Step 1: update the boilerplate

Registers CTRL2 and CTRL3 contain settings for accelerometer and gyro respectively. Let's add those to our Config struct.

#![allow(unused)]
fn main() {
#[derive(Debug)]
pub struct Config {
    ctrl1: u8,
    ctrl2: u8,
    ctrl3: u8,
    ctrl7: u8,
}
}

Define the addresses:

#![allow(unused)]
fn main() {
mod registers {
    // ...
    pub const CTRL2: u8 = 0x03;
    pub const CTRL3: u8 = 0x04;
    // ...
}
}

Update the initialize() function to write the new config registers:

#![allow(unused)]
fn main() {
self.i2c.write(self.address, &[registers::CTRL2, config.ctrl2])?;
self.i2c.write(self.address, &[registers::CTRL3, config.ctrl3])?;
}

Step 2: define types for Config

As the range can only be one of several discrete settings, we'll use enums to represent the values.

Accelerometer range can be configured from 2 g to 16 g.

#![allow(unused)]
fn main() {
pub enum AccelRange {
    PlusMinus2g,
    PlusMinus4g,
    PlusMinus8g,
    PlusMinus16g,
}
}

The gyro range can be configured from 16 dps to 2048 dps.

#![allow(unused)]
fn main() {
pub enum GyroRange {
    PlusMinus16Dps,
    PlusMinus32Dps,
    PlusMinus64Dps,
    PlusMinus128Dps,
    PlusMinus256Dps,
    PlusMinus512Dps,
    PlusMinus1024Dps,
    PlusMinus2048Dps,
}
}

Step 3: implement the config functions

Here's how you can implement the config function. We use match to convert the enum values to the corresponding binary value obtained from the datasheet.

#![allow(unused)]
fn main() {
pub fn with_accel_full_scale_range(mut self, range: AccelRange) -> Config {
    let bits = match range {
        AccelRange::PlusMinus2g => 0b000,
        AccelRange::PlusMinus4g => 0b001,
        AccelRange::PlusMinus8g => 0b010,
        AccelRange::PlusMinus16g => 0b011,
    };

    self.ctrl2 |= bits << 4;
    self
}

pub fn with_gyro_full_scale_range(mut self, range: GyroRange) -> Config {
    let bits = match range {
        GyroRange::PlusMinus16Dps => 0b000,
        GyroRange::PlusMinus32Dps => 0b001,
        GyroRange::PlusMinus64Dps => 0b010,
        GyroRange::PlusMinus128Dps => 0b011,
        GyroRange::PlusMinus256Dps => 0b100,
        GyroRange::PlusMinus512Dps => 0b101,
        GyroRange::PlusMinus1024Dps => 0b110,
        GyroRange::PlusMinus2048Dps => 0b111,
    };

    self.ctrl3 |= bits << 4;
    self
}
}

Step 4: update the main.rs

Use the new configuration functions:

#![allow(unused)]
fn main() {
let imu_config = qmi8658a::Config::default()
    .with_address_auto_increment()
    .with_accel_full_scale_range(qmi8658a::AccelRange::PlusMinus16g)
    .with_gyro_full_scale_range(qmi8658a::GyroRange::PlusMinus2048Dps)
    .with_gyroscope_enabled()
    .with_accelerometer_enabled()
    .with_sync_sample_enabled();
}