w9966.c

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/*
    Winbond w9966cf Webcam parport driver.

    Version 0.33

    Copyright (C) 2001 Jakob Kemi <[email protected]>

    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/videodev2.h>
#include <linux/slab.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-event.h>
#include <linux/parport.h>

/*#define DEBUG*/               /* Undef me for production */

#ifdef DEBUG
#define DPRINTF(x, a...) printk(KERN_DEBUG "W9966: %s(): "x, __func__ , ##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 {
    struct v4l2_device v4l2_dev;
    struct v4l2_ctrl_handler hdl;
    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;
    struct mutex lock;
};

/*
 *  Module specific properties
 */

MODULE_AUTHOR("Jakob Kemi <[email protected]>");
MODULE_DESCRIPTION("Winbond w9966cf WebCam driver (0.32)");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.33.1");

#ifdef MODULE
static char *pardev[] = {[0 ... W9966_MAXCAMS] = ""};
#else
static 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;
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);

static struct w9966 w9966_cams[W9966_MAXCAMS];

/*
 *  Private function defines
 */


/* Set camera phase flags, so we know what to uninit when terminating */
static inline void w9966_set_state(struct w9966 *cam, int mask, int val)
{
    cam->dev_state = (cam->dev_state & ~mask) ^ val;
}

/* Get camera phase flags */
static inline int w9966_get_state(struct w9966 *cam, int mask, int val)
{
    return ((cam->dev_state & mask) == val);
}

/* Claim parport for ourself */
static void w9966_pdev_claim(struct w9966 *cam)
{
    if (w9966_get_state(cam, W9966_STATE_CLAIMED, W9966_STATE_CLAIMED))
        return;
    parport_claim_or_block(cam->pdev);
    w9966_set_state(cam, W9966_STATE_CLAIMED, W9966_STATE_CLAIMED);
}

/* Release parport for others to use */
static void w9966_pdev_release(struct w9966 *cam)
{
    if (w9966_get_state(cam, W9966_STATE_CLAIMED, 0))
        return;
    parport_release(cam->pdev);
    w9966_set_state(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_read_reg(struct w9966 *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_write_reg(struct w9966 *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;
}

/*
 *  Ugly and primitive i2c protocol functions
 */

/* Sets the data line on the i2c bus.
   Expects a claimed pdev. */
static void w9966_i2c_setsda(struct w9966 *cam, int state)
{
    if (state)
        cam->i2c_state |= W9966_I2C_W_DATA;
    else
        cam->i2c_state &= ~W9966_I2C_W_DATA;

    w9966_write_reg(cam, 0x18, cam->i2c_state);
    udelay(5);
}

/* Get peripheral clock line
   Expects a claimed pdev. */
static int w9966_i2c_getscl(struct w9966 *cam)
{
    const unsigned char state = w9966_read_reg(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 int w9966_i2c_setscl(struct w9966 *cam, int state)
{
    unsigned long timeout;

    if (state)
        cam->i2c_state |= W9966_I2C_W_CLOCK;
    else
        cam->i2c_state &= ~W9966_I2C_W_CLOCK;

    w9966_write_reg(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;
}

#if 0
/* Get peripheral data line
   Expects a claimed pdev. */
static int w9966_i2c_getsda(struct w9966 *cam)
{
    const unsigned char state = w9966_read_reg(cam, 0x18);
    return ((state & W9966_I2C_R_DATA) > 0);
}
#endif

/* Write a byte with ack to the i2c bus.
   Expects a claimed pdev. -1 on error */
static int w9966_i2c_wbyte(struct w9966 *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 *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_read_reg_i2c(struct w9966 *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)
        return -1;
    data = w9966_i2c_rbyte(cam);
    if (data == -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_write_reg_i2c(struct w9966 *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;
}

/* 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 *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_write_reg(cam, 0x00, 0x03) == -1)
        return -1;

    /* Write regs to w9966cf chip */
    for (i = 0; i < 0x1c; i++)
        if (w9966_write_reg(cam, i, regs[i]) == -1)
            return -1;

    /* Write regs to saa7111 chip */
    for (i = 0; i < 0x20; i++)
        if (w9966_write_reg_i2c(cam, i, saa7111_regs[i]) == -1)
            return -1;

    return 0;
}

/*
 *  Video4linux interfacing
 */

static int cam_querycap(struct file *file, void  *priv,
                    struct v4l2_capability *vcap)
{
    struct w9966 *cam = video_drvdata(file);

    strlcpy(vcap->driver, cam->v4l2_dev.name, sizeof(vcap->driver));
    strlcpy(vcap->card, W9966_DRIVERNAME, sizeof(vcap->card));
    strlcpy(vcap->bus_info, "parport", sizeof(vcap->bus_info));
    vcap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE;
    vcap->capabilities = vcap->device_caps | V4L2_CAP_DEVICE_CAPS;
    return 0;
}

static int cam_enum_input(struct file *file, void *fh, struct v4l2_input *vin)
{
    if (vin->index > 0)
        return -EINVAL;
    strlcpy(vin->name, "Camera", sizeof(vin->name));
    vin->type = V4L2_INPUT_TYPE_CAMERA;
    vin->audioset = 0;
    vin->tuner = 0;
    vin->std = 0;
    vin->status = 0;
    return 0;
}

static int cam_g_input(struct file *file, void *fh, unsigned int *inp)
{
    *inp = 0;
    return 0;
}

static int cam_s_input(struct file *file, void *fh, unsigned int inp)
{
    return (inp > 0) ? -EINVAL : 0;
}

static int cam_s_ctrl(struct v4l2_ctrl *ctrl)
{
    struct w9966 *cam =
        container_of(ctrl->handler, struct w9966, hdl);
    int ret = 0;

    mutex_lock(&cam->lock);
    switch (ctrl->id) {
    case V4L2_CID_BRIGHTNESS:
        cam->brightness = ctrl->val;
        break;
    case V4L2_CID_CONTRAST:
        cam->contrast = ctrl->val;
        break;
    case V4L2_CID_SATURATION:
        cam->color = ctrl->val;
        break;
    case V4L2_CID_HUE:
        cam->hue = ctrl->val;
        break;
    default:
        ret = -EINVAL;
        break;
    }

    if (ret == 0) {
        w9966_pdev_claim(cam);

        if (w9966_write_reg_i2c(cam, 0x0a, cam->brightness) == -1 ||
            w9966_write_reg_i2c(cam, 0x0b, cam->contrast) == -1 ||
            w9966_write_reg_i2c(cam, 0x0c, cam->color) == -1 ||
            w9966_write_reg_i2c(cam, 0x0d, cam->hue) == -1) {
            ret = -EIO;
        }

        w9966_pdev_release(cam);
    }
    mutex_unlock(&cam->lock);
    return ret;
}

static int cam_g_fmt_vid_cap(struct file *file, void *fh, struct v4l2_format *fmt)
{
    struct w9966 *cam = video_drvdata(file);
    struct v4l2_pix_format *pix = &fmt->fmt.pix;

    pix->width = cam->width;
    pix->height = cam->height;
    pix->pixelformat = V4L2_PIX_FMT_YUYV;
    pix->field = V4L2_FIELD_NONE;
    pix->bytesperline = 2 * cam->width;
    pix->sizeimage = 2 * cam->width * cam->height;
    /* Just a guess */
    pix->colorspace = V4L2_COLORSPACE_SMPTE170M;
    return 0;
}

static int cam_try_fmt_vid_cap(struct file *file, void *fh, struct v4l2_format *fmt)
{
    struct v4l2_pix_format *pix = &fmt->fmt.pix;

    if (pix->width < 2)
        pix->width = 2;
    if (pix->height < 1)
        pix->height = 1;
    if (pix->width > W9966_WND_MAX_W)
        pix->width = W9966_WND_MAX_W;
    if (pix->height > W9966_WND_MAX_H)
        pix->height = W9966_WND_MAX_H;
    pix->pixelformat = V4L2_PIX_FMT_YUYV;
    pix->field = V4L2_FIELD_NONE;
    pix->bytesperline = 2 * pix->width;
    pix->sizeimage = 2 * pix->width * pix->height;
    /* Just a guess */
    pix->colorspace = V4L2_COLORSPACE_SMPTE170M;
    return 0;
}

static int cam_s_fmt_vid_cap(struct file *file, void *fh, struct v4l2_format *fmt)
{
    struct w9966 *cam = video_drvdata(file);
    struct v4l2_pix_format *pix = &fmt->fmt.pix;
    int ret = cam_try_fmt_vid_cap(file, fh, fmt);

    if (ret)
        return ret;

    mutex_lock(&cam->lock);
    /* Update camera regs */
    w9966_pdev_claim(cam);
    ret = w9966_setup(cam, 0, 0, 1023, 1023, pix->width, pix->height);
    w9966_pdev_release(cam);
    mutex_unlock(&cam->lock);
    return ret;
}

static int cam_enum_fmt_vid_cap(struct file *file, void *fh, struct v4l2_fmtdesc *fmt)
{
    static struct v4l2_fmtdesc formats[] = {
        { 0, 0, 0,
          "YUV 4:2:2", V4L2_PIX_FMT_YUYV,
          { 0, 0, 0, 0 }
        },
    };
    enum v4l2_buf_type type = fmt->type;

    if (fmt->index > 0)
        return -EINVAL;

    *fmt = formats[fmt->index];
    fmt->type = type;
    return 0;
}

/* Capture data */
static ssize_t w9966_v4l_read(struct file *file, char  __user *buf,
        size_t count, loff_t *ppos)
{
    struct w9966 *cam = video_drvdata(file);
    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;

    mutex_lock(&cam->lock);
    w9966_pdev_claim(cam);
    w9966_write_reg(cam, 0x00, 0x02);   /* Reset ECP-FIFO buffer */
    w9966_write_reg(cam, 0x00, 0x00);   /* Return to normal operation */
    w9966_write_reg(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);
        mutex_unlock(&cam->lock);
        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_write_reg(cam, 0x01, 0x18);   /* Disable capture */

out:
    kfree(tbuf);
    w9966_pdev_release(cam);
    mutex_unlock(&cam->lock);

    return count;
}

static const struct v4l2_file_operations w9966_fops = {
    .owner      = THIS_MODULE,
    .open       = v4l2_fh_open,
    .release    = v4l2_fh_release,
    .poll       = v4l2_ctrl_poll,
    .unlocked_ioctl = video_ioctl2,
    .read           = w9966_v4l_read,
};

static const struct v4l2_ioctl_ops w9966_ioctl_ops = {
    .vidioc_querycap                = cam_querycap,
    .vidioc_g_input                 = cam_g_input,
    .vidioc_s_input                 = cam_s_input,
    .vidioc_enum_input              = cam_enum_input,
    .vidioc_enum_fmt_vid_cap        = cam_enum_fmt_vid_cap,
    .vidioc_g_fmt_vid_cap           = cam_g_fmt_vid_cap,
    .vidioc_s_fmt_vid_cap           = cam_s_fmt_vid_cap,
    .vidioc_try_fmt_vid_cap         = cam_try_fmt_vid_cap,
    .vidioc_log_status          = v4l2_ctrl_log_status,
    .vidioc_subscribe_event         = v4l2_ctrl_subscribe_event,
    .vidioc_unsubscribe_event       = v4l2_event_unsubscribe,
};

static const struct v4l2_ctrl_ops cam_ctrl_ops = {
    .s_ctrl = cam_s_ctrl,
};


/* 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 *cam, struct parport *port)
{
    struct v4l2_device *v4l2_dev = &cam->v4l2_dev;

    if (cam->dev_state != 0)
        return -1;

    strlcpy(v4l2_dev->name, "w9966", sizeof(v4l2_dev->name));

    if (v4l2_device_register(NULL, v4l2_dev) < 0) {
        v4l2_err(v4l2_dev, "Could not register v4l2_device\n");
        return -1;
    }

    v4l2_ctrl_handler_init(&cam->hdl, 4);
    v4l2_ctrl_new_std(&cam->hdl, &cam_ctrl_ops,
              V4L2_CID_BRIGHTNESS, 0, 255, 1, 128);
    v4l2_ctrl_new_std(&cam->hdl, &cam_ctrl_ops,
              V4L2_CID_CONTRAST, -64, 64, 1, 64);
    v4l2_ctrl_new_std(&cam->hdl, &cam_ctrl_ops,
              V4L2_CID_SATURATION, -64, 64, 1, 64);
    v4l2_ctrl_new_std(&cam->hdl, &cam_ctrl_ops,
              V4L2_CID_HUE, -128, 127, 1, 0);
    if (cam->hdl.error) {
        v4l2_err(v4l2_dev, "couldn't register controls\n");
        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_set_state(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 */
    strlcpy(cam->vdev.name, W9966_DRIVERNAME, sizeof(cam->vdev.name));
    cam->vdev.v4l2_dev = v4l2_dev;
    cam->vdev.fops = &w9966_fops;
    cam->vdev.ioctl_ops = &w9966_ioctl_ops;
    cam->vdev.release = video_device_release_empty;
    cam->vdev.ctrl_handler = &cam->hdl;
    set_bit(V4L2_FL_USE_FH_PRIO, &cam->vdev.flags);
    video_set_drvdata(&cam->vdev, cam);

    mutex_init(&cam->lock);

    if (video_register_device(&cam->vdev, VFL_TYPE_GRABBER, video_nr) < 0)
        return -1;

    w9966_set_state(cam, W9966_STATE_VDEV, W9966_STATE_VDEV);

    /* All ok */
    v4l2_info(v4l2_dev, "Found and initialized a webcam on %s.\n",
            cam->pport->name);
    return 0;
}


/* Terminate everything gracefully */
static void w9966_term(struct w9966 *cam)
{
    /* Unregister from v4l */
    if (w9966_get_state(cam, W9966_STATE_VDEV, W9966_STATE_VDEV)) {
        video_unregister_device(&cam->vdev);
        w9966_set_state(cam, W9966_STATE_VDEV, 0);
    }

    v4l2_ctrl_handler_free(&cam->hdl);

    /* Terminate from IEEE1284 mode and release pdev block */
    if (w9966_get_state(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_get_state(cam, W9966_STATE_PDEV, W9966_STATE_PDEV)) {
        parport_unregister_device(cam->pdev);
        w9966_set_state(cam, W9966_STATE_PDEV, 0);
    }
    memset(cam, 0, sizeof(*cam));
}


/* 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);