linux/Documentation/userspace-api/gpio/gpio-get-lineinfo-unwatch-ioctl.rst
Kent Gibson 16b2bb7fe5 Documentation: gpio: add chardev v1 userspace API documentation
Add documentation for v1 of the GPIO character device userspace API
to the obsolete section of both the admin-guide and userspace-api
books.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2024-01-22 10:49:07 +01:00

50 lines
1.0 KiB
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.. SPDX-License-Identifier: GPL-2.0
.. _GPIO_GET_LINEINFO_UNWATCH_IOCTL:
*******************************
GPIO_GET_LINEINFO_UNWATCH_IOCTL
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Name
====
GPIO_GET_LINEINFO_UNWATCH_IOCTL - Disable watching a line for changes to its
requested state and configuration information.
Synopsis
========
.. c:macro:: GPIO_GET_LINEINFO_UNWATCH_IOCTL
``int ioctl(int chip_fd, GPIO_GET_LINEINFO_UNWATCH_IOCTL, u32 *offset)``
Arguments
=========
``chip_fd``
The file descriptor of the GPIO character device returned by `open()`.
``offset``
The offset of the line to no longer watch.
Description
===========
Remove the line from the list of lines being watched on this ``chip_fd``.
This is the reverse of gpio-v2-get-lineinfo-watch-ioctl.rst (v2) and
gpio-get-lineinfo-watch-ioctl.rst (v1).
Unwatching a line that is not watched is an error (**EBUSY**).
First added in 5.7.
Return Value
============
On success 0.
On error -1 and the ``errno`` variable is set appropriately.
Common error codes are described in error-codes.rst.