Rust I2cdev

Documentation

The Rust i2cdev crate seeks to provide full access to the Linux i2cdev driver interface in Rust without the need to wrap any C code or directly make low-level system calls. The documentation for the i2cdev interace can be found at https://www.kernel.org/doc/Documentation/i2c/dev-interface and in the lm-sensors projects.

Device driver developers should consider building on top of the embedded-hal traits rather than directly coupling to this library. An implementation of those generic traits for Linux can be found in linux-embedded-hal which, at present, uses this crate as the backend for I2C.

Example/API

The source includes an example of using the library to talk to a Wii Nunchuck (which has an i2c interface). Go View the Example.

Here's a real quick example showing the guts of how you create device and start talking to it...

extern crate i2cdev;

use std::thread;
use std::time::Duration;

use i2cdev::core::*;
use i2cdev::linux::{LinuxI2CDevice, LinuxI2CError};

const NUNCHUCK_SLAVE_ADDR: u16 = 0x52;

// real code should probably not use unwrap()
fn i2cfun() -> Result<(), LinuxI2CError> {
    let mut dev = LinuxI2CDevice::new("/dev/i2c-1", NUNCHUCK_SLAVE_ADDR)?;

    // init sequence
    dev.smbus_write_byte_data(0xF0, 0x55)?;
    dev.smbus_write_byte_data(0xFB, 0x00)?;
    thread::sleep(Duration::from_millis(100));

    loop {
        let mut buf: [u8; 6] = [0; 6];
        dev.smbus_write_byte(0x00).unwrap();
        thread::sleep(Duration::from_millis(10));
        dev.read(&mut buf).unwrap();
        println!("Reading: {:?}", buf);
    }
}

In addition to the Read/Write traits, the following methods are available via the I2CDevice trait.

Features

The following features are implemented and planned for the library:

• Implement the Read trait
• Implement the Write trait
• Implement SMBus Methods
• Add Tests/Example for SMBus Methods
• Add sensor library for handy sensors (and examples)
• Add higher-level APIs/Macros for simplifying access to devices with large register sets
• Add Support for Non-SMBus ioctl methods
• Add examples for non-smbus ioctl methods
• Unit Testing

Cross Compiling

Most likely, the machine you are running on is not your development machine (although it could be). In those cases, you will need to cross-compile. See https://github.com/japaric/rust-cross for pointers.

License

Copyright (c) 2015, Paul Osborne <ospbau@gmail.com>

Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
http://www.apache.org/license/LICENSE-2.0> or the MIT license
<LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
option.  This file may not be copied, modified, or distributed
except according to those terms.