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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
af4a4d0d | 3 | .. _VIDIOC_S_HW_FREQ_SEEK: |
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4 | |
5 | *************************** | |
6 | ioctl VIDIOC_S_HW_FREQ_SEEK | |
7 | *************************** | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | VIDIOC_S_HW_FREQ_SEEK - Perform a hardware frequency seek |
5377d91f | 13 | |
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14 | |
15 | Synopsis | |
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16 | ======== |
17 | ||
b7e67f6c | 18 | .. cpp:function:: int ioctl( int fd, int request, struct v4l2_hw_freq_seek *argp ) |
5377d91f | 19 | |
586027ce | 20 | |
15e7d615 | 21 | Arguments |
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22 | ========= |
23 | ||
24 | ``fd`` | |
25 | File descriptor returned by :ref:`open() <func-open>`. | |
26 | ||
27 | ``request`` | |
28 | VIDIOC_S_HW_FREQ_SEEK | |
29 | ||
30 | ``argp`` | |
31 | ||
32 | ||
15e7d615 | 33 | Description |
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34 | =========== |
35 | ||
36 | Start a hardware frequency seek from the current frequency. To do this | |
37 | applications initialize the ``tuner``, ``type``, ``seek_upward``, | |
38 | ``wrap_around``, ``spacing``, ``rangelow`` and ``rangehigh`` fields, and | |
39 | zero out the ``reserved`` array of a struct | |
40 | :ref:`v4l2_hw_freq_seek <v4l2-hw-freq-seek>` and call the | |
41 | ``VIDIOC_S_HW_FREQ_SEEK`` ioctl with a pointer to this structure. | |
42 | ||
43 | The ``rangelow`` and ``rangehigh`` fields can be set to a non-zero value | |
44 | to tell the driver to search a specific band. If the struct | |
45 | :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has the | |
46 | ``V4L2_TUNER_CAP_HWSEEK_PROG_LIM`` flag set, these values must fall | |
47 | within one of the bands returned by | |
7347081e | 48 | :ref:`VIDIOC_ENUM_FREQ_BANDS`. If the |
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49 | ``V4L2_TUNER_CAP_HWSEEK_PROG_LIM`` flag is not set, then these values |
50 | must exactly match those of one of the bands returned by | |
7347081e | 51 | :ref:`VIDIOC_ENUM_FREQ_BANDS`. If the |
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52 | current frequency of the tuner does not fall within the selected band it |
53 | will be clamped to fit in the band before the seek is started. | |
54 | ||
55 | If an error is returned, then the original frequency will be restored. | |
56 | ||
57 | This ioctl is supported if the ``V4L2_CAP_HW_FREQ_SEEK`` capability is | |
58 | set. | |
59 | ||
cdb4af0f | 60 | If this ioctl is called from a non-blocking filehandle, then ``EAGAIN`` |
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61 | error code is returned and no seek takes place. |
62 | ||
63 | ||
64 | .. _v4l2-hw-freq-seek: | |
65 | ||
66 | .. flat-table:: struct v4l2_hw_freq_seek | |
67 | :header-rows: 0 | |
68 | :stub-columns: 0 | |
69 | :widths: 1 1 2 | |
70 | ||
71 | ||
72 | - .. row 1 | |
73 | ||
74 | - __u32 | |
75 | ||
76 | - ``tuner`` | |
77 | ||
78 | - The tuner index number. This is the same value as in the struct | |
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79 | :ref:`v4l2_input <v4l2-input>` ``tuner`` field and the struct |
80 | :ref:`v4l2_tuner <v4l2-tuner>` ``index`` field. | |
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81 | |
82 | - .. row 2 | |
83 | ||
84 | - __u32 | |
85 | ||
86 | - ``type`` | |
87 | ||
88 | - The tuner type. This is the same value as in the struct | |
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89 | :ref:`v4l2_tuner <v4l2-tuner>` ``type`` field. See |
90 | :ref:`v4l2-tuner-type` | |
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91 | |
92 | - .. row 3 | |
93 | ||
94 | - __u32 | |
95 | ||
96 | - ``seek_upward`` | |
97 | ||
98 | - If non-zero, seek upward from the current frequency, else seek | |
0579e6e3 | 99 | downward. |
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100 | |
101 | - .. row 4 | |
102 | ||
103 | - __u32 | |
104 | ||
105 | - ``wrap_around`` | |
106 | ||
107 | - If non-zero, wrap around when at the end of the frequency range, | |
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108 | else stop seeking. The struct :ref:`v4l2_tuner <v4l2-tuner>` |
109 | ``capability`` field will tell you what the hardware supports. | |
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110 | |
111 | - .. row 5 | |
112 | ||
113 | - __u32 | |
114 | ||
115 | - ``spacing`` | |
116 | ||
117 | - If non-zero, defines the hardware seek resolution in Hz. The | |
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118 | driver selects the nearest value that is supported by the device. |
119 | If spacing is zero a reasonable default value is used. | |
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120 | |
121 | - .. row 6 | |
122 | ||
123 | - __u32 | |
124 | ||
125 | - ``rangelow`` | |
126 | ||
127 | - If non-zero, the lowest tunable frequency of the band to search in | |
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128 | units of 62.5 kHz, or if the struct |
129 | :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has the | |
130 | ``V4L2_TUNER_CAP_LOW`` flag set, in units of 62.5 Hz or if the | |
131 | struct :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has | |
132 | the ``V4L2_TUNER_CAP_1HZ`` flag set, in units of 1 Hz. If | |
133 | ``rangelow`` is zero a reasonable default value is used. | |
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134 | |
135 | - .. row 7 | |
136 | ||
137 | - __u32 | |
138 | ||
139 | - ``rangehigh`` | |
140 | ||
141 | - If non-zero, the highest tunable frequency of the band to search | |
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142 | in units of 62.5 kHz, or if the struct |
143 | :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has the | |
144 | ``V4L2_TUNER_CAP_LOW`` flag set, in units of 62.5 Hz or if the | |
145 | struct :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has | |
146 | the ``V4L2_TUNER_CAP_1HZ`` flag set, in units of 1 Hz. If | |
147 | ``rangehigh`` is zero a reasonable default value is used. | |
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148 | |
149 | - .. row 8 | |
150 | ||
151 | - __u32 | |
152 | ||
8968da9b | 153 | - ``reserved``\ [5] |
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154 | |
155 | - Reserved for future extensions. Applications must set the array to | |
0579e6e3 | 156 | zero. |
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157 | |
158 | ||
15e7d615 | 159 | Return Value |
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160 | ============ |
161 | ||
162 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
163 | appropriately. The generic error codes are described at the | |
164 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
165 | ||
166 | EINVAL | |
167 | The ``tuner`` index is out of bounds, the ``wrap_around`` value is | |
168 | not supported or one of the values in the ``type``, ``rangelow`` or | |
169 | ``rangehigh`` fields is wrong. | |
170 | ||
171 | EAGAIN | |
172 | Attempted to call ``VIDIOC_S_HW_FREQ_SEEK`` with the filehandle in | |
173 | non-blocking mode. | |
174 | ||
175 | ENODATA | |
176 | The hardware seek found no channels. | |
177 | ||
178 | EBUSY | |
179 | Another hardware seek is already in progress. |