blob: acbb2cc510f9b02f39feeb907987afa3a1161aea [file] [log] [blame]
/*
* 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 const 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 mutex mtx; /* 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) {
printk(KERN_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 (mutex_lock_interruptible(&dev->mtx)) {
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:
mutex_unlock(&dev->mtx);
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 (mutex_lock_interruptible(&dev->mtx)) {
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 */
mutex_unlock(&dev->mtx);
/* 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:
mutex_unlock(&dev->mtx);
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 (mutex_lock_interruptible(&dev->mtx)) {
retval = -ERESTARTSYS;
goto exit;
}
/* verify that the device wasn't unplugged */
if (dev->intf == NULL) {
retval = -ENODEV;
printk(KERN_ERR "%s: No device or device unplugged %d\n",
__func__, 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 */
mutex_unlock(&dev->mtx);
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 (mutex_lock_interruptible(&dev->mtx)) {
retval = -ERESTARTSYS;
goto exit;
}
/* verify that the device wasn't unplugged */
if (dev->intf == NULL) {
retval = -ENODEV;
printk(KERN_ERR "%s: No device or device unplugged %d\n",
__func__, 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) {
dev_err(&dev->intf->dev, "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;
dev_err(&dev->intf->dev,
"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 */
mutex_unlock(&dev->mtx);
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,
.llseek = no_llseek,
};
/*
* 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 initialize it */
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (dev == NULL) {
dev_err(&intf->dev, "Out of memory\n");
goto exit;
}
mutex_init(&dev->mtx);
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(true_size * sizeof(struct alphatrack_ocmd), 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);
mutex_lock(&dev->mtx);
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) {
mutex_unlock(&dev->mtx);
usb_alphatrack_delete(dev);
} else {
dev->intf = NULL;
mutex_unlock(&dev->mtx);
}
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,
};
module_usb_driver(usb_alphatrack_driver);