v4l2_ctrl_handler_init_class
EXPORT_SYMBOL(v4l2_ctrl_handler_init_class);
int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint, \
v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint, NULL, NULL)