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comparison dmx_usb_module/dmx_usb.c @ 355:4e60444605f6

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add dmx_usb_module
author drewp@bigasterisk.com
date Wed, 13 Jun 2007 06:01:22 +0000
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children 1b56c80b1ee4
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354:f3909c2df943 355:4e60444605f6
1 /*
2 * DMX USB driver
3 *
4 * Copyright (C) 2004,2006 Erwin Rol (erwin@erwinrol.com)
5 *
6 * This driver is based on the usb-skeleton driver;
7 *
8 * Copyright (C) 2001-2003 Greg Kroah-Hartman (greg@kroah.com)
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation, version 2.
13 *
14 * $Id: dmx_usb.c 41 2004-09-14 23:35:25Z erwin $
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/errno.h>
19 #include <linux/init.h>
20 #include <linux/slab.h>
21 #include <linux/module.h>
22 #include <linux/smp_lock.h>
23 #include <linux/completion.h>
24 #include <asm/uaccess.h>
25 #include <linux/usb.h>
26 #include <linux/version.h>
27
28 #include "dmx_usb.h"
29
30 #ifdef CONFIG_USB_DEBUG
31 static int debug = 1;
32 #else
33 static int debug;
34 #endif
35
36 /* Use our own dbg macro */
37 #undef dbg
38 #define dbg(format, arg...) do { if (debug) printk(KERN_DEBUG __FILE__ ": " format "\n" , ## arg); } while (0)
39
40
41 /* Version Information */
42 #define DRIVER_VERSION "v0.1.20060816"
43 #define DRIVER_AUTHOR "Erwin Rol, erwin@erwinrol.com"
44 #define DRIVER_DESC "DMX USB Driver"
45
46 /* Module parameters */
47 #if ( LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16) )
48 MODULE_PARM(debug, "i");
49 MODULE_PARM_DESC(debug, "Debug enabled or not");
50 #else
51 module_param(debug, bool, S_IRUGO | S_IWUSR);
52 MODULE_PARM_DESC(debug, "Debug enabled or not");
53 #endif
54
55 static struct usb_device_id dmx_usb_table [] = {
56 { USB_DEVICE_VER(FTDI_VID, FTDI_8U232AM_PID, 0x400, 0xffff) },
57 { USB_DEVICE_VER(FTDI_VID, FTDI_8U232AM_ALT_PID, 0x400, 0xffff) },
58 { } /* Terminating entry */
59 };
60
61 MODULE_DEVICE_TABLE (usb, dmx_usb_table);
62
63 /* Get a minor range for your devices from the usb maintainer */
64 #define DMX_USB_MINOR_BASE 192
65
66 /* Structure to hold all of our device specific stuff */
67 struct dmx_usb_device {
68 struct usb_device * udev; /* save off the usb device pointer */
69 struct usb_interface * interface; /* the interface for this device */
70 unsigned char minor; /* the starting minor number for this device */
71 unsigned char num_ports; /* the number of ports this device has */
72 char num_interrupt_in; /* number of interrupt in endpoints we have */
73 char num_bulk_in; /* number of bulk in endpoints we have */
74 char num_bulk_out; /* number of bulk out endpoints we have */
75
76 unsigned char * bulk_in_buffer; /* the buffer to receive data */
77 size_t bulk_in_size; /* the size of the receive buffer */
78 __u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
79
80 unsigned char * bulk_out_buffer; /* the buffer to send data */
81 size_t bulk_out_size; /* the size of the send buffer */
82 struct urb * write_urb; /* the urb used to send data */
83 __u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
84 atomic_t write_busy; /* true iff write urb is busy */
85 struct completion write_finished; /* wait for the write to finish */
86
87 int open; /* if the port is open or not */
88 int present; /* if the device is not disconnected */
89 struct semaphore sem; /* locks this structure */
90 };
91
92
93 /* prevent races between open() and disconnect() */
94 static DECLARE_MUTEX (disconnect_sem);
95
96 /* local function prototypes */
97 //static ssize_t dmx_usb_read (struct file *file, char *buffer, size_t count, loff_t *ppos);
98 static ssize_t dmx_usb_write (struct file *file, const char *buffer, size_t count, loff_t *ppos);
99 static int dmx_usb_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg);
100 static int dmx_usb_open (struct inode *inode, struct file *file);
101 static int dmx_usb_release (struct inode *inode, struct file *file);
102
103 static int dmx_usb_probe (struct usb_interface *interface, const struct usb_device_id *id);
104 static void dmx_usb_disconnect (struct usb_interface *interface);
105
106 static void dmx_usb_write_bulk_callback (struct urb *urb, struct pt_regs *regs);
107
108 static struct file_operations dmx_usb_fops = {
109 /*
110 * The owner field is part of the module-locking
111 * mechanism. The idea is that the kernel knows
112 * which module to increment the use-counter of
113 * BEFORE it calls the device's open() function.
114 * This also means that the kernel can decrement
115 * the use-counter again before calling release()
116 * or should the open() function fail.
117 */
118 .owner = THIS_MODULE,
119
120 /* .read = dmx_usb_read, */
121 .write = dmx_usb_write,
122 .ioctl = dmx_usb_ioctl,
123 .open = dmx_usb_open,
124 .release = dmx_usb_release,
125 };
126
127 /*
128 * usb class driver info in order to get a minor number from the usb core,
129 * and to have the device registered with devfs and the driver core
130 */
131 static struct usb_class_driver dmx_usb_class = {
132 .name = "usb/dmx%d",
133 .fops = &dmx_usb_fops,
134 .minor_base = DMX_USB_MINOR_BASE,
135 };
136
137 /* usb specific object needed to register this driver with the usb subsystem */
138 static struct usb_driver dmx_usb_driver = {
139 #if ( LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16) )
140 .owner = THIS_MODULE,
141 #endif
142 .name = "dmx_usb",
143 .probe = dmx_usb_probe,
144 .disconnect = dmx_usb_disconnect,
145 .id_table = dmx_usb_table,
146 };
147
148
149 /**
150 */
151 static inline void dmx_usb_debug_data (const char *function, int size, const unsigned char *data)
152 {
153 int i;
154
155 if (!debug)
156 return;
157
158 printk (KERN_DEBUG __FILE__": %s - length = %d, data = ",
159 function, size);
160 for (i = 0; i < size; ++i) {
161 printk ("%.2x ", data[i]);
162 }
163 printk ("\n");
164 }
165
166 static __u32 dmx_usb_baud_to_divisor(int baud)
167 {
168 static const unsigned char divfrac[8] = { 0, 3, 2, 4, 1, 5, 6, 7 };
169 __u32 divisor;
170 int divisor3 = 48000000 / 2 / baud; // divisor shifted 3 bits to the left
171 divisor = divisor3 >> 3;
172 divisor |= (__u32)divfrac[divisor3 & 0x7] << 14;
173 /* Deal with special cases for highest baud rates. */
174 if (divisor == 1) divisor = 0; else // 1.0
175 if (divisor == 0x4001) divisor = 1; // 1.5
176 return divisor;
177 }
178
179 static int dmx_usb_set_speed(struct dmx_usb_device* dev)
180 {
181 char *buf;
182 __u16 urb_value;
183 __u16 urb_index;
184 __u32 urb_index_value;
185 int rv;
186
187 buf = kmalloc(1, GFP_NOIO);
188 if (!buf)
189 return -ENOMEM;
190
191 urb_index_value = dmx_usb_baud_to_divisor(250000);
192 urb_value = (__u16)urb_index_value;
193 urb_index = (__u16)(urb_index_value >> 16);
194
195 rv = usb_control_msg(dev->udev,
196 usb_sndctrlpipe(dev->udev, 0),
197 FTDI_SIO_SET_BAUDRATE_REQUEST,
198 FTDI_SIO_SET_BAUDRATE_REQUEST_TYPE,
199 urb_value, urb_index,
200 buf, 0, HZ*10);
201
202 kfree(buf);
203 return rv;
204 }
205
206 static int dmx_usb_setup(struct dmx_usb_device* dev)
207 {
208 __u16 urb_value;
209 char buf[1];
210
211 urb_value = FTDI_SIO_SET_DATA_STOP_BITS_2 | FTDI_SIO_SET_DATA_PARITY_NONE;
212 urb_value |= 8; // number of data bits
213
214 if (usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
215 FTDI_SIO_SET_DATA_REQUEST,
216 FTDI_SIO_SET_DATA_REQUEST_TYPE,
217 urb_value , 0,
218 buf, 0, HZ*10) < 0) {
219 err("%s FAILED to set databits/stopbits/parity", __FUNCTION__);
220 }
221
222 if (usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
223 FTDI_SIO_SET_FLOW_CTRL_REQUEST,
224 FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
225 0, 0,
226 buf, 0, HZ*10) < 0) {
227 err("%s error from disable flowcontrol urb", __FUNCTION__);
228 }
229
230 dmx_usb_set_speed(dev);
231
232 return 0;
233 }
234
235 static void dmx_usb_set_break(struct dmx_usb_device* dev, int break_state)
236 {
237 __u16 urb_value = FTDI_SIO_SET_DATA_STOP_BITS_2 | FTDI_SIO_SET_DATA_PARITY_NONE | 8;
238
239 char buf[2];
240
241 if (break_state) {
242 urb_value |= FTDI_SIO_SET_BREAK;
243 }
244
245 if (usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
246 FTDI_SIO_SET_DATA_REQUEST,
247 FTDI_SIO_SET_DATA_REQUEST_TYPE,
248 urb_value , 0,
249 buf, 2, HZ*10) < 0) {
250 err("%s FAILED to enable/disable break state (state was %d)", __FUNCTION__,break_state);
251 }
252
253
254 dbg("%s break state is %d - urb is %d", __FUNCTION__,break_state, urb_value);
255 }
256
257 /**
258 */
259 static inline void dmx_usb_delete (struct dmx_usb_device *dev)
260 {
261 kfree (dev->bulk_in_buffer);
262 usb_buffer_free (dev->udev, dev->bulk_out_size,
263 dev->bulk_out_buffer,
264 dev->write_urb->transfer_dma);
265 usb_free_urb (dev->write_urb);
266 kfree (dev);
267 }
268
269
270 /**
271 */
272 static int dmx_usb_open (struct inode *inode, struct file *file)
273 {
274 struct dmx_usb_device *dev = NULL;
275 struct usb_interface *interface;
276 int subminor;
277 int retval = 0;
278
279 dbg("%s", __FUNCTION__);
280
281 subminor = iminor(inode);
282
283 /* prevent disconnects */
284 down (&disconnect_sem);
285
286 interface = usb_find_interface (&dmx_usb_driver, subminor);
287 if (!interface) {
288 err ("%s - error, can't find device for minor %d",
289 __FUNCTION__, subminor);
290 retval = -ENODEV;
291 goto exit_no_device;
292 }
293
294 dev = usb_get_intfdata(interface);
295 if (!dev) {
296 retval = -ENODEV;
297 goto exit_no_device;
298 }
299
300 /* lock this device */
301 down (&dev->sem);
302
303 /* increment our usage count for the driver */
304 ++dev->open;
305
306 /* save our object in the file's private structure */
307 file->private_data = dev;
308
309 /* unlock this device */
310 up (&dev->sem);
311
312 exit_no_device:
313 up (&disconnect_sem);
314 return retval;
315 }
316
317
318 /**
319 */
320 static int dmx_usb_release (struct inode *inode, struct file *file)
321 {
322 struct dmx_usb_device *dev;
323 int retval = 0;
324
325 dev = (struct dmx_usb_device *)file->private_data;
326 if (dev == NULL) {
327 dbg ("%s - object is NULL", __FUNCTION__);
328 return -ENODEV;
329 }
330
331 dbg("%s - minor %d", __FUNCTION__, dev->minor);
332
333 /* lock our device */
334 down (&dev->sem);
335
336 if (dev->open <= 0) {
337 dbg ("%s - device not opened", __FUNCTION__);
338 retval = -ENODEV;
339 goto exit_not_opened;
340 }
341
342 /* wait for any bulk writes that might be going on to finish up */
343 if (atomic_read (&dev->write_busy))
344 wait_for_completion (&dev->write_finished);
345
346 --dev->open;
347
348 if (!dev->present && !dev->open) {
349 /* the device was unplugged before the file was released */
350 up (&dev->sem);
351 dmx_usb_delete (dev);
352 return 0;
353 }
354
355 exit_not_opened:
356 up (&dev->sem);
357
358 return retval;
359 }
360
361 #if 0
362
363 Read is not yet supported
364
365 /**
366 */
367 static ssize_t dmx_usb_read (struct file *file, char *buffer, size_t count, loff_t *ppos)
368 {
369 struct dmx_usb_device *dev;
370 int retval = 0;
371 int bytes_read;
372
373 dev = (struct dmx_usb_device *)file->private_data;
374
375 dbg("%s - minor %d, count = %Zd", __FUNCTION__, dev->minor, count);
376
377 /* lock this object */
378 down (&dev->sem);
379
380 /* verify that the device wasn't unplugged */
381 if (!dev->present) {
382 up (&dev->sem);
383 return -ENODEV;
384 }
385
386 /* do a blocking bulk read to get data from the device */
387 retval = usb_bulk_msg (dev->udev,
388 usb_rcvbulkpipe (dev->udev,
389 dev->bulk_in_endpointAddr),
390 dev->bulk_in_buffer,
391 min (dev->bulk_in_size, count),
392 &bytes_read, HZ*10);
393
394 /* if the read was successful, copy the data to userspace */
395 if (!retval) {
396 if (copy_to_user (buffer, dev->bulk_in_buffer+2, bytes_read-2))
397 retval = -EFAULT;
398 else
399 retval = bytes_read;
400 }
401
402 /* unlock the device */
403 up (&dev->sem);
404 return retval;
405 }
406
407 #endif
408
409 static __u16 dmx_usb_get_status(struct dmx_usb_device* dev)
410 {
411 int retval = 0;
412 int count = 0;
413 __u16 buf;
414
415 retval = usb_bulk_msg (dev->udev,
416 usb_rcvbulkpipe (dev->udev, dev->bulk_in_endpointAddr),
417 &buf, 2, &count, HZ*10);
418
419 if (retval)
420 return 0;
421
422 return buf;
423 }
424
425
426
427 /**
428 * dmx_usb_write
429 *
430 * A device driver has to decide how to report I/O errors back to the
431 * user. The safest course is to wait for the transfer to finish before
432 * returning so that any errors will be reported reliably. dmx_usb_read()
433 * works like this. But waiting for I/O is slow, so many drivers only
434 * check for errors during I/O initiation and do not report problems
435 * that occur during the actual transfer. That's what we will do here.
436 *
437 * A driver concerned with maximum I/O throughput would use double-
438 * buffering: Two urbs would be devoted to write transfers, so that
439 * one urb could always be active while the other was waiting for the
440 * user to send more data.
441 */
442 static ssize_t dmx_usb_write (struct file *file, const char *buffer, size_t count, loff_t *ppos)
443 {
444 struct dmx_usb_device *dev;
445 ssize_t bytes_written = 0;
446 int retval = 0;
447 __u16 stat;
448
449 dev = (struct dmx_usb_device *)file->private_data;
450
451 dbg("%s - minor %d, count = %Zd", __FUNCTION__, dev->minor, count);
452
453 /* lock this object */
454 down (&dev->sem);
455
456 /* verify that the device wasn't unplugged */
457 if (!dev->present) {
458 retval = -ENODEV;
459 goto exit;
460 }
461
462 /* verify that we actually have some data to write */
463 if (count == 0) {
464 dbg("%s - write request of 0 bytes", __FUNCTION__);
465 goto exit;
466 }
467
468 /* wait for a previous write to finish up; we don't use a timeout
469 * and so a nonresponsive device can delay us indefinitely.
470 */
471 if (atomic_read (&dev->write_busy))
472 wait_for_completion (&dev->write_finished);
473
474 /* we can only write as much as our buffer will hold */
475 bytes_written = min (dev->bulk_out_size, count);
476
477 /* copy the data from userspace into our transfer buffer;
478 * this is the only copy required.
479 */
480 if (copy_from_user(dev->write_urb->transfer_buffer, buffer,
481 bytes_written)) {
482 retval = -EFAULT;
483 goto exit;
484 }
485
486 dmx_usb_debug_data (__FUNCTION__, bytes_written,
487 dev->write_urb->transfer_buffer);
488
489 /* this urb was already set up, except for this write size */
490 dev->write_urb->transfer_buffer_length = bytes_written;
491
492 /* Poll the device to see if the transmit buffer is empty */
493 do {
494 stat = dmx_usb_get_status(dev);
495 if (stat == 0) {
496 retval = -EFAULT;
497 goto exit;
498 }
499 } while ( (stat & ((FTDI_RS_TEMT) << 8) ) == 0 ) ;
500
501 /* the transmit buffer is empty, now toggle the break */
502 dmx_usb_set_break(dev, 1);
503 dmx_usb_set_break(dev, 0);
504
505 /* send the data out the bulk port */
506 /* a character device write uses GFP_KERNEL,
507 unless a spinlock is held */
508 init_completion (&dev->write_finished);
509 atomic_set (&dev->write_busy, 1);
510 retval = usb_submit_urb(dev->write_urb, GFP_KERNEL);
511 if (retval) {
512 atomic_set (&dev->write_busy, 0);
513 err("%s - failed submitting write urb, error %d",
514 __FUNCTION__, retval);
515 } else {
516 retval = bytes_written;
517 }
518
519 exit:
520 /* unlock the device */
521 up (&dev->sem);
522
523 return retval;
524 }
525
526
527 /**
528 */
529 static int dmx_usb_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
530 {
531 struct dmx_usb_device *dev;
532
533 dev = (struct dmx_usb_device *)file->private_data;
534
535 /* lock this object */
536 down (&dev->sem);
537
538 /* verify that the device wasn't unplugged */
539 if (!dev->present) {
540 up (&dev->sem);
541 return -ENODEV;
542 }
543
544 dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __FUNCTION__,
545 dev->minor, cmd, arg);
546
547 /* fill in your device specific stuff here */
548
549 /* unlock the device */
550 up (&dev->sem);
551
552 /* return that we did not understand this ioctl call */
553 return -ENOTTY;
554 }
555
556
557 /**
558 */
559 static void dmx_usb_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
560 {
561 struct dmx_usb_device *dev = (struct dmx_usb_device *)urb->context;
562
563 dbg("%s - minor %d", __FUNCTION__, dev->minor);
564
565 /* sync/async unlink faults aren't errors */
566 if (urb->status && !(urb->status == -ENOENT ||
567 urb->status == -ECONNRESET)) {
568 dbg("%s - nonzero write bulk status received: %d",
569 __FUNCTION__, urb->status);
570 }
571
572 /* notify anyone waiting that the write has finished */
573 atomic_set (&dev->write_busy, 0);
574 complete (&dev->write_finished);
575 }
576
577 /**
578 *
579 * Called by the usb core when a new device is connected that it thinks
580 * this driver might be interested in.
581 */
582 static int dmx_usb_probe(struct usb_interface *interface, const struct usb_device_id *id)
583 {
584 struct usb_device *udev = interface_to_usbdev(interface);
585 struct dmx_usb_device *dev = NULL;
586 struct usb_host_interface *iface_desc;
587 struct usb_endpoint_descriptor *endpoint;
588 size_t buffer_size;
589 int i;
590 int retval = -ENOMEM;
591
592 /* See if the device offered us matches what we can accept */
593 if ((udev->descriptor.idVendor != FTDI_VID) ||
594 (udev->descriptor.idProduct != FTDI_8U232AM_PID)) {
595 return -ENODEV;
596 }
597
598 /* allocate memory for our device state and initialize it */
599 dev = kmalloc (sizeof(struct dmx_usb_device), GFP_KERNEL);
600 if (dev == NULL) {
601 err ("Out of memory");
602 return -ENOMEM;
603 }
604 memset (dev, 0x00, sizeof (*dev));
605
606 init_MUTEX (&dev->sem);
607 dev->udev = udev;
608 dev->interface = interface;
609
610 /* set up the endpoint information */
611 /* check out the endpoints */
612 /* use only the first bulk-in and bulk-out endpoints */
613 iface_desc = &interface->altsetting[0];
614 for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
615 endpoint = &iface_desc->endpoint[i].desc;
616
617 if (!dev->bulk_in_endpointAddr &&
618 (endpoint->bEndpointAddress & USB_DIR_IN) &&
619 ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
620 == USB_ENDPOINT_XFER_BULK)) {
621 /* we found a bulk in endpoint */
622 buffer_size = endpoint->wMaxPacketSize;
623 dev->bulk_in_size = buffer_size;
624 dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
625 dev->bulk_in_buffer = kmalloc (buffer_size, GFP_KERNEL);
626 if (!dev->bulk_in_buffer) {
627 err("Couldn't allocate bulk_in_buffer");
628 goto error;
629 }
630 }
631
632 if (!dev->bulk_out_endpointAddr &&
633 !(endpoint->bEndpointAddress & USB_DIR_IN) &&
634 ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
635 == USB_ENDPOINT_XFER_BULK)) {
636 /* we found a bulk out endpoint */
637 /* a probe() may sleep and has no restrictions on memory allocations */
638 dev->write_urb = usb_alloc_urb(0, GFP_KERNEL);
639 if (!dev->write_urb) {
640 err("No free urbs available");
641 goto error;
642 }
643 dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
644
645 /* on some platforms using this kind of buffer alloc
646 * call eliminates a dma "bounce buffer".
647 *
648 * NOTE: you'd normally want i/o buffers that hold
649 * more than one packet, so that i/o delays between
650 * packets don't hurt throughput.
651 */
652 buffer_size = endpoint->wMaxPacketSize;
653 dev->bulk_out_size = 513;
654 dev->write_urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
655 dev->bulk_out_buffer = usb_buffer_alloc (udev,
656 buffer_size, GFP_KERNEL,
657 &dev->write_urb->transfer_dma);
658 if (!dev->bulk_out_buffer) {
659 err("Couldn't allocate bulk_out_buffer");
660 goto error;
661 }
662 usb_fill_bulk_urb(dev->write_urb, udev,
663 usb_sndbulkpipe(udev,
664 endpoint->bEndpointAddress),
665 dev->bulk_out_buffer, buffer_size,
666 dmx_usb_write_bulk_callback, dev);
667 }
668 }
669 if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
670 err("Couldn't find both bulk-in and bulk-out endpoints");
671 goto error;
672 }
673
674 dmx_usb_setup(dev);
675
676 /* allow device read, write and ioctl */
677 dev->present = 1;
678
679 /* we can register the device now, as it is ready */
680 usb_set_intfdata (interface, dev);
681 retval = usb_register_dev (interface, &dmx_usb_class);
682 if (retval) {
683 /* something prevented us from registering this driver */
684 err ("Not able to get a minor for this device.");
685 usb_set_intfdata (interface, NULL);
686 goto error;
687 }
688
689 dev->minor = interface->minor;
690
691 /* let the user know what node this device is now attached to */
692 info ("DMX USB device now attached to dmx%d", dev->minor);
693 return 0;
694
695 error:
696 dmx_usb_delete (dev);
697 return retval;
698 }
699
700
701 /**
702 *
703 * Called by the usb core when the device is removed from the system.
704 *
705 * This routine guarantees that the driver will not submit any more urbs
706 * by clearing dev->udev. It is also supposed to terminate any currently
707 * active urbs. Unfortunately, usb_bulk_msg(), used in dmx_usb_read(), does
708 * not provide any way to do this. But at least we can cancel an active
709 * write.
710 */
711 static void dmx_usb_disconnect(struct usb_interface *interface)
712 {
713 struct dmx_usb_device *dev;
714 int minor;
715
716 /* prevent races with open() */
717 down (&disconnect_sem);
718
719 dev = usb_get_intfdata (interface);
720 usb_set_intfdata (interface, NULL);
721
722 down (&dev->sem);
723
724 minor = dev->minor;
725
726 /* give back our minor */
727 usb_deregister_dev (interface, &dmx_usb_class);
728
729 /* terminate an ongoing write */
730 if (atomic_read (&dev->write_busy)) {
731 usb_unlink_urb (dev->write_urb);
732 wait_for_completion (&dev->write_finished);
733 }
734
735 /* prevent device read, write and ioctl */
736 dev->present = 0;
737
738 up (&dev->sem);
739
740 /* if the device is opened, dmx_usb_release will clean this up */
741 if (!dev->open)
742 dmx_usb_delete (dev);
743
744 up (&disconnect_sem);
745
746 info("DMX USB #%d now disconnected", minor);
747 }
748
749
750
751 /**
752 * dmx_usb_init
753 */
754 static int __init dmx_usb_init(void)
755 {
756 int result;
757
758 /* register this driver with the USB subsystem */
759 result = usb_register(&dmx_usb_driver);
760 if (result) {
761 err("usb_register failed. Error number %d",
762 result);
763 return result;
764 }
765
766 info(DRIVER_DESC " " DRIVER_VERSION);
767 return 0;
768 }
769
770
771 /**
772 * dmx_usb_exit
773 */
774 static void __exit dmx_usb_exit(void)
775 {
776 /* deregister this driver with the USB subsystem */
777 usb_deregister(&dmx_usb_driver);
778 }
779
780
781 module_init (dmx_usb_init);
782 module_exit (dmx_usb_exit);
783
784 MODULE_AUTHOR(DRIVER_AUTHOR);
785 MODULE_DESCRIPTION(DRIVER_DESC);
786 MODULE_LICENSE("GPL");
787