#17 Support Amplicon PCI cards (5.05)

[Ian Abbott]

serial-5.05. This patch adds support for the followin
Amplicon PCI serial cards: PCI242H (4-port RS-232),
PCI244H (8-port RS-232), PCI247H (2-port RS-232),
PCI248H (2-port RS-422/485) and PCI249H (1 RS-232 + 1
RS-422/485).

Support for the RS-422/485 ports on these cards is not
ideal as they transmit line on these ports is disabled
when DTR is asserted! A program could use an ioctl call
to deassert DTR and enable the transmit line but that
is a bit of a pain.

The patch is a bit bigger than it should be as I had to
work around a problem I had on Debian 2.2r0 which
knackered the PCI interface chip's register values
during some probe on system start-up. Fortunately, this
seemed to happen before the serial module was loaded so
I could reprogram the PCI interface chip during card
intialization.

This patch will work best when combined with my patch
to support clock prescaling on the 16C950 UART (patch
#432453) as these cards use the unusual UART clock
frequency of 40MHz! Without that patch, the baud rates
won't be as accurate as they could be, particularly at
higher baud rates.

[Ian Abbott]

Patch to serial-5.05 to support Amplicon PCI cards