dt-bindings: serial: Convert i.MX uart to json-schema

Convert the i.MX uart binding to DT schema format using json-schema.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1597721685-9280-3-git-send-email-Anson.Huang@nxp.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/serial/fsl-imx-uart.txt

-* Freescale i.MX Universal Asynchronous Receiver/Transmitter (UART)
-
-Required properties:
-- compatible : Should be "fsl,<soc>-uart"
-- reg : Address and length of the register set for the device
-- interrupts : Should contain uart interrupt
-
-Optional properties:
-- fsl,dte-mode : Indicate the uart works in DTE mode. The uart works
-                  in DCE mode by default.
-- fsl,inverted-tx , fsl,inverted-rx : Indicate that the hardware attached
-  to the peripheral inverts the signal transmitted or received,
-  respectively, and that the peripheral should invert its output/input
-  using the INVT/INVR registers.
-- rs485-rts-delay, rs485-rts-active-low, rs485-rx-during-tx,
-  linux,rs485-enabled-at-boot-time: see rs485.txt. Note that for RS485
-  you must enable either the "uart-has-rtscts" or the "rts-gpios"
-  properties. In case you use "uart-has-rtscts" the signal that controls
-  the transceiver is actually CTS_B, not RTS_B. CTS_B is always output,
-  and RTS_B is input, regardless of dte-mode.
-
-Please check Documentation/devicetree/bindings/serial/serial.yaml
-for the complete list of generic properties.
-
-Note: Each uart controller should have an alias correctly numbered
-in "aliases" node.
-
-Example:
-
-aliases {
-	serial0 = &uart1;
-};
-
-uart1: serial@73fbc000 {
-	compatible = "fsl,imx51-uart", "fsl,imx21-uart";
-	reg = <0x73fbc000 0x4000>;
-	interrupts = <31>;
-	uart-has-rtscts;
-	fsl,dte-mode;
-};

Documentation/devicetree/bindings/serial/fsl-imx-uart.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/fsl-imx-uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale i.MX Universal Asynchronous Receiver/Transmitter (UART)
+
+maintainers:
+  - Fabio Estevam <fabio.estevam@nxp.com>
+
+allOf:
+  - $ref: "serial.yaml"
+  - $ref: "rs485.yaml"
+
+properties:
+  compatible:
+    oneOf:
+      - const: fsl,imx1-uart
+      - const: fsl,imx21-uart
+      - const: fsl,imx53-uart
+      - const: fsl,imx6q-uart
+      - items:
+          - enum:
+            - fsl,imx25-uart
+            - fsl,imx27-uart
+            - fsl,imx31-uart
+            - fsl,imx35-uart
+            - fsl,imx50-uart
+            - fsl,imx51-uart
+          - const: fsl,imx21-uart
+      - items:
+          - enum:
+            - fsl,imx6sl-uart
+            - fsl,imx6sll-uart
+            - fsl,imx6sx-uart
+            - fsl,imx6ul-uart
+            - fsl,imx7d-uart
+          - const: fsl,imx6q-uart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  fsl,dte-mode:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: |
+      Indicate the uart works in DTE mode. The uart works in DCE mode by default.
+
+  fsl,inverted-tx:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: |
+      Indicate that the hardware attached to the peripheral inverts the signal
+      transmitted, and that the peripheral should invert its output using the
+      INVT registers.
+
+  fsl,inverted-rx:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: |
+      Indicate that the hardware attached to the peripheral inverts the signal
+      received, and that the peripheral should invert its input using the
+      INVR registers.
+
+  uart-has-rtscts: true
+
+  rs485-rts-delay: true
+  rs485-rts-active-low: true
+  rs485-rx-during-tx: true
+  linux,rs485-enabled-at-boot-time: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    aliases {
+        serial0 = &uart1;
+    };
+
+    uart1: serial@73fbc000 {
+        compatible = "fsl,imx51-uart", "fsl,imx21-uart";
+        reg = <0x73fbc000 0x4000>;
+        interrupts = <31>;
+        uart-has-rtscts;
+        fsl,dte-mode;
+    };