Merge branch 'master' into for-next

Fast-forward merge with Linus to be able to merge patches
based on more recent version of the tree.

1 files changed, 183 insertions, 0 deletions

diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml
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index 000000000000..a67cde6f8c54
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+<refentry id="vidioc-subdev-g-fmt">
+  <refmeta>
+    <refentrytitle>ioctl VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT</refentrytitle>
+    &manvol;
+  </refmeta>
+
+  <refnamediv>
+    <refname>VIDIOC_SUBDEV_G_FMT</refname>
+    <refname>VIDIOC_SUBDEV_S_FMT</refname>
+    <refpurpose>Get or set the data format on a subdev pad</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_format *<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_G_FMT, VIDIOC_SUBDEV_S_FMT</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>These ioctls are used to negotiate the frame format at specific
+    subdev pads in the image pipeline.</para>
+
+    <para>To retrieve the current format applications set the
+    <structfield>pad</structfield> field of a &v4l2-subdev-format; to the
+    desired pad number as reported by the media API and the
+    <structfield>which</structfield> field to
+    <constant>V4L2_SUBDEV_FORMAT_ACTIVE</constant>. When they call the
+    <constant>VIDIOC_SUBDEV_G_FMT</constant> ioctl with a pointer to this
+    structure the driver fills the members of the <structfield>format</structfield>
+    field.</para>
+
+    <para>To change the current format applications set both the
+    <structfield>pad</structfield> and <structfield>which</structfield> fields
+    and all members of the <structfield>format</structfield> field. When they
+    call the <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl with a pointer to this
+    structure the driver verifies the requested format, adjusts it based on the
+    hardware capabilities and configures the device. Upon return the
+    &v4l2-subdev-format; contains the current format as would be returned by a
+    <constant>VIDIOC_SUBDEV_G_FMT</constant> call.</para>
+
+    <para>Applications can query the device capabilities by setting the
+    <structfield>which</structfield> to
+    <constant>V4L2_SUBDEV_FORMAT_TRY</constant>. When set, 'try' formats are not
+    applied to the device by the driver, but are changed exactly as active
+    formats and stored in the sub-device file handle. Two applications querying
+    the same sub-device would thus not interact with each other.</para>
+
+    <para>For instance, to try a format at the output pad of a sub-device,
+    applications would first set the try format at the sub-device input with the
+    <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl. They would then either
+    retrieve the default format at the output pad with the
+    <constant>VIDIOC_SUBDEV_G_FMT</constant> ioctl, or set the desired output
+    pad format with the <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl and check
+    the returned value.</para>
+
+    <para>Try formats do not depend on active formats, but can depend on the
+    current links configuration or sub-device controls value. For instance, a
+    low-pass noise filter might crop pixels at the frame boundaries, modifying
+    its output frame size.</para>
+
+    <para>Drivers must not return an error solely because the requested format
+    doesn't match the device capabilities. They must instead modify the format
+    to match what the hardware can provide. The modified format should be as
+    close as possible to the original request.</para>
+
+    <table pgwide="1" frame="none" id="v4l2-subdev-format">
+      <title>struct <structname>v4l2_subdev_format</structname></title>
+      <tgroup cols="3">
+        &cs-str;
+	<tbody valign="top">
+	  <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>which</structfield></entry>
+	    <entry>Format to modified, from &v4l2-subdev-format-whence;.</entry>
+	  </row>
+	  <row>
+	    <entry>&v4l2-mbus-framefmt;</entry>
+	    <entry><structfield>format</structfield></entry>
+	    <entry>Definition of an image format, see <xref
+	    linkend="v4l2-mbus-framefmt" /> for details.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>reserved</structfield>[8]</entry>
+	    <entry>Reserved for future extensions. Applications and drivers must
+	    set the array to zero.</entry>
+	  </row>
+	</tbody>
+      </tgroup>
+    </table>
+
+    <table pgwide="1" frame="none" id="v4l2-subdev-format-whence">
+      <title>enum <structname>v4l2_subdev_format_whence</structname></title>
+      <tgroup cols="3">
+        &cs-def;
+	<tbody valign="top">
+	  <row>
+	    <entry>V4L2_SUBDEV_FORMAT_TRY</entry>
+	    <entry>0</entry>
+	    <entry>Try formats, used for querying device capabilities.</entry>
+	  </row>
+	  <row>
+	    <entry>V4L2_SUBDEV_FORMAT_ACTIVE</entry>
+	    <entry>1</entry>
+	    <entry>Active formats, applied to the hardware.</entry>
+	  </row>
+	</tbody>
+      </tgroup>
+    </table>
+  </refsect1>
+
+  <refsect1>
+    &return-value;
+
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>EBUSY</errorcode></term>
+	<listitem>
+	  <para>The format can't be changed because the pad is currently busy.
+	  This can be caused, for instance, by an active video stream on the
+	  pad. The ioctl must not be retried without performing another action
+	  to fix the problem first. Only returned by
+	  <constant>VIDIOC_SUBDEV_S_FMT</constant></para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>EINVAL</errorcode></term>
+	<listitem>
+	  <para>The &v4l2-subdev-format; <structfield>pad</structfield>
+	  references a non-existing pad, or the <structfield>which</structfield>
+	  field references a non-existing format.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+  <refsect1>
+    &return-value;
+  </refsect1>
+</refentry>