dt-bindings: watchdog: Convert Samsung SoC watchdog bindings to json-schema

Convert Samsung S3C/S5P/Exynos watchdog bindings to DT schema format
using json-schema.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/watchdog/samsung-wdt.txt

-* Samsung's Watchdog Timer Controller
-
-The Samsung's Watchdog controller is used for resuming system operation
-after a preset amount of time during which the WDT reset event has not
-occurred.
-
-Required properties:
-- compatible : should be one among the following
-	- "samsung,s3c2410-wdt" for S3C2410
-	- "samsung,s3c6410-wdt" for S3C6410, S5PV210 and Exynos4
-	- "samsung,exynos5250-wdt" for Exynos5250
-	- "samsung,exynos5420-wdt" for Exynos5420
-	- "samsung,exynos7-wdt" for Exynos7
-
-- reg : base physical address of the controller and length of memory mapped
-	region.
-- interrupts : interrupt number to the cpu.
-- samsung,syscon-phandle : reference to syscon node (This property required only
-	in case of compatible being "samsung,exynos5250-wdt" or "samsung,exynos5420-wdt".
-	In case of Exynos5250 and 5420 this property points to syscon node holding the PMU
-	base address)
-
-Optional properties:
-- timeout-sec : contains the watchdog timeout in seconds.
-
-Example:
-
-watchdog@101d0000 {
-	compatible = "samsung,exynos5250-wdt";
-	reg = <0x101D0000 0x100>;
-	interrupts = <0 42 0>;
-	clocks = <&clock 336>;
-	clock-names = "watchdog";
-	samsung,syscon-phandle = <&pmu_syscon>;
-};

Documentation/devicetree/bindings/watchdog/samsung-wdt.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/samsung-wdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung SoC Watchdog Timer Controller
+
+maintainers:
+  - Krzysztof Kozlowski <krzk@kernel.org>
+
+description: |+
+  The Samsung's Watchdog controller is used for resuming system operation
+  after a preset amount of time during which the WDT reset event has not
+  occurred.
+
+properties:
+  compatible:
+    enum:
+      - samsung,s3c2410-wdt                   # for S3C2410
+      - samsung,s3c6410-wdt                   # for S3C6410, S5PV210 and Exynos4
+      - samsung,exynos5250-wdt                # for Exynos5250
+      - samsung,exynos5420-wdt                # for Exynos5420
+      - samsung,exynos7-wdt                   # for Exynos7
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  samsung,syscon-phandle:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to the PMU system controller node (in case of Exynos5250
+      and Exynos5420).
+
+required:
+  - compatible
+  - interrupts
+  - reg
+
+allOf:
+  - $ref: watchdog.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - samsung,exynos5250-wdt
+              - samsung,exynos5420-wdt
+    then:
+      required:
+        - samsung,syscon-phandle
+
+examples:
+  - |
+    watchdog@101d0000 {
+        compatible = "samsung,exynos5250-wdt";
+        reg = <0x101D0000 0x100>;
+        interrupts = <0 42 0>;
+        clocks = <&clock 336>;
+        clock-names = "watchdog";
+        samsung,syscon-phandle = <&pmu_syscon>;
+    };