drivers/usb/misc/idmouse.c - kernel/msm-4.19 - Gitiles

 /* Siemens ID Mouse driver v0.6

   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.

   Copyright (C) 2004-5 by Florian 'Floe' Echtler  <echtler@fs.tum.de>
                       and Andreas  'ad'  Deresch <aderesch@fs.tum.de>

   Derived from the USB Skeleton driver 1.1,
   Copyright (C) 2003 Greg Kroah-Hartman (greg@kroah.com)

   Additional information provided by Martin Reising
   <Martin.Reising@natural-computing.de>

 */

 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/smp_lock.h>
 #include <linux/completion.h>
 #include <linux/mutex.h>
 #include <asm/uaccess.h>
 #include <linux/usb.h>

 /* image constants */
 #define WIDTH 225
 #define HEIGHT 289
 #define HEADER "P5 225 289 255 "
 #define IMGSIZE ((WIDTH * HEIGHT) + sizeof(HEADER)-1)

 /* version information */
 #define DRIVER_VERSION "0.6"
 #define DRIVER_SHORT   "idmouse"
 #define DRIVER_AUTHOR  "Florian 'Floe' Echtler <echtler@fs.tum.de>"
 #define DRIVER_DESC    "Siemens ID Mouse FingerTIP Sensor Driver"

 /* minor number for misc USB devices */
 #define USB_IDMOUSE_MINOR_BASE 132

 /* vendor and device IDs */
 #define ID_SIEMENS 0x0681
 #define ID_IDMOUSE 0x0005
 #define ID_CHERRY  0x0010

 /* device ID table */
 static struct usb_device_id idmouse_table[] = {
 	{USB_DEVICE(ID_SIEMENS, ID_IDMOUSE)}, /* Siemens ID Mouse (Professional) */
 	{USB_DEVICE(ID_SIEMENS, ID_CHERRY )}, /* Cherry FingerTIP ID Board       */
 	{}                                    /* terminating null entry          */
 };

 /* sensor commands */
 #define FTIP_RESET   0x20
 #define FTIP_ACQUIRE 0x21
 #define FTIP_RELEASE 0x22
 #define FTIP_BLINK   0x23  /* LSB of value = blink pulse width */
 #define FTIP_SCROLL  0x24

 #define ftip_command(dev, command, value, index) \
 	usb_control_msg (dev->udev, usb_sndctrlpipe (dev->udev, 0), command, \
 	USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT, value, index, NULL, 0, 1000)

 MODULE_DEVICE_TABLE(usb, idmouse_table);

 /* structure to hold all of our device specific stuff */
 struct usb_idmouse {

 	struct usb_device *udev; /* save off the usb device pointer */
 	struct usb_interface *interface; /* the interface for this device */

 	unsigned char *bulk_in_buffer; /* the buffer to receive data */
 	size_t bulk_in_size; /* the maximum bulk packet size */
 	size_t orig_bi_size; /* same as above, but reported by the device */
 	__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */

 	int open; /* if the port is open or not */
 	int present; /* if the device is not disconnected */
 	struct semaphore sem; /* locks this structure */

 };

 /* local function prototypes */
 static ssize_t idmouse_read(struct file *file, char __user *buffer,
 				size_t count, loff_t * ppos);

 static int idmouse_open(struct inode *inode, struct file *file);
 static int idmouse_release(struct inode *inode, struct file *file);

 static int idmouse_probe(struct usb_interface *interface,
 				const struct usb_device_id *id);

 static void idmouse_disconnect(struct usb_interface *interface);

 /* file operation pointers */
 static const struct file_operations idmouse_fops = {
 	.owner = THIS_MODULE,
 	.read = idmouse_read,
 	.open = idmouse_open,
 	.release = idmouse_release,
 };

 /* class driver information */
 static struct usb_class_driver idmouse_class = {
 	.name = "idmouse%d",
 	.fops = &idmouse_fops,
 	.minor_base = USB_IDMOUSE_MINOR_BASE,
 };

 /* usb specific object needed to register this driver with the usb subsystem */
 static struct usb_driver idmouse_driver = {
 	.name = DRIVER_SHORT,
 	.probe = idmouse_probe,
 	.disconnect = idmouse_disconnect,
 	.id_table = idmouse_table,
 };

 /* prevent races between open() and disconnect() */
 static DEFINE_MUTEX(disconnect_mutex);

 static int idmouse_create_image(struct usb_idmouse *dev)
 {
 	int bytes_read = 0;
 	int bulk_read = 0;
 	int result = 0;

 	memcpy(dev->bulk_in_buffer, HEADER, sizeof(HEADER)-1);
 	bytes_read += sizeof(HEADER)-1;

 	/* reset the device and set a fast blink rate */
 	result = ftip_command(dev, FTIP_RELEASE, 0, 0);
 	if (result < 0)
 		goto reset;
 	result = ftip_command(dev, FTIP_BLINK,   1, 0);
 	if (result < 0)
 		goto reset;

 	/* initialize the sensor - sending this command twice */
 	/* significantly reduces the rate of failed reads     */
 	result = ftip_command(dev, FTIP_ACQUIRE, 0, 0);
 	if (result < 0)
 		goto reset;
 	result = ftip_command(dev, FTIP_ACQUIRE, 0, 0);
 	if (result < 0)
 		goto reset;

 	/* start the readout - sending this command twice */
 	/* presumably enables the high dynamic range mode */
 	result = ftip_command(dev, FTIP_RESET,   0, 0);
 	if (result < 0)
 		goto reset;
 	result = ftip_command(dev, FTIP_RESET,   0, 0);
 	if (result < 0)
 		goto reset;

 	/* loop over a blocking bulk read to get data from the device */
 	while (bytes_read < IMGSIZE) {
 		result = usb_bulk_msg (dev->udev,
 				usb_rcvbulkpipe (dev->udev, dev->bulk_in_endpointAddr),
 				dev->bulk_in_buffer + bytes_read,
 				dev->bulk_in_size, &bulk_read, 5000);
 		if (result < 0) {
 			/* Maybe this error was caused by the increased packet size? */
 			/* Reset to the original value and tell userspace to retry.  */
 			if (dev->bulk_in_size != dev->orig_bi_size) {
 				dev->bulk_in_size = dev->orig_bi_size;
 				result = -EAGAIN;
 			}
 			break;
 		}
 		if (signal_pending(current)) {
 			result = -EINTR;
 			break;
 		}
 		bytes_read += bulk_read;
 	}

 	/* reset the device */
 reset:
 	ftip_command(dev, FTIP_RELEASE, 0, 0);

 	/* check for valid image */
 	/* right border should be black (0x00) */
 	for (bytes_read = sizeof(HEADER)-1 + WIDTH-1; bytes_read < IMGSIZE; bytes_read += WIDTH)
 		if (dev->bulk_in_buffer[bytes_read] != 0x00)
 			return -EAGAIN;

 	/* lower border should be white (0xFF) */
 	for (bytes_read = IMGSIZE-WIDTH; bytes_read < IMGSIZE-1; bytes_read++)
 		if (dev->bulk_in_buffer[bytes_read] != 0xFF)
 			return -EAGAIN;

 	/* should be IMGSIZE == 65040 */
 	dbg("read %d bytes fingerprint data", bytes_read);
 	return result;
 }

 static inline void idmouse_delete(struct usb_idmouse *dev)
 {
 	kfree(dev->bulk_in_buffer);
 	kfree(dev);
 }

 static int idmouse_open(struct inode *inode, struct file *file)
 {
 	struct usb_idmouse *dev = NULL;
 	struct usb_interface *interface;
 	int result = 0;

 	/* prevent disconnects */
 	mutex_lock(&disconnect_mutex);

 	/* get the interface from minor number and driver information */
 	interface = usb_find_interface (&idmouse_driver, iminor (inode));
 	if (!interface) {
 		mutex_unlock(&disconnect_mutex);
 		return -ENODEV;
 	}
 	/* get the device information block from the interface */
 	dev = usb_get_intfdata(interface);
 	if (!dev) {
 		mutex_unlock(&disconnect_mutex);
 		return -ENODEV;
 	}

 	/* lock this device */
 	down(&dev->sem);

 	/* check if already open */
 	if (dev->open) {

 		/* already open, so fail */
 		result = -EBUSY;

 	} else {

 		/* create a new image and check for success */
 		result = idmouse_create_image (dev);
 		if (result)
 			goto error;

 		/* increment our usage count for the driver */
 		++dev->open;

 		/* save our object in the file's private structure */
 		file->private_data = dev;

 	}

 error:

 	/* unlock this device */
 	up(&dev->sem);

 	/* unlock the disconnect semaphore */
 	mutex_unlock(&disconnect_mutex);
 	return result;
 }

 static int idmouse_release(struct inode *inode, struct file *file)
 {
 	struct usb_idmouse *dev;

 	/* prevent a race condition with open() */
 	mutex_lock(&disconnect_mutex);

 	dev = (struct usb_idmouse *) file->private_data;

 	if (dev == NULL) {
 		mutex_unlock(&disconnect_mutex);
 		return -ENODEV;
 	}

 	/* lock our device */
 	down(&dev->sem);

 	/* are we really open? */
 	if (dev->open <= 0) {
 		up(&dev->sem);
 		mutex_unlock(&disconnect_mutex);
 		return -ENODEV;
 	}

 	--dev->open;

 	if (!dev->present) {
 		/* the device was unplugged before the file was released */
 		up(&dev->sem);
 		idmouse_delete(dev);
 		mutex_unlock(&disconnect_mutex);
 		return 0;
 	}

 	up(&dev->sem);
 	mutex_unlock(&disconnect_mutex);
 	return 0;
 }

 static ssize_t idmouse_read(struct file *file, char __user *buffer, size_t count,
 				loff_t * ppos)
 {
 	struct usb_idmouse *dev;
 	int result = 0;

 	dev = (struct usb_idmouse *) file->private_data;

 	/* lock this object */
 	down (&dev->sem);

 	/* verify that the device wasn't unplugged */
 	if (!dev->present) {
 		up (&dev->sem);
 		return -ENODEV;
 	}

 	result = simple_read_from_buffer(buffer, count, ppos,
 					dev->bulk_in_buffer, IMGSIZE);
 	/* unlock the device */
 	up(&dev->sem);
 	return result;
 }

 static int idmouse_probe(struct usb_interface *interface,
 				const struct usb_device_id *id)
 {
 	struct usb_device *udev = interface_to_usbdev(interface);
 	struct usb_idmouse *dev = NULL;
 	struct usb_host_interface *iface_desc;
 	struct usb_endpoint_descriptor *endpoint;
 	int result;

 	/* check if we have gotten the data or the hid interface */
 	iface_desc = &interface->altsetting[0];
 	if (iface_desc->desc.bInterfaceClass != 0x0A)
 		return -ENODEV;

 	/* allocate memory for our device state and initialize it */
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (dev == NULL)
 		return -ENOMEM;

 	init_MUTEX(&dev->sem);
 	dev->udev = udev;
 	dev->interface = interface;

 	/* set up the endpoint information - use only the first bulk-in endpoint */
 	endpoint = &iface_desc->endpoint[0].desc;
 	if (!dev->bulk_in_endpointAddr
 		&& (endpoint->bEndpointAddress & USB_DIR_IN)
 		&& ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
 		USB_ENDPOINT_XFER_BULK)) {

 		/* we found a bulk in endpoint */
 		dev->orig_bi_size = le16_to_cpu(endpoint->wMaxPacketSize);
 		dev->bulk_in_size = 0x200; /* works _much_ faster */
 		dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
 		dev->bulk_in_buffer =
 			kmalloc(IMGSIZE + dev->bulk_in_size, GFP_KERNEL);

 		if (!dev->bulk_in_buffer) {
 			err("Unable to allocate input buffer.");
 			idmouse_delete(dev);
 			return -ENOMEM;
 		}
 	}

 	if (!(dev->bulk_in_endpointAddr)) {
 		err("Unable to find bulk-in endpoint.");
 		idmouse_delete(dev);
 		return -ENODEV;
 	}
 	/* allow device read, write and ioctl */
 	dev->present = 1;

 	/* we can register the device now, as it is ready */
 	usb_set_intfdata(interface, dev);
 	result = usb_register_dev(interface, &idmouse_class);
 	if (result) {
 		/* something prevented us from registering this device */
 		err("Unble to allocate minor number.");
 		usb_set_intfdata(interface, NULL);
 		idmouse_delete(dev);
 		return result;
 	}

 	/* be noisy */
 	dev_info(&interface->dev,"%s now attached\n",DRIVER_DESC);

 	return 0;
 }

 static void idmouse_disconnect(struct usb_interface *interface)
 {
 	struct usb_idmouse *dev;

 	/* prevent races with open() */
 	mutex_lock(&disconnect_mutex);

 	/* get device structure */
 	dev = usb_get_intfdata(interface);
 	usb_set_intfdata(interface, NULL);

 	/* lock it */
 	down(&dev->sem);

 	/* give back our minor */
 	usb_deregister_dev(interface, &idmouse_class);

 	/* prevent device read, write and ioctl */
 	dev->present = 0;

 	/* unlock */
 	up(&dev->sem);

 	/* if the device is opened, idmouse_release will clean this up */
 	if (!dev->open)
 		idmouse_delete(dev);

 	mutex_unlock(&disconnect_mutex);

 	info("%s disconnected", DRIVER_DESC);
 }

 static int __init usb_idmouse_init(void)
 {
 	int result;

 	info(DRIVER_DESC " " DRIVER_VERSION);

 	/* register this driver with the USB subsystem */
 	result = usb_register(&idmouse_driver);
 	if (result)
 		err("Unable to register device (error %d).", result);

 	return result;
 }

 static void __exit usb_idmouse_exit(void)
 {
 	/* deregister this driver with the USB subsystem */
 	usb_deregister(&idmouse_driver);
 }

 module_init(usb_idmouse_init);
 module_exit(usb_idmouse_exit);

 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");
	/* Siemens ID Mouse driver v0.6

	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.

	Copyright (C) 2004-5 by Florian 'Floe' Echtler <echtler@fs.tum.de>
	and Andreas 'ad' Deresch <aderesch@fs.tum.de>

	Derived from the USB Skeleton driver 1.1,
	Copyright (C) 2003 Greg Kroah-Hartman (greg@kroah.com)

	Additional information provided by Martin Reising
	<Martin.Reising@natural-computing.de>

	*/

	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/delay.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/smp_lock.h>
	#include <linux/completion.h>
	#include <linux/mutex.h>
	#include <asm/uaccess.h>
	#include <linux/usb.h>

	/* image constants */
	#define WIDTH 225
	#define HEIGHT 289
	#define HEADER "P5 225 289 255 "
	#define IMGSIZE ((WIDTH * HEIGHT) + sizeof(HEADER)-1)

	/* version information */
	#define DRIVER_VERSION "0.6"
	#define DRIVER_SHORT "idmouse"
	#define DRIVER_AUTHOR "Florian 'Floe' Echtler <echtler@fs.tum.de>"
	#define DRIVER_DESC "Siemens ID Mouse FingerTIP Sensor Driver"

	/* minor number for misc USB devices */
	#define USB_IDMOUSE_MINOR_BASE 132

	/* vendor and device IDs */
	#define ID_SIEMENS 0x0681
	#define ID_IDMOUSE 0x0005
	#define ID_CHERRY 0x0010

	/* device ID table */
	static struct usb_device_id idmouse_table[] = {
	{USB_DEVICE(ID_SIEMENS, ID_IDMOUSE)}, /* Siemens ID Mouse (Professional) */
	{USB_DEVICE(ID_SIEMENS, ID_CHERRY )}, /* Cherry FingerTIP ID Board */
	{} /* terminating null entry */
	};

	/* sensor commands */
	#define FTIP_RESET 0x20
	#define FTIP_ACQUIRE 0x21
	#define FTIP_RELEASE 0x22
	#define FTIP_BLINK 0x23 /* LSB of value = blink pulse width */
	#define FTIP_SCROLL 0x24

	#define ftip_command(dev, command, value, index) \
	usb_control_msg (dev->udev, usb_sndctrlpipe (dev->udev, 0), command, \
	USB_TYPE_VENDOR \| USB_RECIP_ENDPOINT \| USB_DIR_OUT, value, index, NULL, 0, 1000)

	MODULE_DEVICE_TABLE(usb, idmouse_table);

	/* structure to hold all of our device specific stuff */
	struct usb_idmouse {

	struct usb_device udev; / save off the usb device pointer */
	struct usb_interface interface; / the interface for this device */

	unsigned char bulk_in_buffer; / the buffer to receive data */
	size_t bulk_in_size; /* the maximum bulk packet size */
	size_t orig_bi_size; /* same as above, but reported by the device */
	__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */

	int open; /* if the port is open or not */
	int present; /* if the device is not disconnected */
	struct semaphore sem; /* locks this structure */

	};

	/* local function prototypes */
	static ssize_t idmouse_read(struct file file, char __user buffer,
	size_t count, loff_t * ppos);

	static int idmouse_open(struct inode inode, struct file file);
	static int idmouse_release(struct inode inode, struct file file);

	static int idmouse_probe(struct usb_interface *interface,
	const struct usb_device_id *id);

	static void idmouse_disconnect(struct usb_interface *interface);

	/* file operation pointers */
	static const struct file_operations idmouse_fops = {
	.owner = THIS_MODULE,
	.read = idmouse_read,
	.open = idmouse_open,
	.release = idmouse_release,
	};

	/* class driver information */
	static struct usb_class_driver idmouse_class = {
	.name = "idmouse%d",
	.fops = &idmouse_fops,
	.minor_base = USB_IDMOUSE_MINOR_BASE,
	};

	/* usb specific object needed to register this driver with the usb subsystem */
	static struct usb_driver idmouse_driver = {
	.name = DRIVER_SHORT,
	.probe = idmouse_probe,
	.disconnect = idmouse_disconnect,
	.id_table = idmouse_table,
	};

	/* prevent races between open() and disconnect() */
	static DEFINE_MUTEX(disconnect_mutex);

	static int idmouse_create_image(struct usb_idmouse *dev)
	{
	int bytes_read = 0;
	int bulk_read = 0;
	int result = 0;

	memcpy(dev->bulk_in_buffer, HEADER, sizeof(HEADER)-1);
	bytes_read += sizeof(HEADER)-1;

	/* reset the device and set a fast blink rate */
	result = ftip_command(dev, FTIP_RELEASE, 0, 0);
	if (result < 0)
	goto reset;
	result = ftip_command(dev, FTIP_BLINK, 1, 0);
	if (result < 0)
	goto reset;

	/* initialize the sensor - sending this command twice */
	/* significantly reduces the rate of failed reads */
	result = ftip_command(dev, FTIP_ACQUIRE, 0, 0);
	if (result < 0)
	goto reset;
	result = ftip_command(dev, FTIP_ACQUIRE, 0, 0);
	if (result < 0)
	goto reset;

	/* start the readout - sending this command twice */
	/* presumably enables the high dynamic range mode */
	result = ftip_command(dev, FTIP_RESET, 0, 0);
	if (result < 0)
	goto reset;
	result = ftip_command(dev, FTIP_RESET, 0, 0);
	if (result < 0)
	goto reset;

	/* loop over a blocking bulk read to get data from the device */
	while (bytes_read < IMGSIZE) {
	result = usb_bulk_msg (dev->udev,
	usb_rcvbulkpipe (dev->udev, dev->bulk_in_endpointAddr),
	dev->bulk_in_buffer + bytes_read,
	dev->bulk_in_size, &bulk_read, 5000);
	if (result < 0) {
	/* Maybe this error was caused by the increased packet size? */
	/* Reset to the original value and tell userspace to retry. */
	if (dev->bulk_in_size != dev->orig_bi_size) {
	dev->bulk_in_size = dev->orig_bi_size;
	result = -EAGAIN;
	}
	break;
	}
	if (signal_pending(current)) {
	result = -EINTR;
	break;
	}
	bytes_read += bulk_read;
	}

	/* reset the device */
	reset:
	ftip_command(dev, FTIP_RELEASE, 0, 0);

	/* check for valid image */
	/* right border should be black (0x00) */
	for (bytes_read = sizeof(HEADER)-1 + WIDTH-1; bytes_read < IMGSIZE; bytes_read += WIDTH)
	if (dev->bulk_in_buffer[bytes_read] != 0x00)
	return -EAGAIN;

	/* lower border should be white (0xFF) */
	for (bytes_read = IMGSIZE-WIDTH; bytes_read < IMGSIZE-1; bytes_read++)
	if (dev->bulk_in_buffer[bytes_read] != 0xFF)
	return -EAGAIN;

	/* should be IMGSIZE == 65040 */
	dbg("read %d bytes fingerprint data", bytes_read);
	return result;
	}

	static inline void idmouse_delete(struct usb_idmouse *dev)
	{
	kfree(dev->bulk_in_buffer);
	kfree(dev);
	}

	static int idmouse_open(struct inode inode, struct file file)
	{
	struct usb_idmouse *dev = NULL;
	struct usb_interface *interface;
	int result = 0;

	/* prevent disconnects */
	mutex_lock(&disconnect_mutex);

	/* get the interface from minor number and driver information */
	interface = usb_find_interface (&idmouse_driver, iminor (inode));
	if (!interface) {
	mutex_unlock(&disconnect_mutex);
	return -ENODEV;
	}
	/* get the device information block from the interface */
	dev = usb_get_intfdata(interface);
	if (!dev) {
	mutex_unlock(&disconnect_mutex);
	return -ENODEV;
	}

	/* lock this device */
	down(&dev->sem);

	/* check if already open */
	if (dev->open) {

	/* already open, so fail */
	result = -EBUSY;

	} else {

	/* create a new image and check for success */
	result = idmouse_create_image (dev);
	if (result)
	goto error;

	/* increment our usage count for the driver */
	++dev->open;

	/* save our object in the file's private structure */
	file->private_data = dev;

	}

	error:

	/* unlock this device */
	up(&dev->sem);

	/* unlock the disconnect semaphore */
	mutex_unlock(&disconnect_mutex);
	return result;
	}

	static int idmouse_release(struct inode inode, struct file file)
	{
	struct usb_idmouse *dev;

	/* prevent a race condition with open() */
	mutex_lock(&disconnect_mutex);

	dev = (struct usb_idmouse *) file->private_data;

	if (dev == NULL) {
	mutex_unlock(&disconnect_mutex);
	return -ENODEV;
	}

	/* lock our device */
	down(&dev->sem);

	/* are we really open? */
	if (dev->open <= 0) {
	up(&dev->sem);
	mutex_unlock(&disconnect_mutex);
	return -ENODEV;
	}

	--dev->open;

	if (!dev->present) {
	/* the device was unplugged before the file was released */
	up(&dev->sem);
	idmouse_delete(dev);
	mutex_unlock(&disconnect_mutex);
	return 0;
	}

	up(&dev->sem);
	mutex_unlock(&disconnect_mutex);
	return 0;
	}

	static ssize_t idmouse_read(struct file file, char __user buffer, size_t count,
	loff_t * ppos)
	{
	struct usb_idmouse *dev;
	int result = 0;

	dev = (struct usb_idmouse *) file->private_data;

	/* lock this object */
	down (&dev->sem);

	/* verify that the device wasn't unplugged */
	if (!dev->present) {
	up (&dev->sem);
	return -ENODEV;
	}

	result = simple_read_from_buffer(buffer, count, ppos,
	dev->bulk_in_buffer, IMGSIZE);
	/* unlock the device */
	up(&dev->sem);
	return result;
	}

	static int idmouse_probe(struct usb_interface *interface,
	const struct usb_device_id *id)
	{
	struct usb_device *udev = interface_to_usbdev(interface);
	struct usb_idmouse *dev = NULL;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	int result;

	/* check if we have gotten the data or the hid interface */
	iface_desc = &interface->altsetting[0];
	if (iface_desc->desc.bInterfaceClass != 0x0A)
	return -ENODEV;

	/* allocate memory for our device state and initialize it */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (dev == NULL)
	return -ENOMEM;

	init_MUTEX(&dev->sem);
	dev->udev = udev;
	dev->interface = interface;

	/* set up the endpoint information - use only the first bulk-in endpoint */
	endpoint = &iface_desc->endpoint[0].desc;
	if (!dev->bulk_in_endpointAddr
	&& (endpoint->bEndpointAddress & USB_DIR_IN)
	&& ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
	USB_ENDPOINT_XFER_BULK)) {

	/* we found a bulk in endpoint */
	dev->orig_bi_size = le16_to_cpu(endpoint->wMaxPacketSize);
	dev->bulk_in_size = 0x200; /* works _much_ faster */
	dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
	dev->bulk_in_buffer =
	kmalloc(IMGSIZE + dev->bulk_in_size, GFP_KERNEL);

	if (!dev->bulk_in_buffer) {
	err("Unable to allocate input buffer.");
	idmouse_delete(dev);
	return -ENOMEM;
	}
	}

	if (!(dev->bulk_in_endpointAddr)) {
	err("Unable to find bulk-in endpoint.");
	idmouse_delete(dev);
	return -ENODEV;
	}
	/* allow device read, write and ioctl */
	dev->present = 1;

	/* we can register the device now, as it is ready */
	usb_set_intfdata(interface, dev);
	result = usb_register_dev(interface, &idmouse_class);
	if (result) {
	/* something prevented us from registering this device */
	err("Unble to allocate minor number.");
	usb_set_intfdata(interface, NULL);
	idmouse_delete(dev);
	return result;
	}

	/* be noisy */
	dev_info(&interface->dev,"%s now attached\n",DRIVER_DESC);

	return 0;
	}

	static void idmouse_disconnect(struct usb_interface *interface)
	{
	struct usb_idmouse *dev;

	/* prevent races with open() */
	mutex_lock(&disconnect_mutex);

	/* get device structure */
	dev = usb_get_intfdata(interface);
	usb_set_intfdata(interface, NULL);

	/* lock it */
	down(&dev->sem);

	/* give back our minor */
	usb_deregister_dev(interface, &idmouse_class);

	/* prevent device read, write and ioctl */
	dev->present = 0;

	/* unlock */
	up(&dev->sem);

	/* if the device is opened, idmouse_release will clean this up */
	if (!dev->open)
	idmouse_delete(dev);

	mutex_unlock(&disconnect_mutex);

	info("%s disconnected", DRIVER_DESC);
	}

	static int __init usb_idmouse_init(void)
	{
	int result;

	info(DRIVER_DESC " " DRIVER_VERSION);

	/* register this driver with the USB subsystem */
	result = usb_register(&idmouse_driver);
	if (result)
	err("Unable to register device (error %d).", result);

	return result;
	}

	static void __exit usb_idmouse_exit(void)
	{
	/* deregister this driver with the USB subsystem */
	usb_deregister(&idmouse_driver);
	}

	module_init(usb_idmouse_init);
	module_exit(usb_idmouse_exit);

	MODULE_AUTHOR(DRIVER_AUTHOR);
	MODULE_DESCRIPTION(DRIVER_DESC);
	MODULE_LICENSE("GPL");