dt-bindings: power: reset: gpio-poweroff: Convert txt bindings to yaml

Driver a GPIO line that can be used to turn the power off.

The driver supports both level triggered and edge triggered power off.

At driver load time, the driver will request the given gpio line and

install a handler to power off the system. If the optional properties

'input' is not found, the GPIO line will be driven in the inactive

state. Otherwise its configured as an input.

When the power-off handler is called, the gpio is configured as an

output, and drive active, so triggering a level triggered power off

condition. This will also cause an inactive->active edge condition, so

triggering positive edge triggered power off. After a delay of 100ms,

the GPIO is set to inactive, thus causing an active->inactive edge,

triggering negative edge triggered power off. After another 100ms

delay the GPIO is driver active again. If the power is still on and

the CPU still running after a 3000ms delay, a WARN_ON(1) is emitted.

Required properties:

- compatible : should be "gpio-poweroff".

- gpios : The GPIO to set high/low, see "gpios property" in

  Documentation/devicetree/bindings/gpio/gpio.txt. If the pin should be

  low to power down the board set it to "Active Low", otherwise set

  gpio to "Active High".

Optional properties:

- input : Initially configure the GPIO line as an input. Only reconfigure

  it to an output when the power-off handler is called. If this optional

  property is not specified, the GPIO is initialized as an output in its

  inactive state.

- active-delay-ms: Delay (default 100) to wait after driving gpio active

- inactive-delay-ms: Delay (default 100) to wait after driving gpio inactive

- timeout-ms: Time to wait before asserting a WARN_ON(1). If nothing is

              specified, 3000 ms is used.

Examples:

gpio-poweroff {

	compatible = "gpio-poweroff";

	gpios = <&gpio 4 0>;

	timeout-ms = <3000>;

};

# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/power/reset/gpio-poweroff.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: GPIO controlled power off

maintainers:

  - Sebastian Reichel <sre@kernel.org>

description: >

  System power off support via a GPIO line. When a shutdown is

  executed the operating system is expected to switch the GPIO

  from inactive to active. After a delay (active-delay-ms) it

  is expected to be switched back to inactive. After another

  delay (inactive-delay-ms) it is configured as active again.

  Finally the operating system assumes the power off failed if

  the system is still running after waiting some time (timeout-ms).

properties:

  compatible:

    const: gpio-poweroff

  gpios:

    maxItems: 1

  input:

    type: boolean

    description: >

      Initially configure the GPIO line as an input. Only reconfigure

      it to an output when the power-off sequence is initiated. If this optional

      property is not specified, the GPIO is initialized as an output in its inactive state.

  active-delay-ms:

    default: 100

    description: Delay to wait after driving gpio active

  inactive-delay-ms:

    default: 100

    description: Delay to wait after driving gpio inactive

  timeout-ms:

    default: 3000

    description: Time to wait before assuming the power off sequence failed.

required:

  - compatible

  - gpios

additionalProperties: false

examples:

  - |

    gpio-poweroff {

        compatible = "gpio-poweroff";

        gpios = <&gpio 4 0>;

        timeout-ms = <3000>;

    };