This changes the naming of USB serial devices to: /dev/ttyU%d and
/dev/cuaU%d for call-in and call-out devices respectively. (Please
notice: capital 'U')
Please also note that we now have .init and .lock devices for USB
serial ports. These are not persistent across device removal. devd(8)
can be used to configure them on attachment time.
These changes also improve the chances of the system surviving if
the USB device is unplugged at an inconvenient time. At least we
do not rip things apart while there are any threads in the device
driver anymore.
Remove cdevsw, rely on the tty generic one.
Don't make_dev(), use ttycreate() which does all the magic.
In detach, do close procesing if we ripped things apart
while the device was open. Call ttyfree() once we're done
cleaning up.
copies.
No current line disciplines have a dynamically changing hotchar, and
expecting to receive anything sensible during a change in ldisc is
insane so no locking of the hotchar field is necessary.
debugging levels to off by default. Now that debug levels can be
tweaked by sysctl we don't need to go through hoops to get the
different usb parts to produce debug data.
