Support for Fieldbus Device Adapters.

Fieldbus device (client) adapters allow data exchange with a PLC aka.
"Fieldbus Controller" over a fieldbus (Profinet, FLNet, etc.)

They are typically used when a Linux device wants to expose itself
as an actuator, motor, console light, switch, etc. over the fieldbus.

This framework is designed to provide a generic interface to Fieldbus
Devices from both the Linux Kernel and the userspace.

If unsure, say no.

source code:

drivers/staging/fieldbus/