dt-bindings: pwm: Convert imx pwm to json-schema

Convert the imx pwm binding to DT schema format using json-schema.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pwm/imx-pwm.txt

-Freescale i.MX PWM controller
-
-Required properties:
-- compatible : should be "fsl,<soc>-pwm" and one of the following
-   compatible strings:
-  - "fsl,imx1-pwm" for PWM compatible with the one integrated on i.MX1
-  - "fsl,imx27-pwm" for PWM compatible with the one integrated on i.MX27
-- reg: physical base address and length of the controller's registers
-- #pwm-cells: 2 for i.MX1 and 3 for i.MX27 and newer SoCs. See pwm.yaml
-  in this directory for a description of the cells format.
-- clocks : Clock specifiers for both ipg and per clocks.
-- clock-names : Clock names should include both "ipg" and "per"
-See the clock consumer binding,
-	Documentation/devicetree/bindings/clock/clock-bindings.txt
-- interrupts: The interrupt for the pwm controller
-
-Example:
-
-pwm1: pwm@53fb4000 {
-	#pwm-cells = <3>;
-	compatible = "fsl,imx53-pwm", "fsl,imx27-pwm";
-	reg = <0x53fb4000 0x4000>;
-	clocks = <&clks IMX5_CLK_PWM1_IPG_GATE>,
-		 <&clks IMX5_CLK_PWM1_HF_GATE>;
-	clock-names = "ipg", "per";
-	interrupts = <61>;
-};

Documentation/devicetree/bindings/pwm/imx-pwm.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/imx-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale i.MX PWM controller
+
+maintainers:
+  - Philipp Zabel <p.zabel@pengutronix.de>
+
+properties:
+  "#pwm-cells":
+    description: |
+      Should be 2 for i.MX1 and 3 for i.MX27 and newer SoCs. See pwm.yaml
+      in this directory for a description of the cells format.
+    enum:
+      - 2
+      - 3
+
+  compatible:
+    enum:
+      - fsl,imx1-pwm
+      - fsl,imx27-pwm
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: SoC PWM ipg clock
+      - description: SoC PWM per clock
+    maxItems: 2
+
+  clock-names:
+    items:
+      - const: ipg
+      - const: per
+    maxItems: 2
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - "#pwm-cells"
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/imx5-clock.h>
+
+    pwm@53fb4000 {
+        #pwm-cells = <3>;
+        compatible = "fsl,imx27-pwm";
+        reg = <0x53fb4000 0x4000>;
+        clocks = <&clks IMX5_CLK_PWM1_IPG_GATE>,
+                 <&clks IMX5_CLK_PWM1_HF_GATE>;
+        clock-names = "ipg", "per";
+        interrupts = <61>;
+    };