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);