,sg2044-aclint-sswi", "thead,c900-aclint-sswi";
+      reg = <0x94000000 0x00004000>;
+      #interrupt-cells = <0>;
+      interrupt-controller;
+      interrupts-extended = <&cpu1intc 1>,
+                            <&cpu2intc 1>,
+                            <&cpu3intc 1>,
+                            <&cpu4intc 1>;
+    };
+...