android_kernel_xiaomi_sm8350/drivers/usb/input/hiddev.c
Stefan Nickl 010988e888 Input: HIDDEV - make HIDIOCSREPORT wait IO completion
When trying to make the hiddev driver issue several Set_Report control
transfers to a custom device with 2.6.13-rc6, only the first transfer in a
row is carried out, while others immediately following it are silently
dropped.

This happens where hid_submit_report() (in hid-core.c) tests for
HID_CTRL_RUNNING, which seems to be still set because the first transfer is
not finished yet.

As a workaround, inserting a delay between the two calls to
ioctl(HIDIOCSREPORT) in userspace "solves" the problem.  The
straightforward fix is to add a call to hid_wait_io() to the implementation
of HIDIOCSREPORT (in hiddev.c), just like for HIDIOCGREPORT.  Works fine
for me.

Apparently, this issue has some history:
http://marc.theaimsgroup.com/?l=linux-usb-users&m=111100670105558&w=2

Signed-off-by: Stefan Nickl <Stefan.Nickl@kontron.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2005-09-05 01:57:46 -05:00

846 lines
21 KiB
C

/*
* 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>
*/
#include <linux/config.h>
#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>
#include <linux/devfs_fs_kernel.h>
#ifdef CONFIG_USB_DYNAMIC_MINORS
#define HIDDEV_MINOR_BASE 0
#define HIDDEV_MINORS 256
#else
#define HIDDEV_MINOR_BASE 96
#define HIDDEV_MINORS 16
#endif
#define HIDDEV_BUFFER_SIZE 64
struct hiddev {
int exist;
int open;
wait_queue_head_t wait;
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];
/*
* 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;
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 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_for_each_entry(report, &report_enum->report_list, 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;
}
}
}
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, struct pt_regs *regs)
{
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;
}
/*
* 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
kfree(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 = iminor(inode) - 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 __user * buffer, size_t count, loff_t *ppos)
{
return -EINVAL;
}
/*
* "read" file op
*/
static ssize_t hiddev_read(struct file * file, char __user * 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;
}
/*
* "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=NULL;
struct hiddev_usage_ref *uref;
struct hiddev_devinfo dinfo;
struct hid_report *report;
struct hid_field *field;
void __user *user_arg = (void __user *)arg;
int i;
if (!hiddev->exist)
return -EIO;
switch (cmd) {
case HIDIOCGVERSION:
return put_user(HID_VERSION, (int __user *)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 = le16_to_cpu(dev->descriptor.idVendor);
dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
dinfo.num_applications = hid->maxapplication;
if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
return -EFAULT;
return 0;
case HIDIOCGFLAG:
if (put_user(list->flags, (int __user *)arg))
return -EFAULT;
return 0;
case HIDIOCSFLAG:
{
int newflags;
if (get_user(newflags, (int __user *)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 __user *)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(user_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, user_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_submit_report(hid, report, USB_DIR_IN);
hid_wait_io(hid);
return 0;
case HIDIOCSREPORT:
if (copy_from_user(&rinfo, user_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_submit_report(hid, report, USB_DIR_OUT);
hid_wait_io(hid);
return 0;
case HIDIOCGREPORTINFO:
if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
return -EFAULT;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
return -EINVAL;
rinfo.num_fields = report->maxfield;
if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
return -EFAULT;
return 0;
case HIDIOCGFIELDINFO:
if (copy_from_user(&finfo, user_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;
if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
return -EFAULT;
return 0;
case HIDIOCGUCODE:
uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
if (!uref_multi)
return -ENOMEM;
uref = &uref_multi->uref;
if (copy_from_user(uref, user_arg, sizeof(*uref)))
goto fault;
rinfo.report_type = uref->report_type;
rinfo.report_id = uref->report_id;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
goto inval;
if (uref->field_index >= report->maxfield)
goto inval;
field = report->field[uref->field_index];
if (uref->usage_index >= field->maxusage)
goto inval;
uref->usage_code = field->usage[uref->usage_index].hid;
if (copy_to_user(user_arg, uref, sizeof(*uref)))
goto fault;
kfree(uref_multi);
return 0;
case HIDIOCGUSAGE:
case HIDIOCSUSAGE:
case HIDIOCGUSAGES:
case HIDIOCSUSAGES:
case HIDIOCGCOLLECTIONINDEX:
uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
if (!uref_multi)
return -ENOMEM;
uref = &uref_multi->uref;
if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
if (copy_from_user(uref_multi, user_arg,
sizeof(*uref_multi)))
goto fault;
} else {
if (copy_from_user(uref, user_arg, sizeof(*uref)))
goto fault;
}
if (cmd != HIDIOCGUSAGE &&
cmd != HIDIOCGUSAGES &&
uref->report_type == HID_REPORT_TYPE_INPUT)
goto inval;
if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
field = hiddev_lookup_usage(hid, uref);
if (field == NULL)
goto inval;
} else {
rinfo.report_type = uref->report_type;
rinfo.report_id = uref->report_id;
if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
goto inval;
if (uref->field_index >= report->maxfield)
goto inval;
field = report->field[uref->field_index];
if (cmd == HIDIOCGCOLLECTIONINDEX) {
if (uref->usage_index >= field->maxusage)
goto inval;
} else if (uref->usage_index >= field->report_count)
goto inval;
else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
(uref_multi->num_values > HID_MAX_MULTI_USAGES ||
uref->usage_index + uref_multi->num_values >= field->report_count))
goto inval;
}
switch (cmd) {
case HIDIOCGUSAGE:
uref->value = field->value[uref->usage_index];
if (copy_to_user(user_arg, uref, sizeof(*uref)))
goto fault;
goto goodreturn;
case HIDIOCSUSAGE:
field->value[uref->usage_index] = uref->value;
goto goodreturn;
case HIDIOCGCOLLECTIONINDEX:
kfree(uref_multi);
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(user_arg, uref_multi,
sizeof(*uref_multi)))
goto fault;
goto goodreturn;
case HIDIOCSUSAGES:
for (i = 0; i < uref_multi->num_values; i++)
field->value[uref->usage_index + i] =
uref_multi->values[i];
goto goodreturn;
}
goodreturn:
kfree(uref_multi);
return 0;
fault:
kfree(uref_multi);
return -EFAULT;
inval:
kfree(uref_multi);
return -EINVAL;
case HIDIOCGCOLLECTIONINFO:
if (copy_from_user(&cinfo, user_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;
if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
return -EFAULT;
return 0;
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(user_arg, hid->name, len) ?
-EFAULT : len;
}
if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
int len;
if (!hid->phys)
return 0;
len = strlen(hid->phys) + 1;
if (len > _IOC_SIZE(cmd))
len = _IOC_SIZE(cmd);
return copy_to_user(user_arg, hid->phys, 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,
};
static struct usb_class_driver hiddev_class = {
.name = "usb/hid/hiddev%d",
.fops = &hiddev_fops,
.mode = S_IFCHR | S_IRUGO | S_IWUSR,
.minor_base = HIDDEV_MINOR_BASE,
};
/*
* 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 i;
int retval;
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 && (hid->quirks & HID_QUIRK_HIDDEV) == 0)
return -1;
if (!(hiddev = kmalloc(sizeof(struct hiddev), GFP_KERNEL)))
return -1;
memset(hiddev, 0, sizeof(struct hiddev));
retval = usb_register_dev(hid->intf, &hiddev_class);
if (retval) {
err("Not able to get a minor for this device.");
kfree(hiddev);
return -1;
}
init_waitqueue_head(&hiddev->wait);
hiddev_table[hid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
hiddev->hid = hid;
hiddev->exist = 1;
hid->minor = hid->intf->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)
*/
static struct usb_class_driver hiddev_class;
void hiddev_disconnect(struct hid_device *hid)
{
struct hiddev *hiddev = hid->hiddev;
hiddev->exist = 0;
hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
usb_deregister_dev(hiddev->hid->intf, &hiddev_class);
if (hiddev->open) {
hid_close(hiddev->hid);
wake_up_interruptible(&hiddev->wait);
} else {
kfree(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 int hiddev_usbd_probe(struct usb_interface *intf,
const struct usb_device_id *hiddev_info)
{
return -ENODEV;
}
static /* const */ struct usb_driver hiddev_driver = {
.owner = THIS_MODULE,
.name = "hiddev",
.probe = hiddev_usbd_probe,
};
int __init hiddev_init(void)
{
devfs_mk_dir("usb/hid");
return usb_register(&hiddev_driver);
}
void hiddev_exit(void)
{
usb_deregister(&hiddev_driver);
devfs_remove("usb/hid");
}