Input range for TPA311x
I also measure an offset of about 2.90V on those pins, but in the ds I
  can't find this value neither.


The DS states the pins are biased at 3 volts (page 2).


  I'm looking for the input range for pins INPR and INPL but I cannot
  find this information.


You take the gain value (programmed at power up) and reverse back from the preferred maximum peak-to-peak output voltage (supply dependent and dictated by your preferred worst case distortion levels) to get the required peak-to-peak input signal.