GPIB overhaul, part #2: make the tnt4882 driver work with the newer
TNT5004 IC. This involved a major rewrite of a number of things, as
this chip no longer supports the NAT7210 legacy mode but requires the
host to use the (more modern) FIFO mode.
In theory, this also ought to work on the older TNT4882C chip. I'll
probably add this as optional support (perhaps by a device.hints flag)
later on. By now, FIFO mode is *only* activates iff a TNT5004 chip
has been detected (where the old code didn't work at all), while
everything else is supposed to use the old code.
Overhaul of the pcii driver:
. Properly allocate all IO space resources. These cards scatter their
IO addresses over a range of 0x1600 bytes, and they require an
additional address for "special interrupt handling".
. Implement the "special interrupt handling" per the GPIB-PCIIA
Technical Reference Manual; this was apparently not declared for the
clone card this driver has been originally implemented for, but it
turned out to be needed for both, an original NI brand PCII/PCIIA
card as well as the Axiom AX5488 clone.
. Add some diagnostic messages for various resource allocation etc.
failures during probe.
. Add some comments about the structure of the IO address space that
is used by these cards.
This driver implements "unaddressed listen only mode", which is what
printers and plotters commonly do on GP-IB busses.
This means that you can capture print/plot like output from your
instruments by configuring them as necessary (good luck!) and
cat -u /dev/gpib0l > /tmp/somefile
Since there is no way to know when no more output is comming you
will have to ctrl-C the cat process when it is done (that is why
the -u is important).
