```
let config = i2c::I2cConfig::new().baudrate(400.kHz().into());
let i2c = i2c::I2cDriver::new(i2c, sda, scl, &config)?;
let i2c_mutex  = Mutex::new(i2c);
let i2c_mutex_device = MutexDevice::new( &i2c_mutex);
``` 

obviously not working, and broken out in many lines to figure out what's going on. Probably a few issues here