1 .. SPDX-License-Identifier: GFDL-1.1-no-invari !! 1 .. Permission is granted to copy, distribute and/or modify this
2 .. c:namespace:: V4L !! 2 .. document under the terms of the GNU Free Documentation License,
>> 3 .. Version 1.1 or any later version published by the Free Software
>> 4 .. Foundation, with no Invariant Sections, no Front-Cover Texts
>> 5 .. and no Back-Cover Texts. A copy of the license is included at
>> 6 .. Documentation/userspace-api/media/fdl-appendix.rst.
>> 7 ..
>> 8 .. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
3 9
4 .. _VIDIOC_ENUM_FREQ_BANDS: 10 .. _VIDIOC_ENUM_FREQ_BANDS:
5 11
6 **************************** 12 ****************************
7 ioctl VIDIOC_ENUM_FREQ_BANDS 13 ioctl VIDIOC_ENUM_FREQ_BANDS
8 **************************** 14 ****************************
9 15
10 Name 16 Name
11 ==== 17 ====
12 18
13 VIDIOC_ENUM_FREQ_BANDS - Enumerate supported f 19 VIDIOC_ENUM_FREQ_BANDS - Enumerate supported frequency bands
14 20
>> 21
15 Synopsis 22 Synopsis
16 ======== 23 ========
17 24
18 .. c:macro:: VIDIOC_ENUM_FREQ_BANDS !! 25 .. c:function:: int ioctl( int fd, VIDIOC_ENUM_FREQ_BANDS, struct v4l2_frequency_band *argp )
>> 26 :name: VIDIOC_ENUM_FREQ_BANDS
19 27
20 ``int ioctl(int fd, VIDIOC_ENUM_FREQ_BANDS, st <<
21 28
22 Arguments 29 Arguments
23 ========= 30 =========
24 31
25 ``fd`` 32 ``fd``
26 File descriptor returned by :c:func:`open( !! 33 File descriptor returned by :ref:`open() <func-open>`.
27 34
28 ``argp`` 35 ``argp``
29 Pointer to struct :c:type:`v4l2_frequency_ 36 Pointer to struct :c:type:`v4l2_frequency_band`.
30 37
>> 38
31 Description 39 Description
32 =========== 40 ===========
33 41
34 Enumerates the frequency bands that a tuner or 42 Enumerates the frequency bands that a tuner or modulator supports. To do
35 this applications initialize the ``tuner``, `` 43 this applications initialize the ``tuner``, ``type`` and ``index``
36 fields, and zero out the ``reserved`` array of 44 fields, and zero out the ``reserved`` array of a struct
37 :c:type:`v4l2_frequency_band` and call the 45 :c:type:`v4l2_frequency_band` and call the
38 :ref:`VIDIOC_ENUM_FREQ_BANDS` ioctl with a poi 46 :ref:`VIDIOC_ENUM_FREQ_BANDS` ioctl with a pointer to this structure.
39 47
40 This ioctl is supported if the ``V4L2_TUNER_CA 48 This ioctl is supported if the ``V4L2_TUNER_CAP_FREQ_BANDS`` capability
41 of the corresponding tuner/modulator is set. 49 of the corresponding tuner/modulator is set.
42 50
43 .. tabularcolumns:: |p{2.9cm}|p{2.9cm}|p{5.8cm !! 51
>> 52 .. tabularcolumns:: |p{2.9cm}|p{2.9cm}|p{5.8cm}|p{2.9cm}|p{3.0cm}|
44 53
45 .. c:type:: v4l2_frequency_band 54 .. c:type:: v4l2_frequency_band
46 55
47 .. flat-table:: struct v4l2_frequency_band 56 .. flat-table:: struct v4l2_frequency_band
48 :header-rows: 0 57 :header-rows: 0
49 :stub-columns: 0 58 :stub-columns: 0
50 :widths: 1 1 2 1 1 59 :widths: 1 1 2 1 1
51 60
52 * - __u32 61 * - __u32
53 - ``tuner`` 62 - ``tuner``
54 - The tuner or modulator index number. T 63 - The tuner or modulator index number. This is the same value as in
55 the struct :c:type:`v4l2_input` ``tune 64 the struct :c:type:`v4l2_input` ``tuner`` field and
56 the struct :c:type:`v4l2_tuner` ``inde 65 the struct :c:type:`v4l2_tuner` ``index`` field, or
57 the struct :c:type:`v4l2_output` ``mod 66 the struct :c:type:`v4l2_output` ``modulator`` field
58 and the struct :c:type:`v4l2_modulator 67 and the struct :c:type:`v4l2_modulator` ``index``
59 field. 68 field.
60 * - __u32 69 * - __u32
61 - ``type`` 70 - ``type``
62 - The tuner type. This is the same value 71 - The tuner type. This is the same value as in the struct
63 :c:type:`v4l2_tuner` ``type`` field. T 72 :c:type:`v4l2_tuner` ``type`` field. The type must be
64 set to ``V4L2_TUNER_RADIO`` for ``/dev 73 set to ``V4L2_TUNER_RADIO`` for ``/dev/radioX`` device nodes, and
65 to ``V4L2_TUNER_ANALOG_TV`` for all ot 74 to ``V4L2_TUNER_ANALOG_TV`` for all others. Set this field to
66 ``V4L2_TUNER_RADIO`` for modulators (c 75 ``V4L2_TUNER_RADIO`` for modulators (currently only radio
67 modulators are supported). See :c:type 76 modulators are supported). See :c:type:`v4l2_tuner_type`
68 * - __u32 77 * - __u32
69 - ``index`` 78 - ``index``
70 - Identifies the frequency band, set by 79 - Identifies the frequency band, set by the application.
71 * - __u32 80 * - __u32
72 - ``capability`` 81 - ``capability``
73 - :cspan:`2` The tuner/modulator capabil 82 - :cspan:`2` The tuner/modulator capability flags for this
74 frequency band, see :ref:`tuner-capabi 83 frequency band, see :ref:`tuner-capability`. The
75 ``V4L2_TUNER_CAP_LOW`` or ``V4L2_TUNER 84 ``V4L2_TUNER_CAP_LOW`` or ``V4L2_TUNER_CAP_1HZ`` capability must
76 be the same for all frequency bands of 85 be the same for all frequency bands of the selected
77 tuner/modulator. So either all bands h 86 tuner/modulator. So either all bands have that capability set, or
78 none of them have that capability. 87 none of them have that capability.
79 * - __u32 88 * - __u32
80 - ``rangelow`` 89 - ``rangelow``
81 - :cspan:`2` The lowest tunable frequenc 90 - :cspan:`2` The lowest tunable frequency in units of 62.5 kHz, or
82 if the ``capability`` flag ``V4L2_TUNE 91 if the ``capability`` flag ``V4L2_TUNER_CAP_LOW`` is set, in units
83 of 62.5 Hz, for this frequency band. A 92 of 62.5 Hz, for this frequency band. A 1 Hz unit is used when the
84 ``capability`` flag ``V4L2_TUNER_CAP_1 93 ``capability`` flag ``V4L2_TUNER_CAP_1HZ`` is set.
85 * - __u32 94 * - __u32
86 - ``rangehigh`` 95 - ``rangehigh``
87 - :cspan:`2` The highest tunable frequen 96 - :cspan:`2` The highest tunable frequency in units of 62.5 kHz,
88 or if the ``capability`` flag ``V4L2_T 97 or if the ``capability`` flag ``V4L2_TUNER_CAP_LOW`` is set, in
89 units of 62.5 Hz, for this frequency b 98 units of 62.5 Hz, for this frequency band. A 1 Hz unit is used
90 when the ``capability`` flag ``V4L2_TU 99 when the ``capability`` flag ``V4L2_TUNER_CAP_1HZ`` is set.
91 * - __u32 100 * - __u32
92 - ``modulation`` 101 - ``modulation``
93 - :cspan:`2` The supported modulation sy 102 - :cspan:`2` The supported modulation systems of this frequency
94 band. See :ref:`band-modulation`. 103 band. See :ref:`band-modulation`.
95 104
96 .. note:: 105 .. note::
97 106
98 Currently only one modulation syste 107 Currently only one modulation system per frequency band
99 is supported. More work will need t 108 is supported. More work will need to be done if multiple
100 modulation systems are possible. Co 109 modulation systems are possible. Contact the linux-media
101 mailing list 110 mailing list
102 (`https://linuxtv.org/lists.php <ht 111 (`https://linuxtv.org/lists.php <https://linuxtv.org/lists.php>`__)
103 if you need such functionality. 112 if you need such functionality.
104 * - __u32 113 * - __u32
105 - ``reserved``\ [9] 114 - ``reserved``\ [9]
106 - Reserved for future extensions. 115 - Reserved for future extensions.
107 116
108 Applications and drivers must set the 117 Applications and drivers must set the array to zero.
109 118
110 119
111 .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.5cm !! 120
>> 121 .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
112 122
113 .. _band-modulation: 123 .. _band-modulation:
114 124
115 .. flat-table:: Band Modulation Systems 125 .. flat-table:: Band Modulation Systems
116 :header-rows: 0 126 :header-rows: 0
117 :stub-columns: 0 127 :stub-columns: 0
118 :widths: 3 1 4 128 :widths: 3 1 4
119 129
120 * - ``V4L2_BAND_MODULATION_VSB`` 130 * - ``V4L2_BAND_MODULATION_VSB``
121 - 0x02 131 - 0x02
122 - Vestigial Sideband modulation, used fo 132 - Vestigial Sideband modulation, used for analog TV.
123 * - ``V4L2_BAND_MODULATION_FM`` 133 * - ``V4L2_BAND_MODULATION_FM``
124 - 0x04 134 - 0x04
125 - Frequency Modulation, commonly used fo 135 - Frequency Modulation, commonly used for analog radio.
126 * - ``V4L2_BAND_MODULATION_AM`` 136 * - ``V4L2_BAND_MODULATION_AM``
127 - 0x08 137 - 0x08
128 - Amplitude Modulation, commonly used fo 138 - Amplitude Modulation, commonly used for analog radio.
>> 139
129 140
130 Return Value 141 Return Value
131 ============ 142 ============
132 143
133 On success 0 is returned, on error -1 and the 144 On success 0 is returned, on error -1 and the ``errno`` variable is set
134 appropriately. The generic error codes are des 145 appropriately. The generic error codes are described at the
135 :ref:`Generic Error Codes <gen-errors>` chapte 146 :ref:`Generic Error Codes <gen-errors>` chapter.
136 147
137 EINVAL 148 EINVAL
138 The ``tuner`` or ``index`` is out of bound 149 The ``tuner`` or ``index`` is out of bounds or the ``type`` field is
139 wrong. 150 wrong.
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