dt-bindings: dmaengine: Add dma multiplexer for CV18XX/SG200X series SoC

The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
an additional channel remap register located in the top system control
area. The DMA channel is exclusive to each core.

In addition, the DMA multiplexer is a subdevice of system controller,
so this binding only contains necessary properties for the multiplexer
itself.

Add the dmamux binding for CV18XX/SG200X series SoC.

Signed-off-by: Inochi Amaoto <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: inochisa

Documentation/devicetree/bindings/dma/sophgo,cv1800b-dmamux.yaml

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/sophgo,cv1800b-dmamux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo CV1800/SG200 Series DMA multiplexer
+
+maintainers:
+  - Inochi Amaoto <[email protected]>
+
+description:
+  The DMA multiplexer of CV1800 is a subdevice of the system
+  controller. It support mapping 8 channels, but each channel
+  can be mapped only once.
+
+allOf:
+  - $ref: dma-router.yaml#
+
+properties:
+  compatible:
+    const: sophgo,cv1800b-dmamux
+
+  reg:
+    items:
+      - description: DMA channal remapping register
+      - description: DMA channel interrupt mapping register
+
+  '#dma-cells':
+    const: 2
+    description:
+      The first cells is device id. The second one is the cpu id.
+
+  dma-masters:
+    maxItems: 1
+
+required:
+  - reg
+  - '#dma-cells'
+  - dma-masters
+
+additionalProperties: false
+
+examples:
+  - |
+    dma-router@154 {
+      compatible = "sophgo,cv1800b-dmamux";
+      reg = <0x154 0x8>, <0x298 0x4>;
+      #dma-cells = <2>;
+      dma-masters = <&dmac>;
+    };