/* * Frontier Designs Alphatrack driver * * Copyright (C) 2007 Michael Taht (m@taht.net) * * Based on the usbled driver and ldusb drivers by * * Copyright (C) 2004 Greg Kroah-Hartman (greg@kroah.com) * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de> * * The ldusb driver was, in turn, derived from Lego USB Tower driver * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net> * 2001-2004 Juergen Stuber <starblue@users.sourceforge.net> * * 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, version 2. * */ /** * This driver uses a ring buffer for time critical reading of * interrupt in reports and provides read and write methods for * raw interrupt reports. */ /* Note: this currently uses a dumb ringbuffer for reads and writes. * A more optimal driver would cache and kill off outstanding urbs that are * now invalid, and ignore ones that already were in the queue but valid * as we only have 30 commands for the alphatrack. In particular this is * key for getting lights to flash in time as otherwise many commands * can be buffered up before the light change makes it to the interface. */ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/kobject.h> #include <linux/mutex.h> #include <linux/uaccess.h> #include <linux/input.h> #include <linux/usb.h> #include <linux/poll.h> #include "alphatrack.h" #define VENDOR_ID 0x165b #define PRODUCT_ID 0xfad1 #ifdef CONFIG_USB_DYNAMIC_MINORS #define USB_ALPHATRACK_MINOR_BASE 0 #else /* FIXME 176 - is another driver's minor - apply for that */ #define USB_ALPHATRACK_MINOR_BASE 176 #endif /* table of devices that work with this driver */ static struct usb_device_id usb_alphatrack_table[] = { {USB_DEVICE(VENDOR_ID, PRODUCT_ID)}, {} /* Terminating entry */ }; MODULE_DEVICE_TABLE(usb, usb_alphatrack_table); MODULE_VERSION("0.41"); MODULE_AUTHOR("Mike Taht <m@taht.net>"); MODULE_DESCRIPTION("Alphatrack USB Driver"); MODULE_LICENSE("GPL"); MODULE_SUPPORTED_DEVICE("Frontier Designs Alphatrack Control Surface"); /* These aren't done yet */ #define SUPPRESS_EXTRA_ONLINE_EVENTS 0 #define BUFFERED_WRITES 0 #define SUPPRESS_EXTRA_OFFLINE_EVENTS 0 #define COMPRESS_FADER_EVENTS 0 #define BUFFERED_READS 1 #define RING_BUFFER_SIZE 512 #define WRITE_BUFFER_SIZE 34 #define ALPHATRACK_USB_TIMEOUT 10 #define OUTPUT_CMD_SIZE 8 #define INPUT_CMD_SIZE 12 #define ALPHATRACK_DEBUG 0 static int debug = ALPHATRACK_DEBUG; /* Use our own dbg macro */ #define dbg_info(dev, format, arg...) do \ { if (debug) dev_info(dev , format , ## arg); } while (0) #define alphatrack_ocmd_info(dev, cmd, format, arg...) #define alphatrack_icmd_info(dev, cmd, format, arg...) /* Module parameters */ module_param(debug, int, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(debug, "Debug enabled or not"); /* All interrupt in transfers are collected in a ring buffer to * avoid racing conditions and get better performance of the driver. */ static int ring_buffer_size = RING_BUFFER_SIZE; module_param(ring_buffer_size, int, S_IRUGO); MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size"); /* The write_buffer can one day contain more than one interrupt out transfer. */ static int write_buffer_size = WRITE_BUFFER_SIZE; module_param(write_buffer_size, int, S_IRUGO); MODULE_PARM_DESC(write_buffer_size, "Write buffer size"); /* * Increase the interval for debugging purposes. * or set to 1 to use the standard interval from the endpoint descriptors. */ static int min_interrupt_in_interval = ALPHATRACK_USB_TIMEOUT; module_param(min_interrupt_in_interval, int, 0); MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms"); static int min_interrupt_out_interval = ALPHATRACK_USB_TIMEOUT; module_param(min_interrupt_out_interval, int, 0); MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms"); /* Structure to hold all of our device specific stuff */ struct usb_alphatrack { struct semaphore sem; /* locks this structure */ struct usb_interface *intf; /* save off the usb interface pointer */ int open_count; /* number of times this port has been opened */ /* make gcc happy */ struct alphatrack_icmd (*ring_buffer)[RING_BUFFER_SIZE]; struct alphatrack_ocmd (*write_buffer)[WRITE_BUFFER_SIZE]; unsigned int ring_head; unsigned int ring_tail; wait_queue_head_t read_wait; wait_queue_head_t write_wait; unsigned char *interrupt_in_buffer; unsigned char *oldi_buffer; struct usb_endpoint_descriptor *interrupt_in_endpoint; struct urb *interrupt_in_urb; int interrupt_in_interval; size_t interrupt_in_endpoint_size; int interrupt_in_running; int interrupt_in_done; char *interrupt_out_buffer; struct usb_endpoint_descriptor *interrupt_out_endpoint; struct urb *interrupt_out_urb; int interrupt_out_interval; size_t interrupt_out_endpoint_size; int interrupt_out_busy; atomic_t writes_pending; int event; /* alternate interface to events */ int fader; /* 10 bits */ int lights; /* 23 bits */ unsigned char dump_state; /* 0 if disabled 1 if enabled */ unsigned char enable; /* 0 if disabled 1 if enabled */ unsigned char offline; /* if the device is out of range or asleep */ unsigned char verbose; /* be verbose in error reporting */ unsigned char last_cmd[OUTPUT_CMD_SIZE]; unsigned char screen[32]; }; /* prevent races between open() and disconnect() */ static DEFINE_MUTEX(disconnect_mutex); /* forward declaration */ static struct usb_driver usb_alphatrack_driver; /** * usb_alphatrack_abort_transfers * aborts transfers and frees associated data structures */ static void usb_alphatrack_abort_transfers(struct usb_alphatrack *dev) { /* shutdown transfer */ if (dev->interrupt_in_running) { dev->interrupt_in_running = 0; if (dev->intf) usb_kill_urb(dev->interrupt_in_urb); } if (dev->interrupt_out_busy) if (dev->intf) usb_kill_urb(dev->interrupt_out_urb); } /** * usb_alphatrack_delete */ static void usb_alphatrack_delete(struct usb_alphatrack *dev) { usb_alphatrack_abort_transfers(dev); usb_free_urb(dev->interrupt_in_urb); usb_free_urb(dev->interrupt_out_urb); kfree(dev->ring_buffer); kfree(dev->interrupt_in_buffer); kfree(dev->interrupt_out_buffer); kfree(dev); /* fixme oldi_buffer */ } /** * usb_alphatrack_interrupt_in_callback */ static void usb_alphatrack_interrupt_in_callback(struct urb *urb) { struct usb_alphatrack *dev = urb->context; unsigned int next_ring_head; int retval = -1; if (urb->status) { if (urb->status == -ENOENT || urb->status == -ECONNRESET || urb->status == -ESHUTDOWN) { goto exit; } else { dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n", __func__, urb->status); goto resubmit; /* maybe we can recover */ } } if (urb->actual_length != INPUT_CMD_SIZE) { dev_warn(&dev->intf->dev, "Urb length was %d bytes!!" "Do something intelligent \n", urb->actual_length); } else { alphatrack_ocmd_info(&dev->intf->dev, &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s", "bla"); if (memcmp (dev->interrupt_in_buffer, dev->oldi_buffer, INPUT_CMD_SIZE) == 0) { goto resubmit; } memcpy(dev->oldi_buffer, dev->interrupt_in_buffer, INPUT_CMD_SIZE); #if SUPPRESS_EXTRA_OFFLINE_EVENTS if (dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff) goto resubmit; if (dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) { dev->offline = 2; goto resubmit; } /* Always pass one offline event up the stack */ if (dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff) dev->offline = 0; if (dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff) dev->offline = 1; #endif dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n", __func__, dev->ring_head, dev->ring_tail); next_ring_head = (dev->ring_head + 1) % ring_buffer_size; if (next_ring_head != dev->ring_tail) { memcpy(&((*dev->ring_buffer)[dev->ring_head]), dev->interrupt_in_buffer, urb->actual_length); dev->ring_head = next_ring_head; retval = 0; memset(dev->interrupt_in_buffer, 0, urb->actual_length); } else { dev_warn(&dev->intf->dev, "Ring buffer overflow, %d bytes dropped\n", urb->actual_length); memset(dev->interrupt_in_buffer, 0, urb->actual_length); } } resubmit: /* resubmit if we're still running */ if (dev->interrupt_in_running && dev->intf) { retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC); if (retval) dev_err(&dev->intf->dev, "usb_submit_urb failed (%d)\n", retval); } exit: dev->interrupt_in_done = 1; wake_up_interruptible(&dev->read_wait); } /** * usb_alphatrack_interrupt_out_callback */ static void usb_alphatrack_interrupt_out_callback(struct urb *urb) { struct usb_alphatrack *dev = urb->context; /* sync/async unlink faults aren't errors */ if (urb->status && !(urb->status == -ENOENT || urb->status == -ECONNRESET || urb->status == -ESHUTDOWN)) dbg_info(&dev->intf->dev, "%s - nonzero write interrupt status received: %d\n", __func__, urb->status); atomic_dec(&dev->writes_pending); dev->interrupt_out_busy = 0; wake_up_interruptible(&dev->write_wait); } /** * usb_alphatrack_open */ static int usb_alphatrack_open(struct inode *inode, struct file *file) { struct usb_alphatrack *dev; int subminor; int retval = 0; struct usb_interface *interface; nonseekable_open(inode, file); subminor = iminor(inode); mutex_lock(&disconnect_mutex); interface = usb_find_interface(&usb_alphatrack_driver, subminor); if (!interface) { err("%s - error, can't find device for minor %d\n", __func__, subminor); retval = -ENODEV; goto unlock_disconnect_exit; } dev = usb_get_intfdata(interface); if (!dev) { retval = -ENODEV; goto unlock_disconnect_exit; } /* lock this device */ if (down_interruptible(&dev->sem)) { retval = -ERESTARTSYS; goto unlock_disconnect_exit; } /* allow opening only once */ if (dev->open_count) { retval = -EBUSY; goto unlock_exit; } dev->open_count = 1; /* initialize in direction */ dev->ring_head = 0; dev->ring_tail = 0; usb_fill_int_urb(dev->interrupt_in_urb, interface_to_usbdev(interface), usb_rcvintpipe(interface_to_usbdev(interface), dev->interrupt_in_endpoint-> bEndpointAddress), dev->interrupt_in_buffer, dev->interrupt_in_endpoint_size, usb_alphatrack_interrupt_in_callback, dev, dev->interrupt_in_interval); dev->interrupt_in_running = 1; dev->interrupt_in_done = 0; dev->enable = 1; dev->offline = 0; retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL); if (retval) { dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval); dev->interrupt_in_running = 0; dev->open_count = 0; goto unlock_exit; } /* save device in the file's private structure */ file->private_data = dev; unlock_exit: up(&dev->sem); unlock_disconnect_exit: mutex_unlock(&disconnect_mutex); return retval; } /** * usb_alphatrack_release */ static int usb_alphatrack_release(struct inode *inode, struct file *file) { struct usb_alphatrack *dev; int retval = 0; dev = file->private_data; if (dev == NULL) { retval = -ENODEV; goto exit; } if (down_interruptible(&dev->sem)) { retval = -ERESTARTSYS; goto exit; } if (dev->open_count != 1) { retval = -ENODEV; goto unlock_exit; } if (dev->intf == NULL) { /* the device was unplugged before the file was released */ up(&dev->sem); /* unlock here as usb_alphatrack_delete frees dev */ usb_alphatrack_delete(dev); retval = -ENODEV; goto exit; } /* wait until write transfer is finished */ if (dev->interrupt_out_busy) wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ); usb_alphatrack_abort_transfers(dev); dev->open_count = 0; unlock_exit: up(&dev->sem); exit: return retval; } /** * usb_alphatrack_poll */ static unsigned int usb_alphatrack_poll(struct file *file, poll_table * wait) { struct usb_alphatrack *dev; unsigned int mask = 0; dev = file->private_data; poll_wait(file, &dev->read_wait, wait); poll_wait(file, &dev->write_wait, wait); if (dev->ring_head != dev->ring_tail) mask |= POLLIN | POLLRDNORM; if (!dev->interrupt_out_busy) mask |= POLLOUT | POLLWRNORM; return mask; } /** * usb_alphatrack_read */ static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) { struct usb_alphatrack *dev; int retval = 0; int c = 0; dev = file->private_data; /* verify that we actually have some data to read */ if (count == 0) goto exit; /* lock this object */ if (down_interruptible(&dev->sem)) { retval = -ERESTARTSYS; goto exit; } /* verify that the device wasn't unplugged */ if (dev->intf == NULL) { retval = -ENODEV; err("No device or device unplugged %d\n", retval); goto unlock_exit; } while (dev->ring_head == dev->ring_tail) { if (file->f_flags & O_NONBLOCK) { retval = -EAGAIN; goto unlock_exit; } dev->interrupt_in_done = 0; retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done); if (retval < 0) goto unlock_exit; } alphatrack_ocmd_info(&dev->intf->dev, &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s", ": copying to userspace"); c = 0; while ((c < count) && (dev->ring_tail != dev->ring_head)) { if (copy_to_user (&buffer[c], &(*dev->ring_buffer)[dev->ring_tail], INPUT_CMD_SIZE)) { retval = -EFAULT; goto unlock_exit; } dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size; c += INPUT_CMD_SIZE; dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n", __func__, dev->ring_head, dev->ring_tail); } retval = c; unlock_exit: /* unlock the device */ up(&dev->sem); exit: return retval; } /** * usb_alphatrack_write */ static ssize_t usb_alphatrack_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { struct usb_alphatrack *dev; size_t bytes_to_write; int retval = 0; dev = file->private_data; /* verify that we actually have some data to write */ if (count == 0) goto exit; /* lock this object */ if (down_interruptible(&dev->sem)) { retval = -ERESTARTSYS; goto exit; } /* verify that the device wasn't unplugged */ if (dev->intf == NULL) { retval = -ENODEV; err("No device or device unplugged %d\n", retval); goto unlock_exit; } /* wait until previous transfer is finished */ if (dev->interrupt_out_busy) { if (file->f_flags & O_NONBLOCK) { retval = -EAGAIN; goto unlock_exit; } retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy); if (retval < 0) goto unlock_exit; } /* write the data into interrupt_out_buffer from userspace */ /* FIXME - if you write more than 12 bytes this breaks */ bytes_to_write = min(count, write_buffer_size * dev->interrupt_out_endpoint_size); if (bytes_to_write < count) dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n", count - bytes_to_write); dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n", __func__, count, bytes_to_write); if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) { retval = -EFAULT; goto unlock_exit; } if (dev->interrupt_out_endpoint == NULL) { err("Endpoint should not be be null! \n"); goto unlock_exit; } /* send off the urb */ usb_fill_int_urb(dev->interrupt_out_urb, interface_to_usbdev(dev->intf), usb_sndintpipe(interface_to_usbdev(dev->intf), dev->interrupt_out_endpoint-> bEndpointAddress), dev->interrupt_out_buffer, bytes_to_write, usb_alphatrack_interrupt_out_callback, dev, dev->interrupt_out_interval); dev->interrupt_out_busy = 1; atomic_inc(&dev->writes_pending); wmb(); retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL); if (retval) { dev->interrupt_out_busy = 0; err("Couldn't submit interrupt_out_urb %d\n", retval); atomic_dec(&dev->writes_pending); goto unlock_exit; } retval = bytes_to_write; unlock_exit: /* unlock the device */ up(&dev->sem); exit: return retval; } /* file operations needed when we register this driver */ static const struct file_operations usb_alphatrack_fops = { .owner = THIS_MODULE, .read = usb_alphatrack_read, .write = usb_alphatrack_write, .open = usb_alphatrack_open, .release = usb_alphatrack_release, .poll = usb_alphatrack_poll, }; /* * usb class driver info in order to get a minor number from the usb core, * and to have the device registered with the driver core */ static struct usb_class_driver usb_alphatrack_class = { .name = "alphatrack%d", .fops = &usb_alphatrack_fops, .minor_base = USB_ALPHATRACK_MINOR_BASE, }; /** * usb_alphatrack_probe * * Called by the usb core when a new device is connected that it thinks * this driver might be interested in. */ static int usb_alphatrack_probe(struct usb_interface *intf, const struct usb_device_id *id) { struct usb_device *udev = interface_to_usbdev(intf); struct usb_alphatrack *dev = NULL; struct usb_host_interface *iface_desc; struct usb_endpoint_descriptor *endpoint; int i; int true_size; int retval = -ENOMEM; /* allocate memory for our device state and intialize it */ dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (dev == NULL) { dev_err(&intf->dev, "Out of memory\n"); goto exit; } init_MUTEX(&dev->sem); dev->intf = intf; init_waitqueue_head(&dev->read_wait); init_waitqueue_head(&dev->write_wait); iface_desc = intf->cur_altsetting; /* 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(&intf->dev, "Interrupt in endpoint not found\n"); goto error; } if (dev->interrupt_out_endpoint == NULL) dev_warn(&intf->dev, "Interrupt out endpoint not found" "(using control endpoint instead)\n"); dev->interrupt_in_endpoint_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize); if (dev->interrupt_in_endpoint_size != 64) dev_warn(&intf->dev, "Interrupt in endpoint size is not 64!\n"); if (ring_buffer_size == 0) ring_buffer_size = RING_BUFFER_SIZE; true_size = min(ring_buffer_size, RING_BUFFER_SIZE); /* FIXME - there are more usb_alloc routines for dma correctness. Needed? */ dev->ring_buffer = kmalloc((true_size * sizeof(struct alphatrack_icmd)), GFP_KERNEL); if (!dev->ring_buffer) { dev_err(&intf->dev, "Couldn't allocate input ring_buffer of size %d\n", true_size); goto error; } dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL); if (!dev->interrupt_in_buffer) { dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n"); goto error; } dev->oldi_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL); if (!dev->oldi_buffer) { dev_err(&intf->dev, "Couldn't allocate old buffer\n"); goto error; } dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL); if (!dev->interrupt_in_urb) { dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n"); goto error; } dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? le16_to_cpu(dev-> interrupt_out_endpoint-> wMaxPacketSize) : udev-> descriptor.bMaxPacketSize0; if (dev->interrupt_out_endpoint_size != 64) dev_warn(&intf->dev, "Interrupt out endpoint size is not 64!)\n"); if (write_buffer_size == 0) write_buffer_size = WRITE_BUFFER_SIZE; true_size = min(write_buffer_size, WRITE_BUFFER_SIZE); dev->interrupt_out_buffer = kmalloc(true_size * dev->interrupt_out_endpoint_size, GFP_KERNEL); if (!dev->interrupt_out_buffer) { dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n"); goto error; } dev->write_buffer = kmalloc(sizeof(struct alphatrack_ocmd) * true_size, GFP_KERNEL); if (!dev->write_buffer) { dev_err(&intf->dev, "Couldn't allocate write_buffer \n"); goto error; } dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL); if (!dev->interrupt_out_urb) { dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n"); goto error; } dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint-> bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint-> bInterval; if (dev->interrupt_out_endpoint) dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint-> bInterval ? min_interrupt_out_interval : dev-> interrupt_out_endpoint->bInterval; /* we can register the device now, as it is ready */ usb_set_intfdata(intf, dev); atomic_set(&dev->writes_pending, 0); retval = usb_register_dev(intf, &usb_alphatrack_class); if (retval) { /* something prevented us from registering this driver */ dev_err(&intf->dev, "Not able to get a minor for this device.\n"); usb_set_intfdata(intf, NULL); goto error; } /* let the user know what node this device is now attached to */ dev_info(&intf->dev, "Alphatrack Device #%d now attached to major %d minor %d\n", (intf->minor - USB_ALPHATRACK_MINOR_BASE), USB_MAJOR, intf->minor); exit: return retval; error: usb_alphatrack_delete(dev); return retval; } /** * usb_alphatrack_disconnect * * Called by the usb core when the device is removed from the system. */ static void usb_alphatrack_disconnect(struct usb_interface *intf) { struct usb_alphatrack *dev; int minor; mutex_lock(&disconnect_mutex); dev = usb_get_intfdata(intf); usb_set_intfdata(intf, NULL); down(&dev->sem); minor = intf->minor; /* give back our minor */ usb_deregister_dev(intf, &usb_alphatrack_class); /* if the device is not opened, then we clean up right now */ if (!dev->open_count) { up(&dev->sem); usb_alphatrack_delete(dev); } else { dev->intf = NULL; up(&dev->sem); } atomic_set(&dev->writes_pending, 0); mutex_unlock(&disconnect_mutex); dev_info(&intf->dev, "Alphatrack Surface #%d now disconnected\n", (minor - USB_ALPHATRACK_MINOR_BASE)); } /* usb specific object needed to register this driver with the usb subsystem */ static struct usb_driver usb_alphatrack_driver = { .name = "alphatrack", .probe = usb_alphatrack_probe, .disconnect = usb_alphatrack_disconnect, .id_table = usb_alphatrack_table, }; /** * usb_alphatrack_init */ static int __init usb_alphatrack_init(void) { int retval; /* register this driver with the USB subsystem */ retval = usb_register(&usb_alphatrack_driver); if (retval) err("usb_register failed for the " __FILE__ " driver. Error number %d\n", retval); return retval; } /** * usb_alphatrack_exit */ static void __exit usb_alphatrack_exit(void) { /* deregister this driver with the USB subsystem */ usb_deregister(&usb_alphatrack_driver); } module_init(usb_alphatrack_init); module_exit(usb_alphatrack_exit);