init() now only does whatever administrative stuff it needs (typically not
much), and returns an error code.
scan() can be called multiple times during the life of an application, and
returns a GSList of struct sr_dev_inst * of devices found during that scan.
The instances are a copy of the ones stored in the driver's own instance
list, to be freed by the caller with g_slist_free() only.
The scan() call can be passed a GSList of struct sr_hwopt *, to direct the
scanning.
SR_HWOPT_* entries are driver options, not device instance parameters, so
they will never be mixed together.
Also, driver options are always passed in a GSList, where the data field
is a struct sr_hwopt.
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.