USB: Add ADU support for Ontrak ADU devices

This patch adds support for Ontrak ADU USB devices.

Fixed for printk issues by Randy Dunlap <rdunlap@xenotime.net>

Signed-off-by: Steven Haigh <netwiz@crc.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 900 insertions, 0 deletions

diff --git a/drivers/usb/misc/adutux.c b/drivers/usb/misc/adutux.c
new file mode 100644
index 000000000000..d3963199b6ec
--- /dev/null
+++ b/drivers/usb/misc/adutux.c
@@ -0,0 +1,900 @@
+/*
+ * 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)
+ *
+ * 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.
+ *
+ * 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)
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <asm/uaccess.h>
+
+#ifdef CONFIG_USB_DEBUG
+static int debug = 5;
+#else
+static int debug = 1;
+#endif
+
+/* Use our own dbg macro */
+#undef dbg
+#define dbg(lvl, format, arg...)                                        \
+do {                                                                    \
+        if (debug >= lvl)                                               \
+                printk(KERN_DEBUG __FILE__ " : " format " \n", ## arg); \
+} while (0)
+
+
+/* Version Information */
+#define DRIVER_VERSION "v0.0.13"
+#define DRIVER_AUTHOR "John Homppi"
+#define DRIVER_DESC "adutux (see www.ontrak.net)"
+
+/* Module parameters */
+module_param(debug, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug enabled or not");
+
+/* 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 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)  /* 60 second timeout for a command */
+
+/* Structure to hold all of our device specific stuff */
+struct adu_device {
+        struct semaphore        sem; /* locks this structure */
+        struct usb_device*      udev; /* save off the usb device pointer */
+        struct usb_interface*   interface;
+        unsigned char           minor; /* the starting minor number for this device */
+        char                    serial_number[8];
+
+        int                     open_count; /* number of times this port has been opened */
+
+        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;
+};
+
+/* prevent races between open() and disconnect */
+static DEFINE_MUTEX(disconnect_mutex);
+static struct usb_driver adu_driver;
+
+static void adu_debug_data(int level, const char *function, int size,
+                           const unsigned char *data)
+{
+        int i;
+
+        if (debug < level)
+                return;
+
+        printk(KERN_DEBUG __FILE__": %s - length = %d, data = ",
+               function, size);
+        for (i = 0; i < size; ++i)
+                printk("%.2x ", data[i]);
+        printk("\n");
+}
+
+/**
+ * adu_abort_transfers
+ *      aborts transfers and frees associated data structures
+ */
+static void adu_abort_transfers(struct adu_device *dev)
+{
+        dbg(2," %s : enter", __FUNCTION__);
+
+        if (dev == NULL) {
+                dbg(1," %s : dev is null", __FUNCTION__);
+                goto exit;
+        }
+
+        if (dev->udev == NULL) {
+                dbg(1," %s : udev is null", __FUNCTION__);
+                goto exit;
+        }
+
+        dbg(2," %s : udev state %d", __FUNCTION__, dev->udev->state);
+        if (dev->udev->state == USB_STATE_NOTATTACHED) {
+                dbg(1," %s : udev is not attached", __FUNCTION__);
+                goto exit;
+        }
+
+        /* shutdown transfer */
+        usb_unlink_urb(dev->interrupt_in_urb);
+        usb_unlink_urb(dev->interrupt_out_urb);
+
+exit:
+        dbg(2," %s : leave", __FUNCTION__);
+}
+
+static void adu_delete(struct adu_device *dev)
+{
+        dbg(2, "%s enter", __FUNCTION__);
+
+        adu_abort_transfers(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);
+        kfree(dev);
+
+        dbg(2, "%s : leave", __FUNCTION__);
+}
+
+static void adu_interrupt_in_callback(struct urb *urb, struct pt_regs *regs)
+{
+        struct adu_device *dev = urb->context;
+
+        dbg(4," %s : enter, status %d", __FUNCTION__, urb->status);
+        adu_debug_data(5, __FUNCTION__, urb->actual_length,
+                       urb->transfer_buffer);
+
+        spin_lock(&dev->buflock);
+
+        if (urb->status != 0) {
+                if ((urb->status != -ENOENT) && (urb->status != -ECONNRESET)) {
+                        dbg(1," %s : nonzero status received: %d",
+                            __FUNCTION__, urb->status);
+                }
+                goto exit;
+        }
+
+        if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
+                if (dev->read_buffer_length <
+                    (4 * le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize)) -
+                     (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;
+                        dbg(2," %s reading  %d ", __FUNCTION__,
+                            urb->actual_length);
+                } else {
+                        dbg(1," %s : read_buffer overflow", __FUNCTION__);
+                }
+        }
+
+exit:
+        dev->read_urb_finished = 1;
+        spin_unlock(&dev->buflock);
+        /* always wake up so we recover from errors */
+        wake_up_interruptible(&dev->read_wait);
+        adu_debug_data(5, __FUNCTION__, urb->actual_length,
+                       urb->transfer_buffer);
+        dbg(4," %s : leave, status %d", __FUNCTION__, urb->status);
+}
+
+static void adu_interrupt_out_callback(struct urb *urb, struct pt_regs *regs)
+{
+        struct adu_device *dev = urb->context;
+
+        dbg(4," %s : enter, status %d", __FUNCTION__, urb->status);
+        adu_debug_data(5,__FUNCTION__, urb->actual_length, urb->transfer_buffer);
+
+        if (urb->status != 0) {
+                if ((urb->status != -ENOENT) &&
+                    (urb->status != -ECONNRESET)) {
+                        dbg(1, " %s :nonzero status received: %d",
+                            __FUNCTION__, urb->status);
+                }
+                goto exit;
+        }
+
+        wake_up_interruptible(&dev->write_wait);
+exit:
+
+        adu_debug_data(5, __FUNCTION__, urb->actual_length,
+                       urb->transfer_buffer);
+        dbg(4," %s : leave, status %d", __FUNCTION__, urb->status);
+}
+
+static int adu_open(struct inode *inode, struct file *file)
+{
+        struct adu_device *dev = NULL;
+        struct usb_interface *interface;
+        int subminor;
+        int retval = 0;
+
+        dbg(2,"%s : enter", __FUNCTION__);
+
+        subminor = iminor(inode);
+
+        mutex_lock(&disconnect_mutex);
+
+        interface = usb_find_interface(&adu_driver, subminor);
+        if (!interface) {
+                err("%s - error, can't find device for minor %d",
+                    __FUNCTION__, subminor);
+                retval = -ENODEV;
+                goto exit_no_device;
+        }
+
+        dev = usb_get_intfdata(interface);
+        if (!dev) {
+                retval = -ENODEV;
+                goto exit_no_device;
+        }
+
+        /* lock this device */
+        if ((retval = down_interruptible(&dev->sem))) {
+                dbg(2, "%s : sem down failed", __FUNCTION__);
+                goto exit_no_device;
+        }
+
+        /* increment our usage count for the device */
+        ++dev->open_count;
+        dbg(2,"%s : open count %d", __FUNCTION__, 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,
+                         le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
+                         adu_interrupt_in_callback, dev,
+                         dev->interrupt_in_endpoint->bInterval);
+        /* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
+        dev->read_urb_finished = 0;
+        usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
+        /* we ignore failure */
+        /* end of fixup for first read */
+
+        up(&dev->sem);
+
+exit_no_device:
+        mutex_unlock(&disconnect_mutex);
+        dbg(2,"%s : leave, return value %d ", __FUNCTION__, retval);
+
+        return retval;
+}
+
+static int adu_release_internal(struct adu_device *dev)
+{
+        int retval = 0;
+
+        dbg(2," %s : enter", __FUNCTION__);
+
+        if (dev->udev == NULL) {
+                /* the device was unplugged before the file was released */
+                adu_delete(dev);
+                goto exit;
+        }
+
+        /* decrement our usage count for the device */
+        --dev->open_count;
+        dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
+        if (dev->open_count <= 0) {
+                adu_abort_transfers(dev);
+                dev->open_count = 0;
+        }
+
+exit:
+        dbg(2," %s : leave", __FUNCTION__);
+        return retval;
+}
+
+static int adu_release(struct inode *inode, struct file *file)
+{
+        struct adu_device *dev = NULL;
+        int retval = 0;
+
+        dbg(2," %s : enter", __FUNCTION__);
+
+        if (file == NULL) {
+                dbg(1," %s : file is NULL", __FUNCTION__);
+                retval = -ENODEV;
+                goto exit;
+        }
+
+        dev = file->private_data;
+
+        if (dev == NULL) {
+                dbg(1," %s : object is NULL", __FUNCTION__);
+                retval = -ENODEV;
+                goto exit;
+        }
+
+        /* lock our device */
+        down(&dev->sem); /* not interruptible */
+
+        if (dev->open_count <= 0) {
+                dbg(1," %s : device not opened", __FUNCTION__);
+                retval = -ENODEV;
+                goto exit;
+        }
+
+        /* do the work */
+        retval = adu_release_internal(dev);
+
+exit:
+        up(&dev->sem);
+        dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
+        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 i;
+        int retval = 0;
+        int timeout = 0;
+        int should_submit = 0;
+        unsigned long flags;
+        DECLARE_WAITQUEUE(wait, current);
+
+        dbg(2," %s : enter, count = %Zd, file=%p", __FUNCTION__, count, file);
+
+        dev = file->private_data;
+        dbg(2," %s : dev=%p", __FUNCTION__, dev);
+        /* lock this object */
+        if (down_interruptible(&dev->sem))
+                return -ERESTARTSYS;
+
+        /* verify that the device wasn't unplugged */
+        if (dev->udev == NULL || dev->minor == 0) {
+                retval = -ENODEV;
+                err("No device or device unplugged %d", retval);
+                goto exit;
+        }
+
+        /* verify that some data was requested */
+        if (count == 0) {
+                dbg(1," %s : read request of 0 bytes", __FUNCTION__);
+                goto exit;
+        }
+
+        timeout = COMMAND_TIMEOUT;
+        dbg(2," %s : about to start looping", __FUNCTION__);
+        while (bytes_to_read) {
+                int data_in_secondary = dev->secondary_tail - dev->secondary_head;
+                dbg(2," %s : while, data_in_secondary=%d, status=%d",
+                    __FUNCTION__, data_in_secondary,
+                    dev->interrupt_in_urb->status);
+
+                if (data_in_secondary) {
+                        /* drain secondary buffer */
+                        int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
+                        i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
+                        if (i < 0) {
+                                retval = -EFAULT;
+                                goto exit;
+                        }
+                        dev->secondary_head += (amount - i);
+                        bytes_read += (amount - i);
+                        bytes_to_read -= (amount - i);
+                        if (i) {
+                                retval = bytes_read ? bytes_read : -EFAULT;
+                                goto exit;
+                        }
+                } else {
+                        /* we check the primary buffer */
+                        spin_lock_irqsave (&dev->buflock, flags);
+                        if (dev->read_buffer_length) {
+                                /* we secure access to the primary */
+                                char *tmp;
+                                dbg(2," %s : swap, read_buffer_length = %d",
+                                    __FUNCTION__, dev->read_buffer_length);
+                                tmp = dev->read_buffer_secondary;
+                                dev->read_buffer_secondary = dev->read_buffer_primary;
+                                dev->read_buffer_primary = tmp;
+                                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->interrupt_in_urb->status == -EINPROGRESS) {
+                                        /* somebody is doing IO */
+                                        spin_unlock_irqrestore(&dev->buflock, flags);
+                                        dbg(2," %s : submitted already", __FUNCTION__);
+                                } else {
+                                        /* we must initiate input */
+                                        dbg(2," %s : initiate input", __FUNCTION__);
+                                        dev->read_urb_finished = 0;
+
+                                        usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
+                                                         usb_rcvintpipe(dev->udev,
+                                                                        dev->interrupt_in_endpoint->bEndpointAddress),
+                                                         dev->interrupt_in_buffer,
+                                                         le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
+                                                         adu_interrupt_in_callback,
+                                                         dev,
+                                                         dev->interrupt_in_endpoint->bInterval);
+                                        retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
+                                        if (!retval) {
+                                                spin_unlock_irqrestore(&dev->buflock, flags);
+                                                dbg(2," %s : submitted OK", __FUNCTION__);
+                                        } else {
+                                                if (retval == -ENOMEM) {
+                                                        retval = bytes_read ? bytes_read : -ENOMEM;
+                                                }
+                                                spin_unlock_irqrestore(&dev->buflock, flags);
+                                                dbg(2," %s : submit failed", __FUNCTION__);
+                                                goto exit;
+                                        }
+                                }
+
+                                /* we wait for I/O to complete */
+                                set_current_state(TASK_INTERRUPTIBLE);
+                                add_wait_queue(&dev->read_wait, &wait);
+                                if (!dev->read_urb_finished)
+                                        timeout = schedule_timeout(COMMAND_TIMEOUT);
+                                else
+                                        set_current_state(TASK_RUNNING);
+                                remove_wait_queue(&dev->read_wait, &wait);
+
+                                if (timeout <= 0) {
+                                        dbg(2," %s : timeout", __FUNCTION__);
+                                        retval = bytes_read ? bytes_read : -ETIMEDOUT;
+                                        goto exit;
+                                }
+
+                                if (signal_pending(current)) {
+                                        dbg(2," %s : signal pending", __FUNCTION__);
+                                        retval = bytes_read ? bytes_read : -EINTR;
+                                        goto exit;
+                                }
+                        }
+                }
+        }
+
+        retval = bytes_read;
+        /* if the primary buffer is empty then use it */
+        if (should_submit && !dev->interrupt_in_urb->status==-EINPROGRESS) {
+                usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
+                                 usb_rcvintpipe(dev->udev,
+                                                dev->interrupt_in_endpoint->bEndpointAddress),
+                                                dev->interrupt_in_buffer,
+                                                le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
+                                                adu_interrupt_in_callback,
+                                                dev,
+                                                dev->interrupt_in_endpoint->bInterval);
+                /* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
+                dev->read_urb_finished = 0;
+                usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
+                /* we ignore failure */
+        }
+
+exit:
+        /* unlock the device */
+        up(&dev->sem);
+
+        dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
+        return retval;
+}
+
+static ssize_t adu_write(struct file *file, const __user char *buffer,
+                         size_t count, loff_t *ppos)
+{
+        struct adu_device *dev;
+        size_t bytes_written = 0;
+        size_t bytes_to_write;
+        size_t buffer_size;
+        int retval = 0;
+        int timeout = 0;
+
+        dbg(2," %s : enter, count = %Zd", __FUNCTION__, count);
+
+        dev = file->private_data;
+
+        /* lock this object */
+        down_interruptible(&dev->sem);
+
+        /* verify that the device wasn't unplugged */
+        if (dev->udev == NULL || dev->minor == 0) {
+                retval = -ENODEV;
+                err("No device or device unplugged %d", retval);
+                goto exit;
+        }
+
+        /* verify that we actually have some data to write */
+        if (count == 0) {
+                dbg(1," %s : write request of 0 bytes", __FUNCTION__);
+                goto exit;
+        }
+
+
+        while (count > 0) {
+                if (dev->interrupt_out_urb->status == -EINPROGRESS) {
+                        timeout = COMMAND_TIMEOUT;
+
+                        while (timeout > 0) {
+                                if (signal_pending(current)) {
+                                dbg(1," %s : interrupted", __FUNCTION__);
+                                retval = -EINTR;
+                                goto exit;
+                        }
+                        up(&dev->sem);
+                        timeout = interruptible_sleep_on_timeout(&dev->write_wait, timeout);
+                        down_interruptible(&dev->sem);
+                        if (timeout > 0) {
+                                break;
+                        }
+                        dbg(1," %s : interrupted timeout: %d", __FUNCTION__, timeout);
+                }
+
+
+                dbg(1," %s : final timeout: %d", __FUNCTION__, timeout);
+
+                if (timeout == 0) {
+                        dbg(1, "%s - command timed out.", __FUNCTION__);
+                        retval = -ETIMEDOUT;
+                        goto exit;
+                }
+
+                dbg(4," %s : in progress, count = %Zd", __FUNCTION__, count);
+
+                } else {
+                        dbg(4," %s : sending, count = %Zd", __FUNCTION__, count);
+
+                        /* write the data into interrupt_out_buffer from userspace */
+                        buffer_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);
+                        bytes_to_write = count > buffer_size ? buffer_size : count;
+                        dbg(4," %s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd",
+                            __FUNCTION__, 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_in_endpoint->bInterval);
+                        /* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
+                        dev->interrupt_out_urb->actual_length = bytes_to_write;
+                        retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
+                        if (retval < 0) {
+                                err("Couldn't submit interrupt_out_urb %d", retval);
+                                goto exit;
+                        }
+
+                        buffer += bytes_to_write;
+                        count -= bytes_to_write;
+
+                        bytes_written += bytes_to_write;
+                }
+        }
+
+        retval = bytes_written;
+
+exit:
+        /* unlock the device */
+        up(&dev->sem);
+
+        dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
+
+        return retval;
+}
+
+/* file operations needed when we register this driver */
+static struct file_operations adu_fops = {
+        .owner = THIS_MODULE,
+        .read  = adu_read,
+        .write = adu_write,
+        .open = adu_open,
+        .release = adu_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 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;
+        struct usb_host_interface *iface_desc;
+        struct usb_endpoint_descriptor *endpoint;
+        int retval = -ENODEV;
+        int in_end_size;
+        int out_end_size;
+        int i;
+
+        dbg(2," %s : enter", __FUNCTION__);
+
+        if (udev == NULL) {
+                dev_err(&interface->dev, "udev is NULL.\n");
+                goto exit;
+        }
+
+        /* allocate memory for our device state and intialize it */
+        dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
+        if (dev == NULL) {
+                dev_err(&interface->dev, "Out of memory\n");
+                retval = -ENOMEM;
+                goto exit;
+        }
+
+        init_MUTEX(&dev->sem);
+        spin_lock_init(&dev->buflock);
+        dev->udev = udev;
+        init_waitqueue_head(&dev->read_wait);
+        init_waitqueue_head(&dev->write_wait);
+
+        iface_desc = &interface->altsetting[0];
+
+        /* set up the endpoint information */
+        for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
+                endpoint = &iface_desc->endpoint[i].desc;
+
+                if (usb_endpoint_is_int_in(endpoint))
+                        dev->interrupt_in_endpoint = endpoint;
+
+                if (usb_endpoint_is_int_out(endpoint))
+                        dev->interrupt_out_endpoint = endpoint;
+        }
+        if (dev->interrupt_in_endpoint == NULL) {
+                dev_err(&interface->dev, "interrupt in endpoint not found\n");
+                goto error;
+        }
+        if (dev->interrupt_out_endpoint == NULL) {
+                dev_err(&interface->dev, "interrupt out endpoint not found\n");
+                goto error;
+        }
+
+        in_end_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
+        out_end_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);
+
+        dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
+        if (!dev->read_buffer_primary) {
+                dev_err(&interface->dev, "Couldn't allocate read_buffer_primary\n");
+                retval = -ENOMEM;
+                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) {
+                dev_err(&interface->dev, "Couldn't allocate read_buffer_secondary\n");
+                retval = -ENOMEM;
+                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) {
+                dev_err(&interface->dev, "Couldn't allocate interrupt_in_buffer\n");
+                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) {
+                dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
+                goto error;
+        }
+        dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
+        if (!dev->interrupt_out_buffer) {
+                dev_err(&interface->dev, "Couldn't allocate interrupt_out_buffer\n");
+                goto error;
+        }
+        dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+        if (!dev->interrupt_out_urb) {
+                dev_err(&interface->dev, "Couldn't allocate interrupt_out_urb\n");
+                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");
+                goto error;
+        }
+        dbg(2," %s : serial_number=%s", __FUNCTION__, 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",
+                 udev->descriptor.idProduct, dev->serial_number,
+                 (dev->minor - ADU_MINOR_BASE));
+exit:
+        dbg(2," %s : leave, return value %p (dev)", __FUNCTION__, dev);
+
+        return retval;
+
+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;
+        int minor;
+
+        dbg(2," %s : enter", __FUNCTION__);
+
+        mutex_lock(&disconnect_mutex); /* not interruptible */
+
+        dev = usb_get_intfdata(interface);
+        usb_set_intfdata(interface, NULL);
+
+        down(&dev->sem); /* not interruptible */
+
+        minor = dev->minor;
+
+        /* give back our minor */
+        usb_deregister_dev(interface, &adu_class);
+        dev->minor = 0;
+
+        /* if the device is not opened, then we clean up right now */
+        dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
+        if (!dev->open_count) {
+                up(&dev->sem);
+                adu_delete(dev);
+        } else {
+                dev->udev = NULL;
+                up(&dev->sem);
+        }
+
+        mutex_unlock(&disconnect_mutex);
+
+        dev_info(&interface->dev, "ADU device adutux%d now disconnected",
+                 (minor - ADU_MINOR_BASE));
+
+        dbg(2," %s : leave", __FUNCTION__);
+}
+
+/* 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,
+};
+
+static int __init adu_init(void)
+{
+        int result;
+
+        dbg(2," %s : enter", __FUNCTION__);
+
+        /* register this driver with the USB subsystem */
+        result = usb_register(&adu_driver);
+        if (result < 0) {
+                err("usb_register failed for the "__FILE__" driver. "
+                    "Error number %d", result);
+                goto exit;
+        }
+
+        info("adutux " DRIVER_DESC " " DRIVER_VERSION);
+        info("adutux is an experimental driver. Use at your own risk");
+
+exit:
+        dbg(2," %s : leave, return value %d", __FUNCTION__, result);
+
+        return result;
+}
+
+static void __exit adu_exit(void)
+{
+        dbg(2," %s : enter", __FUNCTION__);
+        /* deregister this driver with the USB subsystem */
+        usb_deregister(&adu_driver);
+        dbg(2," %s : leave", __FUNCTION__);
+}
+
+module_init(adu_init);
+module_exit(adu_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");