[media] V4L: Add camera exposure metering control

The V4L2_CID_EXPOSURE_METERING control allows to determine
a method used by the camera for measuring the amount of light
available for automatic exposure.

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>
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 593a1bd3..a3e47ad6 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -1733,6 +1733,13 @@
 	V4L2_ISO_SENSITIVITY_AUTO		= 1,
 };
 
+#define V4L2_CID_EXPOSURE_METERING		(V4L2_CID_CAMERA_CLASS_BASE+25)
+enum v4l2_exposure_metering {
+	V4L2_EXPOSURE_METERING_AVERAGE		= 0,
+	V4L2_EXPOSURE_METERING_CENTER_WEIGHTED	= 1,
+	V4L2_EXPOSURE_METERING_SPOT		= 2,
+};
+
 /* FM Modulator class control IDs */
 #define V4L2_CID_FM_TX_CLASS_BASE		(V4L2_CTRL_CLASS_FM_TX | 0x900)
 #define V4L2_CID_FM_TX_CLASS			(V4L2_CTRL_CLASS_FM_TX | 1)