XCAN_FRAME_DLC_OFFSET
priv->write_reg(priv, XCAN_FRAME_DLC_OFFSET(frame_offset), dlc);
dlc = priv->read_reg(priv, XCAN_FRAME_DLC_OFFSET(frame_base)) >>
dlc = priv->read_reg(priv, XCAN_FRAME_DLC_OFFSET(frame_base));