Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="vidioc-s-hw-freq-seek"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_S_HW_FREQ_SEEK</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_S_HW_FREQ_SEEK</refname> 9 <refpurpose>Perform a hardware frequency seek</refpurpose> 10 </refnamediv> 11 12 <refsynopsisdiv> 13 <funcsynopsis> 14 <funcprototype> 15 <funcdef>int <function>ioctl</function></funcdef> 16 <paramdef>int <parameter>fd</parameter></paramdef> 17 <paramdef>int <parameter>request</parameter></paramdef> 18 <paramdef>struct v4l2_hw_freq_seek 19 *<parameter>argp</parameter></paramdef> 20 </funcprototype> 21 </funcsynopsis> 22 </refsynopsisdiv> 23 24 <refsect1> 25 <title>Arguments</title> 26 27 <variablelist> 28 <varlistentry> 29 <term><parameter>fd</parameter></term> 30 <listitem> 31 <para>&fd;</para> 32 </listitem> 33 </varlistentry> 34 <varlistentry> 35 <term><parameter>request</parameter></term> 36 <listitem> 37 <para>VIDIOC_S_HW_FREQ_SEEK</para> 38 </listitem> 39 </varlistentry> 40 <varlistentry> 41 <term><parameter>argp</parameter></term> 42 <listitem> 43 <para></para> 44 </listitem> 45 </varlistentry> 46 </variablelist> 47 </refsect1> 48 49 <refsect1> 50 <title>Description</title> 51 52 <para>Start a hardware frequency seek from the current frequency. 53 To do this applications initialize the <structfield>tuner</structfield>, 54 <structfield>type</structfield>, <structfield>seek_upward</structfield>, 55 <structfield>wrap_around</structfield>, <structfield>spacing</structfield>, 56 <structfield>rangelow</structfield> and <structfield>rangehigh</structfield> 57 fields, and zero out the <structfield>reserved</structfield> array of a 58 &v4l2-hw-freq-seek; and call the <constant>VIDIOC_S_HW_FREQ_SEEK</constant> 59 ioctl with a pointer to this structure.</para> 60 61 <para>The <structfield>rangelow</structfield> and 62 <structfield>rangehigh</structfield> fields can be set to a non-zero value to 63 tell the driver to search a specific band. If the &v4l2-tuner; 64 <structfield>capability</structfield> field has the 65 <constant>V4L2_TUNER_CAP_HWSEEK_PROG_LIM</constant> flag set, these values 66 must fall within one of the bands returned by &VIDIOC-ENUM-FREQ-BANDS;. If 67 the <constant>V4L2_TUNER_CAP_HWSEEK_PROG_LIM</constant> flag is not set, 68 then these values must exactly match those of one of the bands returned by 69 &VIDIOC-ENUM-FREQ-BANDS;. If the current frequency of the tuner does not fall 70 within the selected band it will be clamped to fit in the band before the 71 seek is started.</para> 72 73 <para>If an error is returned, then the original frequency will 74 be restored.</para> 75 76 <para>This ioctl is supported if the <constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability is set.</para> 77 78 <para>If this ioctl is called from a non-blocking filehandle, then &EAGAIN; is 79 returned and no seek takes place.</para> 80 81 <table pgwide="1" frame="none" id="v4l2-hw-freq-seek"> 82 <title>struct <structname>v4l2_hw_freq_seek</structname></title> 83 <tgroup cols="3"> 84 &cs-str; 85 <tbody valign="top"> 86 <row> 87 <entry>__u32</entry> 88 <entry><structfield>tuner</structfield></entry> 89 <entry>The tuner index number. This is the 90 same value as in the &v4l2-input; <structfield>tuner</structfield> 91 field and the &v4l2-tuner; <structfield>index</structfield> field.</entry> 92 </row> 93 <row> 94 <entry>__u32</entry> 95 <entry><structfield>type</structfield></entry> 96 <entry>The tuner type. This is the same value as in the 97 &v4l2-tuner; <structfield>type</structfield> field. See <xref 98 linkend="v4l2-tuner-type" /></entry> 99 </row> 100 <row> 101 <entry>__u32</entry> 102 <entry><structfield>seek_upward</structfield></entry> 103 <entry>If non-zero, seek upward from the current frequency, else seek downward.</entry> 104 </row> 105 <row> 106 <entry>__u32</entry> 107 <entry><structfield>wrap_around</structfield></entry> 108 <entry>If non-zero, wrap around when at the end of the frequency range, else stop seeking. 109 The &v4l2-tuner; <structfield>capability</structfield> field will tell you what the 110 hardware supports. 111 </entry> 112 </row> 113 <row> 114 <entry>__u32</entry> 115 <entry><structfield>spacing</structfield></entry> 116 <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> 117 </row> 118 <row> 119 <entry>__u32</entry> 120 <entry><structfield>rangelow</structfield></entry> 121 <entry>If non-zero, the lowest tunable frequency of the band to 122 search in units of 62.5 kHz, or if the &v4l2-tuner; 123 <structfield>capability</structfield> field has the 124 <constant>V4L2_TUNER_CAP_LOW</constant> flag set, in units of 62.5 Hz or if the &v4l2-tuner; 125 <structfield>capability</structfield> field has the 126 <constant>V4L2_TUNER_CAP_1HZ</constant> flag set, in units of 1 Hz. 127 If <structfield>rangelow</structfield> is zero a reasonable default value 128 is used.</entry> 129 </row> 130 <row> 131 <entry>__u32</entry> 132 <entry><structfield>rangehigh</structfield></entry> 133 <entry>If non-zero, the highest tunable frequency of the band to 134 search in units of 62.5 kHz, or if the &v4l2-tuner; 135 <structfield>capability</structfield> field has the 136 <constant>V4L2_TUNER_CAP_LOW</constant> flag set, in units of 62.5 Hz or if the &v4l2-tuner; 137 <structfield>capability</structfield> field has the 138 <constant>V4L2_TUNER_CAP_1HZ</constant> flag set, in units of 1 Hz. 139 If <structfield>rangehigh</structfield> is zero a reasonable default value 140 is used.</entry> 141 </row> 142 <row> 143 <entry>__u32</entry> 144 <entry><structfield>reserved</structfield>[5]</entry> 145 <entry>Reserved for future extensions. Applications 146 must set the array to zero.</entry> 147 </row> 148 </tbody> 149 </tgroup> 150 </table> 151 </refsect1> 152 153 <refsect1> 154 &return-value; 155 156 <variablelist> 157 <varlistentry> 158 <term><errorcode>EINVAL</errorcode></term> 159 <listitem> 160 <para>The <structfield>tuner</structfield> index is out of 161 bounds, the <structfield>wrap_around</structfield> value is not supported or 162 one of the values in the <structfield>type</structfield>, 163 <structfield>rangelow</structfield> or <structfield>rangehigh</structfield> 164 fields is wrong.</para> 165 </listitem> 166 </varlistentry> 167 <varlistentry> 168 <term><errorcode>EAGAIN</errorcode></term> 169 <listitem> 170 <para>Attempted to call <constant>VIDIOC_S_HW_FREQ_SEEK</constant> 171 with the filehandle in non-blocking mode.</para> 172 </listitem> 173 </varlistentry> 174 <varlistentry> 175 <term><errorcode>ENODATA</errorcode></term> 176 <listitem> 177 <para>The hardware seek found no channels.</para> 178 </listitem> 179 </varlistentry> 180 <varlistentry> 181 <term><errorcode>EBUSY</errorcode></term> 182 <listitem> 183 <para>Another hardware seek is already in progress.</para> 184 </listitem> 185 </varlistentry> 186 </variablelist> 187 </refsect1> 188 </refentry>
