[media] v4l: v4l2_subdev userspace frame interval API
The three new ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL,
VIDIOC_SUBDEV_G_FRAME_INTERVAL and VIDIOC_SUBDEV_S_FRAME_INTERVAL can be
used to enumerate and configure a subdev's frame rate from userspace.
Two new video::g/s_frame_interval subdev operations are introduced to
support those ioctls. The existing video::g/s_parm operations are
deprecated and shouldn't be used anymore.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/DocBook/v4l/vidioc-subdev-enum-frame-interval.xml b/Documentation/DocBook/v4l/vidioc-subdev-enum-frame-interval.xml
new file mode 100644
index 0000000..2f8f4f0
--- /dev/null
+++ b/Documentation/DocBook/v4l/vidioc-subdev-enum-frame-interval.xml
@@ -0,0 +1,152 @@
+<refentry id="vidioc-subdev-enum-frame-interval">
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</refname>
+ <refpurpose>Enumerate frame intervals</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_subdev_frame_interval_enum *
+ <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_SUBDEV_ENUM_FRAME_INTERVAL</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>This ioctl lets applications enumerate available frame intervals on a
+ given sub-device pad. Frame intervals only makes sense for sub-devices that
+ can control the frame period on their own. This includes, for instance,
+ image sensors and TV tuners.</para>
+
+ <para>For the common use case of image sensors, the frame intervals
+ available on the sub-device output pad depend on the frame format and size
+ on the same pad. Applications must thus specify the desired format and size
+ when enumerating frame intervals.</para>
+
+ <para>To enumerate frame intervals applications initialize the
+ <structfield>index</structfield>, <structfield>pad</structfield>,
+ <structfield>code</structfield>, <structfield>width</structfield> and
+ <structfield>height</structfield> fields of
+ &v4l2-subdev-frame-interval-enum; and call the
+ <constant>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</constant> ioctl with a pointer
+ to this structure. Drivers fill the rest of the structure or return
+ an &EINVAL; if one of the input fields is invalid. All frame intervals are
+ enumerable by beginning at index zero and incrementing by one until
+ <errorcode>EINVAL</errorcode> is returned.</para>
+
+ <para>Available frame intervals may depend on the current 'try' formats
+ at other pads of the sub-device, as well as on the current active links. See
+ &VIDIOC-SUBDEV-G-FMT; for more information about the try formats.</para>
+
+ <para>Sub-devices that support the frame interval enumeration ioctl should
+ implemented it on a single pad only. Its behaviour when supported on
+ multiple pads of the same sub-device is not defined.</para>
+
+ <table pgwide="1" frame="none" id="v4l2-subdev-frame-interval-enum">
+ <title>struct <structname>v4l2_subdev_frame_interval_enum</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>index</structfield></entry>
+ <entry>Number of the format in the enumeration, set by the
+ application.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>pad</structfield></entry>
+ <entry>Pad number as reported by the media controller API.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>code</structfield></entry>
+ <entry>The media bus format code, as defined in
+ <xref linkend="v4l2-mbus-format" />.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>width</structfield></entry>
+ <entry>Frame width, in pixels.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>height</structfield></entry>
+ <entry>Frame height, in pixels.</entry>
+ </row>
+ <row>
+ <entry>&v4l2-fract;</entry>
+ <entry><structfield>interval</structfield></entry>
+ <entry>Period, in seconds, between consecutive video frames.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>reserved</structfield>[9]</entry>
+ <entry>Reserved for future extensions. Applications and drivers 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 &v4l2-subdev-frame-interval-enum;
+ <structfield>pad</structfield> references a non-existing pad, one of
+ the <structfield>code</structfield>, <structfield>width</structfield>
+ or <structfield>height</structfield> fields are invalid for the given
+ pad or the <structfield>index</structfield> field is out of bounds.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>