1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
<refentry id="vidioc-s-hw-freq-seek">
<refmeta>
<refentrytitle>ioctl VIDIOC_S_HW_FREQ_SEEK</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_S_HW_FREQ_SEEK</refname>
<refpurpose>Perform a hardware frequency seek</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>ioctl</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>request</parameter></paramdef>
<paramdef>struct v4l2_hw_freq_seek
*<parameter>argp</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>fd</parameter></term>
<listitem>
<para>&fd;</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>request</parameter></term>
<listitem>
<para>VIDIOC_S_HW_FREQ_SEEK</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>Start a hardware frequency seek from the current frequency.
To do this applications initialize the <structfield>tuner</structfield>,
<structfield>type</structfield>, <structfield>seek_upward</structfield>,
<structfield>wrap_around</structfield>, <structfield>spacing</structfield>,
<structfield>rangelow</structfield> and <structfield>rangehigh</structfield>
fields, and zero out the <structfield>reserved</structfield> array of a
&v4l2-hw-freq-seek; and call the <constant>VIDIOC_S_HW_FREQ_SEEK</constant>
ioctl with a pointer to this structure.</para>
<para>The <structfield>rangelow</structfield> and
<structfield>rangehigh</structfield> fields can be set to a non-zero value to
tell the driver to search a specific band. If the &v4l2-tuner;
<structfield>capability</structfield> field has the
<constant>V4L2_TUNER_CAP_HWSEEK_PROG_LIM</constant> flag set, these values
must fall within one of the bands returned by &VIDIOC-ENUM-FREQ-BANDS;. If
the <constant>V4L2_TUNER_CAP_HWSEEK_PROG_LIM</constant> flag is not set,
then these values must exactly match those of one of the bands returned by
&VIDIOC-ENUM-FREQ-BANDS;. If the current frequency of the tuner does not fall
within the selected band it will be clamped to fit in the band before the
seek is started.</para>
<para>If an error is returned, then the original frequency will
be restored.</para>
<para>This ioctl is supported if the <constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability is set.</para>
<para>If this ioctl is called from a non-blocking filehandle, then &EAGAIN; is
returned and no seek takes place.</para>
<table pgwide="1" frame="none" id="v4l2-hw-freq-seek">
<title>struct <structname>v4l2_hw_freq_seek</structname></title>
<tgroup cols="3">
&cs-str;
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>tuner</structfield></entry>
<entry>The tuner index number. This is the
same value as in the &v4l2-input; <structfield>tuner</structfield>
field and the &v4l2-tuner; <structfield>index</structfield> field.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry>The tuner type. This is the same value as in the
&v4l2-tuner; <structfield>type</structfield> field. See <xref
linkend="v4l2-tuner-type" /></entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>seek_upward</structfield></entry>
<entry>If non-zero, seek upward from the current frequency, else seek downward.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>wrap_around</structfield></entry>
<entry>If non-zero, wrap around when at the end of the frequency range, else stop seeking.
The &v4l2-tuner; <structfield>capability</structfield> field will tell you what the
hardware supports.
</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>spacing</structfield></entry>
<entry>If non-zero, defines the hardware seek resolution in Hz. The driver selects the nearest value that is supported by the device. If spacing is zero a reasonable default value is used.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>rangelow</structfield></entry>
<entry>If non-zero, the lowest tunable frequency of the band to
search in units of 62.5 kHz, or if the &v4l2-tuner;
<structfield>capability</structfield> field has the
<constant>V4L2_TUNER_CAP_LOW</constant> flag set, in units of 62.5 Hz.
If <structfield>rangelow</structfield> is zero a reasonable default value
is used.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>rangehigh</structfield></entry>
<entry>If non-zero, the highest tunable frequency of the band to
search in units of 62.5 kHz, or if the &v4l2-tuner;
<structfield>capability</structfield> field has the
<constant>V4L2_TUNER_CAP_LOW</constant> flag set, in units of 62.5 Hz.
If <structfield>rangehigh</structfield> is zero a reasonable default value
is used.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[5]</entry>
<entry>Reserved for future extensions. Applications
must set the array to zero.</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
<refsect1>
&return-value;
<variablelist>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
<para>The <structfield>tuner</structfield> index is out of
bounds, the <structfield>wrap_around</structfield> value is not supported or
one of the values in the <structfield>type</structfield>,
<structfield>rangelow</structfield> or <structfield>rangehigh</structfield>
fields is wrong.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EAGAIN</errorcode></term>
<listitem>
<para>Attempted to call <constant>VIDIOC_S_HW_FREQ_SEEK</constant>
with the filehandle in non-blocking mode.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENODATA</errorcode></term>
<listitem>
<para>The hardware seek found no channels.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EBUSY</errorcode></term>
<listitem>
<para>Another hardware seek is already in progress.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
|
