dt-bindings: memory: Document RZ/G3E support

Document support for the Expanded Serial Peripheral Interface (xSPI)
Controller in the Renesas RZ/G3E (R9A09G047) SoC.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20250424090000.136804-2-biju.das.jz@bp.renesas.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Documentation/devicetree/bindings/memory-controllers/renesas,rzg3e-xspi.yaml

@@ -0,0 +1,135 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/renesas,rzg3e-xspi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas Expanded Serial Peripheral Interface (xSPI)
+
+maintainers:
+  - Biju Das <biju.das.jz@bp.renesas.com>
+
+description: |
+  Renesas xSPI allows a SPI flash connected to the SoC to be accessed via
+  the memory-mapping or the manual command mode.
+
+  The flash chip itself should be represented by a subnode of the XSPI node.
+  The flash interface is selected based on the "compatible" property of this
+  subnode:
+  -  "jedec,spi-nor";
+
+allOf:
+  - $ref: /schemas/spi/spi-controller.yaml#
+
+properties:
+  compatible:
+    const: renesas,r9a09g047-xspi  # RZ/G3E
+
+  reg:
+    items:
+      - description: xSPI registers
+      - description: direct mapping area
+
+  reg-names:
+    items:
+      - const: regs
+      - const: dirmap
+
+  interrupts:
+    items:
+      - description: Interrupt pulse signal by factors excluding errors
+      - description: Interrupt pulse signal by error factors
+
+  interrupt-names:
+    items:
+      - const: pulse
+      - const: err_pulse
+
+  clocks:
+    items:
+      - description: AHB clock
+      - description: AXI clock
+      - description: SPI clock
+      - description: Double speed SPI clock
+
+  clock-names:
+    items:
+      - const: ahb
+      - const: axi
+      - const: spi
+      - const: spix2
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    items:
+      - description: Hardware reset
+      - description: AXI reset
+
+  reset-names:
+    items:
+      - const: hresetn
+      - const: aresetn
+
+  renesas,xspi-cs-addr-sys:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: |
+      Phandle to the system controller (sys) that allows to configure
+      xSPI CS0 and CS1 addresses.
+
+patternProperties:
+  "flash@[0-9a-f]+$":
+    type: object
+    additionalProperties: true
+
+    properties:
+      compatible:
+        contains:
+          const: jedec,spi-nor
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - interrupt-names
+  - clocks
+  - clock-names
+  - power-domains
+  - resets
+  - reset-names
+  - '#address-cells'
+  - '#size-cells'
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/renesas,r9a09g047-cpg.h>
+
+    spi@11030000 {
+        compatible = "renesas,r9a09g047-xspi";
+        reg = <0x11030000 0x10000>, <0x20000000 0x10000000>;
+        reg-names = "regs", "dirmap";
+        interrupts = <GIC_SPI 228 IRQ_TYPE_EDGE_RISING>,
+                     <GIC_SPI 229 IRQ_TYPE_EDGE_RISING>;
+        interrupt-names = "pulse", "err_pulse";
+        clocks = <&cpg CPG_MOD 0x9f>, <&cpg CPG_MOD 0xa0>,
+                 <&cpg CPG_CORE 9>, <&cpg CPG_MOD 0xa1>;
+        clock-names = "ahb", "axi", "spi", "spix2";
+        power-domains = <&cpg>;
+        resets = <&cpg 0xa3>, <&cpg 0xa4>;
+        reset-names = "hresetn", "aresetn";
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        flash@0 {
+          compatible = "jedec,spi-nor";
+          reg = <0>;
+          spi-max-frequency = <40000000>;
+          spi-tx-bus-width = <1>;
+          spi-rx-bus-width = <1>;
+        };
+    };