Kernel-4.18.0-80.el8_gpio-wdt

• GPIO-controlled Watchdog

Required Properties:

• compatible: Should contain “linux,wdt-gpio”.
• gpios: From common gpio binding; gpio connection to WDT reset pin.
• hw_algo: The algorithm used by the driver. Should be one of the
  following values:
  • toggle: 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.
  • level: Low or high level starts counting WDT timeout,
    the opposite level disables the WDT. Active level is determined
    by the GPIO flags.
• hw_margin_ms: Maximum time to reset watchdog circuit (milliseconds).

Optional Properties:

• always-running: 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.

Example:
watchdog: watchdog {
/* ADM706 */
compatible = “linux,wdt-gpio”;
gpios = <&gpio3 9 GPIO_ACTIVE_LOW>;
hw_algo = “toggle”;
hw_margin_ms = <1600>;
};