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/*
 *  Copyright (c) 2001 Paul Stewart
 *  Copyright (c) 2001 Vojtech Pavlik
 *
 *  HID char devices, giving access to raw HID device events.
 *
 */
 
/*
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Should you need to contact me, the author, you can do so either by
 * e-mail - mail your message to Paul Stewart <stewart@wetlogic.net>
 */
 
#define HIDDEV_MINOR_BASE	96
#define HIDDEV_MINORS		16
#define HIDDEV_BUFFER_SIZE	64
 
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/input.h>
#include <linux/usb.h>
#include "hid.h"
#include <linux/hiddev.h>
 
struct hiddev {
	int exist;
	int open;
	int minor;
	wait_queue_head_t wait;
	devfs_handle_t devfs;
	struct hid_device *hid;
	struct hiddev_list *list;
};
 
struct hiddev_list {
	struct hiddev_usage_ref buffer[HIDDEV_BUFFER_SIZE];
	int head;
	int tail;
	unsigned flags;
	struct fasync_struct *fasync;
	struct hiddev *hiddev;
	struct hiddev_list *next;
};
 
static struct hiddev *hiddev_table[HIDDEV_MINORS];
static devfs_handle_t hiddev_devfs_handle;
 
/*
 * Find a report, given the report's type and ID.  The ID can be specified
 * indirectly by REPORT_ID_FIRST (which returns the first report of the given
 * type) or by (REPORT_ID_NEXT | old_id), which returns the next report of the
 * given type which follows old_id.
 */
static struct hid_report *
hiddev_lookup_report(struct hid_device *hid, struct hiddev_report_info *rinfo)
{
	unsigned flags = rinfo->report_id & ~HID_REPORT_ID_MASK;
	struct hid_report_enum *report_enum = NULL;
	struct list_head *list;
 
	if (rinfo->report_type < HID_REPORT_TYPE_MIN ||
	    rinfo->report_type > HID_REPORT_TYPE_MAX) return NULL;
 
	report_enum = hid->report_enum +
		(rinfo->report_type - HID_REPORT_TYPE_MIN);
 
	switch (flags) {
	case 0: /* Nothing to do -- report_id is already set correctly */
		break;
 
	case HID_REPORT_ID_FIRST:
		list = report_enum->report_list.next;
		if (list == &report_enum->report_list) return NULL;
		rinfo->report_id = ((struct hid_report *) list)->id;
		break;
 
	case HID_REPORT_ID_NEXT:
		list = (struct list_head *)
			report_enum->report_id_hash[rinfo->report_id &
						    HID_REPORT_ID_MASK];
		if (list == NULL) return NULL;
		list = list->next;
		if (list == &report_enum->report_list) return NULL;
		rinfo->report_id = ((struct hid_report *) list)->id;
		break;
 
	default:
		return NULL;
	}
 
	return report_enum->report_id_hash[rinfo->report_id];
}
 
/*
 * Perform an exhaustive search of the report table for a usage, given its
 * type and usage id.
 */
static struct hid_field *
hiddev_lookup_usage(struct hid_device *hid, struct hiddev_usage_ref *uref)
{
	int i, j;
	struct hid_report *report;
	struct hid_report_enum *report_enum;
	struct list_head *list;
	struct hid_field *field;
 
	if (uref->report_type < HID_REPORT_TYPE_MIN ||
	    uref->report_type > HID_REPORT_TYPE_MAX) return NULL;
 
	report_enum = hid->report_enum +
		(uref->report_type - HID_REPORT_TYPE_MIN);
	list = report_enum->report_list.next;
	while (list != &report_enum->report_list) {
		report = (struct hid_report *) list;
		for (i = 0; i < report->maxfield; i++) {
			field = report->field[i];
			for (j = 0; j < field->maxusage; j++) {
				if (field->usage[j].hid == uref->usage_code) {
					uref->report_id = report->id;
					uref->field_index = i;
					uref->usage_index = j;
					return field;
				}
			}
		}
		list = list->next;
	}
 
	return NULL;
}
 
static void hiddev_send_event(struct hid_device *hid,
			      struct hiddev_usage_ref *uref)
{
	struct hiddev *hiddev = hid->hiddev;
	struct hiddev_list *list = hiddev->list;
 
	while (list) {
		if (uref->field_index != HID_FIELD_INDEX_NONE ||
		    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
			list->buffer[list->head] = *uref;
			list->head = (list->head + 1) & 
				(HIDDEV_BUFFER_SIZE - 1);
			kill_fasync(&list->fasync, SIGIO, POLL_IN);
		}
 
		list = list->next;
	}
 
	wake_up_interruptible(&hiddev->wait);
}
 
/*
 * This is where hid.c calls into hiddev to pass an event that occurred over
 * the interrupt pipe
 */
void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
		      struct hid_usage *usage, __s32 value)
{
	unsigned type = field->report_type;
	struct hiddev_usage_ref uref;
 
	uref.report_type = 
	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT : 
	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE:0));
	uref.report_id = field->report->id;
	uref.field_index = field->index;
	uref.usage_index = (usage - field->usage);
	uref.usage_code = usage->hid;
	uref.value = value;
 
	hiddev_send_event(hid, &uref);
}
 
 
void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
{
	unsigned type = report->type;
	struct hiddev_usage_ref uref;
 
	memset(&uref, 0, sizeof(uref));
	uref.report_type = 
	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT : 
	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE:0));
	uref.report_id = report->id;
	uref.field_index = HID_FIELD_INDEX_NONE;
 
	hiddev_send_event(hid, &uref);
}
 
/*
 * fasync file op
 */
static int hiddev_fasync(int fd, struct file *file, int on)
{
	int retval;
	struct hiddev_list *list = file->private_data;
	retval = fasync_helper(fd, file, on, &list->fasync);
	return retval < 0 ? retval : 0;
}
 
/*
 * De-allocate a hiddev structure
 */
static void hiddev_cleanup(struct hiddev *hiddev)
{
	devfs_unregister(hiddev->devfs);
	hiddev_table[hiddev->minor] = NULL;
	kfree(hiddev);
}
 
/*
 * release file op
 */
static int hiddev_release(struct inode * inode, struct file * file)
{
	struct hiddev_list *list = file->private_data;
	struct hiddev_list **listptr;
 
	listptr = &list->hiddev->list;
	hiddev_fasync(-1, file, 0);
 
	while (*listptr && (*listptr != list))
		listptr = &((*listptr)->next);
	*listptr = (*listptr)->next;
 
	if (!--list->hiddev->open) {
		if (list->hiddev->exist) 
			hid_close(list->hiddev->hid);
		else
			hiddev_cleanup(list->hiddev);
	}
 
	kfree(list);
 
	return 0;
}
 
/*
 * open file op
 */
static int hiddev_open(struct inode * inode, struct file * file) {
	struct hiddev_list *list;
 
	int i = MINOR(inode->i_rdev) - HIDDEV_MINOR_BASE;
 
	if (i >= HIDDEV_MINORS || !hiddev_table[i])
		return -ENODEV;
 
	if (!(list = kmalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
		return -ENOMEM;
	memset(list, 0, sizeof(struct hiddev_list));
 
	list->hiddev = hiddev_table[i];
	list->next = hiddev_table[i]->list;
	hiddev_table[i]->list = list;
 
	file->private_data = list;
 
	if (!list->hiddev->open++)
		if (list->hiddev->exist)
			hid_open(hiddev_table[i]->hid);
 
	return 0;
}
 
/*
 * "write" file op
 */
static ssize_t hiddev_write(struct file * file, const char * buffer,
			    size_t count, loff_t *ppos)
{
	return -EINVAL;
}
 
/*
 * "read" file op
 */
static ssize_t hiddev_read(struct file * file, char * buffer, size_t count,
			   loff_t *ppos)
{
	DECLARE_WAITQUEUE(wait, current);
	struct hiddev_list *list = file->private_data;
	int event_size;
	int retval = 0;
 
	event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
		sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
 
	if (count < event_size) return 0;
 
	while (retval == 0) {
		if (list->head == list->tail) {
			add_wait_queue(&list->hiddev->wait, &wait);
			set_current_state(TASK_INTERRUPTIBLE);
 
			while (list->head == list->tail) {
				if (file->f_flags & O_NONBLOCK) {
					retval = -EAGAIN;
					break;
				}
				if (signal_pending(current)) {
					retval = -ERESTARTSYS;
					break;
				}
				if (!list->hiddev->exist) {
					retval = -EIO;
					break;
				}
 
				schedule();
			}
 
			set_current_state(TASK_RUNNING);
			remove_wait_queue(&list->hiddev->wait, &wait);
		}
 
		if (retval)
			return retval;
 
		while (list->head != list->tail && 
		       retval + event_size <= count) {
			if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
				if (list->buffer[list->tail].field_index !=
				    HID_FIELD_INDEX_NONE) {
					struct hiddev_event event;
					event.hid = list->buffer[list->tail].usage_code;
					event.value = list->buffer[list->tail].value;
					if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event)))
						return -EFAULT;
					retval += sizeof(struct hiddev_event);
				}
			} else {
				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
				    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
					if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref)))
						return -EFAULT;
					retval += sizeof(struct hiddev_usage_ref);
				}
			}
			list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
		}
 
	}
 
	return retval;
}
 
/*
 * "poll" file op
 * No kernel lock - fine
 */
static unsigned int hiddev_poll(struct file *file, poll_table *wait)
{
	struct hiddev_list *list = file->private_data;
	poll_wait(file, &list->hiddev->wait, wait);
	if (list->head != list->tail)
		return POLLIN | POLLRDNORM;
	if (!list->hiddev->exist)
		return POLLERR | POLLHUP;
	return 0;
}
 
#define GET_TIMEOUT 3
#define SET_TIMEOUT 3
 
/*
 * "ioctl" file op
 */
static int hiddev_ioctl(struct inode *inode, struct file *file,
			unsigned int cmd, unsigned long arg)
{
	struct hiddev_list *list = file->private_data;
	struct hiddev *hiddev = list->hiddev;
	struct hid_device *hid = hiddev->hid;
	struct usb_device *dev = hid->dev;
	struct hiddev_collection_info cinfo;
	struct hiddev_report_info rinfo;
	struct hiddev_field_info finfo;
	struct hiddev_usage_ref_multi uref_multi;
	struct hiddev_usage_ref *uref = &uref_multi.uref;
	struct hiddev_devinfo dinfo;
	struct hid_report *report;
	struct hid_field *field;
	int i;
 
	if (!hiddev->exist) return -EIO;
 
	switch (cmd) {
 
	case HIDIOCGVERSION:
		return put_user(HID_VERSION, (int *) arg);
 
	case HIDIOCAPPLICATION:
		if (arg < 0 || arg >= hid->maxapplication)
			return -EINVAL;
 
		for (i = 0; i < hid->maxcollection; i++)
			if (hid->collection[i].type == 
			    HID_COLLECTION_APPLICATION && arg-- == 0)
				break;
 
		if (i == hid->maxcollection)
			return -EINVAL;
 
		return hid->collection[i].usage;
 
	case HIDIOCGDEVINFO:
		dinfo.bustype = BUS_USB;
		dinfo.busnum = dev->bus->busnum;
		dinfo.devnum = dev->devnum;
		dinfo.ifnum = hid->ifnum;
		dinfo.vendor = dev->descriptor.idVendor;
		dinfo.product = dev->descriptor.idProduct;
		dinfo.version = dev->descriptor.bcdDevice;
		dinfo.num_applications = hid->maxapplication;
		return copy_to_user((void *) arg, &dinfo, sizeof(dinfo));
 
	case HIDIOCGFLAG:
		return put_user(list->flags, (int *) arg);
 
	case HIDIOCSFLAG:
		{
			int newflags;
			if (get_user(newflags, (int *) arg))
				return -EFAULT;
 
			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
			     (newflags & HIDDEV_FLAG_UREF) == 0))
				return -EINVAL;
 
			list->flags = newflags;
 
			return 0;
		}
 
	case HIDIOCGSTRING:
		{
			int idx, len;
			char *buf;
 
			if (get_user(idx, (int *) arg))
				return -EFAULT;
 
			if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
				return -ENOMEM;
 
			if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
				kfree(buf);
				return -EINVAL;
			}
 
			if (copy_to_user((void *) (arg+sizeof(int)), buf, len+1)) {
				kfree(buf);
				return -EFAULT;
			}
 
			kfree(buf);
 
			return len;
		}
 
	case HIDIOCINITREPORT:
		hid_init_reports(hid);
 
		return 0;
 
	case HIDIOCGREPORT:
		if (copy_from_user(&rinfo, (void *) arg, sizeof(rinfo)))
			return -EFAULT;
 
		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
			return -EINVAL;
 
		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;
 
		hid_read_report(hid, report);
 
		return 0;
 
	case HIDIOCSREPORT:
		if (copy_from_user(&rinfo, (void *) arg, sizeof(rinfo)))
			return -EFAULT;
 
		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
			return -EINVAL;
 
		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;
 
		hid_write_report(hid, report);
 
		return 0;
 
	case HIDIOCGREPORTINFO:
		if (copy_from_user(&rinfo, (void *) arg, sizeof(rinfo)))
			return -EFAULT;
 
		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;
 
		rinfo.num_fields = report->maxfield;
 
		return copy_to_user((void *) arg, &rinfo, sizeof(rinfo));
 
	case HIDIOCGFIELDINFO:
		if (copy_from_user(&finfo, (void *) arg, sizeof(finfo)))
			return -EFAULT;
		rinfo.report_type = finfo.report_type;
		rinfo.report_id = finfo.report_id;
		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;
 
		if (finfo.field_index >= report->maxfield)
			return -EINVAL;
 
		field = report->field[finfo.field_index];
		memset(&finfo, 0, sizeof(finfo));
		finfo.report_type = rinfo.report_type;
		finfo.report_id = rinfo.report_id;
		finfo.field_index = field->report_count - 1;
		finfo.maxusage = field->maxusage;
		finfo.flags = field->flags;
		finfo.physical = field->physical;
		finfo.logical = field->logical;
		finfo.application = field->application;
		finfo.logical_minimum = field->logical_minimum;
		finfo.logical_maximum = field->logical_maximum;
		finfo.physical_minimum = field->physical_minimum;
		finfo.physical_maximum = field->physical_maximum;
		finfo.unit_exponent = field->unit_exponent;
		finfo.unit = field->unit;
 
		return copy_to_user((void *) arg, &finfo, sizeof(finfo));
 
	case HIDIOCGUCODE:
		if (copy_from_user(uref, (void *) arg, sizeof(*uref)))
			return -EFAULT;
 
		rinfo.report_type = uref->report_type;
		rinfo.report_id = uref->report_id;
		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;
 
		if (uref->field_index >= report->maxfield)
			return -EINVAL;
 
		field = report->field[uref->field_index];
		if (uref->usage_index >= field->maxusage)
			return -EINVAL;
 
		uref->usage_code = field->usage[uref->usage_index].hid;
 
		return copy_to_user((void *) arg, uref, sizeof(*uref));
 
	case HIDIOCGUSAGE:
	case HIDIOCSUSAGE:
	case HIDIOCGUSAGES:
	case HIDIOCSUSAGES:
	case HIDIOCGCOLLECTIONINDEX:
		if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
			if (copy_from_user(&uref_multi, (void *) arg, 
					   sizeof(uref_multi)))
				return -EFAULT;
		} else {
			if (copy_from_user(uref, (void *) arg, sizeof(*uref)))
				return -EFAULT;
		}
 
		if (cmd != HIDIOCGUSAGE && 
		    cmd != HIDIOCGUSAGES &&
		    uref->report_type == HID_REPORT_TYPE_INPUT)
			return -EINVAL;
 
		if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
			field = hiddev_lookup_usage(hid, uref);
			if (field == NULL)
				return -EINVAL;
		} else {
			rinfo.report_type = uref->report_type;
			rinfo.report_id = uref->report_id;
			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
				return -EINVAL;
 
			if (uref->field_index >= report->maxfield)
				return -EINVAL;
 
			field = report->field[uref->field_index];
			if (uref->usage_index >= field->maxusage)
				return -EINVAL;
 
			if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
				if (uref_multi.num_values >= HID_MAX_USAGES || 
				    uref->usage_index >= field->maxusage || 
				   (uref->usage_index + uref_multi.num_values) >= field->maxusage)
					return -EINVAL;
			}
		}
 
		switch (cmd) {
		case HIDIOCGUSAGE:
			uref->value = field->value[uref->usage_index];
			return copy_to_user((void *) arg, uref, sizeof(*uref));
 
		case HIDIOCSUSAGE:
			field->value[uref->usage_index] = uref->value;
			return 0;
 
		case HIDIOCGCOLLECTIONINDEX:
			return field->usage[uref->usage_index].collection_index;
		case HIDIOCGUSAGES:
			for (i = 0; i < uref_multi.num_values; i++)
				uref_multi.values[i] = 
				    field->value[uref->usage_index + i];
			if (copy_to_user((void *) arg, &uref_multi, 
					 sizeof(uref_multi)))
				return -EFAULT;
			return 0;
		case HIDIOCSUSAGES:
			for (i = 0; i < uref_multi.num_values; i++)
				field->value[uref->usage_index + i] = 
				    uref_multi.values[i];
			return 0;
		}
		break;
 
	case HIDIOCGCOLLECTIONINFO:
		if (copy_from_user(&cinfo, (void *) arg, sizeof(cinfo)))
			return -EFAULT;
 
		if (cinfo.index >= hid->maxcollection)
			return -EINVAL;
 
		cinfo.type = hid->collection[cinfo.index].type;
		cinfo.usage = hid->collection[cinfo.index].usage;
		cinfo.level = hid->collection[cinfo.index].level;
 
		return copy_to_user((void *) arg, &cinfo, sizeof(cinfo));
 
	default:
 
		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
			return -EINVAL;
 
		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
			int len;
			if (!hid->name) return 0;
			len = strlen(hid->name) + 1;
			if (len > _IOC_SIZE(cmd)) len = _IOC_SIZE(cmd);
			return copy_to_user((char *) arg, hid->name, len) ?
				-EFAULT : len;
		}
	}
	return -EINVAL;
}
 
static struct file_operations hiddev_fops = {
	owner:		THIS_MODULE,
	read:		hiddev_read,
	write:		hiddev_write,
	poll:		hiddev_poll,
	open:		hiddev_open,
	release:	hiddev_release,
	ioctl:		hiddev_ioctl,
	fasync:		hiddev_fasync,
};
 
/*
 * This is where hid.c calls us to connect a hid device to the hiddev driver
 */
int hiddev_connect(struct hid_device *hid)
{
	struct hiddev *hiddev;
	int minor, i;
	char devfs_name[16];
 
 
 
	if ((hid->quirks & HID_QUIRK_HIDDEV) == 0) {
		for (i = 0; i < hid->maxcollection; i++)
			if (hid->collection[i].type == 
			    HID_COLLECTION_APPLICATION &&
			    !IS_INPUT_APPLICATION(hid->collection[i].usage))
				break;
 
		if (i == hid->maxcollection)
			return -1;
	}
 
	for (minor = 0; minor < HIDDEV_MINORS && hiddev_table[minor]; minor++);
	if (minor == HIDDEV_MINORS) {
		printk(KERN_ERR "hiddev: no more free hiddev devices\n");
		return -1;
	}
 
	if (!(hiddev = kmalloc(sizeof(struct hiddev), GFP_KERNEL)))
		return -1;
	memset(hiddev, 0, sizeof(struct hiddev));
 
	init_waitqueue_head(&hiddev->wait);
 
	hiddev->minor = minor;
	hiddev_table[minor] = hiddev;
 
	hiddev->hid = hid;
	hiddev->exist = 1;
 
	sprintf(devfs_name, "hiddev%d", minor);
	hiddev->devfs = devfs_register(hiddev_devfs_handle, devfs_name,
				       DEVFS_FL_DEFAULT, USB_MAJOR,
				       minor + HIDDEV_MINOR_BASE,
				       S_IFCHR | S_IRUGO | S_IWUSR,
				       &hiddev_fops, NULL);
	hid->minor = minor;
	hid->hiddev = hiddev;
 
	return 0;
}
 
/*
 * This is where hid.c calls us to disconnect a hiddev device from the
 * corresponding hid device (usually because the usb device has disconnected)
 */
void hiddev_disconnect(struct hid_device *hid)
{
	struct hiddev *hiddev = hid->hiddev;
 
	hiddev->exist = 0;
 
	if (hiddev->open) {
		hid_close(hiddev->hid);
		wake_up_interruptible(&hiddev->wait);
	} else {
		hiddev_cleanup(hiddev);
	}
}
 
/* Currently this driver is a USB driver.  It's not a conventional one in
 * the sense that it doesn't probe at the USB level.  Instead it waits to
 * be connected by HID through the hiddev_connect / hiddev_disconnect
 * routines.  The reason to register as a USB device is to gain part of the
 * minor number space from the USB major.
 *
 * In theory, should the HID code be generalized to more than one physical
 * medium (say, IEEE 1384), this driver will probably need to register its
 * own major number, and in doing so, no longer need to register with USB.
 * At that point the probe routine and hiddev_driver struct below will no
 * longer be useful.
 */
 
 
/* We never attach in this manner, and rely on HID to connect us.  This
 * is why there is no disconnect routine defined in the usb_driver either.
 */
static void *hiddev_usbd_probe(struct usb_device *dev, unsigned int ifnum,
			  const struct usb_device_id *hiddev_info)
{
	return NULL;
}
 
 
static /* const */ struct usb_driver hiddev_driver = {
	name:	"hiddev",
	probe:	hiddev_usbd_probe,
	fops:	&hiddev_fops,
	minor:	HIDDEV_MINOR_BASE
};
 
int __init hiddev_init(void)
{
	hiddev_devfs_handle =
		devfs_mk_dir(devfs_find_handle(NULL, "usb", 0, 0, 0, 0), "hid", NULL);
	usb_register(&hiddev_driver);
	return 0;
}
 
void __exit hiddev_exit(void)
{
	devfs_unregister(hiddev_devfs_handle);
	usb_deregister(&hiddev_driver);
}