Getting the device name from a struct tty *

[Marc Balmer <marc%msys.ch@localhost>]

In a tty line discipline, I want to get the name of the tty driver
instance, e.g. "dtyU0".  The line disciplines are called with a "struct
tty *" as argument, is there any (halfway sane) way to get at the name
of the driver instance?  I need the name of the instance, not only the
name of the driver.

"struct tty *" contains a "dev_t" element, fwiw.

Is that possible?