USB: add driver for iowarrior devices.

The ioctl is commented out for now, until we verify some userspace
application issues.

Cc: Christian Lucht <lucht@codemercs.com>
Cc: Robert Marquardt <marquardt@codemercs.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 940 insertions, 0 deletions

diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index 4907e8b80070..9c7eb6144d02 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -244,6 +244,20 @@ config USB_TRANCEVIBRATOR
 	  To compile this driver as a module, choose M here: the
 	  module will be called trancevibrator.
 
+config USB_IOWARRIOR
+	tristate "IO Warrior driver support"
+	depends on USB
+	help
+	  Say Y here if you want to support the IO Warrior devices from Code
+	  Mercenaries.  This includes support for the following devices:
+	  	IO Warrior 40
+		IO Warrior 24
+		IO Warrior 56
+		IO Warrior 24 Power Vampire
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iowarrior.
+
 config USB_TEST
 	tristate "USB testing driver (DEVELOPMENT)"
 	depends on USB && USB_DEVICEFS && EXPERIMENTAL
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index dac2d5b71566..b68e6b774f1a 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_USB_EMI26)		+= emi26.o
 obj-$(CONFIG_USB_EMI62)		+= emi62.o
 obj-$(CONFIG_USB_FTDI_ELAN)	+= ftdi-elan.o
 obj-$(CONFIG_USB_IDMOUSE)	+= idmouse.o
+obj-$(CONFIG_USB_IOWARRIOR)	+= iowarrior.o
 obj-$(CONFIG_USB_LCD)		+= usblcd.o
 obj-$(CONFIG_USB_LD)		+= ldusb.o
 obj-$(CONFIG_USB_LED)		+= usbled.o
diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
new file mode 100644
index 000000000000..d69665c8de02
--- /dev/null
+++ b/drivers/usb/misc/iowarrior.c
@@ -0,0 +1,925 @@
+/*
+ *  Native support for the I/O-Warrior USB devices
+ *
+ *  Copyright (c) 2003-2005  Code Mercenaries GmbH
+ *  written by Christian Lucht <lucht@codemercs.com>
+ *
+ *  based on
+
+ *  usb-skeleton.c by Greg Kroah-Hartman  <greg@kroah.com>
+ *  brlvger.c by Stephane Dalton  <sdalton@videotron.ca>
+ *           and St�hane Doyon   <s.doyon@videotron.ca>
+ *
+ *  Released under the GPLv2.
+ */
+
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/poll.h>
+#include <linux/version.h>
+#include <linux/usb/iowarrior.h>
+
+/* Version Information */
+#define DRIVER_VERSION "v0.4.0"
+#define DRIVER_AUTHOR "Christian Lucht <lucht@codemercs.com>"
+#define DRIVER_DESC "USB IO-Warrior driver (Linux 2.6.x)"
+
+#define USB_VENDOR_ID_CODEMERCS		1984
+/* low speed iowarrior */
+#define USB_DEVICE_ID_CODEMERCS_IOW40	0x1500
+#define USB_DEVICE_ID_CODEMERCS_IOW24	0x1501
+#define USB_DEVICE_ID_CODEMERCS_IOWPV1	0x1511
+#define USB_DEVICE_ID_CODEMERCS_IOWPV2	0x1512
+/* full speed iowarrior */
+#define USB_DEVICE_ID_CODEMERCS_IOW56	0x1503
+
+/* Get a minor range for your devices from the usb maintainer */
+#ifdef CONFIG_USB_DYNAMIC_MINORS
+#define IOWARRIOR_MINOR_BASE	0
+#else
+#define IOWARRIOR_MINOR_BASE	208	// SKELETON_MINOR_BASE 192 + 16, not offical yet
+#endif
+
+/* interrupt input queue size */
+#define MAX_INTERRUPT_BUFFER 16
+/*
+   maximum number of urbs that are submitted for writes at the same time,
+   this applies to the IOWarrior56 only!
+   IOWarrior24 and IOWarrior40 use synchronous usb_control_msg calls.
+*/
+#define MAX_WRITES_IN_FLIGHT 4
+
+/* Use our own dbg macro */
+#undef dbg
+#define dbg( format, arg... ) do { if( debug ) printk( KERN_DEBUG __FILE__ ": " format "\n" , ## arg ); } while ( 0 )
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/* Module parameters */
+static int debug = 0;
+module_param(debug, bool, 0644);
+MODULE_PARM_DESC(debug, "debug=1 enables debugging messages");
+
+static struct usb_driver iowarrior_driver;
+
+/*--------------*/
+/*     data     */
+/*--------------*/
+
+/* Structure to hold all of our device specific stuff */
+struct iowarrior {
+	struct mutex mutex;			/* locks this structure */
+	struct usb_device *udev;		/* save off the usb device pointer */
+	struct usb_interface *interface;	/* the interface for this device */
+	unsigned char minor;			/* the starting minor number for this device */
+	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
+	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
+	struct urb *int_in_urb;		/* the urb for reading data */
+	unsigned char *int_in_buffer;	/* buffer for data to be read */
+	unsigned char serial_number;	/* to detect lost packages */
+	unsigned char *read_queue;	/* size is MAX_INTERRUPT_BUFFER * packet size */
+	wait_queue_head_t read_wait;
+	wait_queue_head_t write_wait;	/* wait-queue for writing to the device */
+	atomic_t write_busy;		/* number of write-urbs submitted */
+	atomic_t read_idx;
+	atomic_t intr_idx;
+	spinlock_t intr_idx_lock;	/* protects intr_idx */
+	atomic_t overflow_flag;		/* signals an index 'rollover' */
+	int present;			/* this is 1 as long as the device is connected */
+	int opened;			/* this is 1 if the device is currently open */
+	char chip_serial[9];		/* the serial number string of the chip connected */
+	int report_size;		/* number of bytes in a report */
+	u16 product_id;
+};
+
+/*--------------*/
+/*    globals   */
+/*--------------*/
+/* prevent races between open() and disconnect() */
+static DECLARE_MUTEX(disconnect_sem);
+
+/*
+ *  USB spec identifies 5 second timeouts.
+ */
+#define GET_TIMEOUT 5
+#define USB_REQ_GET_REPORT  0x01
+//#if 0
+static int usb_get_report(struct usb_device *dev,
+			  struct usb_host_interface *inter, unsigned char type,
+			  unsigned char id, void *buf, int size)
+{
+	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+			       USB_REQ_GET_REPORT,
+			       USB_DIR_IN | USB_TYPE_CLASS |
+			       USB_RECIP_INTERFACE, (type << 8) + id,
+			       inter->desc.bInterfaceNumber, buf, size,
+			       GET_TIMEOUT);
+}
+//#endif
+
+#define USB_REQ_SET_REPORT 0x09
+
+static int usb_set_report(struct usb_interface *intf, unsigned char type,
+			  unsigned char id, void *buf, int size)
+{
+	return usb_control_msg(interface_to_usbdev(intf),
+			       usb_sndctrlpipe(interface_to_usbdev(intf), 0),
+			       USB_REQ_SET_REPORT,
+			       USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+			       (type << 8) + id,
+			       intf->cur_altsetting->desc.bInterfaceNumber, buf,
+			       size, 1);
+}
+
+/*---------------------*/
+/* driver registration */
+/*---------------------*/
+/* table of devices that work with this driver */
+static struct usb_device_id iowarrior_ids[] = {
+	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
+	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
+	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
+	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
+	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
+	{}			/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, iowarrior_ids);
+
+/*
+ * USB callback handler for reading data
+ */
+static void iowarrior_callback(struct urb *urb)
+{
+	struct iowarrior *dev = (struct iowarrior *)urb->context;
+	int intr_idx;
+	int read_idx;
+	int aux_idx;
+	int offset;
+	int status;
+
+	switch (urb->status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		return;
+	default:
+		goto exit;
+	}
+
+	spin_lock(&dev->intr_idx_lock);
+	intr_idx = atomic_read(&dev->intr_idx);
+	/* aux_idx become previous intr_idx */
+	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
+	read_idx = atomic_read(&dev->read_idx);
+
+	/* queue is not empty and it's interface 0 */
+	if ((intr_idx != read_idx)
+	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
+		/* + 1 for serial number */
+		offset = aux_idx * (dev->report_size + 1);
+		if (!memcmp
+		    (dev->read_queue + offset, urb->transfer_buffer,
+		     dev->report_size)) {
+			/* equal values on interface 0 will be ignored */
+			spin_unlock(&dev->intr_idx_lock);
+			goto exit;
+		}
+	}
+
+	/* aux_idx become next intr_idx */
+	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
+	if (read_idx == aux_idx) {
+		/* queue full, dropping oldest input */
+		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
+		atomic_set(&dev->read_idx, read_idx);
+		atomic_set(&dev->overflow_flag, 1);
+	}
+
+	/* +1 for serial number */
+	offset = intr_idx * (dev->report_size + 1);
+	memcpy(dev->read_queue + offset, urb->transfer_buffer,
+	       dev->report_size);
+	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
+
+	atomic_set(&dev->intr_idx, aux_idx);
+	spin_unlock(&dev->intr_idx_lock);
+	/* tell the blocking read about the new data */
+	wake_up_interruptible(&dev->read_wait);
+
+exit:
+	status = usb_submit_urb(urb, GFP_ATOMIC);
+	if (status)
+		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d",
+			__FUNCTION__, status);
+
+}
+
+/*
+ * USB Callback handler for write-ops
+ */
+static void iowarrior_write_callback(struct urb *urb)
+{
+	struct iowarrior *dev;
+	dev = (struct iowarrior *)urb->context;
+	/* sync/async unlink faults aren't errors */
+	if (urb->status &&
+	    !(urb->status == -ENOENT ||
+	      urb->status == -ECONNRESET || urb->status == -ESHUTDOWN)) {
+		dbg("%s - nonzero write bulk status received: %d",
+		    __func__, urb->status);
+	}
+	/* free up our allocated buffer */
+	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
+			urb->transfer_buffer, urb->transfer_dma);
+	/* tell a waiting writer the interrupt-out-pipe is available again */
+	atomic_dec(&dev->write_busy);
+	wake_up_interruptible(&dev->write_wait);
+}
+
+/**
+ *	iowarrior_delete
+ */
+static inline void iowarrior_delete(struct iowarrior *dev)
+{
+	dbg("%s - minor %d", __func__, dev->minor);
+	kfree(dev->int_in_buffer);
+	usb_free_urb(dev->int_in_urb);
+	kfree(dev->read_queue);
+	kfree(dev);
+}
+
+/*---------------------*/
+/* fops implementation */
+/*---------------------*/
+
+static int read_index(struct iowarrior *dev)
+{
+	int intr_idx, read_idx;
+
+	read_idx = atomic_read(&dev->read_idx);
+	intr_idx = atomic_read(&dev->intr_idx);
+
+	return (read_idx == intr_idx ? -1 : read_idx);
+}
+
+/**
+ *  iowarrior_read
+ */
+static ssize_t iowarrior_read(struct file *file, char __user *buffer,
+			      size_t count, loff_t *ppos)
+{
+	struct iowarrior *dev;
+	int read_idx;
+	int offset;
+
+	dev = (struct iowarrior *)file->private_data;
+
+	/* verify that the device wasn't unplugged */
+	if (dev == NULL || !dev->present)
+		return -ENODEV;
+
+	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
+
+	/* read count must be packet size (+ time stamp) */
+	if ((count != dev->report_size)
+	    && (count != (dev->report_size + 1)))
+		return -EINVAL;
+
+	/* repeat until no buffer overrun in callback handler occur */
+	do {
+		atomic_set(&dev->overflow_flag, 0);
+		if ((read_idx = read_index(dev)) == -1) {
+			/* queue emty */
+			if (file->f_flags & O_NONBLOCK)
+				return -EAGAIN;
+			else {
+				//next line will return when there is either new data, or the device is unplugged
+				int r = wait_event_interruptible(dev->read_wait,
+								 (!dev->present
+								  || (read_idx =
+								      read_index
+								      (dev)) !=
+								  -1));
+				if (r) {
+					//we were interrupted by a signal
+					return -ERESTART;
+				}
+				if (!dev->present) {
+					//The device was unplugged
+					return -ENODEV;
+				}
+				if (read_idx == -1) {
+					// Can this happen ???
+					return 0;
+				}
+			}
+		}
+
+		offset = read_idx * (dev->report_size + 1);
+		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
+			return -EFAULT;
+		}
+	} while (atomic_read(&dev->overflow_flag));
+
+	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
+	atomic_set(&dev->read_idx, read_idx);
+	return count;
+}
+
+/*
+ * iowarrior_write
+ */
+static ssize_t iowarrior_write(struct file *file,
+			       const char __user *user_buffer,
+			       size_t count, loff_t *ppos)
+{
+	struct iowarrior *dev;
+	int retval = 0;
+	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
+	struct urb *int_out_urb = NULL;
+
+	dev = (struct iowarrior *)file->private_data;
+
+	mutex_lock(&dev->mutex);
+	/* verify that the device wasn't unplugged */
+	if (dev == NULL || !dev->present) {
+		retval = -ENODEV;
+		goto exit;
+	}
+	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
+	/* if count is 0 we're already done */
+	if (count == 0) {
+		retval = 0;
+		goto exit;
+	}
+	/* We only accept full reports */
+	if (count != dev->report_size) {
+		retval = -EINVAL;
+		goto exit;
+	}
+	switch (dev->product_id) {
+	case USB_DEVICE_ID_CODEMERCS_IOW24:
+	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
+	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
+	case USB_DEVICE_ID_CODEMERCS_IOW40:
+		/* IOW24 and IOW40 use a synchronous call */
+		buf = kmalloc(8, GFP_KERNEL);	/* 8 bytes are enough for both products */
+		if (!buf) {
+			retval = -ENOMEM;
+			goto exit;
+		}
+		if (copy_from_user(buf, user_buffer, count)) {
+			retval = -EFAULT;
+			kfree(buf);
+			goto exit;
+		}
+		retval = usb_set_report(dev->interface, 2, 0, buf, count);
+		kfree(buf);
+		goto exit;
+		break;
+	case USB_DEVICE_ID_CODEMERCS_IOW56:
+		/* The IOW56 uses asynchronous IO and more urbs */
+		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
+			/* Wait until we are below the limit for submitted urbs */
+			if (file->f_flags & O_NONBLOCK) {
+				retval = -EAGAIN;
+				goto exit;
+			} else {
+				retval = wait_event_interruptible(dev->write_wait,
+								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
+				if (retval) {
+					/* we were interrupted by a signal */
+					retval = -ERESTART;
+					goto exit;
+				}
+				if (!dev->present) {
+					/* The device was unplugged */
+					retval = -ENODEV;
+					goto exit;
+				}
+				if (!dev->opened) {
+					/* We were closed while waiting for an URB */
+					retval = -ENODEV;
+					goto exit;
+				}
+			}
+		}
+		atomic_inc(&dev->write_busy);
+		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!int_out_urb) {
+			retval = -ENOMEM;
+			dbg("%s Unable to allocate urb ", __func__);
+			goto error;
+		}
+		buf = usb_buffer_alloc(dev->udev, dev->report_size,
+				       GFP_KERNEL, &int_out_urb->transfer_dma);
+		if (!buf) {
+			retval = -ENOMEM;
+			dbg("%s Unable to allocate buffer ", __func__);
+			goto error;
+		}
+		usb_fill_int_urb(int_out_urb, dev->udev,
+				 usb_sndintpipe(dev->udev,
+						dev->int_out_endpoint->bEndpointAddress),
+				 buf, dev->report_size,
+				 iowarrior_write_callback, dev,
+				 dev->int_out_endpoint->bInterval);
+		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+		if (copy_from_user(buf, user_buffer, count)) {
+			retval = -EFAULT;
+			goto error;
+		}
+		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
+		if (retval) {
+			dbg("%s submit error %d for urb nr.%d", __func__,
+			    retval, atomic_read(&dev->write_busy));
+			goto error;
+		}
+		/* submit was ok */
+		retval = count;
+		usb_free_urb(int_out_urb);
+		goto exit;
+		break;
+	default:
+		/* what do we have here ? An unsupported Product-ID ? */
+		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x",
+			__FUNCTION__, dev->product_id);
+		retval = -EFAULT;
+		goto exit;
+		break;
+	}
+error:
+	usb_buffer_free(dev->udev, dev->report_size, buf,
+			int_out_urb->transfer_dma);
+	usb_free_urb(int_out_urb);
+	atomic_dec(&dev->write_busy);
+	wake_up_interruptible(&dev->write_wait);
+exit:
+	mutex_unlock(&dev->mutex);
+	return retval;
+}
+
+/**
+ *	iowarrior_ioctl
+ */
+static int iowarrior_ioctl(struct inode *inode, struct file *file,
+			   unsigned int cmd, unsigned long arg)
+{
+	struct iowarrior *dev = NULL;
+	__u8 *buffer;
+	__u8 __user *user_buffer;
+	int retval;
+	int io_res;		/* checks for bytes read/written and copy_to/from_user results */
+
+	dev = (struct iowarrior *)file->private_data;
+	if (dev == NULL) {
+		return -ENODEV;
+	}
+
+	buffer = kzalloc(dev->report_size, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	/* lock this object */
+	mutex_lock(&dev->mutex);
+
+	/* verify that the device wasn't unplugged */
+	if (!dev->present) {
+		mutex_unlock(&dev->mutex);
+		return -ENODEV;
+	}
+
+	dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __func__, dev->minor, cmd,
+	    arg);
+
+	retval = 0;
+	io_res = 0;
+	switch (cmd) {
+	case IOW_WRITE:
+		if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
+		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
+		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
+		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
+			user_buffer = (__u8 __user *)arg;
+			io_res = copy_from_user(buffer, user_buffer,
+						dev->report_size);
+			if (io_res) {
+				retval = -EFAULT;
+			} else {
+				io_res = usb_set_report(dev->interface, 2, 0,
+							buffer,
+							dev->report_size);
+				if (io_res < 0)
+					retval = io_res;
+			}
+		} else {
+			retval = -EINVAL;
+			dev_err(&dev->interface->dev,
+				"ioctl 'IOW_WRITE' is not supported for product=0x%x.",
+				dev->product_id);
+		}
+		break;
+	case IOW_READ:
+		user_buffer = (__u8 __user *)arg;
+		io_res = usb_get_report(dev->udev,
+					dev->interface->cur_altsetting, 1, 0,
+					buffer, dev->report_size);
+		if (io_res < 0)
+			retval = io_res;
+		else {
+			io_res = copy_to_user(user_buffer, buffer, dev->report_size);
+			if (io_res < 0)
+				retval = -EFAULT;
+		}
+		break;
+	case IOW_GETINFO:
+		{
+			/* Report available information for the device */
+			struct iowarrior_info info;
+			/* needed for power consumption */
+			struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
+
+			/* directly from the descriptor */
+			info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
+			info.product = dev->product_id;
+			info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
+
+			/* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
+			info.speed = le16_to_cpu(dev->udev->speed);
+			info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
+			info.report_size = dev->report_size;
+
+			/* serial number string has been read earlier 8 chars or empty string */
+			memcpy(info.serial, dev->chip_serial,
+			       sizeof(dev->chip_serial));
+			if (cfg_descriptor == NULL) {
+				info.power = -1;	/* no information available */
+			} else {
+				/* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
+				info.power = cfg_descriptor->bMaxPower * 2;
+			}
+			io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
+					 sizeof(struct iowarrior_info));
+			if (io_res < 0)
+				retval = -EFAULT;
+			break;
+		}
+	default:
+		/* return that we did not understand this ioctl call */
+		retval = -ENOTTY;
+		break;
+	}
+
+	/* unlock the device */
+	mutex_unlock(&dev->mutex);
+	return retval;
+}
+
+/**
+ *	iowarrior_open
+ */
+static int iowarrior_open(struct inode *inode, struct file *file)
+{
+	struct iowarrior *dev = NULL;
+	struct usb_interface *interface;
+	int subminor;
+	int retval = 0;
+
+	dbg("%s", __func__);
+
+	subminor = iminor(inode);
+
+	/* prevent disconnects */
+	down(&disconnect_sem);
+
+	interface = usb_find_interface(&iowarrior_driver, subminor);
+	if (!interface) {
+		err("%s - error, can't find device for minor %d", __FUNCTION__,
+		    subminor);
+		retval = -ENODEV;
+		goto out;
+	}
+
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		retval = -ENODEV;
+		goto out;
+	}
+
+	/* Only one process can open each device, no sharing. */
+	if (dev->opened) {
+		retval = -EBUSY;
+		goto out;
+	}
+
+	/* setup interrupt handler for receiving values */
+	if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
+		dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
+		retval = -EFAULT;
+		goto out;
+	}
+	/* increment our usage count for the driver */
+	++dev->opened;
+	/* save our object in the file's private structure */
+	file->private_data = dev;
+	retval = 0;
+
+out:
+	up(&disconnect_sem);
+	return retval;
+}
+
+/**
+ *	iowarrior_release
+ */
+static int iowarrior_release(struct inode *inode, struct file *file)
+{
+	struct iowarrior *dev;
+	int retval = 0;
+
+	dev = (struct iowarrior *)file->private_data;
+	if (dev == NULL) {
+		return -ENODEV;
+	}
+
+	dbg("%s - minor %d", __func__, dev->minor);
+
+	/* lock our device */
+	mutex_lock(&dev->mutex);
+
+	if (dev->opened <= 0) {
+		retval = -ENODEV;	/* close called more than once */
+		mutex_unlock(&dev->mutex);
+	} else {
+		dev->opened = 0;	/* we're closeing now */
+		retval = 0;
+		if (dev->present) {
+			/*
+			   The device is still connected so we only shutdown
+			   pending read-/write-ops.
+			 */
+			usb_kill_urb(dev->int_in_urb);
+			wake_up_interruptible(&dev->read_wait);
+			wake_up_interruptible(&dev->write_wait);
+			mutex_unlock(&dev->mutex);
+		} else {
+			/* The device was unplugged, cleanup resources */
+			mutex_unlock(&dev->mutex);
+			iowarrior_delete(dev);
+		}
+	}
+	return retval;
+}
+
+static unsigned iowarrior_poll(struct file *file, poll_table * wait)
+{
+	struct iowarrior *dev = file->private_data;
+	unsigned int mask = 0;
+
+	if (!dev->present)
+		return POLLERR | POLLHUP;
+
+	poll_wait(file, &dev->read_wait, wait);
+	poll_wait(file, &dev->write_wait, wait);
+
+	if (!dev->present)
+		return POLLERR | POLLHUP;
+
+	if (read_index(dev) != -1)
+		mask |= POLLIN | POLLRDNORM;
+
+	if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
+		mask |= POLLOUT | POLLWRNORM;
+	return mask;
+}
+
+/*
+ * File operations needed when we register this driver.
+ * This assumes that this driver NEEDS file operations,
+ * of course, which means that the driver is expected
+ * to have a node in the /dev directory. If the USB
+ * device were for a network interface then the driver
+ * would use "struct net_driver" instead, and a serial
+ * device would use "struct tty_driver".
+ */
+static struct file_operations iowarrior_fops = {
+	.owner = THIS_MODULE,
+	.write = iowarrior_write,
+	.read = iowarrior_read,
+	.ioctl = iowarrior_ioctl,
+	.open = iowarrior_open,
+	.release = iowarrior_release,
+	.poll = iowarrior_poll,
+};
+
+/*
+ * 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 iowarrior_class = {
+	.name = "iowarrior%d",
+	.fops = &iowarrior_fops,
+	.minor_base = IOWARRIOR_MINOR_BASE,
+};
+
+/*---------------------------------*/
+/*  probe and disconnect functions */
+/*---------------------------------*/
+/**
+ *	iowarrior_probe
+ *
+ *	Called by the usb core when a new device is connected that it thinks
+ *	this driver might be interested in.
+ */
+static int iowarrior_probe(struct usb_interface *interface,
+			   const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(interface);
+	struct iowarrior *dev = NULL;
+	struct usb_host_interface *iface_desc;
+	struct usb_endpoint_descriptor *endpoint;
+	int i;
+	int retval = -ENOMEM;
+	int idele = 0;
+
+	/* allocate memory for our device state and intialize it */
+	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
+	if (dev == NULL) {
+		dev_err(&interface->dev, "Out of memory");
+		return retval;
+	}
+
+	mutex_init(&dev->mutex);
+
+	atomic_set(&dev->intr_idx, 0);
+	atomic_set(&dev->read_idx, 0);
+	spin_lock_init(&dev->intr_idx_lock);
+	atomic_set(&dev->overflow_flag, 0);
+	init_waitqueue_head(&dev->read_wait);
+	atomic_set(&dev->write_busy, 0);
+	init_waitqueue_head(&dev->write_wait);
+
+	dev->udev = udev;
+	dev->interface = interface;
+
+	iface_desc = interface->cur_altsetting;
+	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
+
+	/* 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->int_in_endpoint = endpoint;
+		if (usb_endpoint_is_int_out(endpoint))
+			/* this one will match for the IOWarrior56 only */
+			dev->int_out_endpoint = endpoint;
+	}
+	/* we have to check the report_size often, so remember it in the endianess suitable for our machine */
+	dev->report_size = le16_to_cpu(dev->int_in_endpoint->wMaxPacketSize);
+	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
+	    (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
+		/* IOWarrior56 has wMaxPacketSize different from report size */
+		dev->report_size = 7;
+
+	/* create the urb and buffer for reading */
+	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->int_in_urb) {
+		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
+		goto error;
+	}
+	dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
+	if (!dev->int_in_buffer) {
+		dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
+		goto error;
+	}
+	usb_fill_int_urb(dev->int_in_urb, dev->udev,
+			 usb_rcvintpipe(dev->udev,
+					dev->int_in_endpoint->bEndpointAddress),
+			 dev->int_in_buffer, dev->report_size,
+			 iowarrior_callback, dev,
+			 dev->int_in_endpoint->bInterval);
+	/* create an internal buffer for interrupt data from the device */
+	dev->read_queue =
+	    kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
+		    GFP_KERNEL);
+	if (!dev->read_queue) {
+		dev_err(&interface->dev, "Couldn't allocate read_queue\n");
+		goto error;
+	}
+	/* Get the serial-number of the chip */
+	memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
+	usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
+		   sizeof(dev->chip_serial));
+	if (strlen(dev->chip_serial) != 8)
+		memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
+
+	/* Set the idle timeout to 0, if this is interface 0 */
+	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
+		idele = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+					0x0A,
+					USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
+					0, NULL, 0, USB_CTRL_SET_TIMEOUT);
+		dbg("idele = %d", idele);
+	}
+	/* allow device read and ioctl */
+	dev->present = 1;
+
+	/* we can register the device now, as it is ready */
+	usb_set_intfdata(interface, dev);
+
+	retval = usb_register_dev(interface, &iowarrior_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, "IOWarrior product=0x%x, serial=%s interface=%d "
+		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
+		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
+	return retval;
+
+error:
+	iowarrior_delete(dev);
+	return retval;
+}
+
+/**
+ *	iowarrior_disconnect
+ *
+ *	Called by the usb core when the device is removed from the system.
+ */
+static void iowarrior_disconnect(struct usb_interface *interface)
+{
+	struct iowarrior *dev;
+	int minor;
+
+	/* prevent races with open() */
+	down(&disconnect_sem);
+
+	dev = usb_get_intfdata(interface);
+	usb_set_intfdata(interface, NULL);
+
+	mutex_lock(&dev->mutex);
+
+	minor = dev->minor;
+
+	/* give back our minor */
+	usb_deregister_dev(interface, &iowarrior_class);
+
+	/* prevent device read, write and ioctl */
+	dev->present = 0;
+
+	mutex_unlock(&dev->mutex);
+
+	if (dev->opened) {
+		/* There is a process that holds a filedescriptor to the device ,
+		   so we only shutdown read-/write-ops going on.
+		   Deleting the device is postponed until close() was called.
+		 */
+		usb_kill_urb(dev->int_in_urb);
+		wake_up_interruptible(&dev->read_wait);
+		wake_up_interruptible(&dev->write_wait);
+	} else {
+		/* no process is using the device, cleanup now */
+		iowarrior_delete(dev);
+	}
+	up(&disconnect_sem);
+
+	dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
+		 minor - IOWARRIOR_MINOR_BASE);
+}
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver iowarrior_driver = {
+	.name = "iowarrior",
+	.probe = iowarrior_probe,
+	.disconnect = iowarrior_disconnect,
+	.id_table = iowarrior_ids,
+};
+
+static int __init iowarrior_init(void)
+{
+	return usb_register(&iowarrior_driver);
+}
+
+static void __exit iowarrior_exit(void)
+{
+	usb_deregister(&iowarrior_driver);
+}
+
+module_init(iowarrior_init);
+module_exit(iowarrior_exit);