Add custom HDLC idle pattern feature.

It allows the user to specify an arbitrary 8 or 16 bit repeating pattern on
the transmit data pin between HDLC frames.

In most cases the idle pattern is continuous ones or flags as supported by off
the shelf synchronous controllers and defined in the ISO3309 standard.  Some
applications (radio/satellite modems, connections to legacy military hardware)
require non-standard patterns.
Signed-off-by: NPaul Fulghum <paulkf@microgate.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add driver support for general purpose I/O feature of the Synclink GT
adapters.
Signed-off-by: NPaul Fulghum <paulkf@micrgate.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

New character device driver for the SyncLink GT and SyncLink AC families of
synchronous and asynchronous serial adapters
Signed-off-by: NPaul Fulghum <paulkf@microgate.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!