spi: dt-bindings: rspi: Convert to json-schema

Convert the Renesas (Quad) Serial Peripheral Interface (RSPI/QSPI)
Device Tree binding documentation to json-schema.

Document missing properties.
Update the second example to match reality.
Drop the first example, as it doesn't add much value.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200408091129.25429-1-geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/renesas,rspi.yaml

@@ -0,0 +1,144 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/renesas,rspi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas (Quad) Serial Peripheral Interface (RSPI/QSPI)
+
+maintainers:
+  - Geert Uytterhoeven <geert+renesas@glider.be>
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - renesas,rspi-sh7757    # SH7757
+          - const: renesas,rspi        # Legacy SH
+
+      - items:
+          - enum:
+              - renesas,rspi-r7s72100  # RZ/A1H
+              - renesas,rspi-r7s9210   # RZ/A2
+          - const: renesas,rspi-rz     # RZ/A
+
+      - items:
+          - enum:
+              - renesas,qspi-r8a7743   # RZ/G1M
+              - renesas,qspi-r8a7744   # RZ/G1N
+              - renesas,qspi-r8a7745   # RZ/G1E
+              - renesas,qspi-r8a77470  # RZ/G1C
+              - renesas,qspi-r8a7790   # R-Car H2
+              - renesas,qspi-r8a7791   # R-Car M2-W
+              - renesas,qspi-r8a7792   # R-Car V2H
+              - renesas,qspi-r8a7793   # R-Car M2-N
+              - renesas,qspi-r8a7794   # R-Car E2
+          - const: renesas,qspi        # R-Car Gen2 and RZ/G1
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    oneOf:
+      - items:
+          - description: A combined interrupt
+      - items:
+          - description: Error interrupt (SPEI)
+          - description: Receive Interrupt (SPRI)
+          - description: Transmit Interrupt (SPTI)
+
+  interrupt-names:
+    oneOf:
+      - items:
+          - const: mux
+      - items:
+          - const: error
+          - const: rx
+          - const: tx
+
+  clocks:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  dmas:
+    description:
+      Must contain a list of pairs of references to DMA specifiers, one for
+      transmission, and one for reception.
+
+  dma-names:
+    minItems: 2
+    maxItems: 4
+    items:
+      enum:
+        - tx
+        - rx
+
+  num-cs:
+    description: |
+      Total number of native chip selects.
+      Hardware limitations related to chip selects:
+        - When using GPIO chip selects, at least one native chip select must
+          be left unused, as it will be driven anyway.
+    minimum: 1
+    maximum: 2
+    default: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - power-domains
+  - '#address-cells'
+  - '#size-cells'
+
+allOf:
+  - $ref: spi-controller.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - renesas,rspi-rz
+    then:
+      properties:
+        interrupts:
+          minItems: 3
+      required:
+        - interrupt-names
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - renesas,qspi
+    then:
+      required:
+        - resets
+
+examples:
+  - |
+    #include <dt-bindings/clock/r8a7791-cpg-mssr.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/power/r8a7791-sysc.h>
+
+    qspi: spi@e6b10000 {
+            compatible = "renesas,qspi-r8a7791", "renesas,qspi";
+            reg = <0xe6b10000 0x2c>;
+            interrupts = <GIC_SPI 184 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&cpg CPG_MOD 917>;
+            dmas = <&dmac0 0x17>, <&dmac0 0x18>, <&dmac1 0x17>, <&dmac1 0x18>;
+            dma-names = "tx", "rx", "tx", "rx";
+            power-domains = <&sysc R8A7791_PD_ALWAYS_ON>;
+            resets = <&cpg 917>;
+            num-cs = <1>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+    };