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| author | Rob Herring (Arm) <robh@kernel.org> | 2026-08-31 14:43:51 -0500 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2026-09-13 18:17:31 -0700 |
| commit | 55fc280e951ab2b39f3dcb640edc1b1eebc6d173 (patch) | |
| tree | f0b5f37b42fc13b9908a31b657c646b024231cdd /Documentation/driver-api/tty/index.rst | |
| download | linux-stable-55fc280e951ab2b39f3dcb640edc1b1eebc6d173.tar.gz linux-stable-55fc280e951ab2b39f3dcb640edc1b1eebc6d173.zip | |
Input: tsc2007 - read "ti,poll-period" as u32grafted
The "ti,poll-period" property is documented as a normal uint32 cell.
The driver used a u64 helper, which makes the helper type disagree with
the schema even though the stored value is still small.
Read "ti,poll-period" with the u32 helper matching the documented DT
cell size.
Assisted-by: Codex:gpt-5-5
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260831194352.1185860-1-robh@kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'Documentation/driver-api/tty/index.rst')
| -rw-r--r-- | Documentation/driver-api/tty/index.rst | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/Documentation/driver-api/tty/index.rst b/Documentation/driver-api/tty/index.rst new file mode 100644 index 000000000..c1ffe3d1e --- /dev/null +++ b/Documentation/driver-api/tty/index.rst @@ -0,0 +1,75 @@ +.. 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 + tty_ioctl + tty_internals + console + +Writing TTY Driver +================== + +Before one starts writing a TTY driver, they must consider +:doc:`Serial <../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`. + +Other Documentation +=================== + +Miscellaneous documentation can be further found in these documents: + +.. toctree:: + :maxdepth: 2 + + moxa-smartio + n_gsm + n_tty |
