dt-bindings: memory: convert Qualcomm Atheros DDR to dtschema

Convert Qualcomm Atheros AR7xxx/AR9xxx DDR controller to DT schema
format using json-schema.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210813143537.130310-1-krzysztof.kozlowski@canonical.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/memory-controllers/ath79-ddr-controller.txt

-Binding for Qualcomm  Atheros AR7xxx/AR9xxx DDR controller
-
-The DDR controller of the AR7xxx and AR9xxx families provides an interface
-to flush the FIFO between various devices and the DDR. This is mainly used
-by the IRQ controller to flush the FIFO before running the interrupt handler
-of such devices.
-
-Required properties:
-
-- compatible: has to be "qca,<soc-type>-ddr-controller",
-  "qca,[ar7100|ar7240]-ddr-controller" as fallback.
-  On SoC with PCI support "qca,ar7100-ddr-controller" should be used as
-  fallback, otherwise "qca,ar7240-ddr-controller" should be used.
-- reg: Base address and size of the controller's memory area
-- #qca,ddr-wb-channel-cells: Specifies the number of cells needed to encode
-			     the write buffer channel index, should be 1.
-
-Example:
-
-	ddr_ctrl: memory-controller@18000000 {
-		compatible = "qca,ar9132-ddr-controller",
-				"qca,ar7240-ddr-controller";
-		reg = <0x18000000 0x100>;
-
-		#qca,ddr-wb-channel-cells = <1>;
-	};
-
-	...
-
-	interrupt-controller {
-		...
-		qca,ddr-wb-channel-interrupts = <2>, <3>, <4>, <5>;
-		qca,ddr-wb-channels = <&ddr_ctrl 3>, <&ddr_ctrl 2>,
-					<&ddr_ctrl 0>, <&ddr_ctrl 1>;
-	};

Documentation/devicetree/bindings/memory-controllers/qca,ath79-ddr-controller.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/qca,ath79-ddr-controller.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Atheros AR7xxx/AR9xxx DDR controller
+
+maintainers:
+  - Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
+
+description: |
+  The DDR controller of the AR7xxx and AR9xxx families provides an interface to
+  flush the FIFO between various devices and the DDR. This is mainly used by
+  the IRQ controller to flush the FIFO before running the interrupt handler of
+  such devices.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: qca,ar9132-ddr-controller
+          - const: qca,ar7240-ddr-controller
+      - items:
+          - enum:
+              - qca,ar7100-ddr-controller
+              - qca,ar7240-ddr-controller
+
+  "#qca,ddr-wb-channel-cells":
+    description: |
+      Specifies the number of cells needed to encode the write buffer channel
+      index.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 1
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - "#qca,ddr-wb-channel-cells"
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    ddr_ctrl: memory-controller@18000000 {
+        compatible = "qca,ar9132-ddr-controller",
+                     "qca,ar7240-ddr-controller";
+        reg = <0x18000000 0x100>;
+
+        #qca,ddr-wb-channel-cells = <1>;
+    };
+
+    interrupt-controller {
+        // ...
+        qca,ddr-wb-channel-interrupts = <2>, <3>, <4>, <5>;
+        qca,ddr-wb-channels = <&ddr_ctrl 3>, <&ddr_ctrl 2>,
+                              <&ddr_ctrl 0>, <&ddr_ctrl 1>;
+    };