Im posting my question here, as this might only be valid for Fedora 26-28 OS atm.
(im on F27 not yet upgraded to 28)
I have made an GUI (Gtkmm) application in C++ for working with GPIO, and different chips like mcp23017 port expander (and more to come)
All based on the new gpiochip char device, so no need for any additional libs.
It all works fine, even my threads for polling GPIO Events (interrupts), so its a nice GUI to work with GPIO pins on RPI3 B, and chips.
Ive tested it with mcp23017 int pins to a gpio pin (ex. 25) and GPIO events works. (using poll)
My question is, as im a novice in GPIO, what are all the 54 Offset lines referring too, as there is only 40 Pins ?
.... any information on this is welcome, as i dont really got any, but just went ahead making this application.
(im in the progress of polishing the code and bind it together etc.)