Documentation/devicetree/bindings/gpio/gpio-delay.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/gpio/gpio-delay.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: GPIO delay controller

maintainers:
  - Alexander Stein <linux@ew.tq-group.com>

description: |
  This binding describes an electrical setup where setting an GPIO output
  is delayed by some external setup, e.g. RC circuit.

  +----------+                    +-----------+
  |          |             VCC_B  |           |
  |          |              |     |           |
  |          | VCC_A        _     |           |
  |  GPIO    |             | | R  |  Consumer |
  |controller|        ___  |_|    |           |
  |          |       |   |  |     |           |
  |      [IOx|-------|   |--+-----|-----+     |
  |          |       |___|  |     |   input   |
  |          |              |     |           |
  +----------+             --- C  +-----------+
                           ---
                            |
                            -
                           GND

  If the input on the consumer is controlled by an open-drain signal
  attached to an RC circuit the ramp-up delay is not under control
  of the GPIO controller.

properties:
  compatible:
    const: gpio-delay

  "#gpio-cells":
    description: |
      Specifies the pin, ramp-up and ramp-down delays. The
      delays are specified in microseconds.
    const: 3

  gpios:
    description: Array of GPIOs which output signal change is delayed
    minItems: 1
    maxItems: 32

  gpio-controller: true

  gpio-line-names:
    minItems: 1
    maxItems: 32

required:
  - compatible
  - "#gpio-cells"
  - gpio-controller
  - gpios

additionalProperties: false

examples:
  - |
    #include <dt-bindings/gpio/gpio.h>

    enable_delay: enable-delay {
        compatible = "gpio-delay";
        #gpio-cells = <3>;
        gpio-controller;
        gpios = <&gpio0 3 GPIO_ACTIVE_LOW>,
                <&gpio3 1 GPIO_ACTIVE_HIGH>;
    };

    consumer {
        enable-gpios = <&enable_delay 0 130000 30000>;
    };