v4l2_control
int uvideo_g_ctrl(void *, struct v4l2_control *);
int uvideo_s_ctrl(void *, struct v4l2_control *);
uvideo_g_ctrl(void *v, struct v4l2_control *gctrl)
uvideo_s_ctrl(void *v, struct v4l2_control *sctrl)
(struct v4l2_control *)data);
(struct v4l2_control *)data);
int (*g_ctrl)(void *, struct v4l2_control *);
int (*s_ctrl)(void *, struct v4l2_control *);
#define VIDIOC_G_CTRL _IOWR('V', 27, struct v4l2_control)
#define VIDIOC_S_CTRL _IOWR('V', 28, struct v4l2_control)