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zephyr,gpio-emul-sdl

Vendor: Zephyr-specific binding

Description

SDL keyboard GPIO input Emulator

Simulate GPIO state/interrupts using SDL keyboard events. This node has
to be a child of a `zephyr,gpio-emul` compatible.
Add a list of scancodes for the desired keys to be mapped.

Refer to https://www.usb.org/sites/default/files/documents/hut1_12v2.pdf
section Keyboard/Keypad (p53) for a list of scancode values.

The following example maps the first 3 numeric keys to GPIO pins:

/* gpio0 has to be a zephyr,gpio-emul device */
&gpio0 {
  ngpios = <3>;

  sdl_gpio {
    compatible = "zephyr,gpio-emul-sdl";
    scancodes = <30 31 32>;
  };
};

keypad: keypad {
  compatible = "gpio-keys";
  key1: key1 {
    gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
  };
  key2: key2 {
    gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
  };
  key3: key3 {
    gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>;
  };
};

The limitations of usage are:
- Only active high as we don't get events for keys that aren't pressed
- Pressing multiple keys is best effort, state will be kept but no events
  are generated once the last key is released

Properties

Properties not inherited from the base binding file.

Name

Type

Details

scancodes

array

An array of SDL scancodes mapped to its GPIO index

This property is required.