Hold the View, Menu and Home buttons until the controller vibrates once to enter the calibration. The indicator will flash slowly in white during entry.
Ensure that the triggers and sticks are not being touched. Press the A button once. Then, push both sticks fully to their limits and rotate them 2-3 times. Press each trigger fully down 3 times. Finally, press the A button to exit the calibration. The indicator will return to its normal state.