Radio Modul Drivers - Initialization of Chip-Select-, Reset-, Sleep-, Interrupt-Pin of the MCU

Hello all together, just a question for a better understanding of the initialization process:

I thought that the correct way to set up the MCU interface is to implement an auto_init-function for the radio module. The MCU interface pins should be setup during the auto-initialization. Is this correct?

I found the _init(netdev2_t *netdev) function in the <driver-name>_netdev.c file and for me it looks like this is exactly the place where the initialization of the pins are done. Is this correct?

While debugging a driver I set a breakpoint onto this function, but the breakpoint is never reached.

Now my question: From where ist the _init function invoked? What is necessary to force this initialization?

Best regards, Neo