Rock 5B GPIO Alternate Function

Hi,

I would like to know if there’s any other way to enable the GPIO alternate function instead of using rsetup to enable the overlay.

For instance, I want to enable an I2C function one of the GPIO pins, instead of going to rsetup > overlays > manage overlays, I was thinking if there’s any other possible way to this using Linux terminal/console commands?

Thanks,
Spartan86