123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188 |
- <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 or if the &v4l2-tuner;
- <structfield>capability</structfield> field has the
- <constant>V4L2_TUNER_CAP_1HZ</constant> flag set, in units of 1 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 or if the &v4l2-tuner;
- <structfield>capability</structfield> field has the
- <constant>V4L2_TUNER_CAP_1HZ</constant> flag set, in units of 1 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>
|