Line disciplines have been in Unix since a long time. While they are not device drivers, they interact with tty devices in a very peculiar manner: They attach to a tty device and can then look at, or manipulate, the data as it flows through the tty device. Line disciplines are thus the natural choice when serial data is used in the kernel, e.g. to exchange TCP/IP packets over a serial link using the SLIP protocol or decoding date and time information and provide a timedelta sensor.
Selected articles of all aspects of our work, mostly in open source projects, usually quite technical.