dt-bindings: spi: nuvoton,ma35d1-qspi: Add Nuvoton MA35D1 QSPI

Add a devicetree binding for the Quad SPI controller found in
Nuvoton MA35D1 SoCs.

The controller supports SPI memory devices such as SPI NOR and SPI NAND
flashes. It has one register range, one clock input and one reset line,
and supports up to two chip selects.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Chi-Wen Weng <cwweng@nuvoton.com>
Link: https://patch.msgid.link/20260731023818.1626075-2-cwweng.linux@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/nuvoton,ma35d1-qspi.yaml

@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/nuvoton,ma35d1-qspi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton MA35D1 Quad SPI Controller
+
+maintainers:
+  - Chi-Wen Weng <cwweng@nuvoton.com>
+
+allOf:
+  - $ref: /schemas/spi/spi-controller.yaml#
+
+properties:
+  compatible:
+    const: nuvoton,ma35d1-qspi
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  num-cs:
+    minimum: 1
+    maximum: 2
+    default: 2
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - resets
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/nuvoton,ma35d1-clk.h>
+    #include <dt-bindings/reset/nuvoton,ma35d1-reset.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        spi@40680000 {
+            compatible = "nuvoton,ma35d1-qspi";
+            reg = <0 0x40680000 0 0x100>;
+            interrupts = <GIC_SPI 57 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&clk QSPI0_GATE>;
+            resets = <&sys MA35D1_RESET_QSPI0>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+        };
+    };