dt-bindings: watchdog: Convert GPIO binding to json-schema

Convert the DT binding for GPIO WDT to JSON schema.

Cc: luka.perkov@sartura.hr
Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221125112904.48652-1-robert.marko@sartura.hrSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

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

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/gpio-wdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: GPIO controlled watchdog
+
+maintainers:
+  - Robert Marko <robert.marko@sartura.hr>
+
+properties:
+  compatible:
+    const: linux,wdt-gpio
+
+  gpios:
+    maxItems: 1
+    description: GPIO connected to the WDT reset pin
+
+  hw_algo:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: Algorithm used by the driver
+    oneOf:
+      - description:
+          Either a high-to-low or a low-to-high transition clears the WDT counter.
+          The watchdog timer is disabled when GPIO is left floating or connected
+          to a three-state buffer.
+        const: toggle
+      - description:
+          Low or high level starts counting WDT timeout, the opposite level
+          disables the WDT.
+          Active level is determined by the GPIO flags.
+        const: level
+
+  hw_margin_ms:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Maximum time to reset watchdog circuit (in milliseconds)
+    minimum: 2
+    maximum: 65535
+
+  always-running:
+    type: boolean
+    description:
+      If the watchdog timer cannot be disabled, add this flag to have the driver
+      keep toggling the signal without a client.
+      It will only cease to toggle the signal when the device is open and the
+      timeout elapsed.
+
+required:
+  - compatible
+  - gpios
+  - hw_algo
+  - hw_margin_ms
+
+unevaluatedProperties: false