Smartphone microphone sensitivity
Most phone mics have automatic gain control, active noise cancellation, and other processing which makes having a sensitivity spec somewhat useless.  

Additionally you don't care about a mV/Pa spec since you do not have access to the analog signal anyway.  You might want something like dbFS/Pa.  

And to make matters worse, there is likely a wide variation from phone to phone.  Even with phones of the same make and model.  Phones are not known for having high quality microphones.
It wouldn't surprise me to see a 6 dB variation between the same model of phone.

You'll have to do some experiments and measure the sensitivity.  Even then, don't expect things to be good or consistent.