[media] V4L: Add camera wide dynamic range control

Add V4L2_CID_WIDE_DYNAMIC_RANGE camera class control for the
camera wide dynamic range (WDR, HDR) feature. This control
can be used to enable/disable wide dynamic range. It might
get converted to a menu control in future if more options
are needed.

Signed-off-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/media/v4l/controls.xml

@@ -3092,6 +3092,21 @@ sky. It corresponds approximately to 9000...10000 K color temperature.
 	  </row>
 	  <row><entry></entry></row>
 
+	  <row id="v4l2-wide-dynamic-range">
+	    <entry spanname="id"><constant>V4L2_CID_WIDE_DYNAMIC_RANGE</constant></entry>
+	    <entry>boolean</entry>
+	  </row>
+	  <row>
+	    <entry spanname="descr">Enables or disables the camera's wide dynamic
+range feature. This feature allows to obtain clear images in situations where
+intensity of the illumination varies significantly throughout the scene, i.e.
+there are simultaneously very dark and very bright areas. It is most commonly
+realized in cameras by combining two subsequent frames with different exposure
+times. <footnote id="ctypeconv"><para> This control may be changed to a menu
+control in the future, if more options are required.</para></footnote></entry>
+	  </row>
+	  <row><entry></entry></row>
+
 	</tbody>
       </tgroup>
     </table>