tty: new PPS line discipline. Add a new line discipline for "pulse per second" devices connected to a serial port. Signed-off-by: Rodolfo Giometti include/linux/tty.h URL: http://gitweb.enneenne.com/?p=linuxpps;a=commit;h=89216db79a900d3b7f49de0f3c79a34b6df33b96