subdev_to_histo
struct vsp1_histogram *histo = subdev_to_histo(subdev);
struct vsp1_histogram *histo = subdev_to_histo(subdev);
struct vsp1_histogram *histo = subdev_to_histo(subdev);
struct vsp1_histogram *histo = subdev_to_histo(subdev);
struct vsp1_histogram *histo = subdev_to_histo(&entity->subdev);