[media] V4L2 spec: document the new V4L2 DV timings ioctls
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml b/Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml
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+<refentry id="vidioc-enum-dv-timings">
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_ENUM_DV_TIMINGS</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_ENUM_DV_TIMINGS</refname>
+ <refpurpose>Enumerate supported Digital Video timings</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_enum_dv_timings *<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_ENUM_DV_TIMINGS</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>argp</parameter></term>
+ <listitem>
+ <para></para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Description</title>
+
+ <note>
+ <title>Experimental</title>
+ <para>This is an <link linkend="experimental"> experimental </link>
+ interface and may change in the future.</para>
+ </note>
+
+ <para>While some DV receivers or transmitters support a wide range of timings, others
+support only a limited number of timings. With this ioctl applications can enumerate a list
+of known supported timings. Call &VIDIOC-DV-TIMINGS-CAP; to check if it also supports other
+standards or even custom timings that are not in this list.</para>
+
+ <para>To query the available timings, applications initialize the
+<structfield>index</structfield> field and zero the reserved array of &v4l2-enum-dv-timings;
+and call the <constant>VIDIOC_ENUM_DV_TIMINGS</constant> ioctl with a pointer to this
+structure. Drivers fill the rest of the structure or return an
+&EINVAL; when the index is out of bounds. To enumerate all supported DV timings,
+applications shall begin at index zero, incrementing by one until the
+driver returns <errorcode>EINVAL</errorcode>. Note that drivers may enumerate a
+different set of DV timings after switching the video input or
+output.</para>
+
+ <table pgwide="1" frame="none" id="v4l2-enum-dv-timings">
+ <title>struct <structname>v4l2_enum_dv_timings</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>index</structfield></entry>
+ <entry>Number of the DV timings, set by the
+application.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>reserved</structfield>[3]</entry>
+ <entry>Reserved for future extensions. Drivers must set the array to zero.</entry>
+ </row>
+ <row>
+ <entry>&v4l2-dv-timings;</entry>
+ <entry><structfield>timings</structfield></entry>
+ <entry>The timings.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EINVAL</errorcode></term>
+ <listitem>
+ <para>The &v4l2-enum-dv-timings; <structfield>index</structfield>
+is out of bounds.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->