First you have to put in a request to have that model covered by CHIRP, then one of the developers had to volunteer to add coverage for that model, then the developer contacts you for the loan, when he receives the radio, he can start working on developing support for it.
The time depends on volunteer developer's time availability, his ability to discover how the radio programming is implemented in the particular radio, how he can implement it in CHIRP, time for testing, then a BETA release of the module and if it works without any problems, a merge request to add it to CHIRP.
Start the ball rolling by putting in a request and be sure to answer if you'd be willing to loan your transceiver.
As you can see a loan is needed except in the unlikely event that one of the developers has the same model radio.
Best wishes,
David
N1EA