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diff --git a/Documentation/tty/index.rst b/Documentation/tty/index.rst deleted file mode 100644 index 21ea0cb21e55..000000000000 --- a/Documentation/tty/index.rst +++ /dev/null @@ -1,63 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -=== -TTY -=== - -Teletypewriter (TTY) layer takes care of all those serial devices. Including -the virtual ones like pseudoterminal (PTY). - -TTY structures -============== - -There are several major TTY structures. Every TTY device in a system has a -corresponding struct tty_port. These devices are maintained by a TTY driver -which is struct tty_driver. This structure describes the driver but also -contains a reference to operations which could be performed on the TTYs. It is -struct tty_operations. Then, upon open, a struct tty_struct is allocated and -lives until the final close. During this time, several callbacks from struct -tty_operations are invoked by the TTY layer. - -Every character received by the kernel (both from devices and users) is passed -through a preselected :doc:`tty_ldisc` (in -short ldisc; in C, struct tty_ldisc_ops). Its task is to transform characters -as defined by a particular ldisc or by user too. The default one is n_tty, -implementing echoes, signal handling, jobs control, special characters -processing, and more. The transformed characters are passed further to -user/device, depending on the source. - -In-detail description of the named TTY structures is in separate documents: - -.. toctree:: - :maxdepth: 2 - - tty_driver - tty_port - tty_struct - tty_ldisc - tty_buffer - n_tty - tty_internals - -Writing TTY Driver -================== - -Before one starts writing a TTY driver, they must consider -:doc:`Serial <../driver-api/serial/driver>` and :doc:`USB Serial -<../usb/usb-serial>` layers -first. Drivers for serial devices can often use one of these specific layers to -implement a serial driver. Only special devices should be handled directly by -the TTY Layer. If you are about to write such a driver, read on. - -A *typical* sequence a TTY driver performs is as follows: - -#. Allocate and register a TTY driver (module init) -#. Create and register TTY devices as they are probed (probe function) -#. Handle TTY operations and events like interrupts (TTY core invokes the - former, the device the latter) -#. Remove devices as they are going away (remove function) -#. Unregister and free the TTY driver (module exit) - -Steps regarding driver, i.e. 1., 3., and 5. are described in detail in -:doc:`tty_driver`. For the other two (devices handling), look into -:doc:`tty_port`. |