Safe wrapper around Rust FFI bindings for libgpiod

libgpiod is a C library that provides an easy to use abstraction over the Linux GPIO character driver. This crate builds on top of libgpiod-sys and exports a safe interface to the C library.

Build requirements

By default, libgpiod-sys builds against the libgpiod version identified via pkg-config. See the README.md of libgpiod-sys for options to override that.

Currently at least libgpiod 2.0 is required with the default feature set.

Features

The Rust bindings will usually be built against whatever libgpiod version a system provides. Hence, only the functionality of the oldest supported libgpiod C library will be exposed by default.

Setting flags allows to increase the base version and export features of newer versions:

• v2_1: Minimum version of 2.1.x
• vnext: The upcoming, still unreleased version of the C lib

Examples

Get GPIO chip information:

let chip = Chip::open(&Path::new("/dev/gpiochip0"))?;
let info = chip.info()?;

println!("{} [{}] ({} lines)", info.name()?, info.label()?, info.num_lines());

Print GPIO line name:

let chip = Chip::open(&Path::new("/dev/gpiochip0"))?;
let info = chip.line_info(0)?;
let name = info.name().unwrap_or("unnamed");

println!("{name}");

Toggle GPIO line output value:

let mut settings = line::Settings::new()?;
settings
    .set_direction(line::Direction::Output)?
    .set_output_value(Value::Active)?;

let mut line_cfg = line::Config::new()?;
line_cfg.add_line_settings(&[line_offset], settings)?;

let mut req_cfg = request::Config::new()?;
req_cfg.set_consumer("toggle-line-value")?;

let chip = Chip::open(&Path::new("/dev/gpiochip0"))?;

/* Request with value 1 */
let mut req = chip.request_lines(Some(&req_cfg), &line_cfg)?;

/* Toggle to value 0 */
req.set_value(line_offset, Value::InActive)?;

Read GPIO line event:

let mut lsettings = line::Settings::new()?;
lsettings
    .set_direction(line::Direction::Input)?
    .set_edge_detection(Some(line::Edge::Both))?;

let mut line_cfg = line::Config::new()?;
line_cfg.add_line_settings(&[line_offset], settings)?;

let mut req_cfg = request::Config::new()?;
req_cfg.set_consumer("toggle-line-value")?;

let chip = Chip::open(&Path::new("/dev/gpiochip0"))?;
let req = chip.request_lines(Some(&req_cfg), &line_cfg)?;

let mut buffer = request::Buffer::new(1)?;

loop {
    let events = req.read_edge_events(&mut buffer)?;
    for event in events {
        println!(
            "line: {} type: {}",
            event.line_offset(),
            match event.event_type()? {
                EdgeKind::Rising => "Rising",
                EdgeKind::Falling => "Falling",
            }
        );
    }
}

License

This project is licensed under either of

• Apache License, Version 2.0
• BSD-3-Clause License