text: /*
  	Winbond w9966cf Webcam parport driver.
  
  	Version 0.32
  
  	Copyright (C) 2001 Jakob Kemi <jakob.kemi@post.utfors.se>
  
  	This program is free software; you can redistribute it and/or modify
  	it under the terms of the GNU General Public License as published by
  	the Free Software Foundation; either version 2 of the License, or
  	(at your option) any later version.
  
  	This program is distributed in the hope that it will be useful,
  	but WITHOUT ANY WARRANTY; without even the implied warranty of
  	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  	GNU General Public License for more details.
  
  	You should have received a copy of the GNU General Public License
  	along with this program; if not, write to the Free Software
  	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
  /*
  	Supported devices:
  	*Lifeview FlyCam Supra (using the Philips saa7111a chip)
  
  	Does any other model using the w9966 interface chip exist ?
  
  	Todo:
  	
  	*Add a working EPP mode, since DMA ECP read isn't implemented
  	in the parport drivers. (That's why it's so sloow)
  
  	*Add support for other ccd-control chips than the saa7111
  	please send me feedback on what kind of chips you have.
  
  	*Add proper probing. I don't know what's wrong with the IEEE1284
  	parport drivers but (IEEE1284_MODE_NIBBLE|IEEE1284_DEVICE_ID)
  	and nibble read seems to be broken for some peripherals.
  
  	*Add probing for onboard SRAM, port directions etc. (if possible)
  
  	*Add support for the hardware compressed modes (maybe using v4l2)
  
  	*Fix better support for the capture window (no skewed images, v4l
  	interface to capt. window)
  
  	*Probably some bugs that I don't know of
  
  	Please support me by sending feedback!
  	
  	Changes:
  	
  	Alan Cox:	Removed RGB mode for kernel merge, added THIS_MODULE
  			and owner support for newer module locks
  */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/delay.h>
  #include <linux/videodev.h>
  #include <linux/parport.h>
  
  //#define DEBUG				// Undef me for production
  
  #ifdef DEBUG
  #define DPRINTF(x, a...) printk(KERN_DEBUG "W9966: %s(): "x, __FUNCTION__ , ##a)
  #else
  #define DPRINTF(x...)
  #endif
  
  /*
   *	Defines, simple typedefs etc.
   */
  
  #define W9966_DRIVERNAME	"W9966CF Webcam"
  #define W9966_MAXCAMS		4	// Maximum number of cameras
  #define W9966_RBUFFER		2048	// Read buffer (must be an even number)
  #define W9966_SRAMSIZE		131072	// 128kb
  #define W9966_SRAMID		0x02	// check w9966cf.pdf
  
  // Empirically determined window limits
  #define W9966_WND_MIN_X		16
  #define W9966_WND_MIN_Y		14
  #define W9966_WND_MAX_X		705
  #define W9966_WND_MAX_Y		253
  #define W9966_WND_MAX_W		(W9966_WND_MAX_X - W9966_WND_MIN_X)
  #define W9966_WND_MAX_H		(W9966_WND_MAX_Y - W9966_WND_MIN_Y)
  
  // Keep track of our current state
  #define W9966_STATE_PDEV	0x01
  #define W9966_STATE_CLAIMED	0x02
  #define W9966_STATE_VDEV	0x04
  
  #define W9966_I2C_W_ID		0x48
  #define W9966_I2C_R_ID		0x49
  #define W9966_I2C_R_DATA	0x08
  #define W9966_I2C_R_CLOCK	0x04
  #define W9966_I2C_W_DATA	0x02
  #define W9966_I2C_W_CLOCK	0x01
  
  struct w9966_dev {
  	unsigned char dev_state;
  	unsigned char i2c_state;
  	unsigned short ppmode;
  	struct parport* pport;
  	struct pardevice* pdev;
  	struct video_device vdev;
  	unsigned short width;
  	unsigned short height;
  	unsigned char brightness;
  	signed char contrast;
  	signed char color;
  	signed char hue;
  };
  
  /*
   *	Module specific properties
   */
  
  MODULE_AUTHOR("Jakob Kemi <jakob.kemi@post.utfors.se>");
  MODULE_DESCRIPTION("Winbond w9966cf WebCam driver (0.32)");
  MODULE_LICENSE("GPL");
  
  
  #ifdef MODULE
  static const char* pardev[] = {[0 ... W9966_MAXCAMS] = ""};
  #else
  static const char* pardev[] = {[0 ... W9966_MAXCAMS] = "aggressive"};
  #endif
  module_param_array(pardev, charp, NULL, 0);
  MODULE_PARM_DESC(pardev, "pardev: where to search for\n\
  \teach camera. 'aggressive' means brute-force search.\n\
  \tEg: >pardev=parport3,aggressive,parport2,parport1< would assign\n\
  \tcam 1 to parport3 and search every parport for cam 2 etc...");
  
  static int parmode = 0;
  module_param(parmode, int, 0);
  MODULE_PARM_DESC(parmode, "parmode: transfer mode (0=auto, 1=ecp, 2=epp");
  
  static int video_nr = -1;
  module_param(video_nr, int, 0);
  
  /*
   *	Private data
   */
  
  static struct w9966_dev w9966_cams[W9966_MAXCAMS];
  
  /*
   *	Private function declares
   */
  
  static inline void w9966_setState(struct w9966_dev* cam, int mask, int val);
  static inline int  w9966_getState(struct w9966_dev* cam, int mask, int val);
  static inline void w9966_pdev_claim(struct w9966_dev *vdev);
  static inline void w9966_pdev_release(struct w9966_dev *vdev);
  
  static int w9966_rReg(struct w9966_dev* cam, int reg);
  static int w9966_wReg(struct w9966_dev* cam, int reg, int data);
  #if 0
  static int w9966_rReg_i2c(struct w9966_dev* cam, int reg);
  #endif
  static int w9966_wReg_i2c(struct w9966_dev* cam, int reg, int data);
  static int w9966_findlen(int near, int size, int maxlen);
  static int w9966_calcscale(int size, int min, int max, int* beg, int* end, unsigned char* factor);
  static int w9966_setup(struct w9966_dev* cam, int x1, int y1, int x2, int y2, int w, int h);
  
  static int  w9966_init(struct w9966_dev* cam, struct parport* port);
  static void w9966_term(struct w9966_dev* cam);
  
  static inline void w9966_i2c_setsda(struct w9966_dev* cam, int state);
  static inline int  w9966_i2c_setscl(struct w9966_dev* cam, int state);
  static inline int  w9966_i2c_getsda(struct w9966_dev* cam);
  static inline int  w9966_i2c_getscl(struct w9966_dev* cam);
  static int w9966_i2c_wbyte(struct w9966_dev* cam, int data);
  #if 0
  static int w9966_i2c_rbyte(struct w9966_dev* cam);
  #endif
  
  static int w9966_v4l_ioctl(struct inode *inode, struct file *file,
  			   unsigned int cmd, unsigned long arg);
  static ssize_t w9966_v4l_read(struct file *file, char __user *buf,
  			      size_t count, loff_t *ppos);
  
  static struct file_operations w9966_fops = {
  	.owner		= THIS_MODULE,
  	.open           = video_exclusive_open,
  	.release        = video_exclusive_release,
  	.ioctl          = w9966_v4l_ioctl,
  	.compat_ioctl	= v4l_compat_ioctl32,
  	.read           = w9966_v4l_read,
  	.llseek         = no_llseek,
  };
  static struct video_device w9966_template = {
  	.owner		= THIS_MODULE,
  	.name           = W9966_DRIVERNAME,
  	.type           = VID_TYPE_CAPTURE | VID_TYPE_SCALES,
  	.hardware       = VID_HARDWARE_W9966,
  	.fops           = &w9966_fops,
  };
  
  /*
   *	Private function defines
   */
  
  
  // Set camera phase flags, so we know what to uninit when terminating 
  static inline void w9966_setState(struct w9966_dev* cam, int mask, int val)
  {
  	cam->dev_state = (cam->dev_state & ~mask) ^ val;
  }
  
  // Get camera phase flags
  static inline int w9966_getState(struct w9966_dev* cam, int mask, int val)
  {
  	return ((cam->dev_state & mask) == val);
  }
  
  // Claim parport for ourself
  static inline void w9966_pdev_claim(struct w9966_dev* cam)
  {
  	if (w9966_getState(cam, W9966_STATE_CLAIMED, W9966_STATE_CLAIMED))
  		return;
  	parport_claim_or_block(cam->pdev);
  	w9966_setState(cam, W9966_STATE_CLAIMED, W9966_STATE_CLAIMED);
  }
  
  // Release parport for others to use
  static inline void w9966_pdev_release(struct w9966_dev* cam)
  {
  	if (w9966_getState(cam, W9966_STATE_CLAIMED, 0))
  		return;
  	parport_release(cam->pdev);
  	w9966_setState(cam, W9966_STATE_CLAIMED, 0);
  }
   
  // Read register from W9966 interface-chip
  // Expects a claimed pdev
  // -1 on error, else register data (byte)
  static int w9966_rReg(struct w9966_dev* cam, int reg)
  {
  	// ECP, read, regtransfer, REG, REG, REG, REG, REG
  	const unsigned char addr = 0x80 | (reg & 0x1f);
  	unsigned char val;
  	
  	if (parport_negotiate(cam->pport, cam->ppmode | IEEE1284_ADDR) != 0)
  		return -1;
  	if (parport_write(cam->pport, &addr, 1) != 1)
  		return -1;
  	if (parport_negotiate(cam->pport, cam->ppmode | IEEE1284_DATA) != 0)
  		return -1;
  	if (parport_read(cam->pport, &val, 1) != 1)
  		return -1;
  
  	return val;
  }
  
  // Write register to W9966 interface-chip
  // Expects a claimed pdev
  // -1 on error
  static int w9966_wReg(struct w9966_dev* cam, int reg, int data)
  {
  	// ECP, write, regtransfer, REG, REG, REG, REG, REG
  	const unsigned char addr = 0xc0 | (reg & 0x1f);
  	const unsigned char val = data;
  	
  	if (parport_negotiate(cam->pport, cam->ppmode | IEEE1284_ADDR) != 0)
  		return -1;
  	if (parport_write(cam->pport, &addr, 1) != 1)
  		return -1;
  	if (parport_negotiate(cam->pport, cam->ppmode | IEEE1284_DATA) != 0)
  		return -1;
  	if (parport_write(cam->pport, &val, 1) != 1)
  		return -1;
  
  	return 0;
  }
  
  // Initialize camera device. Setup all internal flags, set a
  // default video mode, setup ccd-chip, register v4l device etc..
  // Also used for 'probing' of hardware.
  // -1 on error
  static int w9966_init(struct w9966_dev* cam, struct parport* port)
  {
  	if (cam->dev_state != 0)
  		return -1;
  	
  	cam->pport = port;
  	cam->brightness = 128;
  	cam->contrast = 64;
  	cam->color = 64;
  	cam->hue = 0;
  
  // Select requested transfer mode
  	switch(parmode)
  	{
  	default:	// Auto-detect (priority: hw-ecp, hw-epp, sw-ecp)
  	case 0:
  		if (port->modes & PARPORT_MODE_ECP)
  			cam->ppmode = IEEE1284_MODE_ECP;
  		else if (port->modes & PARPORT_MODE_EPP)
  			cam->ppmode = IEEE1284_MODE_EPP;
  		else
  			cam->ppmode = IEEE1284_MODE_ECP;
  		break;	
  	case 1:		// hw- or sw-ecp
  		cam->ppmode = IEEE1284_MODE_ECP;
  		break;
  	case 2:		// hw- or sw-epp
  		cam->ppmode = IEEE1284_MODE_EPP;
  	break;
  	}
  	
  // Tell the parport driver that we exists
  	cam->pdev = parport_register_device(port, "w9966", NULL, NULL, NULL, 0, NULL);
  	if (cam->pdev == NULL) {
  		DPRINTF("parport_register_device() failed\n");
  		return -1;
  	}
  	w9966_setState(cam, W9966_STATE_PDEV, W9966_STATE_PDEV);
  
  	w9966_pdev_claim(cam);
  	
  // Setup a default capture mode
  	if (w9966_setup(cam, 0, 0, 1023, 1023, 200, 160) != 0) {
  		DPRINTF("w9966_setup() failed.\n");
  		return -1;
  	}
  
  	w9966_pdev_release(cam);
  
  // Fill in the video_device struct and register us to v4l
  	memcpy(&cam->vdev, &w9966_template, sizeof(struct video_device));
  	cam->vdev.priv = cam;
  
  	if (video_register_device(&cam->vdev, VFL_TYPE_GRABBER, video_nr) == -1)		 
  		return -1;
  	
  	w9966_setState(cam, W9966_STATE_VDEV, W9966_STATE_VDEV);
  	
  	// All ok
  	printk(
  		"w9966cf: Found and initialized a webcam on %s.\n",
  		cam->pport->name
  	);
  	return 0;
  }
  
  
  // Terminate everything gracefully
  static void w9966_term(struct w9966_dev* cam)
  {
  // Unregister from v4l
  	if (w9966_getState(cam, W9966_STATE_VDEV, W9966_STATE_VDEV)) {
  		video_unregister_device(&cam->vdev);
  		w9966_setState(cam, W9966_STATE_VDEV, 0);
  	}
  
  // Terminate from IEEE1284 mode and release pdev block
  	if (w9966_getState(cam, W9966_STATE_PDEV, W9966_STATE_PDEV)) {
  		w9966_pdev_claim(cam);
  		parport_negotiate(cam->pport, IEEE1284_MODE_COMPAT);
  		w9966_pdev_release(cam);
  	}
  
  // Unregister from parport
  	if (w9966_getState(cam, W9966_STATE_PDEV, W9966_STATE_PDEV)) {
  		parport_unregister_device(cam->pdev);
  		w9966_setState(cam, W9966_STATE_PDEV, 0);
  	}
  }
  
  
  // Find a good length for capture window (used both for W and H)
  // A bit ugly but pretty functional. The capture length
  // have to match the downscale
  static int w9966_findlen(int near, int size, int maxlen)
  {
  	int bestlen = size;
  	int besterr = abs(near - bestlen);
  	int len;
  
  	for(len = size+1;len < maxlen;len++)
  	{
  		int err;
  		if ( ((64*size) %len) != 0)
  			continue;
  
  		err = abs(near - len);
  
  		// Only continue as long as we keep getting better values
  		if (err > besterr)
  			break;
  		
  		besterr = err;
  		bestlen = len;
  	}
  
  	return bestlen;
  }
  
  // Modify capture window (if necessary) 
  // and calculate downscaling
  // Return -1 on error
  static int w9966_calcscale(int size, int min, int max, int* beg, int* end, unsigned char* factor)
  {
  	int maxlen = max - min;
  	int len = *end - *beg + 1;
  	int newlen = w9966_findlen(len, size, maxlen);
  	int err = newlen - len; 
  
  	// Check for bad format
  	if (newlen > maxlen || newlen < size)
  		return -1;
  
  	// Set factor (6 bit fixed)
  	*factor = (64*size) / newlen;
  	if (*factor == 64)
  		*factor = 0x00;	// downscale is disabled
  	else
  		*factor |= 0x80; // set downscale-enable bit
  
  	// Modify old beginning and end
  	*beg -= err / 2;
  	*end += err - (err / 2);
  
  	// Move window if outside borders
  	if (*beg < min) {
  		*end += min - *beg;
  		*beg += min - *beg;
  	}
  	if (*end > max) {
  		*beg -= *end - max;
  		*end -= *end - max;
  	}
  
  	return 0;
  }
  
  // Setup the cameras capture window etc.
  // Expects a claimed pdev
  // return -1 on error
  static int w9966_setup(struct w9966_dev* cam, int x1, int y1, int x2, int y2, int w, int h)
  {
  	unsigned int i;
  	unsigned int enh_s, enh_e;
  	unsigned char scale_x, scale_y;
  	unsigned char regs[0x1c];
  	unsigned char saa7111_regs[] = {
  		0x21, 0x00, 0xd8, 0x23, 0x00, 0x80, 0x80, 0x00,
  		0x88, 0x10, 0x80, 0x40, 0x40, 0x00, 0x01, 0x00,
  		0x48, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  		0x00, 0x00, 0x00, 0x71, 0xe7, 0x00, 0x00, 0xc0
  	};
  	
  	
  	if (w*h*2 > W9966_SRAMSIZE)
  	{
  		DPRINTF("capture window exceeds SRAM size!.\n");
  		w = 200; h = 160;	// Pick default values
  	}
  
  	w &= ~0x1;
  	if (w < 2) w = 2;
  	if (h < 1) h = 1;
  	if (w > W9966_WND_MAX_W) w = W9966_WND_MAX_W;
  	if (h > W9966_WND_MAX_H) h = W9966_WND_MAX_H;
  
  	cam->width = w;
  	cam->height = h;
  
  	enh_s = 0;	
  	enh_e = w*h*2;
  	
  // Modify capture window if necessary and calculate downscaling
  	if (
  		w9966_calcscale(w, W9966_WND_MIN_X, W9966_WND_MAX_X, &x1, &x2, &scale_x) != 0 ||
  		w9966_calcscale(h, W9966_WND_MIN_Y, W9966_WND_MAX_Y, &y1, &y2, &scale_y) != 0
  	) return -1;
  
  	DPRINTF(
  		"%dx%d, x: %d<->%d, y: %d<->%d, sx: %d/64, sy: %d/64.\n",
  		w, h, x1, x2, y1, y2, scale_x&~0x80, scale_y&~0x80
  	);
  	
  // Setup registers
  	regs[0x00] = 0x00;			// Set normal operation
  	regs[0x01] = 0x18;			// Capture mode
  	regs[0x02] = scale_y;			// V-scaling
  	regs[0x03] = scale_x;			// H-scaling
  	
  	// Capture window	
  	regs[0x04] = (x1 & 0x0ff);		// X-start (8 low bits)
  	regs[0x05] = (x1 & 0x300)>>8;		// X-start (2 high bits)
  	regs[0x06] = (y1 & 0x0ff);		// Y-start (8 low bits)
  	regs[0x07] = (y1 & 0x300)>>8;		// Y-start (2 high bits)
  	regs[0x08] = (x2 & 0x0ff);		// X-end (8 low bits)
  	regs[0x09] = (x2 & 0x300)>>8;		// X-end (2 high bits)
  	regs[0x0a] = (y2 & 0x0ff);		// Y-end (8 low bits)
  
  	regs[0x0c] = W9966_SRAMID;		// SRAM-banks (1x 128kb)
  	
  	// Enhancement layer
  	regs[0x0d] = (enh_s& 0x000ff);		// Enh. start (0-7)
  	regs[0x0e] = (enh_s& 0x0ff00)>>8;	// Enh. start (8-15)
  	regs[0x0f] = (enh_s& 0x70000)>>16;	// Enh. start (16-17/18??)
  	regs[0x10] = (enh_e& 0x000ff);		// Enh. end (0-7)
  	regs[0x11] = (enh_e& 0x0ff00)>>8;	// Enh. end (8-15)
  	regs[0x12] = (enh_e& 0x70000)>>16;	// Enh. end (16-17/18??)
  
  	// Misc
  	regs[0x13] = 0x40;			// VEE control (raw 4:2:2)
  	regs[0x17] = 0x00;			// ???
  	regs[0x18] = cam->i2c_state = 0x00;	// Serial bus
  	regs[0x19] = 0xff;			// I/O port direction control
  	regs[0x1a] = 0xff;			// I/O port data register
  	regs[0x1b] = 0x10;			// ???
  	
  	// SAA7111 chip settings
  	saa7111_regs[0x0a] = cam->brightness;
  	saa7111_regs[0x0b] = cam->contrast;
  	saa7111_regs[0x0c] = cam->color;
  	saa7111_regs[0x0d] = cam->hue;
  
  // Reset (ECP-fifo & serial-bus)
  	if (w9966_wReg(cam, 0x00, 0x03) == -1)
  		return -1;
  
  // Write regs to w9966cf chip
  	for (i = 0; i < 0x1c; i++)
  		if (w9966_wReg(cam, i, regs[i]) == -1)
  			return -1;
  
  // Write regs to saa7111 chip
  	for (i = 0; i < 0x20; i++)
  		if (w9966_wReg_i2c(cam, i, saa7111_regs[i]) == -1)
  			return -1;
  
  	return 0;
  }
  
  /*
   *	Ugly and primitive i2c protocol functions
   */
  
  // Sets the data line on the i2c bus.
  // Expects a claimed pdev.
  static inline void w9966_i2c_setsda(struct w9966_dev* cam, int state)
  {
  	if (state)
  		cam->i2c_state |= W9966_I2C_W_DATA;
  	else
  		cam->i2c_state &= ~W9966_I2C_W_DATA;
  	
  	w9966_wReg(cam, 0x18, cam->i2c_state);
  	udelay(5);
  }
  
  // Get peripheral clock line
  // Expects a claimed pdev.
  static inline int w9966_i2c_getscl(struct w9966_dev* cam)
  {
  	const unsigned char state = w9966_rReg(cam, 0x18);
  	return ((state & W9966_I2C_R_CLOCK) > 0);
  }
  
  // Sets the clock line on the i2c bus.
  // Expects a claimed pdev. -1 on error
  static inline int w9966_i2c_setscl(struct w9966_dev* cam, int state)
  {
  	unsigned long timeout;
  
  	if (state)
  		cam->i2c_state |= W9966_I2C_W_CLOCK;
  	else
  		cam->i2c_state &= ~W9966_I2C_W_CLOCK;
  
  	w9966_wReg(cam, 0x18, cam->i2c_state);
  	udelay(5);
  	
  	// we go to high, we also expect the peripheral to ack.
  	if (state) {
  		timeout = jiffies + 100;
  		while (!w9966_i2c_getscl(cam)) {
  			if (time_after(jiffies, timeout))
  				return -1;
  		}
  	}
  	return 0;
  }
  
  // Get peripheral data line
  // Expects a claimed pdev.
  static inline int w9966_i2c_getsda(struct w9966_dev* cam)
  {
  	const unsigned char state = w9966_rReg(cam, 0x18);
  	return ((state & W9966_I2C_R_DATA) > 0);
  }
  
  // Write a byte with ack to the i2c bus.
  // Expects a claimed pdev. -1 on error
  static int w9966_i2c_wbyte(struct w9966_dev* cam, int data)
  {
  	int i;
  	for (i = 7; i >= 0; i--)
  	{
  		w9966_i2c_setsda(cam, (data >> i) & 0x01);
  
  		if (w9966_i2c_setscl(cam, 1) == -1)
  			return -1;			
  		w9966_i2c_setscl(cam, 0);
  	}
  
  	w9966_i2c_setsda(cam, 1);
  	
  	if (w9966_i2c_setscl(cam, 1) == -1)
  		return -1;
  	w9966_i2c_setscl(cam, 0);
  	
  	return 0;
  }
  
  // Read a data byte with ack from the i2c-bus
  // Expects a claimed pdev. -1 on error
  #if 0
  static int w9966_i2c_rbyte(struct w9966_dev* cam)
  {
  	unsigned char data = 0x00;
  	int i;	
  	
  	w9966_i2c_setsda(cam, 1);
  
  	for (i = 0; i < 8; i++)
  	{
  		if (w9966_i2c_setscl(cam, 1) == -1)
  			return -1;
  		data = data << 1;
  		if (w9966_i2c_getsda(cam))
  			data |= 0x01;
  		
  		w9966_i2c_setscl(cam, 0);
  	}
  	return data;
  }
  #endif
  
  // Read a register from the i2c device.
  // Expects claimed pdev. -1 on error
  #if 0
  static int w9966_rReg_i2c(struct w9966_dev* cam, int reg)
  {
  	int data;
  
  	w9966_i2c_setsda(cam, 0);
  	w9966_i2c_setscl(cam, 0);
  
  	if (
  		w9966_i2c_wbyte(cam, W9966_I2C_W_ID) == -1 ||
  		w9966_i2c_wbyte(cam, reg) == -1
  	)
  		return -1;
  
  	w9966_i2c_setsda(cam, 1);
  	if (w9966_i2c_setscl(cam, 1) == -1)
  		return -1;
  	w9966_i2c_setsda(cam, 0);
  	w9966_i2c_setscl(cam, 0);
  
  	if (
  		w9966_i2c_wbyte(cam, W9966_I2C_R_ID) == -1 ||
  		(data = w9966_i2c_rbyte(cam)) == -1
  	)
  		return -1;
  
  	w9966_i2c_setsda(cam, 0);
  	
  	if (w9966_i2c_setscl(cam, 1) == -1)
  		return -1;
  	w9966_i2c_setsda(cam, 1);
  	
  	return data;
  }
  #endif
  
  // Write a register to the i2c device.
  // Expects claimed pdev. -1 on error
  static int w9966_wReg_i2c(struct w9966_dev* cam, int reg, int data)
  {
  	w9966_i2c_setsda(cam, 0);
  	w9966_i2c_setscl(cam, 0);
  
  	if (
  		w9966_i2c_wbyte(cam, W9966_I2C_W_ID) == -1 ||
  		w9966_i2c_wbyte(cam, reg) == -1 ||
  		w9966_i2c_wbyte(cam, data) == -1
  	)
  		return -1;
  
  	w9966_i2c_setsda(cam, 0);
  	if (w9966_i2c_setscl(cam, 1) == -1)
  		return -1;
  		
  	w9966_i2c_setsda(cam, 1);
  
  	return 0;
  }
  
  /*
   *	Video4linux interfacing
   */
  
  static int w9966_v4l_do_ioctl(struct inode *inode, struct file *file,
  			      unsigned int cmd, void *arg)
  {
  	struct video_device *vdev = video_devdata(file);
  	struct w9966_dev *cam = vdev->priv;
  	
  	switch(cmd)
  	{
  	case VIDIOCGCAP:
  	{
  		static struct video_capability vcap = {
  			.name      = W9966_DRIVERNAME,
  			.type      = VID_TYPE_CAPTURE | VID_TYPE_SCALES,
  			.channels  = 1,
  			.maxwidth  = W9966_WND_MAX_W,
  			.maxheight = W9966_WND_MAX_H,
  			.minwidth  = 2,
  			.minheight = 1,
  		};
  		struct video_capability *cap = arg;
  		*cap = vcap;
  		return 0;
  	}
  	case VIDIOCGCHAN:
  	{
  		struct video_channel *vch = arg;
  		if(vch->channel != 0)	// We only support one channel (#0)
  			return -EINVAL;
  		memset(vch,0,sizeof(*vch));
  		strcpy(vch->name, "CCD-input");
  		vch->type = VIDEO_TYPE_CAMERA;
  		return 0;
  	}
  	case VIDIOCSCHAN:
  	{
  		struct video_channel *vch = arg;
  		if(vch->channel != 0)
  			return -EINVAL;
  		return 0;
  	}
  	case VIDIOCGTUNER:
  	{
  		struct video_tuner *vtune = arg;
  		if(vtune->tuner != 0)
  			return -EINVAL;
  		strcpy(vtune->name, "no tuner");
  		vtune->rangelow = 0;
  		vtune->rangehigh = 0;
  		vtune->flags = VIDEO_TUNER_NORM;
  		vtune->mode = VIDEO_MODE_AUTO;
  		vtune->signal = 0xffff;
  		return 0;
  	}
  	case VIDIOCSTUNER:
  	{
  		struct video_tuner *vtune = arg;
  		if (vtune->tuner != 0)
  			return -EINVAL;
  		if (vtune->mode != VIDEO_MODE_AUTO)
  			return -EINVAL;
  		return 0;
  	}
  	case VIDIOCGPICT:
  	{
  		struct video_picture vpic = {
  			cam->brightness << 8,	// brightness
  			(cam->hue + 128) << 8,	// hue
  			cam->color << 9,	// color
  			cam->contrast << 9,	// contrast
  			0x8000,			// whiteness
  			16, VIDEO_PALETTE_YUV422// bpp, palette format
  		};
  		struct video_picture *pic = arg;
  		*pic = vpic;
  		return 0;
  	}
  	case VIDIOCSPICT:
  	{
  		struct video_picture *vpic = arg;
  		if (vpic->depth != 16 || vpic->palette != VIDEO_PALETTE_YUV422)
  			return -EINVAL;
  			
  		cam->brightness = vpic->brightness >> 8;
  		cam->hue = (vpic->hue >> 8) - 128;
  		cam->color = vpic->colour >> 9;
  		cam->contrast = vpic->contrast >> 9;
  
  		w9966_pdev_claim(cam);
  		
  		if (
  			w9966_wReg_i2c(cam, 0x0a, cam->brightness) == -1 ||
  			w9966_wReg_i2c(cam, 0x0b, cam->contrast) == -1 ||
  			w9966_wReg_i2c(cam, 0x0c, cam->color) == -1 ||
  			w9966_wReg_i2c(cam, 0x0d, cam->hue) == -1
  		) {
  			w9966_pdev_release(cam);
  			return -EIO;
  		}
  		
  		w9966_pdev_release(cam);
  		return 0;
  	}
  	case VIDIOCSWIN:
  	{
  		int ret;
  		struct video_window *vwin = arg;
  		
  		if (vwin->flags != 0)
  			return -EINVAL;
  		if (vwin->clipcount != 0)
  			return -EINVAL;
  		if (vwin->width < 2 || vwin->width > W9966_WND_MAX_W)
  			return -EINVAL;		
  		if (vwin->height < 1 || vwin->height > W9966_WND_MAX_H)
  			return -EINVAL;
  
  		// Update camera regs
  		w9966_pdev_claim(cam);
  		ret = w9966_setup(cam, 0, 0, 1023, 1023, vwin->width, vwin->height);
  		w9966_pdev_release(cam);
  		
  		if (ret != 0) {
  			DPRINTF("VIDIOCSWIN: w9966_setup() failed.\n");
  			return -EIO;
  		}
  		
  		return 0;
  	}
  	case VIDIOCGWIN:
  	{
  		struct video_window *vwin = arg;
  		memset(vwin, 0, sizeof(*vwin));
  		vwin->width = cam->width;
  		vwin->height = cam->height;
  		return 0;
  	}
  	// Unimplemented
  	case VIDIOCCAPTURE:	
  	case VIDIOCGFBUF:
  	case VIDIOCSFBUF:
  	case VIDIOCKEY:
  	case VIDIOCGFREQ:
  	case VIDIOCSFREQ:
  	case VIDIOCGAUDIO:
  	case VIDIOCSAUDIO:
  		return -EINVAL;
  	default:
  		return -ENOIOCTLCMD;
  	}
  	return 0;
  }
  
  static int w9966_v4l_ioctl(struct inode *inode, struct file *file,
  			   unsigned int cmd, unsigned long arg)
  {
  	return video_usercopy(inode, file, cmd, arg, w9966_v4l_do_ioctl);
  }
  
  // Capture data
  static ssize_t w9966_v4l_read(struct file *file, char  __user *buf,
  			      size_t count, loff_t *ppos)
  {
  	struct video_device *vdev = video_devdata(file);
  	struct w9966_dev *cam = vdev->priv;
  	unsigned char addr = 0xa0;	// ECP, read, CCD-transfer, 00000
  	unsigned char __user *dest = (unsigned char __user *)buf;
  	unsigned long dleft = count;
  	unsigned char *tbuf;
  	
  	// Why would anyone want more than this??
  	if (count > cam->width * cam->height * 2)
  		return -EINVAL;
  	
  	w9966_pdev_claim(cam);
  	w9966_wReg(cam, 0x00, 0x02);	// Reset ECP-FIFO buffer
  	w9966_wReg(cam, 0x00, 0x00);	// Return to normal operation
  	w9966_wReg(cam, 0x01, 0x98);	// Enable capture
  
  	// write special capture-addr and negotiate into data transfer	
  	if (
  		(parport_negotiate(cam->pport, cam->ppmode|IEEE1284_ADDR) != 0	)||
  		(parport_write(cam->pport, &addr, 1) != 1						)||
  		(parport_negotiate(cam->pport, cam->ppmode|IEEE1284_DATA) != 0	)
  	) {
  		w9966_pdev_release(cam);
  		return -EFAULT;
  	}
  
  	tbuf = kmalloc(W9966_RBUFFER, GFP_KERNEL);
  	if (tbuf == NULL) {
  		count = -ENOMEM;
  		goto out;
  	}
  
  	while(dleft > 0)
  	{
  		unsigned long tsize = (dleft > W9966_RBUFFER) ? W9966_RBUFFER : dleft;
  	
  		if (parport_read(cam->pport, tbuf, tsize) < tsize) {
  			count = -EFAULT;
  			goto out;
  		}
  		if (copy_to_user(dest, tbuf, tsize) != 0) {
  			count = -EFAULT;
  			goto out;
  		}
  		dest += tsize;
  		dleft -= tsize;
  	}
  
  	w9966_wReg(cam, 0x01, 0x18);	// Disable capture
  
  out:
  	kfree(tbuf);
  	w9966_pdev_release(cam);
  
  	return count;
  }
  
  
  // Called once for every parport on init
  static void w9966_attach(struct parport *port)
  {
  	int i;
  	
  	for (i = 0; i < W9966_MAXCAMS; i++)
  	{
  		if (w9966_cams[i].dev_state != 0)	// Cam is already assigned
  			continue;
  		if (
  			strcmp(pardev[i], "aggressive") == 0 ||
  			strcmp(pardev[i], port->name) == 0
  		) {
  			if (w9966_init(&w9966_cams[i], port) != 0)
  			w9966_term(&w9966_cams[i]);
  			break;	// return
  		}
  	}
  }
  
  // Called once for every parport on termination
  static void w9966_detach(struct parport *port)
  {
  	int i;
  	for (i = 0; i < W9966_MAXCAMS; i++)
  	if (w9966_cams[i].dev_state != 0 && w9966_cams[i].pport == port)
  		w9966_term(&w9966_cams[i]);
  }
  
  
  static struct parport_driver w9966_ppd = {
  	.name = W9966_DRIVERNAME,
  	.attach = w9966_attach,
  	.detach = w9966_detach,
  };
  
  // Module entry point
  static int __init w9966_mod_init(void)
  {
  	int i;
  	for (i = 0; i < W9966_MAXCAMS; i++)
  		w9966_cams[i].dev_state = 0;
  
  	return parport_register_driver(&w9966_ppd);
  }
  
  // Module cleanup
  static void __exit w9966_mod_term(void)
  {
  	parport_unregister_driver(&w9966_ppd);
  }
  
  module_init(w9966_mod_init);
  module_exit(w9966_mod_term);
  