dt-bindings: serial: Convert MXS auart to json-schema

Convert the MXS auart binding to DT schema format using json-schema.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1597721685-9280-4-git-send-email-Anson.Huang@nxp.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/serial/fsl-mxs-auart.txt

-* Freescale MXS Application UART (AUART)
-
-Required properties for all SoCs:
-- compatible : Should be one of fallowing variants:
-	"fsl,imx23-auart" - Freescale i.MX23
-	"fsl,imx28-auart" - Freescale i.MX28
-	"alphascale,asm9260-auart" - Alphascale ASM9260
-- reg : Address and length of the register set for the device
-- interrupts : Should contain the auart interrupt numbers
-- dmas: DMA specifier, consisting of a phandle to DMA controller node
-  and AUART DMA channel ID.
-  Refer to dma.txt and fsl-mxs-dma.txt for details.
-- dma-names: "rx" for RX channel, "tx" for TX channel.
-
-Required properties for "alphascale,asm9260-auart":
-- clocks : the clocks feeding the watchdog timer. See clock-bindings.txt
-- clock-names : should be set to
-	"mod" - source for tick counter.
-	"ahb" - ahb gate.
-
-Optional properties:
-- uart-has-rtscts : Indicate the UART has RTS and CTS lines
-  for hardware flow control,
-	it also means you enable the DMA support for this UART.
-- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD
-  line respectively. It will use specified PIO instead of the peripheral
-  function pin for the USART feature.
-  If unsure, don't specify this property.
-
-Example:
-auart0: serial@8006a000 {
-	compatible = "fsl,imx28-auart", "fsl,imx23-auart";
-	reg = <0x8006a000 0x2000>;
-	interrupts = <112>;
-	dmas = <&dma_apbx 8>, <&dma_apbx 9>;
-	dma-names = "rx", "tx";
-	cts-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>;
-	dsr-gpios = <&gpio1 16 GPIO_ACTIVE_LOW>;
-	dcd-gpios = <&gpio1 17 GPIO_ACTIVE_LOW>;
-};
-
-Note: Each auart port should have an alias correctly numbered in "aliases"
-node.
-
-Example:
-
-aliases {
-	serial0 = &auart0;
-	serial1 = &auart1;
-	serial2 = &auart2;
-	serial3 = &auart3;
-	serial4 = &auart4;
-};

Documentation/devicetree/bindings/serial/fsl-mxs-auart.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/fsl-mxs-auart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale MXS Application UART (AUART)
+
+maintainers:
+  - Fabio Estevam <fabio.estevam@nxp.com>
+
+allOf:
+  - $ref: "serial.yaml"
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx23-auart
+      - fsl,imx28-auart
+      - alphascale,asm9260-auart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  dmas:
+    items:
+      - description: DMA controller phandle and request line for RX
+      - description: DMA controller phandle and request line for TX
+
+  dma-names:
+    items:
+      - const: rx
+      - const: tx
+
+  clocks:
+    items:
+      - description: mod clock
+      - description: ahb clock
+    minItems: 1
+
+  clock-names:
+    items:
+      - const: mod
+      - const: ahb
+    minItems: 1
+
+  uart-has-rtscts: true
+  rts-gpios: true
+  cts-gpios: true
+  dtr-gpios: true
+  dsr-gpios: true
+  rng-gpios: true
+  dcd-gpios: true
+
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - alphascale,asm9260-auart
+then:
+  required:
+    - clocks
+    - clock-names
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - dmas
+  - dma-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    aliases {
+        serial0 = &auart0;
+    };
+
+    auart0: serial@8006a000 {
+        compatible = "fsl,imx28-auart";
+        reg = <0x8006a000 0x2000>;
+        interrupts = <112>;
+        dmas = <&dma_apbx 8>, <&dma_apbx 9>;
+        dma-names = "rx", "tx";
+        clocks = <&clks 45>;
+    };