dt-bindings: watchdog: Convert arm,sbsa-gwdt to DT schema

Convert the arm,sbsa-gwdt binding to DT schema format.

Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Fu Wei <fu.wei@linaro.org>
Cc: linux-watchdog@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210607194022.3095736-1-robh@kernel.org

Documentation/devicetree/bindings/watchdog/arm,sbsa-gwdt.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/arm,sbsa-gwdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SBSA (Server Base System Architecture) Generic Watchdog
+
+maintainers:
+  - Fu Wei <fu.wei@linaro.org>
+
+description: |
+  The SBSA Generic Watchdog Timer is used to force a reset of the system after
+  two stages of timeout have elapsed. A detailed definition of the watchdog
+  timer can be found in the ARM document: ARM-DEN-0029 - Server Base System
+  Architecture (SBSA)
+
+allOf:
+  - $ref: watchdog.yaml#
+
+properties:
+  compatible:
+    const: arm,sbsa-gwdt
+
+  reg:
+    items:
+      - description: Watchdog control frame
+      - description: Refresh frame
+
+  interrupts:
+    description: The Watchdog Signal 0 (WS0) SPI (Shared Peripheral Interrupt)
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+
+    watchdog@2a440000 {
+        compatible = "arm,sbsa-gwdt";
+        reg = <0x2a440000 0x1000>,
+              <0x2a450000 0x1000>;
+        interrupts = <0 27 4>;
+        timeout-sec = <30>;
+    };
+...

Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt

-* SBSA (Server Base System Architecture) Generic Watchdog
-
-The SBSA Generic Watchdog Timer is used to force a reset of the system
-after two stages of timeout have elapsed.  A detailed definition of the
-watchdog timer can be found in the ARM document: ARM-DEN-0029 - Server
-Base System Architecture (SBSA)
-
-Required properties:
-- compatible: Should at least contain "arm,sbsa-gwdt".
-
-- reg: Each entry specifies the base physical address of a register frame
-  and the length of that frame; currently, two frames must be defined,
-  in this order:
-  1: Watchdog control frame;
-  2: Refresh frame.
-
-- interrupts: Should contain the Watchdog Signal 0 (WS0) SPI (Shared
-  Peripheral Interrupt) number of SBSA Generic Watchdog.
-
-Optional properties
-- timeout-sec: Watchdog timeout values (in seconds).
-
-Example for FVP Foundation Model v8:
-
-watchdog@2a440000 {
-	compatible = "arm,sbsa-gwdt";
-	reg = <0x0 0x2a440000 0 0x1000>,
-	      <0x0 0x2a450000 0 0x1000>;
-	interrupts = <0 27 4>;
-	timeout-sec = <30>;
-};