mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-19 18:53:52 +08:00
8e080c2e6c
The V4L and DVB API's are there for a long time. however, up to now, no efforts were done to merge them to kernel DocBook. This patch adds the current versions of the specs as an unique compendium. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
146 lines
4.5 KiB
XML
146 lines
4.5 KiB
XML
<refentry id="vidioc-g-frequency">
|
|
<refmeta>
|
|
<refentrytitle>ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY</refentrytitle>
|
|
&manvol;
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>VIDIOC_G_FREQUENCY</refname>
|
|
<refname>VIDIOC_S_FREQUENCY</refname>
|
|
<refpurpose>Get or set tuner or modulator radio
|
|
frequency</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_frequency
|
|
*<parameter>argp</parameter></paramdef>
|
|
</funcprototype>
|
|
</funcsynopsis>
|
|
<funcsynopsis>
|
|
<funcprototype>
|
|
<funcdef>int <function>ioctl</function></funcdef>
|
|
<paramdef>int <parameter>fd</parameter></paramdef>
|
|
<paramdef>int <parameter>request</parameter></paramdef>
|
|
<paramdef>const struct v4l2_frequency
|
|
*<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_G_FREQUENCY, VIDIOC_S_FREQUENCY</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><parameter>argp</parameter></term>
|
|
<listitem>
|
|
<para></para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>To get the current tuner or modulator radio frequency
|
|
applications set the <structfield>tuner</structfield> field of a
|
|
&v4l2-frequency; to the respective tuner or modulator number (only
|
|
input devices have tuners, only output devices have modulators), zero
|
|
out the <structfield>reserved</structfield> array and
|
|
call the <constant>VIDIOC_G_FREQUENCY</constant> ioctl with a pointer
|
|
to this structure. The driver stores the current frequency in the
|
|
<structfield>frequency</structfield> field.</para>
|
|
|
|
<para>To change the current tuner or modulator radio frequency
|
|
applications initialize the <structfield>tuner</structfield>,
|
|
<structfield>type</structfield> and
|
|
<structfield>frequency</structfield> fields, and the
|
|
<structfield>reserved</structfield> array of a &v4l2-frequency; and
|
|
call the <constant>VIDIOC_S_FREQUENCY</constant> ioctl with a pointer
|
|
to this structure. When the requested frequency is not possible the
|
|
driver assumes the closest possible value. However
|
|
<constant>VIDIOC_S_FREQUENCY</constant> is a write-only ioctl, it does
|
|
not return the actual new frequency.</para>
|
|
|
|
<table pgwide="1" frame="none" id="v4l2-frequency">
|
|
<title>struct <structname>v4l2_frequency</structname></title>
|
|
<tgroup cols="3">
|
|
&cs-str;
|
|
<tbody valign="top">
|
|
<row>
|
|
<entry>__u32</entry>
|
|
<entry><structfield>tuner</structfield></entry>
|
|
<entry>The tuner or modulator index number. This is the
|
|
same value as in the &v4l2-input; <structfield>tuner</structfield>
|
|
field and the &v4l2-tuner; <structfield>index</structfield> field, or
|
|
the &v4l2-output; <structfield>modulator</structfield> field and the
|
|
&v4l2-modulator; <structfield>index</structfield> field.</entry>
|
|
</row>
|
|
<row>
|
|
<entry>&v4l2-tuner-type;</entry>
|
|
<entry><structfield>type</structfield></entry>
|
|
<entry>The tuner type. This is the same value as in the
|
|
&v4l2-tuner; <structfield>type</structfield> field. The field is not
|
|
applicable to modulators, &ie; ignored by drivers.</entry>
|
|
</row>
|
|
<row>
|
|
<entry>__u32</entry>
|
|
<entry><structfield>frequency</structfield></entry>
|
|
<entry>Tuning frequency in units of 62.5 kHz, or if the
|
|
&v4l2-tuner; or &v4l2-modulator; <structfield>capabilities</structfield> flag
|
|
<constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5
|
|
Hz.</entry>
|
|
</row>
|
|
<row>
|
|
<entry>__u32</entry>
|
|
<entry><structfield>reserved</structfield>[8]</entry>
|
|
<entry>Reserved for future extensions. Drivers and
|
|
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 or the value in the <structfield>type</structfield> field is
|
|
wrong.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
</refentry>
|
|
|
|
<!--
|
|
Local Variables:
|
|
mode: sgml
|
|
sgml-parent-document: "v4l2.sgml"
|
|
indent-tabs-mode: nil
|
|
End:
|
|
-->
|