Crate gpiod

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§libgpiod in Rust

github crate docs MIT CI

Rust crate for interfacing with Linux GPIO character devices.

It provides an interface to the Linux GPIO using the chardev module. This interface involves calling ioctl funcions which are unsafe and require some unintuitive variable mapping. To ease this process, this crate provides a Chip struct which encapsulates the interface in safe Rust functions. The functionality provided here is highly inspired by libgpiod.

Since all functionality is dependent on Linux function calls, this crate only compiles for Linux systems.

§ABI compatibility

Both ABI v1 (linux >= 4.0) and v2 (linux >= v5.10) supported but edge detection implemented for v2 only. Deprecated sysfs-based API (linux < 4.0) currently is not supported at all.

§Crates

  • gpiod-core - core abstractions and low level interface (not for end users)
  • gpiod - sync interface which supports synchronous operation only
  • tokio-gpiod - async interface for tokio fans
  • async-gpiod - async interface to use with non-tokio async runtimes

§Usage examples

Input values:

use gpiod::{Chip, Options, Masked, AsValuesMut};

fn main() -> std::io::Result<()> {
    let chip = Chip::new(0)?; // open chip

    let opts = Options::input([27, 3, 11]) // configure lines offsets
        .consumer("my-inputs"); // optionally set consumer string

    let inputs = chip.request_lines(opts)?;

    // get all three values
    let values = inputs.get_values([false; 3])?;

    println!("values: {:?}", values);

    // get second value only
    let values = inputs.get_values([None, Some(false), None])?;

    println!("values: {:?}", values);

    // get values via bits
    let values = inputs.get_values(0u8)?;

    println!("values: {:#b}", values);

    // get only second value via bits
    let values = inputs.get_values(Masked::<u8>::default().with(1, Some(false)))?;

    println!("values: {:#b}", values);

    Ok(())
}

Output values:

use gpiod::{Chip, Options, Masked, AsValuesMut};

fn main() -> std::io::Result<()> {
    let chip = Chip::new("gpiochip0")?; // open chip

    let opts = Options::output([9, 21]) // configure lines offsets
        .values([false, true]) // optionally set initial values
        .consumer("my-outputs"); // optionally set consumer string

    let outputs = chip.request_lines(opts)?;

    // set all two values
    outputs.set_values([true, false])?;

    // set second value only
    outputs.set_values([None, Some(false)])?;

    // set values from bits
    outputs.set_values(0b01u8)?;

    // set only second value from bits
    outputs.set_values(Masked::<u8>::default().with(1, Some(true)))?;

    Ok(())
}

Monitor values:

use gpiod::{Chip, Options, EdgeDetect};

fn main() -> std::io::Result<()> {
    let chip = Chip::new("gpiochip0")?; // open chip

    let opts = Options::input([4, 7]) // configure lines offsets
        .edge(EdgeDetect::Both) // configure edges to detect
        .consumer("my-inputs"); // optionally set consumer string

    let mut inputs = chip.request_lines(opts)?;

    loop {
        let event = inputs.read_event()?;

        println!("event: {:?}", event);
    }

    Ok(())
}

Structs§

  • Chip
    A Linux chardev GPIO chip interface
  • ChipInfo
    GPIO chip interface info
  • Event
    Signal edge detection event
  • Input
    Input direction
  • LineInfo
    The information of a specific GPIO line
  • Lines
    The interface for accessing to the values of GPIO lines
  • Masked
    Line values with mask
  • Options
    GPIO line values request options
  • Output
    Output direction
  • ValuesInfo
    GPIO lines values interface info

Enums§

  • Active
    Active state condition of a line
  • Bias
    Input bias of a GPIO line
  • Direction
    Direction of a GPIO line
  • Drive
    Output drive mode of a GPIO line
  • Edge
    Signal edge or level transition of a GPIO line
  • EdgeDetect
    Edge detection setting for GPIO line

Constants§

  • MAX_BITS
    Maximum number of bits which can be get or set per time
  • MAX_VALUES
    Maximum number of values which can be get or set per time

Traits§

Type Aliases§