bme680-rust/src/i2c.rs

use anyhow::anyhow;
use core::fmt::{Display, Formatter};
use embedded_hal::i2c::I2c;

///
/// Represents the I2C address of the BME680 Sensor.
///
#[derive(Debug, Clone, Copy, Default)]
pub enum Address {
    /// Primary Address 0x76
    #[default]
    Primary,
    /// Secondary Address 0x77
    Secondary,
    /// Alternative address
    Other(u8),
}

impl Address {
    pub fn addr(&self) -> u8 {
        match &self {
            Address::Primary => 0x76u8,
            Address::Secondary => 0x77u8,
            Address::Other(addr) => *addr,
        }
    }
}

impl Display for Address {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        write!(f, "Address={:#01x}", self.addr())
    }
}

/// I2CUtility is a simple wrapper over the I2c trait to make reading and writing data easier.
pub(crate) struct I2CUtility {}

impl I2CUtility {
    /// Reads a byte from the I2C bus.
    pub fn read_byte<I2C: I2c>(
        i2c_handle: &mut I2C,
        device_address: u8,
        register_address: u8,
    ) -> Result<u8, anyhow::Error> {
        let mut buf = [0; 1];

        i2c_handle
            .write(device_address, &[register_address])
            .map_err(|e| {
                anyhow!(
                    "Failed to write a byte {} to device {}: {:?}",
                    register_address,
                    device_address,
                    e
                )
            })?;

        match i2c_handle.read(device_address, &mut buf) {
            Ok(()) => Ok(buf[0]),
            Err(_e) => Err(anyhow!(
                "Failed to read byte {} from device {}",
                register_address,
                device_address
            )),
        }
    }

    /// Reads bytes from the I2C bus.
    pub fn read_bytes<I2C: I2c>(
        i2c_handle: &mut I2C,
        device_address: u8,
        register_address: u8,
        buffer: &mut [u8],
    ) -> Result<(), anyhow::Error> {
        i2c_handle
            .write(device_address, &[register_address])
            .map_err(|_e| {
                anyhow!(
                    "Failed to write a byte {} from device {}",
                    register_address,
                    device_address
                )
            })?;

        match i2c_handle.read(device_address, buffer) {
            Ok(()) => Ok(()),
            Err(_e) => Err(anyhow!(
                "Failed to read bytes from register {} and device {}",
                register_address,
                device_address
            )),
        }
    }

    /// Writes bytes to the I2C bus.
    pub fn write_bytes<I2C: I2c>(
        i2c_handle: &mut I2C,
        device_address: u8,
        buffer: &[u8],
    ) -> Result<(), anyhow::Error> {
        i2c_handle
            .write(device_address, buffer)
            .map_err(|_e| anyhow!("Failed to write bytes to address {}", device_address))
    }
}