There is, indeed no source code available from NXP. The data sheet is detailed enough to create a driver from scratch for the majority of the functionality.
There are several source code repositories that provide code for the PCF8523.
Here below are some examples:
The Arduino library for PCF8523 is explained at
All the examples above implement a subset of the functionality provided by the NXP chip PCF8523.
We are searching for some examples of the use of the TIMER B and the INT2 line for a specific application.
So far we have no success.
This little note may help you to a starting point