dt-bindings: perf: Convert i.MX DDR to json-schema

Convert the i.MX DDR perf binding to DT schema format using json-schema.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1596609387-23542-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/perf/fsl-imx-ddr.txt

@@ -1,22 +0,0 @@
-* Freescale(NXP) IMX8 DDR performance monitor
-
-Required properties:
-
-- compatible: should be one of:
-	"fsl,imx8-ddr-pmu"
-	"fsl,imx8m-ddr-pmu"
-	"fsl,imx8mp-ddr-pmu"
-
-- reg: physical address and size
-
-- interrupts: single interrupt
-	generated by the control block
-
-Example:
-
-	ddr-pmu@5c020000 {
-		compatible = "fsl,imx8-ddr-pmu";
-		reg = <0x5c020000 0x10000>;
-		interrupt-parent = <&gic>;
-		interrupts = <GIC_SPI 131 IRQ_TYPE_LEVEL_HIGH>;
-	};

Documentation/devicetree/bindings/perf/fsl-imx-ddr.yaml

@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/perf/fsl-imx-ddr.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale(NXP) IMX8 DDR performance monitor
+
+maintainers:
+  - Frank Li <frank.li@nxp.com>
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx8-ddr-pmu
+      - fsl,imx8m-ddr-pmu
+      - fsl,imx8mp-ddr-pmu
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    ddr-pmu@5c020000 {
+        compatible = "fsl,imx8-ddr-pmu";
+        reg = <0x5c020000 0x10000>;
+        interrupt-parent = <&gic>;
+        interrupts = <GIC_SPI 131 IRQ_TYPE_LEVEL_HIGH>;
+    };