xref: /linux/Documentation/userspace-api/media/rc/lirc-get-rec-resolution.rst (revision cdd38c5f1ce4398ec58fec95904b75824daab7b5)
1.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
2.. c:namespace:: RC
3
4.. _lirc_get_rec_resolution:
5
6*****************************
7ioctl LIRC_GET_REC_RESOLUTION
8*****************************
9
10Name
11====
12
13LIRC_GET_REC_RESOLUTION - Obtain the value of receive resolution, in microseconds.
14
15Synopsis
16========
17
18.. c:macro:: LIRC_GET_REC_RESOLUTION
19
20``int ioctl(int fd, LIRC_GET_REC_RESOLUTION, __u32 *microseconds)``
21
22Arguments
23=========
24
25``fd``
26    File descriptor returned by open().
27
28``microseconds``
29    Resolution, in microseconds.
30
31Description
32===========
33
34Some receivers have maximum resolution which is defined by internal
35sample rate or data format limitations. E.g. it's common that
36signals can only be reported in 50 microsecond steps.
37
38This ioctl returns the integer value with such resolution, with can be
39used by userspace applications like lircd to automatically adjust the
40tolerance value.
41
42Return Value
43============
44
45On success 0 is returned, on error -1 and the ``errno`` variable is set
46appropriately. The generic error codes are described at the
47:ref:`Generic Error Codes <gen-errors>` chapter.
48