Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 796 insertions, 0 deletions

diff --git a/drivers/usb/misc/adutux.c b/drivers/usb/misc/adutux.c
new file mode 100644
index 000000000..ed6a19254
--- /dev/null
+++ b/drivers/usb/misc/adutux.c
@@ -0,0 +1,796 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * adutux - driver for ADU devices from Ontrak Control Systems
+ * This is an experimental driver. Use at your own risk.
+ * This driver is not supported by Ontrak Control Systems.
+ *
+ * Copyright (c) 2003 John Homppi (SCO, leave this notice here)
+ *
+ * derived from the Lego USB Tower driver 0.56:
+ * Copyright (c) 2003 David Glance <davidgsf@sourceforge.net>
+ *               2001 Juergen Stuber <stuber@loria.fr>
+ * that was derived from USB Skeleton driver - 0.5
+ * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+
+#define DRIVER_AUTHOR "John Homppi"
+#define DRIVER_DESC "adutux (see www.ontrak.net)"
+
+/* Define these values to match your device */
+#define ADU_VENDOR_ID 0x0a07
+#define ADU_PRODUCT_ID 0x0064
+
+/* table of devices that work with this driver */
+static const struct usb_device_id device_table[] = {
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },		/* ADU100 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) },	/* ADU120 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) },	/* ADU130 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },	/* ADU200 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },	/* ADU208 */
+	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },	/* ADU218 */
+	{ } /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, device_table);
+
+#ifdef CONFIG_USB_DYNAMIC_MINORS
+#define ADU_MINOR_BASE	0
+#else
+#define ADU_MINOR_BASE	67
+#endif
+
+/* we can have up to this number of device plugged in at once */
+#define MAX_DEVICES	16
+
+#define COMMAND_TIMEOUT	(2*HZ)
+
+/*
+ * The locking scheme is a vanilla 3-lock:
+ *   adu_device.buflock: A spinlock, covers what IRQs touch.
+ *   adutux_mutex:       A Static lock to cover open_count. It would also cover
+ *                       any globals, but we don't have them in 2.6.
+ *   adu_device.mtx:     A mutex to hold across sleepers like copy_from_user.
+ *                       It covers all of adu_device, except the open_count
+ *                       and what .buflock covers.
+ */
+
+/* Structure to hold all of our device specific stuff */
+struct adu_device {
+	struct mutex		mtx;
+	struct usb_device *udev; /* save off the usb device pointer */
+	struct usb_interface *interface;
+	unsigned int		minor; /* the starting minor number for this device */
+	char			serial_number[8];
+
+	int			open_count; /* number of times this port has been opened */
+	unsigned long		disconnected:1;
+
+	char		*read_buffer_primary;
+	int			read_buffer_length;
+	char		*read_buffer_secondary;
+	int			secondary_head;
+	int			secondary_tail;
+	spinlock_t		buflock;
+
+	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			read_urb_finished;
+
+	char		*interrupt_out_buffer;
+	struct usb_endpoint_descriptor *interrupt_out_endpoint;
+	struct urb	*interrupt_out_urb;
+	int			out_urb_finished;
+};
+
+static DEFINE_MUTEX(adutux_mutex);
+
+static struct usb_driver adu_driver;
+
+static inline void adu_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);
+}
+
+/*
+ * adu_abort_transfers
+ *      aborts transfers and frees associated data structures
+ */
+static void adu_abort_transfers(struct adu_device *dev)
+{
+	unsigned long flags;
+
+	if (dev->disconnected)
+		return;
+
+	/* shutdown transfer */
+
+	/* XXX Anchor these instead */
+	spin_lock_irqsave(&dev->buflock, flags);
+	if (!dev->read_urb_finished) {
+		spin_unlock_irqrestore(&dev->buflock, flags);
+		usb_kill_urb(dev->interrupt_in_urb);
+	} else
+		spin_unlock_irqrestore(&dev->buflock, flags);
+
+	spin_lock_irqsave(&dev->buflock, flags);
+	if (!dev->out_urb_finished) {
+		spin_unlock_irqrestore(&dev->buflock, flags);
+		wait_event_timeout(dev->write_wait, dev->out_urb_finished,
+			COMMAND_TIMEOUT);
+		usb_kill_urb(dev->interrupt_out_urb);
+	} else
+		spin_unlock_irqrestore(&dev->buflock, flags);
+}
+
+static void adu_delete(struct adu_device *dev)
+{
+	/* free data structures */
+	usb_free_urb(dev->interrupt_in_urb);
+	usb_free_urb(dev->interrupt_out_urb);
+	kfree(dev->read_buffer_primary);
+	kfree(dev->read_buffer_secondary);
+	kfree(dev->interrupt_in_buffer);
+	kfree(dev->interrupt_out_buffer);
+	usb_put_dev(dev->udev);
+	kfree(dev);
+}
+
+static void adu_interrupt_in_callback(struct urb *urb)
+{
+	struct adu_device *dev = urb->context;
+	int status = urb->status;
+	unsigned long flags;
+
+	adu_debug_data(&dev->udev->dev, __func__,
+		       urb->actual_length, urb->transfer_buffer);
+
+	spin_lock_irqsave(&dev->buflock, flags);
+
+	if (status != 0) {
+		if ((status != -ENOENT) && (status != -ECONNRESET) &&
+			(status != -ESHUTDOWN)) {
+			dev_dbg(&dev->udev->dev,
+				"%s : nonzero status received: %d\n",
+				__func__, status);
+		}
+		goto exit;
+	}
+
+	if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
+		if (dev->read_buffer_length <
+		    (4 * usb_endpoint_maxp(dev->interrupt_in_endpoint)) -
+		     (urb->actual_length)) {
+			memcpy (dev->read_buffer_primary +
+				dev->read_buffer_length,
+				dev->interrupt_in_buffer, urb->actual_length);
+
+			dev->read_buffer_length += urb->actual_length;
+			dev_dbg(&dev->udev->dev, "%s reading  %d\n", __func__,
+				urb->actual_length);
+		} else {
+			dev_dbg(&dev->udev->dev, "%s : read_buffer overflow\n",
+				__func__);
+		}
+	}
+
+exit:
+	dev->read_urb_finished = 1;
+	spin_unlock_irqrestore(&dev->buflock, flags);
+	/* always wake up so we recover from errors */
+	wake_up_interruptible(&dev->read_wait);
+}
+
+static void adu_interrupt_out_callback(struct urb *urb)
+{
+	struct adu_device *dev = urb->context;
+	int status = urb->status;
+	unsigned long flags;
+
+	adu_debug_data(&dev->udev->dev, __func__,
+		       urb->actual_length, urb->transfer_buffer);
+
+	if (status != 0) {
+		if ((status != -ENOENT) &&
+		    (status != -ESHUTDOWN) &&
+		    (status != -ECONNRESET)) {
+			dev_dbg(&dev->udev->dev,
+				"%s :nonzero status received: %d\n", __func__,
+				status);
+		}
+		return;
+	}
+
+	spin_lock_irqsave(&dev->buflock, flags);
+	dev->out_urb_finished = 1;
+	wake_up(&dev->write_wait);
+	spin_unlock_irqrestore(&dev->buflock, flags);
+}
+
+static int adu_open(struct inode *inode, struct file *file)
+{
+	struct adu_device *dev = NULL;
+	struct usb_interface *interface;
+	int subminor;
+	int retval;
+
+	subminor = iminor(inode);
+
+	retval = mutex_lock_interruptible(&adutux_mutex);
+	if (retval)
+		goto exit_no_lock;
+
+	interface = usb_find_interface(&adu_driver, subminor);
+	if (!interface) {
+		pr_err("%s - error, can't find device for minor %d\n",
+		       __func__, subminor);
+		retval = -ENODEV;
+		goto exit_no_device;
+	}
+
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		retval = -ENODEV;
+		goto exit_no_device;
+	}
+
+	/* check that nobody else is using the device */
+	if (dev->open_count) {
+		retval = -EBUSY;
+		goto exit_no_device;
+	}
+
+	++dev->open_count;
+	dev_dbg(&dev->udev->dev, "%s: open count %d\n", __func__,
+		dev->open_count);
+
+	/* save device in the file's private structure */
+	file->private_data = dev;
+
+	/* initialize in direction */
+	dev->read_buffer_length = 0;
+
+	/* fixup first read by having urb waiting for it */
+	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),
+			 adu_interrupt_in_callback, dev,
+			 dev->interrupt_in_endpoint->bInterval);
+	dev->read_urb_finished = 0;
+	if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
+		dev->read_urb_finished = 1;
+	/* we ignore failure */
+	/* end of fixup for first read */
+
+	/* initialize out direction */
+	dev->out_urb_finished = 1;
+
+	retval = 0;
+
+exit_no_device:
+	mutex_unlock(&adutux_mutex);
+exit_no_lock:
+	return retval;
+}
+
+static void adu_release_internal(struct adu_device *dev)
+{
+	/* decrement our usage count for the device */
+	--dev->open_count;
+	dev_dbg(&dev->udev->dev, "%s : open count %d\n", __func__,
+		dev->open_count);
+	if (dev->open_count <= 0) {
+		adu_abort_transfers(dev);
+		dev->open_count = 0;
+	}
+}
+
+static int adu_release(struct inode *inode, struct file *file)
+{
+	struct adu_device *dev;
+	int retval = 0;
+
+	if (file == NULL) {
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	dev = file->private_data;
+	if (dev == NULL) {
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	mutex_lock(&adutux_mutex); /* not interruptible */
+
+	if (dev->open_count <= 0) {
+		dev_dbg(&dev->udev->dev, "%s : device not opened\n", __func__);
+		retval = -ENODEV;
+		goto unlock;
+	}
+
+	adu_release_internal(dev);
+	if (dev->disconnected) {
+		/* the device was unplugged before the file was released */
+		if (!dev->open_count)	/* ... and we're the last user */
+			adu_delete(dev);
+	}
+unlock:
+	mutex_unlock(&adutux_mutex);
+exit:
+	return retval;
+}
+
+static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
+			loff_t *ppos)
+{
+	struct adu_device *dev;
+	size_t bytes_read = 0;
+	size_t bytes_to_read = count;
+	int retval = 0;
+	int timeout = 0;
+	int should_submit = 0;
+	unsigned long flags;
+	DECLARE_WAITQUEUE(wait, current);
+
+	dev = file->private_data;
+	if (mutex_lock_interruptible(&dev->mtx))
+		return -ERESTARTSYS;
+
+	/* verify that the device wasn't unplugged */
+	if (dev->disconnected) {
+		retval = -ENODEV;
+		pr_err("No device or device unplugged %d\n", retval);
+		goto exit;
+	}
+
+	/* verify that some data was requested */
+	if (count == 0) {
+		dev_dbg(&dev->udev->dev, "%s : read request of 0 bytes\n",
+			__func__);
+		goto exit;
+	}
+
+	timeout = COMMAND_TIMEOUT;
+	dev_dbg(&dev->udev->dev, "%s : about to start looping\n", __func__);
+	while (bytes_to_read) {
+		size_t data_in_secondary = dev->secondary_tail - dev->secondary_head;
+		dev_dbg(&dev->udev->dev,
+			"%s : while, data_in_secondary=%zu, status=%d\n",
+			__func__, data_in_secondary,
+			dev->interrupt_in_urb->status);
+
+		if (data_in_secondary) {
+			/* drain secondary buffer */
+			size_t amount = min(bytes_to_read, data_in_secondary);
+			if (copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount)) {
+				retval = -EFAULT;
+				goto exit;
+			}
+			dev->secondary_head += amount;
+			bytes_read += amount;
+			bytes_to_read -= amount;
+		} else {
+			/* we check the primary buffer */
+			spin_lock_irqsave (&dev->buflock, flags);
+			if (dev->read_buffer_length) {
+				/* we secure access to the primary */
+				dev_dbg(&dev->udev->dev,
+					"%s : swap, read_buffer_length = %d\n",
+					__func__, dev->read_buffer_length);
+				swap(dev->read_buffer_primary, dev->read_buffer_secondary);
+				dev->secondary_head = 0;
+				dev->secondary_tail = dev->read_buffer_length;
+				dev->read_buffer_length = 0;
+				spin_unlock_irqrestore(&dev->buflock, flags);
+				/* we have a free buffer so use it */
+				should_submit = 1;
+			} else {
+				/* even the primary was empty - we may need to do IO */
+				if (!dev->read_urb_finished) {
+					/* somebody is doing IO */
+					spin_unlock_irqrestore(&dev->buflock, flags);
+					dev_dbg(&dev->udev->dev,
+						"%s : submitted already\n",
+						__func__);
+				} else {
+					/* we must initiate input */
+					dev_dbg(&dev->udev->dev,
+						"%s : initiate input\n",
+						__func__);
+					dev->read_urb_finished = 0;
+					spin_unlock_irqrestore(&dev->buflock, flags);
+
+					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),
+							 adu_interrupt_in_callback,
+							 dev,
+							 dev->interrupt_in_endpoint->bInterval);
+					retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
+					if (retval) {
+						dev->read_urb_finished = 1;
+						if (retval == -ENOMEM) {
+							retval = bytes_read ? bytes_read : -ENOMEM;
+						}
+						dev_dbg(&dev->udev->dev,
+							"%s : submit failed\n",
+							__func__);
+						goto exit;
+					}
+				}
+
+				/* we wait for I/O to complete */
+				set_current_state(TASK_INTERRUPTIBLE);
+				add_wait_queue(&dev->read_wait, &wait);
+				spin_lock_irqsave(&dev->buflock, flags);
+				if (!dev->read_urb_finished) {
+					spin_unlock_irqrestore(&dev->buflock, flags);
+					timeout = schedule_timeout(COMMAND_TIMEOUT);
+				} else {
+					spin_unlock_irqrestore(&dev->buflock, flags);
+					set_current_state(TASK_RUNNING);
+				}
+				remove_wait_queue(&dev->read_wait, &wait);
+
+				if (timeout <= 0) {
+					dev_dbg(&dev->udev->dev,
+						"%s : timeout\n", __func__);
+					retval = bytes_read ? bytes_read : -ETIMEDOUT;
+					goto exit;
+				}
+
+				if (signal_pending(current)) {
+					dev_dbg(&dev->udev->dev,
+						"%s : signal pending\n",
+						__func__);
+					retval = bytes_read ? bytes_read : -EINTR;
+					goto exit;
+				}
+			}
+		}
+	}
+
+	retval = bytes_read;
+	/* if the primary buffer is empty then use it */
+	spin_lock_irqsave(&dev->buflock, flags);
+	if (should_submit && dev->read_urb_finished) {
+		dev->read_urb_finished = 0;
+		spin_unlock_irqrestore(&dev->buflock, flags);
+		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),
+				adu_interrupt_in_callback,
+				dev,
+				dev->interrupt_in_endpoint->bInterval);
+		if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
+			dev->read_urb_finished = 1;
+		/* we ignore failure */
+	} else {
+		spin_unlock_irqrestore(&dev->buflock, flags);
+	}
+
+exit:
+	/* unlock the device */
+	mutex_unlock(&dev->mtx);
+
+	return retval;
+}
+
+static ssize_t adu_write(struct file *file, const __user char *buffer,
+			 size_t count, loff_t *ppos)
+{
+	DECLARE_WAITQUEUE(waita, current);
+	struct adu_device *dev;
+	size_t bytes_written = 0;
+	size_t bytes_to_write;
+	size_t buffer_size;
+	unsigned long flags;
+	int retval;
+
+	dev = file->private_data;
+
+	retval = mutex_lock_interruptible(&dev->mtx);
+	if (retval)
+		goto exit_nolock;
+
+	/* verify that the device wasn't unplugged */
+	if (dev->disconnected) {
+		retval = -ENODEV;
+		pr_err("No device or device unplugged %d\n", retval);
+		goto exit;
+	}
+
+	/* verify that we actually have some data to write */
+	if (count == 0) {
+		dev_dbg(&dev->udev->dev, "%s : write request of 0 bytes\n",
+			__func__);
+		goto exit;
+	}
+
+	while (count > 0) {
+		add_wait_queue(&dev->write_wait, &waita);
+		set_current_state(TASK_INTERRUPTIBLE);
+		spin_lock_irqsave(&dev->buflock, flags);
+		if (!dev->out_urb_finished) {
+			spin_unlock_irqrestore(&dev->buflock, flags);
+
+			mutex_unlock(&dev->mtx);
+			if (signal_pending(current)) {
+				dev_dbg(&dev->udev->dev, "%s : interrupted\n",
+					__func__);
+				set_current_state(TASK_RUNNING);
+				retval = -EINTR;
+				goto exit_onqueue;
+			}
+			if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
+				dev_dbg(&dev->udev->dev,
+					"%s - command timed out.\n", __func__);
+				retval = -ETIMEDOUT;
+				goto exit_onqueue;
+			}
+			remove_wait_queue(&dev->write_wait, &waita);
+			retval = mutex_lock_interruptible(&dev->mtx);
+			if (retval) {
+				retval = bytes_written ? bytes_written : retval;
+				goto exit_nolock;
+			}
+
+			dev_dbg(&dev->udev->dev,
+				"%s : in progress, count = %zd\n",
+				__func__, count);
+		} else {
+			spin_unlock_irqrestore(&dev->buflock, flags);
+			set_current_state(TASK_RUNNING);
+			remove_wait_queue(&dev->write_wait, &waita);
+			dev_dbg(&dev->udev->dev, "%s : sending, count = %zd\n",
+				__func__, count);
+
+			/* write the data into interrupt_out_buffer from userspace */
+			buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
+			bytes_to_write = count > buffer_size ? buffer_size : count;
+			dev_dbg(&dev->udev->dev,
+				"%s : buffer_size = %zd, count = %zd, bytes_to_write = %zd\n",
+				__func__, buffer_size, count, bytes_to_write);
+
+			if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
+				retval = -EFAULT;
+				goto 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,
+				adu_interrupt_out_callback,
+				dev,
+				dev->interrupt_out_endpoint->bInterval);
+			dev->interrupt_out_urb->actual_length = bytes_to_write;
+			dev->out_urb_finished = 0;
+			retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
+			if (retval < 0) {
+				dev->out_urb_finished = 1;
+				dev_err(&dev->udev->dev, "Couldn't submit "
+					"interrupt_out_urb %d\n", retval);
+				goto exit;
+			}
+
+			buffer += bytes_to_write;
+			count -= bytes_to_write;
+
+			bytes_written += bytes_to_write;
+		}
+	}
+	mutex_unlock(&dev->mtx);
+	return bytes_written;
+
+exit:
+	mutex_unlock(&dev->mtx);
+exit_nolock:
+	return retval;
+
+exit_onqueue:
+	remove_wait_queue(&dev->write_wait, &waita);
+	return retval;
+}
+
+/* file operations needed when we register this driver */
+static const struct file_operations adu_fops = {
+	.owner = THIS_MODULE,
+	.read  = adu_read,
+	.write = adu_write,
+	.open = adu_open,
+	.release = adu_release,
+	.llseek = noop_llseek,
+};
+
+/*
+ * 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 adu_class = {
+	.name = "usb/adutux%d",
+	.fops = &adu_fops,
+	.minor_base = ADU_MINOR_BASE,
+};
+
+/*
+ * adu_probe
+ *
+ * Called by the usb core when a new device is connected that it thinks
+ * this driver might be interested in.
+ */
+static int adu_probe(struct usb_interface *interface,
+		     const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(interface);
+	struct adu_device *dev = NULL;
+	int retval = -ENOMEM;
+	int in_end_size;
+	int out_end_size;
+	int res;
+
+	/* allocate memory for our device state and initialize it */
+	dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	mutex_init(&dev->mtx);
+	spin_lock_init(&dev->buflock);
+	dev->udev = usb_get_dev(udev);
+	init_waitqueue_head(&dev->read_wait);
+	init_waitqueue_head(&dev->write_wait);
+
+	res = usb_find_common_endpoints_reverse(interface->cur_altsetting,
+			NULL, NULL,
+			&dev->interrupt_in_endpoint,
+			&dev->interrupt_out_endpoint);
+	if (res) {
+		dev_err(&interface->dev, "interrupt endpoints not found\n");
+		retval = res;
+		goto error;
+	}
+
+	in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
+	out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
+
+	dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
+	if (!dev->read_buffer_primary)
+		goto error;
+
+	/* debug code prime the buffer */
+	memset(dev->read_buffer_primary, 'a', in_end_size);
+	memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
+	memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
+	memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
+
+	dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
+	if (!dev->read_buffer_secondary)
+		goto error;
+
+	/* debug code prime the buffer */
+	memset(dev->read_buffer_secondary, 'e', in_end_size);
+	memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
+	memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
+	memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
+
+	dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
+	if (!dev->interrupt_in_buffer)
+		goto error;
+
+	/* debug code prime the buffer */
+	memset(dev->interrupt_in_buffer, 'i', in_end_size);
+
+	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->interrupt_in_urb)
+		goto error;
+	dev->interrupt_out_buffer = kmalloc(out_end_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;
+
+	if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
+			sizeof(dev->serial_number))) {
+		dev_err(&interface->dev, "Could not retrieve serial number\n");
+		retval = -EIO;
+		goto error;
+	}
+	dev_dbg(&interface->dev, "serial_number=%s", dev->serial_number);
+
+	/* we can register the device now, as it is ready */
+	usb_set_intfdata(interface, dev);
+
+	retval = usb_register_dev(interface, &adu_class);
+
+	if (retval) {
+		/* something prevented us from registering this driver */
+		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
+		usb_set_intfdata(interface, NULL);
+		goto error;
+	}
+
+	dev->minor = interface->minor;
+
+	/* let the user know what node this device is now attached to */
+	dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
+		 le16_to_cpu(udev->descriptor.idProduct), dev->serial_number,
+		 (dev->minor - ADU_MINOR_BASE));
+
+	return 0;
+
+error:
+	adu_delete(dev);
+	return retval;
+}
+
+/*
+ * adu_disconnect
+ *
+ * Called by the usb core when the device is removed from the system.
+ */
+static void adu_disconnect(struct usb_interface *interface)
+{
+	struct adu_device *dev;
+
+	dev = usb_get_intfdata(interface);
+
+	usb_deregister_dev(interface, &adu_class);
+
+	usb_poison_urb(dev->interrupt_in_urb);
+	usb_poison_urb(dev->interrupt_out_urb);
+
+	mutex_lock(&adutux_mutex);
+	usb_set_intfdata(interface, NULL);
+
+	mutex_lock(&dev->mtx);	/* not interruptible */
+	dev->disconnected = 1;
+	mutex_unlock(&dev->mtx);
+
+	/* if the device is not opened, then we clean up right now */
+	if (!dev->open_count)
+		adu_delete(dev);
+
+	mutex_unlock(&adutux_mutex);
+}
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver adu_driver = {
+	.name = "adutux",
+	.probe = adu_probe,
+	.disconnect = adu_disconnect,
+	.id_table = device_table,
+};
+
+module_usb_driver(adu_driver);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");