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

   1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/gpio/gpio-delay.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: GPIO delay controller
   8
   9 maintainers:
  10   - Alexander Stein <linux@ew.tq-group.com>
  11
  12 description: |
  13   This binding describes an electrical setup where setting an GPIO output
  14   is delayed by some external setup, e.g. RC circuit.
  15
  16   +----------+                    +-----------+
  17   |          |             VCC_B  |           |
  18   |          |              |     |           |
  19   |          | VCC_A        _     |           |
  20   |  GPIO    |             | | R  |  Consumer |
  21   |controller|        ___  |_|    |           |
  22   |          |       |   |  |     |           |
  23   |      [IOx|-------|   |--+-----|-----+     |
  24   |          |       |___|  |     |   input   |
  25   |          |              |     |           |
  26   +----------+             --- C  +-----------+
  27                            ---
  28                             |
  29                             -
  30                            GND
  31
  32   If the input on the consumer is controlled by an open-drain signal
  33   attached to an RC circuit the ramp-up delay is not under control
  34   of the GPIO controller.
  35
  36 properties:
  37   compatible:
  38     const: gpio-delay
  39
  40   "#gpio-cells":
  41     description: |
  42       Specifies the pin, ramp-up and ramp-down delays. The
  43       delays are specified in microseconds.
  44     const: 3
  45
  46   gpios:
  47     description: Array of GPIOs which output signal change is delayed
  48     minItems: 1
  49     maxItems: 32
  50
  51   gpio-controller: true
  52
  53   gpio-line-names:
  54     minItems: 1
  55     maxItems: 32
  56
  57 required:
  58   - compatible
  59   - "#gpio-cells"
  60   - gpio-controller
  61   - gpios
  62
  63 additionalProperties: false
  64
  65 examples:
  66   - |
  67     #include <dt-bindings/gpio/gpio.h>
  68
  69     enable_delay: enable-delay {
  70         compatible = "gpio-delay";
  71         #gpio-cells = <3>;
  72         gpio-controller;
  73         gpios = <&gpio0 3 GPIO_ACTIVE_LOW>,
  74                 <&gpio3 1 GPIO_ACTIVE_HIGH>;
  75     };
  76
  77     consumer {
  78         enable-gpios = <&enable_delay 0 130000 30000>;
  79     };