dt-bindings: watchdog: Add watchdog yaml file for Sunplus SP7021

This adds the documentation for the devicetree bindings of the Sunplus
SP7021 watchdog driver, found from SP7021 SoCs and newer.
Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220324031805.61316-2-xt.hu@cqplus1.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) Sunplus Co., Ltd. 2021
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/sunplus,sp7021-wdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sunplus SoCs Watchdog
+
+maintainers:
+  - XianTao Hu <xt.hu@cqplus1.com>
+
+allOf:
+  - $ref: watchdog.yaml#
+
+properties:
+  compatible:
+    const: sunplus,sp7021-wdt
+
+  reg:
+    items:
+      - description: watchdog registers regions
+      - description: miscellaneous control registers regions
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    watchdog: watchdog@9c000630 {
+        compatible = "sunplus,sp7021-wdt";
+        reg = <0x9c000630 0x08>, <0x9c000274 0x04>;
+        clocks = <&clkc 0x24>;
+        resets = <&rstc 0x14>;
+    };
+...

MAINTAINERS

@@ -18902,6 +18902,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/serial/sunplus,sp7021-uart.yaml
 F:	drivers/tty/serial/sunplus-uart.c
 
+SUNPLUS WATCHDOG DRIVER
+M:	Xiantao Hu <xt.hu@cqplus1.com>
+L:	linux-watchdog@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
+
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
 M:	Rich Felker <dalias@libc.org>