Calibration - acoustics
First you need to know something about your calibration signal. Lets say you know that it is a 1kHz sine with an RMS amplitude of 94dB SPL. If you are confident that this is all your calibration recording includes (which is likely), then your calibration factor, is the difference between the actual dB SPL level and the 'digital' dBFS level. In matlab code, it looks like this:

caldb = 94 - 20*log10(rms(calibration_signal);

It could be that the calibration level is specified as peak SPL, then you would just substitute the peak value for the rms value above.

Now you can calculate all your values (LAeq etc) in dBFS (i.e. -inf to 0dB) and simply add the calibration factor, to get a calibrated SPL.