linux/drivers/staging/fieldbus/Documentation/ABI/fieldbus-dev-cdev

What:		/dev/fieldbus_devX
Date:		December 2018
KernelVersion:	5.1 (staging)
Contact:	Sven Van Asbroeck <[email protected]>
Description:
		The cdev interface to drivers for Fieldbus Device Memory
			(aka. Process Memory).

		The following file operations are supported:

		open(2)
		Create an I/O context associated with the file descriptor.

		read(2)
		Read from Process Memory's "read area".
		Clears POLLERR | POLLPRI from the file descriptor.

		write(2)
		Write to Process Memory's "write area".

		poll(2), select(2), epoll_wait(2) etc.
		When a "Process Memory Read Area Changed" event occurs,
		POLLERR | POLLPRI will be set on the file descriptor.
		Note that POLLIN | POLLOUT events are always set, because the
		process memory area is always readable and writable.

		close(2)
		Free up the I/O context that was associated
		with the file descriptor.

Users:		TBD