blob: 41620c0fb0463fa998e84b113815611e3ce6c5fc [file] [log] [blame]
Andrea Paterniani814a8d52007-05-08 00:32:15 -07001/*
2 * spidev.c -- simple synchronous userspace interface to SPI devices
3 *
4 * Copyright (C) 2006 SWAPP
5 * Andrea Paterniani <a.paterniani@swapp-eng.it>
6 * Copyright (C) 2007 David Brownell (simplification, cleanup)
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#include <linux/init.h>
24#include <linux/module.h>
25#include <linux/ioctl.h>
26#include <linux/fs.h>
27#include <linux/device.h>
28#include <linux/list.h>
29#include <linux/errno.h>
30#include <linux/mutex.h>
31#include <linux/slab.h>
32
33#include <linux/spi/spi.h>
34#include <linux/spi/spidev.h>
35
36#include <asm/uaccess.h>
37
38
39/*
40 * This supports acccess to SPI devices using normal userspace I/O calls.
41 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
42 * and often mask message boundaries, full SPI support requires full duplex
43 * transfers. There are several kinds of of internal message boundaries to
44 * handle chipselect management and other protocol options.
45 *
46 * SPI has a character major number assigned. We allocate minor numbers
47 * dynamically using a bitmask. You must use hotplug tools, such as udev
48 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
49 * nodes, since there is no fixed association of minor numbers with any
50 * particular SPI bus or device.
51 */
52#define SPIDEV_MAJOR 153 /* assigned */
53#define N_SPI_MINORS 32 /* ... up to 256 */
54
55static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG];
56
57
Anton Vorontsov6f166e32007-07-31 00:38:43 -070058/* Bit masks for spi_device.mode management. Note that incorrect
59 * settings for CS_HIGH and 3WIRE can cause *lots* of trouble for other
60 * devices on a shared bus: CS_HIGH, because this device will be
61 * active when it shouldn't be; 3WIRE, because when active it won't
62 * behave as it should.
63 *
64 * REVISIT should changing those two modes be privileged?
65 */
66#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
67 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP)
Andrea Paterniani814a8d52007-05-08 00:32:15 -070068
69struct spidev_data {
70 struct device dev;
David Brownell25d5cb42008-05-23 13:05:03 -070071 spinlock_t spi_lock;
Andrea Paterniani814a8d52007-05-08 00:32:15 -070072 struct spi_device *spi;
73 struct list_head device_entry;
74
75 struct mutex buf_lock;
76 unsigned users;
77 u8 *buffer;
78};
79
80static LIST_HEAD(device_list);
81static DEFINE_MUTEX(device_list_lock);
82
83static unsigned bufsiz = 4096;
84module_param(bufsiz, uint, S_IRUGO);
85MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
86
87/*-------------------------------------------------------------------------*/
88
David Brownell25d5cb42008-05-23 13:05:03 -070089/*
90 * We can't use the standard synchronous wrappers for file I/O; we
91 * need to protect against async removal of the underlying spi_device.
92 */
93static void spidev_complete(void *arg)
94{
95 complete(arg);
96}
97
98static ssize_t
99spidev_sync(struct spidev_data *spidev, struct spi_message *message)
100{
101 DECLARE_COMPLETION_ONSTACK(done);
102 int status;
103
104 message->complete = spidev_complete;
105 message->context = &done;
106
107 spin_lock_irq(&spidev->spi_lock);
108 if (spidev->spi == NULL)
109 status = -ESHUTDOWN;
110 else
111 status = spi_async(spidev->spi, message);
112 spin_unlock_irq(&spidev->spi_lock);
113
114 if (status == 0) {
115 wait_for_completion(&done);
116 status = message->status;
117 if (status == 0)
118 status = message->actual_length;
119 }
120 return status;
121}
122
123static inline ssize_t
124spidev_sync_write(struct spidev_data *spidev, size_t len)
125{
126 struct spi_transfer t = {
127 .tx_buf = spidev->buffer,
128 .len = len,
129 };
130 struct spi_message m;
131
132 spi_message_init(&m);
133 spi_message_add_tail(&t, &m);
134 return spidev_sync(spidev, &m);
135}
136
137static inline ssize_t
138spidev_sync_read(struct spidev_data *spidev, size_t len)
139{
140 struct spi_transfer t = {
141 .rx_buf = spidev->buffer,
142 .len = len,
143 };
144 struct spi_message m;
145
146 spi_message_init(&m);
147 spi_message_add_tail(&t, &m);
148 return spidev_sync(spidev, &m);
149}
150
151/*-------------------------------------------------------------------------*/
152
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700153/* Read-only message with current device setup */
154static ssize_t
155spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
156{
157 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700158 ssize_t status = 0;
159
160 /* chipselect only toggles at start or end of operation */
161 if (count > bufsiz)
162 return -EMSGSIZE;
163
164 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700165
166 mutex_lock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700167 status = spidev_sync_read(spidev, count);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700168 if (status == 0) {
169 unsigned long missing;
170
171 missing = copy_to_user(buf, spidev->buffer, count);
172 if (count && missing == count)
173 status = -EFAULT;
174 else
175 status = count - missing;
176 }
177 mutex_unlock(&spidev->buf_lock);
178
179 return status;
180}
181
182/* Write-only message with current device setup */
183static ssize_t
184spidev_write(struct file *filp, const char __user *buf,
185 size_t count, loff_t *f_pos)
186{
187 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700188 ssize_t status = 0;
189 unsigned long missing;
190
191 /* chipselect only toggles at start or end of operation */
192 if (count > bufsiz)
193 return -EMSGSIZE;
194
195 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700196
197 mutex_lock(&spidev->buf_lock);
198 missing = copy_from_user(spidev->buffer, buf, count);
199 if (missing == 0) {
David Brownell25d5cb42008-05-23 13:05:03 -0700200 status = spidev_sync_write(spidev, count);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700201 if (status == 0)
202 status = count;
203 } else
204 status = -EFAULT;
205 mutex_unlock(&spidev->buf_lock);
206
207 return status;
208}
209
210static int spidev_message(struct spidev_data *spidev,
211 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
212{
213 struct spi_message msg;
214 struct spi_transfer *k_xfers;
215 struct spi_transfer *k_tmp;
216 struct spi_ioc_transfer *u_tmp;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700217 unsigned n, total;
218 u8 *buf;
219 int status = -EFAULT;
220
221 spi_message_init(&msg);
222 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
223 if (k_xfers == NULL)
224 return -ENOMEM;
225
226 /* Construct spi_message, copying any tx data to bounce buffer.
227 * We walk the array of user-provided transfers, using each one
228 * to initialize a kernel version of the same transfer.
229 */
230 mutex_lock(&spidev->buf_lock);
231 buf = spidev->buffer;
232 total = 0;
233 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
234 n;
235 n--, k_tmp++, u_tmp++) {
236 k_tmp->len = u_tmp->len;
237
Domen Puncerda90fa82007-05-23 13:57:39 -0700238 total += k_tmp->len;
239 if (total > bufsiz) {
240 status = -EMSGSIZE;
241 goto done;
242 }
243
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700244 if (u_tmp->rx_buf) {
245 k_tmp->rx_buf = buf;
David Brownell96ddbf52007-08-10 13:01:09 -0700246 if (!access_ok(VERIFY_WRITE, (u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000247 (uintptr_t) u_tmp->rx_buf,
David Brownell96ddbf52007-08-10 13:01:09 -0700248 u_tmp->len))
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700249 goto done;
250 }
251 if (u_tmp->tx_buf) {
252 k_tmp->tx_buf = buf;
David Brownell4917d922007-07-17 04:04:04 -0700253 if (copy_from_user(buf, (const u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000254 (uintptr_t) u_tmp->tx_buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700255 u_tmp->len))
256 goto done;
257 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700258 buf += k_tmp->len;
259
260 k_tmp->cs_change = !!u_tmp->cs_change;
261 k_tmp->bits_per_word = u_tmp->bits_per_word;
262 k_tmp->delay_usecs = u_tmp->delay_usecs;
263 k_tmp->speed_hz = u_tmp->speed_hz;
264#ifdef VERBOSE
265 dev_dbg(&spi->dev,
266 " xfer len %zd %s%s%s%dbits %u usec %uHz\n",
267 u_tmp->len,
268 u_tmp->rx_buf ? "rx " : "",
269 u_tmp->tx_buf ? "tx " : "",
270 u_tmp->cs_change ? "cs " : "",
271 u_tmp->bits_per_word ? : spi->bits_per_word,
272 u_tmp->delay_usecs,
273 u_tmp->speed_hz ? : spi->max_speed_hz);
274#endif
275 spi_message_add_tail(k_tmp, &msg);
276 }
277
David Brownell25d5cb42008-05-23 13:05:03 -0700278 status = spidev_sync(spidev, &msg);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700279 if (status < 0)
280 goto done;
281
282 /* copy any rx data out of bounce buffer */
283 buf = spidev->buffer;
284 for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
285 if (u_tmp->rx_buf) {
David Brownell4917d922007-07-17 04:04:04 -0700286 if (__copy_to_user((u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000287 (uintptr_t) u_tmp->rx_buf, buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700288 u_tmp->len)) {
289 status = -EFAULT;
290 goto done;
291 }
292 }
293 buf += u_tmp->len;
294 }
295 status = total;
296
297done:
298 mutex_unlock(&spidev->buf_lock);
299 kfree(k_xfers);
300 return status;
301}
302
303static int
304spidev_ioctl(struct inode *inode, struct file *filp,
305 unsigned int cmd, unsigned long arg)
306{
307 int err = 0;
308 int retval = 0;
309 struct spidev_data *spidev;
310 struct spi_device *spi;
311 u32 tmp;
312 unsigned n_ioc;
313 struct spi_ioc_transfer *ioc;
314
315 /* Check type and command number */
316 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
317 return -ENOTTY;
318
319 /* Check access direction once here; don't repeat below.
320 * IOC_DIR is from the user perspective, while access_ok is
321 * from the kernel perspective; so they look reversed.
322 */
323 if (_IOC_DIR(cmd) & _IOC_READ)
324 err = !access_ok(VERIFY_WRITE,
325 (void __user *)arg, _IOC_SIZE(cmd));
326 if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
327 err = !access_ok(VERIFY_READ,
328 (void __user *)arg, _IOC_SIZE(cmd));
329 if (err)
330 return -EFAULT;
331
David Brownell25d5cb42008-05-23 13:05:03 -0700332 /* guard against device removal before, or while,
333 * we issue this ioctl.
334 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700335 spidev = filp->private_data;
David Brownell25d5cb42008-05-23 13:05:03 -0700336 spin_lock_irq(&spidev->spi_lock);
337 spi = spi_dev_get(spidev->spi);
338 spin_unlock_irq(&spidev->spi_lock);
339
340 if (spi == NULL)
341 return -ESHUTDOWN;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700342
343 switch (cmd) {
344 /* read requests */
345 case SPI_IOC_RD_MODE:
346 retval = __put_user(spi->mode & SPI_MODE_MASK,
347 (__u8 __user *)arg);
348 break;
349 case SPI_IOC_RD_LSB_FIRST:
350 retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
351 (__u8 __user *)arg);
352 break;
353 case SPI_IOC_RD_BITS_PER_WORD:
354 retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
355 break;
356 case SPI_IOC_RD_MAX_SPEED_HZ:
357 retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg);
358 break;
359
360 /* write requests */
361 case SPI_IOC_WR_MODE:
362 retval = __get_user(tmp, (u8 __user *)arg);
363 if (retval == 0) {
364 u8 save = spi->mode;
365
366 if (tmp & ~SPI_MODE_MASK) {
367 retval = -EINVAL;
368 break;
369 }
370
371 tmp |= spi->mode & ~SPI_MODE_MASK;
372 spi->mode = (u8)tmp;
373 retval = spi_setup(spi);
374 if (retval < 0)
375 spi->mode = save;
376 else
377 dev_dbg(&spi->dev, "spi mode %02x\n", tmp);
378 }
379 break;
380 case SPI_IOC_WR_LSB_FIRST:
381 retval = __get_user(tmp, (__u8 __user *)arg);
382 if (retval == 0) {
383 u8 save = spi->mode;
384
385 if (tmp)
386 spi->mode |= SPI_LSB_FIRST;
387 else
388 spi->mode &= ~SPI_LSB_FIRST;
389 retval = spi_setup(spi);
390 if (retval < 0)
391 spi->mode = save;
392 else
393 dev_dbg(&spi->dev, "%csb first\n",
394 tmp ? 'l' : 'm');
395 }
396 break;
397 case SPI_IOC_WR_BITS_PER_WORD:
398 retval = __get_user(tmp, (__u8 __user *)arg);
399 if (retval == 0) {
400 u8 save = spi->bits_per_word;
401
402 spi->bits_per_word = tmp;
403 retval = spi_setup(spi);
404 if (retval < 0)
405 spi->bits_per_word = save;
406 else
407 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
408 }
409 break;
410 case SPI_IOC_WR_MAX_SPEED_HZ:
411 retval = __get_user(tmp, (__u32 __user *)arg);
412 if (retval == 0) {
413 u32 save = spi->max_speed_hz;
414
415 spi->max_speed_hz = tmp;
416 retval = spi_setup(spi);
417 if (retval < 0)
418 spi->max_speed_hz = save;
419 else
420 dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
421 }
422 break;
423
424 default:
425 /* segmented and/or full-duplex I/O request */
426 if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
David Brownell25d5cb42008-05-23 13:05:03 -0700427 || _IOC_DIR(cmd) != _IOC_WRITE) {
428 retval = -ENOTTY;
429 break;
430 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700431
432 tmp = _IOC_SIZE(cmd);
433 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) {
434 retval = -EINVAL;
435 break;
436 }
437 n_ioc = tmp / sizeof(struct spi_ioc_transfer);
438 if (n_ioc == 0)
439 break;
440
441 /* copy into scratch area */
442 ioc = kmalloc(tmp, GFP_KERNEL);
443 if (!ioc) {
444 retval = -ENOMEM;
445 break;
446 }
447 if (__copy_from_user(ioc, (void __user *)arg, tmp)) {
Florin Malita9bea3f22007-05-23 13:57:45 -0700448 kfree(ioc);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700449 retval = -EFAULT;
450 break;
451 }
452
453 /* translate to spi_message, execute */
454 retval = spidev_message(spidev, ioc, n_ioc);
455 kfree(ioc);
456 break;
457 }
David Brownell25d5cb42008-05-23 13:05:03 -0700458 spi_dev_put(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700459 return retval;
460}
461
462static int spidev_open(struct inode *inode, struct file *filp)
463{
464 struct spidev_data *spidev;
465 int status = -ENXIO;
466
467 mutex_lock(&device_list_lock);
468
469 list_for_each_entry(spidev, &device_list, device_entry) {
470 if (spidev->dev.devt == inode->i_rdev) {
471 status = 0;
472 break;
473 }
474 }
475 if (status == 0) {
476 if (!spidev->buffer) {
477 spidev->buffer = kmalloc(bufsiz, GFP_KERNEL);
478 if (!spidev->buffer) {
479 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
480 status = -ENOMEM;
481 }
482 }
483 if (status == 0) {
484 spidev->users++;
485 filp->private_data = spidev;
486 nonseekable_open(inode, filp);
487 }
488 } else
489 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
490
491 mutex_unlock(&device_list_lock);
492 return status;
493}
494
495static int spidev_release(struct inode *inode, struct file *filp)
496{
497 struct spidev_data *spidev;
498 int status = 0;
499
500 mutex_lock(&device_list_lock);
501 spidev = filp->private_data;
502 filp->private_data = NULL;
503 spidev->users--;
504 if (!spidev->users) {
505 kfree(spidev->buffer);
506 spidev->buffer = NULL;
507 }
508 mutex_unlock(&device_list_lock);
509
510 return status;
511}
512
513static struct file_operations spidev_fops = {
514 .owner = THIS_MODULE,
515 /* REVISIT switch to aio primitives, so that userspace
516 * gets more complete API coverage. It'll simplify things
517 * too, except for the locking.
518 */
519 .write = spidev_write,
520 .read = spidev_read,
521 .ioctl = spidev_ioctl,
522 .open = spidev_open,
523 .release = spidev_release,
524};
525
526/*-------------------------------------------------------------------------*/
527
528/* The main reason to have this class is to make mdev/udev create the
529 * /dev/spidevB.C character device nodes exposing our userspace API.
530 * It also simplifies memory management.
531 */
532
533static void spidev_classdev_release(struct device *dev)
534{
535 struct spidev_data *spidev;
536
537 spidev = container_of(dev, struct spidev_data, dev);
538 kfree(spidev);
539}
540
541static struct class spidev_class = {
542 .name = "spidev",
543 .owner = THIS_MODULE,
544 .dev_release = spidev_classdev_release,
545};
546
547/*-------------------------------------------------------------------------*/
548
549static int spidev_probe(struct spi_device *spi)
550{
551 struct spidev_data *spidev;
552 int status;
553 unsigned long minor;
554
555 /* Allocate driver data */
556 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
557 if (!spidev)
558 return -ENOMEM;
559
560 /* Initialize the driver data */
561 spidev->spi = spi;
David Brownell25d5cb42008-05-23 13:05:03 -0700562 spin_lock_init(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700563 mutex_init(&spidev->buf_lock);
564
565 INIT_LIST_HEAD(&spidev->device_entry);
566
567 /* If we can allocate a minor number, hook up this device.
568 * Reusing minors is fine so long as udev or mdev is working.
569 */
570 mutex_lock(&device_list_lock);
Domen Puncer0a4dd772007-05-15 23:57:05 -0700571 minor = find_first_zero_bit(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700572 if (minor < N_SPI_MINORS) {
573 spidev->dev.parent = &spi->dev;
574 spidev->dev.class = &spidev_class;
575 spidev->dev.devt = MKDEV(SPIDEV_MAJOR, minor);
576 snprintf(spidev->dev.bus_id, sizeof spidev->dev.bus_id,
577 "spidev%d.%d",
578 spi->master->bus_num, spi->chip_select);
579 status = device_register(&spidev->dev);
580 } else {
581 dev_dbg(&spi->dev, "no minor number available!\n");
582 status = -ENODEV;
583 }
584 if (status == 0) {
585 set_bit(minor, minors);
586 dev_set_drvdata(&spi->dev, spidev);
587 list_add(&spidev->device_entry, &device_list);
588 }
589 mutex_unlock(&device_list_lock);
590
591 if (status != 0)
592 kfree(spidev);
593
594 return status;
595}
596
597static int spidev_remove(struct spi_device *spi)
598{
599 struct spidev_data *spidev = dev_get_drvdata(&spi->dev);
600
David Brownell25d5cb42008-05-23 13:05:03 -0700601 /* make sure ops on existing fds can abort cleanly */
602 spin_lock_irq(&spidev->spi_lock);
603 spidev->spi = NULL;
604 spin_unlock_irq(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700605
David Brownell25d5cb42008-05-23 13:05:03 -0700606 /* prevent new opens */
607 mutex_lock(&device_list_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700608 list_del(&spidev->device_entry);
609 dev_set_drvdata(&spi->dev, NULL);
610 clear_bit(MINOR(spidev->dev.devt), minors);
611 device_unregister(&spidev->dev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700612 mutex_unlock(&device_list_lock);
613
614 return 0;
615}
616
617static struct spi_driver spidev_spi = {
618 .driver = {
619 .name = "spidev",
620 .owner = THIS_MODULE,
621 },
622 .probe = spidev_probe,
623 .remove = __devexit_p(spidev_remove),
624
625 /* NOTE: suspend/resume methods are not necessary here.
626 * We don't do anything except pass the requests to/from
627 * the underlying controller. The refrigerator handles
628 * most issues; the controller driver handles the rest.
629 */
630};
631
632/*-------------------------------------------------------------------------*/
633
634static int __init spidev_init(void)
635{
636 int status;
637
638 /* Claim our 256 reserved device numbers. Then register a class
639 * that will key udev/mdev to add/remove /dev nodes. Last, register
640 * the driver which manages those device numbers.
641 */
642 BUILD_BUG_ON(N_SPI_MINORS > 256);
643 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
644 if (status < 0)
645 return status;
646
647 status = class_register(&spidev_class);
648 if (status < 0) {
649 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
650 return status;
651 }
652
653 status = spi_register_driver(&spidev_spi);
654 if (status < 0) {
655 class_unregister(&spidev_class);
656 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
657 }
658 return status;
659}
660module_init(spidev_init);
661
662static void __exit spidev_exit(void)
663{
664 spi_unregister_driver(&spidev_spi);
665 class_unregister(&spidev_class);
666 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
667}
668module_exit(spidev_exit);
669
670MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
671MODULE_DESCRIPTION("User mode SPI device interface");
672MODULE_LICENSE("GPL");