// SPDX-License-Identifier: GPL-2.0+
/*
* LEGO USB Tower driver
*
* Copyright (C) 2003 David Glance <[email protected]>
* 2001-2004 Juergen Stuber <[email protected]>
*
* derived from USB Skeleton driver - 0.5
* Copyright (C) 2001 Greg Kroah-Hartman ([email protected])
*
* History:
*
* 2001-10-13 - 0.1 js
* - first version
* 2001-11-03 - 0.2 js
* - simplified buffering, one-shot URBs for writing
* 2001-11-10 - 0.3 js
* - removed IOCTL (setting power/mode is more complicated, postponed)
* 2001-11-28 - 0.4 js
* - added vendor commands for mode of operation and power level in open
* 2001-12-04 - 0.5 js
* - set IR mode by default (by oversight 0.4 set VLL mode)
* 2002-01-11 - 0.5? pcchan
* - make read buffer reusable and work around bytes_to_write issue between
* uhci and legusbtower
* 2002-09-23 - 0.52 david ([email protected])
* - imported into lejos project
* - changed wake_up to wake_up_interruptible
* - changed to use lego0 rather than tower0
* - changed dbg() to use __func__ rather than deprecated __func__
* 2003-01-12 - 0.53 david ([email protected])
* - changed read and write to write everything or
* timeout (from a patch by Chris Riesen and Brett Thaeler driver)
* - added ioctl functionality to set timeouts
* 2003-07-18 - 0.54 davidgsf ([email protected])
* - initial import into LegoUSB project
* - merge of existing LegoUSB.c driver
* 2003-07-18 - 0.56 davidgsf ([email protected])
* - port to 2.6 style driver
* 2004-02-29 - 0.6 Juergen Stuber <[email protected]>
* - fix locking
* - unlink read URBs which are no longer needed
* - allow increased buffer size, eliminates need for timeout on write
* - have read URB running continuously
* - added poll
* - forbid seeking
* - added nonblocking I/O
* - changed back __func__ to __func__
* - read and log tower firmware version
* - reset tower on probe, avoids failure of first write
* 2004-03-09 - 0.7 Juergen Stuber <[email protected]>
* - timeout read now only after inactivity, shorten default accordingly
* 2004-03-11 - 0.8 Juergen Stuber <[email protected]>
* - log major, minor instead of possibly confusing device filename
* - whitespace cleanup
* 2004-03-12 - 0.9 Juergen Stuber <[email protected]>
* - normalize whitespace in debug messages
* - take care about endianness in control message responses
* 2004-03-13 - 0.91 Juergen Stuber <[email protected]>
* - make default intervals longer to accommodate current EHCI driver
* 2004-03-19 - 0.92 Juergen Stuber <[email protected]>
* - replaced atomic_t by memory barriers
* 2004-04-21 - 0.93 Juergen Stuber <[email protected]>
* - wait for completion of write urb in release (needed for remotecontrol)
* - corrected poll for write direction (missing negation)
* 2004-04-22 - 0.94 Juergen Stuber <[email protected]>
* - make device locking interruptible
* 2004-04-30 - 0.95 Juergen Stuber <[email protected]>
* - check for valid udev on resubmitting and unlinking urbs
* 2004-08-03 - 0.96 Juergen Stuber <[email protected]>
* - move reset into open to clean out spurious data
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/poll.h>
#define DRIVER_AUTHOR "Juergen Stuber <[email protected]>"
#define DRIVER_DESC "LEGO USB Tower Driver"
/* The defaults are chosen to work with the latest versions of leJOS and NQC.
*/
/* Some legacy software likes to receive packets in one piece.
* In this case read_buffer_size should exceed the maximal packet length
* (417 for datalog uploads), and packet_timeout should be set.
*/
static int read_buffer_size = 480;
module_param(read_buffer_size, int, 0);
MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
/* Some legacy software likes to send packets in one piece.
* In this case write_buffer_size should exceed the maximal packet length
* (417 for firmware and program downloads).
* A problem with long writes is that the following read may time out
* if the software is not prepared to wait long enough.
*/
static int write_buffer_size = 480;
module_param(write_buffer_size, int, 0);
MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
/* Some legacy software expects reads to contain whole LASM packets.
* To achieve this, characters which arrive before a packet timeout
* occurs will be returned in a single read operation.
* A problem with long reads is that the software may time out
* if it is not prepared to wait long enough.
* The packet timeout should be greater than the time between the
* reception of subsequent characters, which should arrive about
* every 5ms for the standard 2400 baud.
* Set it to 0 to disable.
*/
static int packet_timeout = 50;
module_param(packet_timeout, int, 0);
MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
/* Some legacy software expects blocking reads to time out.
* Timeout occurs after the specified time of read and write inactivity.
* Set it to 0 to disable.
*/
static int read_timeout = 200;
module_param(read_timeout, int, 0);
MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
/* As of kernel version 2.6.4 ehci-hcd uses an
* "only one interrupt transfer per frame" shortcut
* to simplify the scheduling of periodic transfers.
* This conflicts with our standard 1ms intervals for in and out URBs.
* We use default intervals of 2ms for in and 8ms for out transfers,
* which is fast enough for 2400 baud and allows a small additional load.
* Increase the interval to allow more devices that do interrupt transfers,
* or set to 0 to use the standard interval from the endpoint descriptors.
*/
static int interrupt_in_interval = 2;
module_param(interrupt_in_interval, int, 0);
MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
static int interrupt_out_interval = 8;
module_param(interrupt_out_interval, int, 0);
MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
/* Define these values to match your device */
#define LEGO_USB_TOWER_VENDOR_ID 0x0694
#define LEGO_USB_TOWER_PRODUCT_ID 0x0001
/* Vendor requests */
#define LEGO_USB_TOWER_REQUEST_RESET 0x04
#define LEGO_USB_TOWER_REQUEST_GET_VERSION 0xFD
struct tower_reset_reply {
__le16 size;
__u8 err_code;
__u8 spare;
};
struct tower_get_version_reply {
__le16 size;
__u8 err_code;
__u8 spare;
__u8 major;
__u8 minor;
__le16 build_no;
};
/* table of devices that work with this driver */
static const struct usb_device_id tower_table[] = {
{ USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, tower_table);
#define LEGO_USB_TOWER_MINOR_BASE 160
/* Structure to hold all of our device specific stuff */
struct lego_usb_tower {
struct mutex lock; /* locks this structure */
struct usb_device *udev; /* save off the usb device pointer */
unsigned char minor; /* the starting minor number for this device */
int open_count; /* number of times this port has been opened */
unsigned long disconnected:1;
char *read_buffer;
size_t read_buffer_length; /* this much came in */
size_t read_packet_length; /* this much will be returned on read */
spinlock_t read_buffer_lock;
int packet_timeout_jiffies;
unsigned long read_last_arrival;
wait_queue_head_t read_wait;
wait_queue_head_t write_wait;
char *interrupt_in_buffer;
struct usb_endpoint_descriptor *interrupt_in_endpoint;
struct urb *interrupt_in_urb;
int interrupt_in_interval;
int interrupt_in_done;
char *interrupt_out_buffer;
struct usb_endpoint_descriptor *interrupt_out_endpoint;
struct urb *interrupt_out_urb;
int interrupt_out_interval;
int interrupt_out_busy;
};
/* local function prototypes */
static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos);
static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
static inline void tower_delete(struct lego_usb_tower *dev);
static int tower_open(struct inode *inode, struct file *file);
static int tower_release(struct inode *inode, struct file *file);
static __poll_t tower_poll(struct file *file, poll_table *wait);
static loff_t tower_llseek(struct file *file, loff_t off, int whence);
static void tower_check_for_read_packet(struct lego_usb_tower *dev);
static void tower_interrupt_in_callback(struct urb *urb);
static void tower_interrupt_out_callback(struct urb *urb);
static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id);
static void tower_disconnect(struct usb_interface *interface);
/* file operations needed when we register this driver */
static const struct file_operations tower_fops = {
.owner = THIS_MODULE,
.read = tower_read,
.write = tower_write,
.open = tower_open,
.release = tower_release,
.poll = tower_poll,
.llseek = tower_llseek,
};
static char *legousbtower_devnode(const struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
}
/*
* usb class driver info in order to get a minor number from the usb core,
* and to have the device registered with the driver core
*/
static struct usb_class_driver tower_class = {
.name = "legousbtower%d",
.devnode = legousbtower_devnode,
.fops = &tower_fops,
.minor_base = LEGO_USB_TOWER_MINOR_BASE,
};
/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver tower_driver = {
.name = "legousbtower",
.probe = tower_probe,
.disconnect = tower_disconnect,
.id_table = tower_table,
};
/*
* lego_usb_tower_debug_data
*/
static inline void lego_usb_tower_debug_data(struct device *dev,
const char *function, int size,
const unsigned char *data)
{
dev_dbg(dev, "%s - length = %d, data = %*ph\n",
function, size, size, data);
}
/*
* tower_delete
*/
static inline void tower_delete(struct lego_usb_tower *dev)
{
/* free data structures */
usb_free_urb(dev->interrupt_in_urb);
usb_free_urb(dev->interrupt_out_urb);
kfree(dev->read_buffer);
kfree(dev->interrupt_in_buffer);
kfree(dev->interrupt_out_buffer);
usb_put_dev(dev->udev);
kfree(dev);
}
/*
* tower_open
*/
static int tower_open(struct inode *inode, struct file *file)
{
struct lego_usb_tower *dev = NULL;
int subminor;
int retval = 0;
struct usb_interface *interface;
struct tower_reset_reply reset_reply;
int result;
nonseekable_open(inode, file);
subminor = iminor(inode);
interface = usb_find_interface(&tower_driver, subminor);
if (!interface) {
pr_err("error, can't find device for minor %d\n", subminor);
retval = -ENODEV;
goto exit;
}
dev = usb_get_intfdata(interface);
if (!dev) {
retval = -ENODEV;
goto exit;
}
/* lock this device */
if (mutex_lock_interruptible(&dev->lock)) {
retval = -ERESTARTSYS;
goto exit;
}
/* allow opening only once */
if (dev->open_count) {
retval = -EBUSY;
goto unlock_exit;
}
/* reset the tower */
result = usb_control_msg_recv(dev->udev, 0,
LEGO_USB_TOWER_REQUEST_RESET,
USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
0, 0,
&reset_reply, sizeof(reset_reply), 1000,
GFP_KERNEL);
if (result < 0) {
dev_err(&dev->udev->dev,
"LEGO USB Tower reset control request failed\n");
retval = result;
goto unlock_exit;
}
/* initialize in direction */
dev->read_buffer_length = 0;
dev->read_packet_length = 0;
usb_fill_int_urb(dev->interrupt_in_urb,
dev->udev,
usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
dev->interrupt_in_buffer,
usb_endpoint_maxp(dev->interrupt_in_endpoint),
tower_interrupt_in_callback,
dev,
dev->interrupt_in_interval);
dev->interrupt_in_done = 0;
mb();
retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
if (retval) {
dev_err(&dev->udev->dev,
"Couldn't submit interrupt_in_urb %d\n", retval);
goto unlock_exit;
}
/* save device in the file's private structure */
file->private_data = dev;
dev->open_count = 1;
unlock_exit:
mutex_unlock(&dev->lock);
exit:
return retval;
}
/*
* tower_release
*/
static int tower_release(struct inode *inode, struct file *file)
{
struct lego_usb_tower *dev;
int retval = 0;
dev = file->private_data;
if (dev == NULL) {
retval = -ENODEV;
goto exit;
}
mutex_lock(&dev->lock);
if (dev->disconnected) {
/* the device was unplugged before the file was released */
/* unlock here as tower_delete frees dev */
mutex_unlock(&dev->lock);
tower_delete(dev);
goto exit;
}
/* wait until write transfer is finished */
if (dev->interrupt_out_busy) {
wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy,
2 * HZ);
}
/* shutdown transfers */
usb_kill_urb(dev->interrupt_in_urb);
usb_kill_urb(dev->interrupt_out_urb);
dev->open_count = 0;
mutex_unlock(&dev->lock);
exit:
return retval;
}
/*
* tower_check_for_read_packet
*
* To get correct semantics for signals and non-blocking I/O
* with packetizing we pretend not to see any data in the read buffer
* until it has been there unchanged for at least
* dev->packet_timeout_jiffies, or until the buffer is full.
*/
static void tower_check_for_read_packet(struct lego_usb_tower *dev)
{
spin_lock_irq(&dev->read_buffer_lock);
if (!packet_timeout
|| time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
|| dev->read_buffer_length == read_buffer_size) {
dev->read_packet_length = dev->read_buffer_length;
}
dev->interrupt_in_done = 0;
spin_unlock_irq(&dev->read_buffer_lock);
}
/*
* tower_poll
*/
static __poll_t tower_poll(struct file *file, poll_table *wait)
{
struct lego_usb_tower *dev;
__poll_t mask = 0;
dev = file->private_data;
if (dev->disconnected)
return EPOLLERR | EPOLLHUP;
poll_wait(file, &dev->read_wait, wait);
poll_wait(file, &dev->write_wait, wait);
tower_check_for_read_packet(dev);
if (dev->read_packet_length > 0)
mask |= EPOLLIN | EPOLLRDNORM;
if (!dev->interrupt_out_busy)
mask |= EPOLLOUT | EPOLLWRNORM;
return mask;
}
/*
* tower_llseek
*/
static loff_t tower_llseek(struct file *file, loff_t off, int whence)
{
return -ESPIPE; /* unseekable */
}
/*
* tower_read
*/
static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct lego_usb_tower *dev;
size_t bytes_to_read;
int i;
int retval = 0;
unsigned long timeout = 0;
dev = file->private_data;
/* lock this object */
if (mutex_lock_interruptible(&dev->lock)) {
retval = -ERESTARTSYS;
goto exit;
}
/* verify that the device wasn't unplugged */
if (dev->disconnected) {
retval = -ENODEV;
goto unlock_exit;
}
/* verify that we actually have some data to read */
if (count == 0) {
dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
goto unlock_exit;
}
if (read_timeout)
timeout = jiffies + msecs_to_jiffies(read_timeout);
/* wait for data */
tower_check_for_read_packet(dev);
while (dev->read_packet_length == 0) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
goto unlock_exit;
}
retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
if (retval < 0)
goto unlock_exit;
/* reset read timeout during read or write activity */
if (read_timeout
&& (dev->read_buffer_length || dev->interrupt_out_busy)) {
timeout = jiffies + msecs_to_jiffies(read_timeout);
}
/* check for read timeout */
if (read_timeout && time_after(jiffies, timeout)) {
retval = -ETIMEDOUT;
goto unlock_exit;
}
tower_check_for_read_packet(dev);
}
/* copy the data from read_buffer into userspace */
bytes_to_read = min(count, dev->read_packet_length);
if (copy_to_user(buffer, dev->read_buffer, bytes_to_read)) {
retval = -EFAULT;
goto unlock_exit;
}
spin_lock_irq(&dev->read_buffer_lock);
dev->read_buffer_length -= bytes_to_read;
dev->read_packet_length -= bytes_to_read;
for (i = 0; i < dev->read_buffer_length; i++)
dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
spin_unlock_irq(&dev->read_buffer_lock);
retval = bytes_to_read;
unlock_exit:
/* unlock the device */
mutex_unlock(&dev->lock);
exit:
return retval;
}
/*
* tower_write
*/
static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
struct lego_usb_tower *dev;
size_t bytes_to_write;
int retval = 0;
dev = file->private_data;
/* lock this object */
if (mutex_lock_interruptible(&dev->lock)) {
retval = -ERESTARTSYS;
goto exit;
}
/* verify that the device wasn't unplugged */
if (dev->disconnected) {
retval = -ENODEV;
goto unlock_exit;
}
/* verify that we actually have some data to write */
if (count == 0) {
dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
goto unlock_exit;
}
/* wait until previous transfer is finished */
while (dev->interrupt_out_busy) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
goto unlock_exit;
}
retval = wait_event_interruptible(dev->write_wait,
!dev->interrupt_out_busy);
if (retval)
goto unlock_exit;
}
/* write the data into interrupt_out_buffer from userspace */
bytes_to_write = min_t(int, count, write_buffer_size);
dev_dbg(&dev->udev->dev, "%s: count = %zd, bytes_to_write = %zd\n",
__func__, count, bytes_to_write);
if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
retval = -EFAULT;
goto unlock_exit;
}
/* send off the urb */
usb_fill_int_urb(dev->interrupt_out_urb,
dev->udev,
usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
dev->interrupt_out_buffer,
bytes_to_write,
tower_interrupt_out_callback,
dev,
dev->interrupt_out_interval);
dev->interrupt_out_busy = 1;
wmb();
retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
if (retval) {
dev->interrupt_out_busy = 0;
dev_err(&dev->udev->dev,
"Couldn't submit interrupt_out_urb %d\n", retval);
goto unlock_exit;
}
retval = bytes_to_write;
unlock_exit:
/* unlock the device */
mutex_unlock(&dev->lock);
exit:
return retval;
}
/*
* tower_interrupt_in_callback
*/
static void tower_interrupt_in_callback(struct urb *urb)
{
struct lego_usb_tower *dev = urb->context;
int status = urb->status;
int retval;
unsigned long flags;
lego_usb_tower_debug_data(&dev->udev->dev, __func__,
urb->actual_length, urb->transfer_buffer);
if (status) {
if (status == -ENOENT ||
status == -ECONNRESET ||
status == -ESHUTDOWN) {
goto exit;
} else {
dev_dbg(&dev->udev->dev,
"%s: nonzero status received: %d\n", __func__,
status);
goto resubmit; /* maybe we can recover */
}
}
if (urb->actual_length > 0) {
spin_lock_irqsave(&dev->read_buffer_lock, flags);
if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
memcpy(dev->read_buffer + dev->read_buffer_length,
dev->interrupt_in_buffer,
urb->actual_length);
dev->read_buffer_length += urb->actual_length;
dev->read_last_arrival = jiffies;
dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
__func__, urb->actual_length);
} else {
pr_warn("read_buffer overflow, %d bytes dropped\n",
urb->actual_length);
}
spin_unlock_irqrestore(&dev->read_buffer_lock, flags);
}
resubmit:
retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
if (retval) {
dev_err(&dev->udev->dev, "%s: usb_submit_urb failed (%d)\n",
__func__, retval);
}
exit:
dev->interrupt_in_done = 1;
wake_up_interruptible(&dev->read_wait);
}
/*
* tower_interrupt_out_callback
*/
static void tower_interrupt_out_callback(struct urb *urb)
{
struct lego_usb_tower *dev = urb->context;
int status = urb->status;
lego_usb_tower_debug_data(&dev->udev->dev, __func__,
urb->actual_length, urb->transfer_buffer);
/* sync/async unlink faults aren't errors */
if (status && !(status == -ENOENT ||
status == -ECONNRESET ||
status == -ESHUTDOWN)) {
dev_dbg(&dev->udev->dev,
"%s: nonzero write bulk status received: %d\n", __func__,
status);
}
dev->interrupt_out_busy = 0;
wake_up_interruptible(&dev->write_wait);
}
/*
* tower_probe
*
* Called by the usb core when a new device is connected that it thinks
* this driver might be interested in.
*/
static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
struct device *idev = &interface->dev;
struct usb_device *udev = interface_to_usbdev(interface);
struct lego_usb_tower *dev;
struct tower_get_version_reply get_version_reply;
int retval = -ENOMEM;
int result;
/* allocate memory for our device state and initialize it */
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
goto exit;
mutex_init(&dev->lock);
dev->udev = usb_get_dev(udev);
spin_lock_init(&dev->read_buffer_lock);
dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
dev->read_last_arrival = jiffies;
init_waitqueue_head(&dev->read_wait);
init_waitqueue_head(&dev->write_wait);
result = usb_find_common_endpoints_reverse(interface->cur_altsetting,
NULL, NULL,
&dev->interrupt_in_endpoint,
&dev->interrupt_out_endpoint);
if (result) {
dev_err(idev, "interrupt endpoints not found\n");
retval = result;
goto error;
}
dev->read_buffer = kmalloc(read_buffer_size, GFP_KERNEL);
if (!dev->read_buffer)
goto error;
dev->interrupt_in_buffer = kmalloc(usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
if (!dev->interrupt_in_buffer)
goto error;
dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
if (!dev->interrupt_in_urb)
goto error;
dev->interrupt_out_buffer = kmalloc(write_buffer_size, GFP_KERNEL);
if (!dev->interrupt_out_buffer)
goto error;
dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
if (!dev->interrupt_out_urb)
goto error;
dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
/* get the firmware version and log it */
result = usb_control_msg_recv(udev, 0,
LEGO_USB_TOWER_REQUEST_GET_VERSION,
USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
0,
0,
&get_version_reply,
sizeof(get_version_reply),
1000, GFP_KERNEL);
if (result) {
dev_err(idev, "get version request failed: %d\n", result);
retval = result;
goto error;
}
dev_info(&interface->dev,
"LEGO USB Tower firmware version is %d.%d build %d\n",
get_version_reply.major,
get_version_reply.minor,
le16_to_cpu(get_version_reply.build_no));
/* we can register the device now, as it is ready */
usb_set_intfdata(interface, dev);
retval = usb_register_dev(interface, &tower_class);
if (retval) {
/* something prevented us from registering this driver */
dev_err(idev, "Not able to get a minor for this device.\n");
goto error;
}
dev->minor = interface->minor;
/* let the user know what node this device is now attached to */
dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
"%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
USB_MAJOR, dev->minor);
exit:
return retval;
error:
tower_delete(dev);
return retval;
}
/*
* tower_disconnect
*
* Called by the usb core when the device is removed from the system.
*/
static void tower_disconnect(struct usb_interface *interface)
{
struct lego_usb_tower *dev;
int minor;
dev = usb_get_intfdata(interface);
minor = dev->minor;
/* give back our minor and prevent further open() */
usb_deregister_dev(interface, &tower_class);
/* stop I/O */
usb_poison_urb(dev->interrupt_in_urb);
usb_poison_urb(dev->interrupt_out_urb);
mutex_lock(&dev->lock);
/* if the device is not opened, then we clean up right now */
if (!dev->open_count) {
mutex_unlock(&dev->lock);
tower_delete(dev);
} else {
dev->disconnected = 1;
/* wake up pollers */
wake_up_interruptible_all(&dev->read_wait);
wake_up_interruptible_all(&dev->write_wait);
mutex_unlock(&dev->lock);
}
dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
(minor - LEGO_USB_TOWER_MINOR_BASE));
}
module_usb_driver(tower_driver);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
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