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

   1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/watchdog/linux,wdt-gpio.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: GPIO-controlled Watchdog
   8
   9 maintainers:
  10   - Guenter Roeck <linux@roeck-us.net>
  11   - Robert Marko <robert.marko@sartura.hr>
  12
  13 properties:
  14   compatible:
  15     const: linux,wdt-gpio
  16
  17   gpios:
  18     description: gpio connection to WDT reset pin
  19     maxItems: 1
  20
  21   hw_algo:
  22     description: The algorithm used by the driver.
  23     oneOf:
  24       - description:
  25           Either a high-to-low or a low-to-high transition clears the WDT counter.
  26           The watchdog timer is disabled when GPIO is left floating or connected
  27           to a three-state buffer.
  28         const: toggle
  29       - description:
  30           Low or high level starts counting WDT timeout, the opposite level
  31           disables the WDT.
  32           Active level is determined by the GPIO flags.
  33         const: level
  34
  35   hw_margin_ms:
  36     description: Maximum time to reset watchdog circuit (milliseconds).
  37     $ref: /schemas/types.yaml#/definitions/uint32
  38     minimum: 2
  39     maximum: 65535
  40
  41   always-running:
  42     type: boolean
  43     description:
  44       If the watchdog timer cannot be disabled, add this flag to have the driver
  45       keep toggling the signal without a client.
  46       It will only cease to toggle the signal when the device is open and the
  47       timeout elapsed.
  48
  49 required:
  50   - compatible
  51   - gpios
  52   - hw_algo
  53   - hw_margin_ms
  54
  55 allOf:
  56   - $ref: watchdog.yaml#
  57
  58 unevaluatedProperties: false
  59
  60 examples:
  61   - |
  62     #include <dt-bindings/gpio/gpio.h>
  63     watchdog {
  64         compatible = "linux,wdt-gpio";
  65         gpios = <&gpio3 9 GPIO_ACTIVE_LOW>;
  66         hw_algo = "toggle";
  67         hw_margin_ms = <1600>;
  68     };