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00002_leds.md

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driver number
2

LEDs

Overview

The LEDs driver provides userspace with synchronous control of an array of discrete LEDs. The LEDs can be turned on, off, and toggled.

LEDs are indexed in the array starting at 0. The order of the LEDs and the mapping between indexes and actual LEDs is set by the kernel in the board's main file.

Command

  • Command number: 0

    Description: How many LEDs are supported on this board.

    Argument 1: unused

    Argument 2: unused

    Returns: The number of LEDs on the board, or NODEVICE if this driver is not present on the board.

  • Command number: 1

    Description: Turn on an LED.

    Argument 1: The index of the LED to turn on, starting at 0.

    Argument 2: unused

    Returns: Ok(()) if the LED index is valid, INVAL otherwise.

  • Command number: 2

    Description: Turn off an LED.

    Argument 1: The index of the LED to turn off, starting at 0.

    Argument 2: unused

    Returns: Ok(()) if the LED index is valid, INVAL otherwise.

  • Command number: 3

    Description: Toggle an LED. If the LED is currently on it will be turned off, and vice-versa.

    Argument 1: The index of the LED to toggle, starting at 0.

    Argument 2: unused

    Returns: Ok(()) if the LED index is valid, INVAL otherwise.

Subscribe

Unused for the LED driver. Will always return ENOSUPPORT.

Allow

Unused for the LED driver. Will always return ENOSUPPORT.