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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml')
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diff --git a/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml new file mode 100644 index 00000000..5b379e75 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml @@ -0,0 +1,184 @@ +<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> |