xref: /OK3568_Linux_fs/kernel/Documentation/userspace-api/media/dvb/fe-get-property.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2*4882a593Smuzhiyun.. c:namespace:: DTV.fe
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun.. _FE_GET_PROPERTY:
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun**************************************
7*4882a593Smuzhiyunioctl FE_SET_PROPERTY, FE_GET_PROPERTY
8*4882a593Smuzhiyun**************************************
9*4882a593Smuzhiyun
10*4882a593SmuzhiyunName
11*4882a593Smuzhiyun====
12*4882a593Smuzhiyun
13*4882a593SmuzhiyunFE_SET_PROPERTY - FE_GET_PROPERTY - FE_SET_PROPERTY sets one or more frontend properties. - FE_GET_PROPERTY returns one or more frontend properties.
14*4882a593Smuzhiyun
15*4882a593SmuzhiyunSynopsis
16*4882a593Smuzhiyun========
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun.. c:macro:: FE_GET_PROPERTY
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun``int ioctl(int fd, FE_GET_PROPERTY, struct dtv_properties *argp)``
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun.. c:macro:: FE_SET_PROPERTY
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun``int ioctl(int fd, FE_SET_PROPERTY, struct dtv_properties *argp)``
25*4882a593Smuzhiyun
26*4882a593SmuzhiyunArguments
27*4882a593Smuzhiyun=========
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun``fd``
30*4882a593Smuzhiyun    File descriptor returned by :c:func:`open()`.
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun``argp``
33*4882a593Smuzhiyun    Pointer to struct :c:type:`dtv_properties`.
34*4882a593Smuzhiyun
35*4882a593SmuzhiyunDescription
36*4882a593Smuzhiyun===========
37*4882a593Smuzhiyun
38*4882a593SmuzhiyunAll Digital TV frontend devices support the ``FE_SET_PROPERTY`` and
39*4882a593Smuzhiyun``FE_GET_PROPERTY`` ioctls. The supported properties and statistics
40*4882a593Smuzhiyundepends on the delivery system and on the device:
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun-  ``FE_SET_PROPERTY:``
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun   -  This ioctl is used to set one or more frontend properties.
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun   -  This is the basic command to request the frontend to tune into
47*4882a593Smuzhiyun      some frequency and to start decoding the digital TV signal.
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun   -  This call requires read/write access to the device.
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun.. note::
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun   At return, the values aren't updated to reflect the actual
54*4882a593Smuzhiyun   parameters used. If the actual parameters are needed, an explicit
55*4882a593Smuzhiyun   call to ``FE_GET_PROPERTY`` is needed.
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun-  ``FE_GET_PROPERTY:``
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun   -  This ioctl is used to get properties and statistics from the
60*4882a593Smuzhiyun      frontend.
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun   -  No properties are changed, and statistics aren't reset.
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun   -  This call only requires read-only access to the device.
65*4882a593Smuzhiyun
66*4882a593SmuzhiyunReturn Value
67*4882a593Smuzhiyun============
68*4882a593Smuzhiyun
69*4882a593SmuzhiyunOn success 0 is returned.
70*4882a593Smuzhiyun
71*4882a593SmuzhiyunOn error -1 is returned, and the ``errno`` variable is set
72*4882a593Smuzhiyunappropriately.
73*4882a593Smuzhiyun
74*4882a593SmuzhiyunGeneric error codes are described at the
75*4882a593Smuzhiyun:ref:`Generic Error Codes <gen-errors>` chapter.
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