[deliverable/linux.git] / drivers / usb / usb-skeleton.c

/*
 * USB Skeleton driver - 2.0
 *
 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
 *
 *	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, version 2.
 *
 * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c 
 * but has been rewritten to be easy to read and use, as no locks are now
 * needed anymore.
 *
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <asm/uaccess.h>
#include <linux/usb.h>


/* Define these values to match your devices */
#define USB_SKEL_VENDOR_ID	0xfff0
#define USB_SKEL_PRODUCT_ID	0xfff0

/* table of devices that work with this driver */
static struct usb_device_id skel_table [] = {
	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
	{ }					/* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, skel_table);


/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE	192

/* our private defines. if this grows any larger, use your own .h file */
#define MAX_TRANSFER		( PAGE_SIZE - 512 )
#define WRITES_IN_FLIGHT	8

/* Structure to hold all of our device specific stuff */
struct usb_skel {
	struct usb_device *	udev;			/* the usb device for this device */
	struct usb_interface *	interface;		/* the interface for this device */
	struct semaphore	limit_sem;		/* limiting the number of writes in progress */
	unsigned char *		bulk_in_buffer;		/* the buffer to receive data */
	size_t			bulk_in_size;		/* the size of the receive buffer */
	__u8			bulk_in_endpointAddr;	/* the address of the bulk in endpoint */
	__u8			bulk_out_endpointAddr;	/* the address of the bulk out endpoint */
	struct kref		kref;
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)

static struct usb_driver skel_driver;

static void skel_delete(struct kref *kref)
{	
	struct usb_skel *dev = to_skel_dev(kref);

	usb_put_dev(dev->udev);
	kfree (dev->bulk_in_buffer);
	kfree (dev);
}

static int skel_open(struct inode *inode, struct file *file)
{
	struct usb_skel *dev;
	struct usb_interface *interface;
	int subminor;
	int retval = 0;

	subminor = iminor(inode);

	interface = usb_find_interface(&skel_driver, subminor);
	if (!interface) {
		err ("%s - error, can't find device for minor %d",
		     __FUNCTION__, subminor);
		retval = -ENODEV;
		goto exit;
	}

	dev = usb_get_intfdata(interface);
	if (!dev) {
		retval = -ENODEV;
		goto exit;
	}

	/* increment our usage count for the device */
	kref_get(&dev->kref);

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

exit:
	return retval;
}

static int skel_release(struct inode *inode, struct file *file)
{
	struct usb_skel *dev;

	dev = (struct usb_skel *)file->private_data;
	if (dev == NULL)
		return -ENODEV;

	/* decrement the count on our device */
	kref_put(&dev->kref, skel_delete);
	return 0;
}

static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
{
	struct usb_skel *dev;
	int retval = 0;
	int bytes_read;

	dev = (struct usb_skel *)file->private_data;
	
	/* do a blocking bulk read to get data from the device */
	retval = usb_bulk_msg(dev->udev,
			      usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
			      dev->bulk_in_buffer,
			      min(dev->bulk_in_size, count),
			      &bytes_read, 10000);

	/* if the read was successful, copy the data to userspace */
	if (!retval) {
		if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
			retval = -EFAULT;
		else
			retval = bytes_read;
	}

	return retval;
}

static void skel_write_bulk_callback(struct urb *urb, struct pt_regs *regs)
{
	struct usb_skel *dev;

	dev = (struct usb_skel *)urb->context;

	/* sync/async unlink faults aren't errors */
	if (urb->status && 
	    !(urb->status == -ENOENT || 
	      urb->status == -ECONNRESET ||
	      urb->status == -ESHUTDOWN)) {
		dbg("%s - nonzero write bulk status received: %d",
		    __FUNCTION__, urb->status);
	}

	/* free up our allocated buffer */
	usb_buffer_free(urb->dev, urb->transfer_buffer_length, 
			urb->transfer_buffer, urb->transfer_dma);
	up(&dev->limit_sem);
}

static ssize_t skel_write(struct file *file, const char *user_buffer, size_t count, loff_t *ppos)
{
	struct usb_skel *dev;
	int retval = 0;
	struct urb *urb = NULL;
	char *buf = NULL;
	size_t writesize = min(count, MAX_TRANSFER);

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

	/* verify that we actually have some data to write */
	if (count == 0)
		goto exit;

	/* limit the number of URBs in flight to stop a user from using up all RAM */
	down (&dev->limit_sem);

	/* create a urb, and a buffer for it, and copy the data to the urb */
	urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!urb) {
		retval = -ENOMEM;
		goto error;
	}

	buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
	if (!buf) {
		retval = -ENOMEM;
		goto error;
	}

	if (copy_from_user(buf, user_buffer, writesize)) {
		retval = -EFAULT;
		goto error;
	}

	/* initialize the urb properly */
	usb_fill_bulk_urb(urb, dev->udev,
			  usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
			  buf, writesize, skel_write_bulk_callback, dev);
	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	/* send the data out the bulk port */
	retval = usb_submit_urb(urb, GFP_KERNEL);
	if (retval) {
		err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
		goto error;
	}

	/* release our reference to this urb, the USB core will eventually free it entirely */
	usb_free_urb(urb);

exit:
	return writesize;

error:
	usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
	usb_free_urb(urb);
	up(&dev->limit_sem);
	return retval;
}

static struct file_operations skel_fops = {
	.owner =	THIS_MODULE,
	.read =		skel_read,
	.write =	skel_write,
	.open =		skel_open,
	.release =	skel_release,
};

/* 
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with devfs and the driver core
 */
static struct usb_class_driver skel_class = {
	.name =		"skel%d",
	.fops =		&skel_fops,
	.minor_base =	USB_SKEL_MINOR_BASE,
};

static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
	struct usb_skel *dev = NULL;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	size_t buffer_size;
	int i;
	int retval = -ENOMEM;

	/* allocate memory for our device state and initialize it */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (dev == NULL) {
		err("Out of memory");
		goto error;
	}
	kref_init(&dev->kref);
	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);

	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	dev->interface = interface;

	/* set up the endpoint information */
	/* use only the first bulk-in and bulk-out endpoints */
	iface_desc = interface->cur_altsetting;
	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
		endpoint = &iface_desc->endpoint[i].desc;

		if (!dev->bulk_in_endpointAddr &&
		    ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
					== USB_DIR_IN) &&
		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
					== USB_ENDPOINT_XFER_BULK)) {
			/* we found a bulk in endpoint */
			buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
			dev->bulk_in_size = buffer_size;
			dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
			dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
			if (!dev->bulk_in_buffer) {
				err("Could not allocate bulk_in_buffer");
				goto error;
			}
		}

		if (!dev->bulk_out_endpointAddr &&
		    ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
					== USB_DIR_OUT) &&
		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
					== USB_ENDPOINT_XFER_BULK)) {
			/* we found a bulk out endpoint */
			dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
		}
	}
	if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
		err("Could not find both bulk-in and bulk-out endpoints");
		goto error;
	}

	/* save our data pointer in this interface device */
	usb_set_intfdata(interface, dev);

	/* we can register the device now, as it is ready */
	retval = usb_register_dev(interface, &skel_class);
	if (retval) {
		/* something prevented us from registering this driver */
		err("Not able to get a minor for this device.");
		usb_set_intfdata(interface, NULL);
		goto error;
	}

	/* let the user know what node this device is now attached to */
	info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
	return 0;

error:
	if (dev)
		kref_put(&dev->kref, skel_delete);
	return retval;
}

static void skel_disconnect(struct usb_interface *interface)
{
	struct usb_skel *dev;
	int minor = interface->minor;

	/* prevent skel_open() from racing skel_disconnect() */
	lock_kernel();

	dev = usb_get_intfdata(interface);
	usb_set_intfdata(interface, NULL);

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

	unlock_kernel();

	/* decrement our usage count */
	kref_put(&dev->kref, skel_delete);

	info("USB Skeleton #%d now disconnected", minor);
}

static struct usb_driver skel_driver = {
	.name =		"skeleton",
	.probe =	skel_probe,
	.disconnect =	skel_disconnect,
	.id_table =	skel_table,
};

static int __init usb_skel_init(void)
{
	int result;

	/* register this driver with the USB subsystem */
	result = usb_register(&skel_driver);
	if (result)
		err("usb_register failed. Error number %d", result);

	return result;
}

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

module_init (usb_skel_init);
module_exit (usb_skel_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* USB Skeleton driver - 2.0
	3	*
	4	* Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License as
	8	* published by the Free Software Foundation, version 2.
	9	*
	10	* This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
	11	* but has been rewritten to be easy to read and use, as no locks are now
	12	* needed anymore.
	13	*
	14	*/
	15
	16	#include <linux/config.h>
	17	#include <linux/kernel.h>
	18	#include <linux/errno.h>
	19	#include <linux/init.h>
	20	#include <linux/slab.h>
	21	#include <linux/module.h>
	22	#include <linux/kref.h>
	23	#include <asm/uaccess.h>
	24	#include <linux/usb.h>
	25
	26
	27	/* Define these values to match your devices */
	28	#define USB_SKEL_VENDOR_ID 0xfff0
	29	#define USB_SKEL_PRODUCT_ID 0xfff0
	30
	31	/* table of devices that work with this driver */
	32	static struct usb_device_id skel_table [] = {
	33	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
	34	{ } /* Terminating entry */
	35	};
	36	MODULE_DEVICE_TABLE (usb, skel_table);
	37
	38
	39	/* Get a minor range for your devices from the usb maintainer */
	40	#define USB_SKEL_MINOR_BASE 192
	41
ff906518 ON	42	/* our private defines. if this grows any larger, use your own .h file */
	43	#define MAX_TRANSFER ( PAGE_SIZE - 512 )
	44	#define WRITES_IN_FLIGHT 8
	45
1da177e4 LT	46	/* Structure to hold all of our device specific stuff */
	47	struct usb_skel {
	48	struct usb_device * udev; /* the usb device for this device */
	49	struct usb_interface * interface; /* the interface for this device */
ff906518	50	struct semaphore limit_sem; /* limiting the number of writes in progress */
1da177e4 LT	51	unsigned char * bulk_in_buffer; /* the buffer to receive data */
	52	size_t bulk_in_size; /* the size of the receive buffer */
	53	__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
	54	__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
	55	struct kref kref;
	56	};
	57	#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
	58
	59	static struct usb_driver skel_driver;
	60
	61	static void skel_delete(struct kref *kref)
	62	{
	63	struct usb_skel *dev = to_skel_dev(kref);
	64
	65	usb_put_dev(dev->udev);
	66	kfree (dev->bulk_in_buffer);
	67	kfree (dev);
	68	}
	69
	70	static int skel_open(struct inode inode, struct file file)
	71	{
	72	struct usb_skel *dev;
	73	struct usb_interface *interface;
	74	int subminor;
	75	int retval = 0;
	76
	77	subminor = iminor(inode);
	78
	79	interface = usb_find_interface(&skel_driver, subminor);
	80	if (!interface) {
	81	err ("%s - error, can't find device for minor %d",
	82	__FUNCTION__, subminor);
	83	retval = -ENODEV;
	84	goto exit;
	85	}
	86
	87	dev = usb_get_intfdata(interface);
	88	if (!dev) {
	89	retval = -ENODEV;
	90	goto exit;
	91	}
	92
	93	/* increment our usage count for the device */
	94	kref_get(&dev->kref);
	95
	96	/* save our object in the file's private structure */
	97	file->private_data = dev;
	98
	99	exit:
	100	return retval;
	101	}
	102
	103	static int skel_release(struct inode inode, struct file file)
	104	{
	105	struct usb_skel *dev;
	106
	107	dev = (struct usb_skel *)file->private_data;
	108	if (dev == NULL)
	109	return -ENODEV;
	110
	111	/* decrement the count on our device */
	112	kref_put(&dev->kref, skel_delete);
	113	return 0;
	114	}
115
116	static ssize_t skel_read(struct file file, char buffer, size_t count, loff_t *ppos)
117	{
118	struct usb_skel *dev;
119	int retval = 0;
120	int bytes_read;
121
122	dev = (struct usb_skel *)file->private_data;
123
124	/* do a blocking bulk read to get data from the device */
125	retval = usb_bulk_msg(dev->udev,
126	usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
127	dev->bulk_in_buffer,
128	min(dev->bulk_in_size, count),
129	&bytes_read, 10000);
130
131	/* if the read was successful, copy the data to userspace */
132	if (!retval) {
133	if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
134	retval = -EFAULT;
135	else
136	retval = bytes_read;
137	}
138
139	return retval;
140	}
141
142	static void skel_write_bulk_callback(struct urb urb, struct pt_regs regs)
143	{
144	struct usb_skel *dev;
145
146	dev = (struct usb_skel *)urb->context;
147
148	/* sync/async unlink faults aren't errors */
149	if (urb->status &&
150	!(urb->status == -ENOENT \|\|
151	urb->status == -ECONNRESET \|\|
152	urb->status == -ESHUTDOWN)) {
153	dbg("%s - nonzero write bulk status received: %d",
154	__FUNCTION__, urb->status);
155	}
156
157	/* free up our allocated buffer */
158	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
159	urb->transfer_buffer, urb->transfer_dma);
ff906518	160	up(&dev->limit_sem);
1da177e4 LT	161	}
	162
	163	static ssize_t skel_write(struct file file, const char user_buffer, size_t count, loff_t *ppos)
	164	{
	165	struct usb_skel *dev;
	166	int retval = 0;
	167	struct urb *urb = NULL;
	168	char *buf = NULL;
cb5b3f69	169	size_t writesize = min(count, MAX_TRANSFER);
1da177e4 LT	170
	171	dev = (struct usb_skel *)file->private_data;
	172
	173	/* verify that we actually have some data to write */
	174	if (count == 0)
	175	goto exit;
	176
ff906518 ON	177	/* limit the number of URBs in flight to stop a user from using up all RAM */
	178	down (&dev->limit_sem);
	179
1da177e4 LT	180	/* create a urb, and a buffer for it, and copy the data to the urb */
	181	urb = usb_alloc_urb(0, GFP_KERNEL);
	182	if (!urb) {
	183	retval = -ENOMEM;
	184	goto error;
	185	}
	186
ff906518	187	buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
1da177e4 LT	188	if (!buf) {
	189	retval = -ENOMEM;
	190	goto error;
	191	}
	192
ff906518	193	if (copy_from_user(buf, user_buffer, writesize)) {
1da177e4 LT	194	retval = -EFAULT;
	195	goto error;
	196	}
	197
	198	/* initialize the urb properly */
	199	usb_fill_bulk_urb(urb, dev->udev,
	200	usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
ff906518	201	buf, writesize, skel_write_bulk_callback, dev);
1da177e4 LT	202	urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP;
	203
	204	/* send the data out the bulk port */
	205	retval = usb_submit_urb(urb, GFP_KERNEL);
	206	if (retval) {
	207	err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
	208	goto error;
	209	}
	210
	211	/* release our reference to this urb, the USB core will eventually free it entirely */
	212	usb_free_urb(urb);
	213
	214	exit:
ff906518	215	return writesize;
1da177e4 LT	216
1da177e4 LT	217	error:
ff906518	218	usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
1da177e4	219	usb_free_urb(urb);
ff906518	220	up(&dev->limit_sem);
1da177e4 LT	221	return retval;
	222	}
	223
	224	static struct file_operations skel_fops = {
	225	.owner = THIS_MODULE,
	226	.read = skel_read,
	227	.write = skel_write,
	228	.open = skel_open,
	229	.release = skel_release,
	230	};
	231
	232	/*
	233	* usb class driver info in order to get a minor number from the usb core,
	234	* and to have the device registered with devfs and the driver core
	235	*/
	236	static struct usb_class_driver skel_class = {
d6e5bcf4	237	.name = "skel%d",
1da177e4	238	.fops = &skel_fops,
1da177e4 LT	239	.minor_base = USB_SKEL_MINOR_BASE,
	240	};
	241
	242	static int skel_probe(struct usb_interface interface, const struct usb_device_id id)
	243	{
	244	struct usb_skel *dev = NULL;
	245	struct usb_host_interface *iface_desc;
	246	struct usb_endpoint_descriptor *endpoint;
	247	size_t buffer_size;
	248	int i;
	249	int retval = -ENOMEM;
	250
	251	/* allocate memory for our device state and initialize it */
ff906518	252	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1da177e4 LT	253	if (dev == NULL) {
	254	err("Out of memory");
	255	goto error;
	256	}
1da177e4	257	kref_init(&dev->kref);
ff906518	258	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
1da177e4 LT	259
	260	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	261	dev->interface = interface;
	262
	263	/* set up the endpoint information */
	264	/* use only the first bulk-in and bulk-out endpoints */
	265	iface_desc = interface->cur_altsetting;
	266	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
	267	endpoint = &iface_desc->endpoint[i].desc;
	268
	269	if (!dev->bulk_in_endpointAddr &&
6b216df8 CC	270	((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
6b216df8 CC	271	== USB_DIR_IN) &&
1da177e4 LT	272	((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
	273	== USB_ENDPOINT_XFER_BULK)) {
	274	/* we found a bulk in endpoint */
	275	buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
	276	dev->bulk_in_size = buffer_size;
	277	dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
	278	dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
	279	if (!dev->bulk_in_buffer) {
	280	err("Could not allocate bulk_in_buffer");
	281	goto error;
	282	}
	283	}
	284
	285	if (!dev->bulk_out_endpointAddr &&
6b216df8 CC	286	((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
6b216df8 CC	287	== USB_DIR_OUT) &&
1da177e4 LT	288	((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
	289	== USB_ENDPOINT_XFER_BULK)) {
	290	/* we found a bulk out endpoint */
	291	dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
	292	}
	293	}
	294	if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
	295	err("Could not find both bulk-in and bulk-out endpoints");
	296	goto error;
	297	}
	298
	299	/* save our data pointer in this interface device */
	300	usb_set_intfdata(interface, dev);
	301
	302	/* we can register the device now, as it is ready */
	303	retval = usb_register_dev(interface, &skel_class);
	304	if (retval) {
	305	/* something prevented us from registering this driver */
	306	err("Not able to get a minor for this device.");
	307	usb_set_intfdata(interface, NULL);
	308	goto error;
	309	}
	310
	311	/* let the user know what node this device is now attached to */
	312	info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
	313	return 0;
	314
	315	error:
	316	if (dev)
	317	kref_put(&dev->kref, skel_delete);
	318	return retval;
	319	}
	320
	321	static void skel_disconnect(struct usb_interface *interface)
	322	{
	323	struct usb_skel *dev;
	324	int minor = interface->minor;
	325
	326	/* prevent skel_open() from racing skel_disconnect() */
	327	lock_kernel();
	328
	329	dev = usb_get_intfdata(interface);
	330	usb_set_intfdata(interface, NULL);
	331
	332	/* give back our minor */
	333	usb_deregister_dev(interface, &skel_class);
	334
	335	unlock_kernel();
	336
	337	/* decrement our usage count */
	338	kref_put(&dev->kref, skel_delete);
	339
	340	info("USB Skeleton #%d now disconnected", minor);
	341	}
	342
	343	static struct usb_driver skel_driver = {
1da177e4 LT	344	.name = "skeleton",
	345	.probe = skel_probe,
	346	.disconnect = skel_disconnect,
	347	.id_table = skel_table,
	348	};
	349
	350	static int __init usb_skel_init(void)
	351	{
	352	int result;
	353
	354	/* register this driver with the USB subsystem */
	355	result = usb_register(&skel_driver);
	356	if (result)
	357	err("usb_register failed. Error number %d", result);
	358
	359	return result;
	360	}
	361
	362	static void __exit usb_skel_exit(void)
	363	{
	364	/* deregister this driver with the USB subsystem */
	365	usb_deregister(&skel_driver);
	366	}
	367
	368	module_init (usb_skel_init);
	369	module_exit (usb_skel_exit);
	370
	371	MODULE_LICENSE("GPL");