text: #ifndef GSPCAV2_H
  #define GSPCAV2_H
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/usb.h>
  #include <linux/videodev2.h>
  #include <media/v4l2-common.h>
  #include <linux/mutex.h>
  
  /* compilation option */
  #define GSPCA_DEBUG 1
  
  #ifdef GSPCA_DEBUG
  /* GSPCA our debug messages */
  extern int gspca_debug;
  #define PDEBUG(level, fmt, args...) \
  	do {\
  		if (gspca_debug & (level)) \
  			printk(KERN_INFO MODULE_NAME ": " fmt "\n", ## args); \
  	} while (0)
  #define D_ERR  0x01
  #define D_PROBE 0x02
  #define D_CONF 0x04
  #define D_STREAM 0x08
  #define D_FRAM 0x10
  #define D_PACK 0x20
  #define D_USBI 0x40
  #define D_USBO 0x80
  #define D_V4L2 0x0100
  #else
  #define PDEBUG(level, fmt, args...)
  #endif
  #undef err
  #define err(fmt, args...) \
  	printk(KERN_ERR MODULE_NAME ": " fmt "\n", ## args)
  #undef info
  #define info(fmt, args...) \
  	printk(KERN_INFO MODULE_NAME ": " fmt "\n", ## args)
  #undef warn
  #define warn(fmt, args...) \
  	printk(KERN_WARNING MODULE_NAME ": " fmt "\n", ## args)
  
  #define GSPCA_MAX_FRAMES 16	/* maximum number of video frame buffers */
  /* image transfers */
  #define MAX_NURBS 4		/* max number of URBs */
  
  
  /* used to list framerates supported by a camera mode (resolution) */
  struct framerates {
  	const u8 *rates;
  	int nrates;
  };
  
  /* device information - set at probe time */
  struct cam {
  	const struct v4l2_pix_format *cam_mode;	/* size nmodes */
  	const struct framerates *mode_framerates; /* must have size nmode,
  						   * just like cam_mode */
  	u32 bulk_size;		/* buffer size when image transfer by bulk */
  	u32 input_flags;	/* value for ENUM_INPUT status flags */
  	u8 nmodes;		/* size of cam_mode */
  	u8 no_urb_create;	/* don't create transfer URBs */
  	u8 bulk_nurbs;		/* number of URBs in bulk mode
  				 * - cannot be > MAX_NURBS
  				 * - when 0 and bulk_size != 0 means
  				 *   1 URB and submit done by subdriver */
  	u8 bulk;		/* image transfer by 0:isoc / 1:bulk */
  	u8 npkt;		/* number of packets in an ISOC message
  				 * 0 is the default value: 32 packets */
  	u8 reverse_alts;	/* Alt settings are in high to low order */
  };
  
  struct gspca_dev;
  struct gspca_frame;
  
  /* subdriver operations */
  typedef int (*cam_op) (struct gspca_dev *);
  typedef void (*cam_v_op) (struct gspca_dev *);
  typedef int (*cam_cf_op) (struct gspca_dev *, const struct usb_device_id *);
  typedef int (*cam_jpg_op) (struct gspca_dev *,
  				struct v4l2_jpegcompression *);
  typedef int (*cam_reg_op) (struct gspca_dev *,
  				struct v4l2_dbg_register *);
  typedef int (*cam_ident_op) (struct gspca_dev *,
  				struct v4l2_dbg_chip_ident *);
  typedef int (*cam_streamparm_op) (struct gspca_dev *,
  				  struct v4l2_streamparm *);
  typedef int (*cam_qmnu_op) (struct gspca_dev *,
  			struct v4l2_querymenu *);
  typedef void (*cam_pkt_op) (struct gspca_dev *gspca_dev,
  				u8 *data,
  				int len);
  typedef int (*cam_int_pkt_op) (struct gspca_dev *gspca_dev,
  				u8 *data,
  				int len);
  
  struct ctrl {
  	struct v4l2_queryctrl qctrl;
  	int (*set)(struct gspca_dev *, __s32);
  	int (*get)(struct gspca_dev *, __s32 *);
  };
  
  /* subdriver description */
  struct sd_desc {
  /* information */
  	const char *name;	/* sub-driver name */
  /* controls */
  	const struct ctrl *ctrls;
  	int nctrls;
  /* mandatory operations */
  	cam_cf_op config;	/* called on probe */
  	cam_op init;		/* called on probe and resume */
  	cam_op start;		/* called on stream on after URBs creation */
  	cam_pkt_op pkt_scan;
  /* optional operations */
  	cam_op isoc_init;	/* called on stream on before getting the EP */
  	cam_op isoc_nego;	/* called when URB submit failed with NOSPC */
  	cam_v_op stopN;		/* called on stream off - main alt */
  	cam_v_op stop0;		/* called on stream off & disconnect - alt 0 */
  	cam_v_op dq_callback;	/* called when a frame has been dequeued */
  	cam_jpg_op get_jcomp;
  	cam_jpg_op set_jcomp;
  	cam_qmnu_op querymenu;
  	cam_streamparm_op get_streamparm;
  	cam_streamparm_op set_streamparm;
  #ifdef CONFIG_VIDEO_ADV_DEBUG
  	cam_reg_op set_register;
  	cam_reg_op get_register;
  #endif
  	cam_ident_op get_chip_ident;
  #if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
  	cam_int_pkt_op int_pkt_scan;
  	/* other_input makes the gspca core create gspca_dev->input even when
  	   int_pkt_scan is NULL, for cams with non interrupt driven buttons */
  	u8 other_input;
  #endif
  };
  
  /* packet types when moving from iso buf to frame buf */
  enum gspca_packet_type {
  	DISCARD_PACKET,
  	FIRST_PACKET,
  	INTER_PACKET,
  	LAST_PACKET
  };
  
  struct gspca_frame {
  	__u8 *data;			/* frame buffer */
  	int vma_use_count;
  	struct v4l2_buffer v4l2_buf;
  };
  
  struct gspca_dev {
  	struct video_device vdev;	/* !! must be the first item */
  	struct module *module;		/* subdriver handling the device */
  	struct usb_device *dev;
  	struct file *capt_file;		/* file doing video capture */
  #if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
  	struct input_dev *input_dev;
  	char phys[64];			/* physical device path */
  #endif
  
  	struct cam cam;				/* device information */
  	const struct sd_desc *sd_desc;		/* subdriver description */
  	unsigned ctrl_dis;		/* disabled controls (bit map) */
  	unsigned ctrl_inac;		/* inactive controls (bit map) */
  
  #define USB_BUF_SZ 64
  	__u8 *usb_buf;				/* buffer for USB exchanges */
  	struct urb *urb[MAX_NURBS];
  #if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
  	struct urb *int_urb;
  #endif
  
  	__u8 *frbuf;				/* buffer for nframes */
  	struct gspca_frame frame[GSPCA_MAX_FRAMES];
  	u8 *image;				/* image beeing filled */
  	__u32 frsz;				/* frame size */
  	u32 image_len;				/* current length of image */
  	atomic_t fr_q;				/* next frame to queue */
  	atomic_t fr_i;				/* frame being filled */
  	signed char fr_queue[GSPCA_MAX_FRAMES];	/* frame queue */
  	char nframes;				/* number of frames */
  	u8 fr_o;				/* next frame to dequeue */
  	__u8 last_packet_type;
  	__s8 empty_packet;		/* if (-1) don't check empty packets */
  	__u8 streaming;
  
  	__u8 curr_mode;			/* current camera mode */
  	__u32 pixfmt;			/* current mode parameters */
  	__u16 width;
  	__u16 height;
  	__u32 sequence;			/* frame sequence number */
  
  	wait_queue_head_t wq;		/* wait queue */
  	struct mutex usb_lock;		/* usb exchange protection */
  	struct mutex read_lock;		/* read protection */
  	struct mutex queue_lock;	/* ISOC queue protection */
  	int usb_err;			/* USB error - protected by usb_lock */
  	u16 pkt_size;			/* ISOC packet size */
  #ifdef CONFIG_PM
  	char frozen;			/* suspend - resume */
  #endif
  	char users;			/* number of opens */
  	char present;			/* device connected */
  	char nbufread;			/* number of buffers for read() */
  	char memory;			/* memory type (V4L2_MEMORY_xxx) */
  	__u8 iface;			/* USB interface number */
  	__u8 alt;			/* USB alternate setting */
  	__u8 nbalt;			/* number of USB alternate settings */
  	u8 audio;			/* presence of audio device */
  };
  
  int gspca_dev_probe(struct usb_interface *intf,
  		const struct usb_device_id *id,
  		const struct sd_desc *sd_desc,
  		int dev_size,
  		struct module *module);
  int gspca_dev_probe2(struct usb_interface *intf,
  		const struct usb_device_id *id,
  		const struct sd_desc *sd_desc,
  		int dev_size,
  		struct module *module);
  void gspca_disconnect(struct usb_interface *intf);
  void gspca_frame_add(struct gspca_dev *gspca_dev,
  			enum gspca_packet_type packet_type,
  			const u8 *data,
  			int len);
  #ifdef CONFIG_PM
  int gspca_suspend(struct usb_interface *intf, pm_message_t message);
  int gspca_resume(struct usb_interface *intf);
  #endif
  int gspca_auto_gain_n_exposure(struct gspca_dev *gspca_dev, int avg_lum,
  	int desired_avg_lum, int deadzone, int gain_knee, int exposure_knee);
  #endif /* GSPCAV2_H */
  