dt-bindings: serial: convert Cadence UART bindings to YAML

Convert serial for Cadence UART bindings documentation to YAML.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20210715092252.225740-1-iwamatsu@nigauri.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/cdns,uart.txt

-Binding for Cadence UART Controller
-
-Required properties:
-- compatible :
-  Use "xlnx,xuartps","cdns,uart-r1p8" for Zynq-7xxx SoC.
-  Use "xlnx,zynqmp-uart","cdns,uart-r1p12" for Zynq Ultrascale+ MPSoC.
-- reg: Should contain UART controller registers location and length.
-- interrupts: Should contain UART controller interrupts.
-- clocks: Must contain phandles to the UART clocks
-  See ../clocks/clock-bindings.txt for details.
-- clock-names: Tuple to identify input clocks, must contain "uart_clk" and "pclk"
-  See ../clocks/clock-bindings.txt for details.
-
-
-Optional properties:
-- cts-override : Override the CTS modem status signal. This signal will
-  always be reported as active instead of being obtained from the modem status
-  register. Define this if your serial port does not use this pin
-
-Example:
-	uart@e0000000 {
-		compatible = "cdns,uart-r1p8";
-		clocks = <&clkc 23>, <&clkc 40>;
-		clock-names = "uart_clk", "pclk";
-		reg = <0xE0000000 0x1000>;
-		interrupts = <0 27 4>;
-	};

Documentation/devicetree/bindings/serial/cdns,uart.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/cdns,uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Cadence UART Controller Device Tree Bindings
+
+maintainers:
+  - Michal Simek <michal.simek@xilinx.com>
+
+allOf:
+  - $ref: /schemas/serial.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      - description: UART controller for Zynq-7xxx SoC
+        items:
+          - const: xlnx,xuartps
+          - const: cdns,uart-r1p8
+      - description: UART controller for Zynq Ultrascale+ MPSoC
+        items:
+          - const: xlnx,zynqmp-uart
+          - const: cdns,uart-r1p12
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 2
+
+  clock-names:
+    items:
+      - const: uart_clk
+      - const: pclk
+
+  cts-override:
+    description: |
+      Override the CTS modem status signal. This signal will
+      always be reported as active instead of being obtained
+      from the modem status register. Define this if your serial
+      port does not use this pin.
+    type: boolean
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    uart0: serial@e0000000 {
+      compatible = "xlnx,xuartps", "cdns,uart-r1p8";
+      clocks = <&clkc 23>, <&clkc 40>;
+      clock-names = "uart_clk", "pclk";
+      reg = <0xE0000000 0x1000>;
+      interrupts = <0 27 4>;
+    };