[PATCH V3 1/3] dt-bindings: spi: Add support for ATCSPI200 SPI controller

[CL Wang <cl634@andestech.com>]

Document devicetree bindings for the Andes ATCSPI200 SPI controller.

Signed-off-by: CL Wang <cl634@andestech.com>
---
Changes for v3:
  - Reworked the DT binding to properly describe the compatible fallback
    relationship, defining "andestech,qilai-spi" as a platform-specific
    compatible that falls back to the generic "andestech,ae350-spi".
  - Renamed the DT binding file from 'andestech,qilai-spi.yaml' to
    'andestech,ae350-spi.yaml' to match the generic fallback compatible.
  - Updated the 'compatible' property to use a 'oneOf' schema, enforcing
    the fallback requirement for the specific compatible string.

Changes for v2:
  - Dropped the "spi_" prefix from dma-names as suggested.
  - Updated the DT binding and documented all compatible strings.
  - Added the "andestech,ae350-spi" compatible string.
 
---
 .../bindings/spi/andestech,ae350-spi.yaml     | 85 +++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/andestech,ae350-spi.yaml

diff --git a/Documentation/devicetree/bindings/spi/andestech,ae350-spi.yaml b/Documentation/devicetree/bindings/spi/andestech,ae350-spi.yaml
new file mode 100644
index 000000000000..78093468dd5e
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/andestech,ae350-spi.yaml
@@ -0,0 +1,85 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/andestech,ae350-spi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Andes ATCSPI200 SPI controller
+
+maintainers:
+  - CL Wang <cl634@andestech.com>
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - andestech,qilai-spi
+          - const: andestech,ae350-spi
+      - const: andestech,ae350-spi
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  num-cs:
+    description: Number of chip selects supported
+    maxItems: 1
+
+  dmas:
+    items:
+      - description: Transmit FIFO DMA channel
+      - description: Receive FIFO DMA channel
+
+  dma-names:
+    items:
+      - const: tx
+      - const: rx
+
+patternProperties:
+  "@[0-9a-f]+$":
+    type: object
+    additionalProperties: true
+
+    properties:
+      spi-rx-bus-width:
+        enum: [1, 4]
+
+      spi-tx-bus-width:
+        enum: [1, 4]
+
+allOf:
+  - $ref: spi-controller.yaml#
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - dmas
+  - dma-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi@f0b00000 {
+        compatible = "andestech,ae350-spi";
+        reg = <0xf0b00000 0x100>;
+        clocks = <&clk_spi>;
+        dmas = <&dma0 0>, <&dma0 1>;
+        dma-names = "tx", "rx";
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        flash@0 {
+            compatible = "jedec,spi-nor";
+            reg = <0>;
+            spi-tx-bus-width = <4>;
+            spi-rx-bus-width = <4>;
+            spi-cpol;
+            spi-cpha;
+        };
+    };
-- 
2.34.1