These are used to list the device instances currently known to the driver,
and clear that list.
Drivers that don't necessarily clear their list of instances on every scan,
such as genericdmm, need to provide these to the frontend to keep instance
management sane.
It's obsolete: no frontend ever used it, and neither did libsigrok.
The sdi->status field is only used internally by some drivers, and
should probably be moved to the driver-specific context structs.
This changes the semantics of the init() call as well. That now only
initializes the driver -- an administrative affair, no hardware gets
touched during this call. It returns a standard SR_OK or SR_ERR* code.
The scan() call does a discovery run for devices it knows, and returns
the number found. It can be called at any time.
It was actually used in one way: the session file loaded abused it for
passing in the filename -- something it definitely wasn't intended for.
This now uses the proper way to pass arguments to a driver: the new
SR_HWCAP_SESSIONFILE.
The OLS driver could also use it as an indication of the serial port to
use instead of actively probing all serial ports on the system, but there
wasn't any frontend code that passed in such a parameter, making it
entirely useless. That will soon be handled differently with the new
scan() API call, regardless.
All frontends will have to include <libsigrok/libsigrok.h> from now on.
This header includes proto.h and version.h, both installed from the
distribution into $INCLUDE/libsigrok/ as well.
The only dynamically changed header is now version.h, which has both
libsigrok and libtool compile-time versions in it.