libcamera: camera_lens: Add function to fetch subdev controls

Add a function to the CameraLens class to fetch the V4L2 controls
for its V4L2 subdev

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/camera_lens.cpp

@@ -139,4 +139,15 @@ std::string CameraLens::logPrefix() const
 	return "'" + entity_->name() + "'";
 }
 
+/**
+ * \fn CameraLens::controls()
+ * \brief Retrieve the V4L2 controls of the lens' subdev
+ *
+ * \return A map of the V4L2 controls supported by the lens' driver
+ */
+const ControlInfoMap &CameraLens::controls() const
+{
+	return subdev_->controls();
+}
+
 } /* namespace libcamera */