Hi Guillaume,

> 4) Having 2 drivers can be a solution to make difference between CSIM
> and (U)SIM:
>         - "atmodem/sim.c" drivers
>         - "cdmamodem/sim.c" drivers
> There can be a lib simutil for PIN management and IMSI retrieval whose
> APIs would be called by "atmodem" and "cdmamodem" drivers to avoid
> duplicated code.
> 

Why don't you try adding a 'atmodem-noef' driver to
drivers/atmodem/sim.c and see how far you get?  You only need ~13 lines
of code and a register / unregister driver call.

Regards,
-Denis