dt-bindings: serial: Add bindings doc for Sunplus SoC UART Driver

Add bindings doc for Sunplus SoC UART Driver
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hammer Hsieh <hammerh0314@gmail.com>
Link: https://lore.kernel.org/r/1645522563-17183-2-git-send-email-hammerh0314@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/sunplus,sp7021-uart.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) Sunplus Co., Ltd. 2021
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/serial/sunplus,sp7021-uart.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Sunplus SoC SP7021 UART Controller Device Tree Bindings
+
+maintainers:
+  - Hammer Hsieh <hammerh0314@gmail.com>
+
+allOf:
+  - $ref: serial.yaml#
+
+properties:
+  compatible:
+    const: sunplus,sp7021-uart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    aliases {
+        serial0 = &uart0;
+    };
+
+    uart0: serial@9c000900 {
+        compatible = "sunplus,sp7021-uart";
+        reg = <0x9c000900 0x80>;
+        interrupt-parent = <&intc>;
+        interrupts = <53 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clkc 0x28>;
+        resets = <&rstc 0x18>;
+    };
+...

MAINTAINERS

@@ -18549,6 +18549,11 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/rtc/sunplus,sp7021-rtc.yaml
 F:	drivers/rtc/rtc-sunplus.c
 
+SUNPLUS UART DRIVER
+M:	Hammer Hsieh <hammerh0314@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/serial/sunplus,sp7021-uart.yaml
+
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
 M:	Rich Felker <dalias@libc.org>