blob: 5d869c4d3eb2a2e3dd9f46ae3ebf1cfbd333e61f [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>
David Brownellb2c8dad2008-06-05 22:45:50 -070028#include <linux/err.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070029#include <linux/list.h>
30#include <linux/errno.h>
31#include <linux/mutex.h>
32#include <linux/slab.h>
Jonathan Corbet609f9e92008-05-16 13:46:14 -060033#include <linux/smp_lock.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070034
35#include <linux/spi/spi.h>
36#include <linux/spi/spidev.h>
37
38#include <asm/uaccess.h>
39
40
41/*
42 * This supports acccess to SPI devices using normal userspace I/O calls.
43 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
44 * and often mask message boundaries, full SPI support requires full duplex
45 * transfers. There are several kinds of of internal message boundaries to
46 * handle chipselect management and other protocol options.
47 *
48 * SPI has a character major number assigned. We allocate minor numbers
49 * dynamically using a bitmask. You must use hotplug tools, such as udev
50 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
51 * nodes, since there is no fixed association of minor numbers with any
52 * particular SPI bus or device.
53 */
54#define SPIDEV_MAJOR 153 /* assigned */
55#define N_SPI_MINORS 32 /* ... up to 256 */
56
57static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG];
58
59
Anton Vorontsov6f166e32007-07-31 00:38:43 -070060/* Bit masks for spi_device.mode management. Note that incorrect
61 * settings for CS_HIGH and 3WIRE can cause *lots* of trouble for other
62 * devices on a shared bus: CS_HIGH, because this device will be
63 * active when it shouldn't be; 3WIRE, because when active it won't
64 * behave as it should.
65 *
66 * REVISIT should changing those two modes be privileged?
67 */
68#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
69 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP)
Andrea Paterniani814a8d52007-05-08 00:32:15 -070070
71struct spidev_data {
David Brownellb2c8dad2008-06-05 22:45:50 -070072 dev_t devt;
David Brownell25d5cb42008-05-23 13:05:03 -070073 spinlock_t spi_lock;
Andrea Paterniani814a8d52007-05-08 00:32:15 -070074 struct spi_device *spi;
75 struct list_head device_entry;
76
David Brownellb2c8dad2008-06-05 22:45:50 -070077 /* buffer is NULL unless this device is open (users > 0) */
Andrea Paterniani814a8d52007-05-08 00:32:15 -070078 struct mutex buf_lock;
79 unsigned users;
80 u8 *buffer;
81};
82
83static LIST_HEAD(device_list);
84static DEFINE_MUTEX(device_list_lock);
85
86static unsigned bufsiz = 4096;
87module_param(bufsiz, uint, S_IRUGO);
88MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
89
90/*-------------------------------------------------------------------------*/
91
David Brownell25d5cb42008-05-23 13:05:03 -070092/*
93 * We can't use the standard synchronous wrappers for file I/O; we
94 * need to protect against async removal of the underlying spi_device.
95 */
96static void spidev_complete(void *arg)
97{
98 complete(arg);
99}
100
101static ssize_t
102spidev_sync(struct spidev_data *spidev, struct spi_message *message)
103{
104 DECLARE_COMPLETION_ONSTACK(done);
105 int status;
106
107 message->complete = spidev_complete;
108 message->context = &done;
109
110 spin_lock_irq(&spidev->spi_lock);
111 if (spidev->spi == NULL)
112 status = -ESHUTDOWN;
113 else
114 status = spi_async(spidev->spi, message);
115 spin_unlock_irq(&spidev->spi_lock);
116
117 if (status == 0) {
118 wait_for_completion(&done);
119 status = message->status;
120 if (status == 0)
121 status = message->actual_length;
122 }
123 return status;
124}
125
126static inline ssize_t
127spidev_sync_write(struct spidev_data *spidev, size_t len)
128{
129 struct spi_transfer t = {
130 .tx_buf = spidev->buffer,
131 .len = len,
132 };
133 struct spi_message m;
134
135 spi_message_init(&m);
136 spi_message_add_tail(&t, &m);
137 return spidev_sync(spidev, &m);
138}
139
140static inline ssize_t
141spidev_sync_read(struct spidev_data *spidev, size_t len)
142{
143 struct spi_transfer t = {
144 .rx_buf = spidev->buffer,
145 .len = len,
146 };
147 struct spi_message m;
148
149 spi_message_init(&m);
150 spi_message_add_tail(&t, &m);
151 return spidev_sync(spidev, &m);
152}
153
154/*-------------------------------------------------------------------------*/
155
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700156/* Read-only message with current device setup */
157static ssize_t
158spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
159{
160 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700161 ssize_t status = 0;
162
163 /* chipselect only toggles at start or end of operation */
164 if (count > bufsiz)
165 return -EMSGSIZE;
166
167 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700168
169 mutex_lock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700170 status = spidev_sync_read(spidev, count);
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700171 if (status > 0) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700172 unsigned long missing;
173
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700174 missing = copy_to_user(buf, spidev->buffer, status);
175 if (missing == status)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700176 status = -EFAULT;
177 else
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700178 status = status - missing;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700179 }
180 mutex_unlock(&spidev->buf_lock);
181
182 return status;
183}
184
185/* Write-only message with current device setup */
186static ssize_t
187spidev_write(struct file *filp, const char __user *buf,
188 size_t count, loff_t *f_pos)
189{
190 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700191 ssize_t status = 0;
192 unsigned long missing;
193
194 /* chipselect only toggles at start or end of operation */
195 if (count > bufsiz)
196 return -EMSGSIZE;
197
198 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700199
200 mutex_lock(&spidev->buf_lock);
201 missing = copy_from_user(spidev->buffer, buf, count);
202 if (missing == 0) {
David Brownell25d5cb42008-05-23 13:05:03 -0700203 status = spidev_sync_write(spidev, count);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700204 } else
205 status = -EFAULT;
206 mutex_unlock(&spidev->buf_lock);
207
208 return status;
209}
210
211static int spidev_message(struct spidev_data *spidev,
212 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
213{
214 struct spi_message msg;
215 struct spi_transfer *k_xfers;
216 struct spi_transfer *k_tmp;
217 struct spi_ioc_transfer *u_tmp;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700218 unsigned n, total;
219 u8 *buf;
220 int status = -EFAULT;
221
222 spi_message_init(&msg);
223 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
224 if (k_xfers == NULL)
225 return -ENOMEM;
226
227 /* Construct spi_message, copying any tx data to bounce buffer.
228 * We walk the array of user-provided transfers, using each one
229 * to initialize a kernel version of the same transfer.
230 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700231 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:
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700298 kfree(k_xfers);
299 return status;
300}
301
Alan Cox4ef754b2008-07-23 21:29:55 -0700302static long
303spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700304{
305 int err = 0;
306 int retval = 0;
307 struct spidev_data *spidev;
308 struct spi_device *spi;
309 u32 tmp;
310 unsigned n_ioc;
311 struct spi_ioc_transfer *ioc;
312
313 /* Check type and command number */
314 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
315 return -ENOTTY;
316
317 /* Check access direction once here; don't repeat below.
318 * IOC_DIR is from the user perspective, while access_ok is
319 * from the kernel perspective; so they look reversed.
320 */
321 if (_IOC_DIR(cmd) & _IOC_READ)
322 err = !access_ok(VERIFY_WRITE,
323 (void __user *)arg, _IOC_SIZE(cmd));
324 if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
325 err = !access_ok(VERIFY_READ,
326 (void __user *)arg, _IOC_SIZE(cmd));
327 if (err)
328 return -EFAULT;
329
David Brownell25d5cb42008-05-23 13:05:03 -0700330 /* guard against device removal before, or while,
331 * we issue this ioctl.
332 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700333 spidev = filp->private_data;
David Brownell25d5cb42008-05-23 13:05:03 -0700334 spin_lock_irq(&spidev->spi_lock);
335 spi = spi_dev_get(spidev->spi);
336 spin_unlock_irq(&spidev->spi_lock);
337
338 if (spi == NULL)
339 return -ESHUTDOWN;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700340
Alan Cox4ef754b2008-07-23 21:29:55 -0700341 /* use the buffer lock here for triple duty:
342 * - prevent I/O (from us) so calling spi_setup() is safe;
343 * - prevent concurrent SPI_IOC_WR_* from morphing
344 * data fields while SPI_IOC_RD_* reads them;
345 * - SPI_IOC_MESSAGE needs the buffer locked "normally".
346 */
347 mutex_lock(&spidev->buf_lock);
348
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700349 switch (cmd) {
350 /* read requests */
351 case SPI_IOC_RD_MODE:
352 retval = __put_user(spi->mode & SPI_MODE_MASK,
353 (__u8 __user *)arg);
354 break;
355 case SPI_IOC_RD_LSB_FIRST:
356 retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
357 (__u8 __user *)arg);
358 break;
359 case SPI_IOC_RD_BITS_PER_WORD:
360 retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
361 break;
362 case SPI_IOC_RD_MAX_SPEED_HZ:
363 retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg);
364 break;
365
366 /* write requests */
367 case SPI_IOC_WR_MODE:
368 retval = __get_user(tmp, (u8 __user *)arg);
369 if (retval == 0) {
370 u8 save = spi->mode;
371
372 if (tmp & ~SPI_MODE_MASK) {
373 retval = -EINVAL;
374 break;
375 }
376
377 tmp |= spi->mode & ~SPI_MODE_MASK;
378 spi->mode = (u8)tmp;
379 retval = spi_setup(spi);
380 if (retval < 0)
381 spi->mode = save;
382 else
383 dev_dbg(&spi->dev, "spi mode %02x\n", tmp);
384 }
385 break;
386 case SPI_IOC_WR_LSB_FIRST:
387 retval = __get_user(tmp, (__u8 __user *)arg);
388 if (retval == 0) {
389 u8 save = spi->mode;
390
391 if (tmp)
392 spi->mode |= SPI_LSB_FIRST;
393 else
394 spi->mode &= ~SPI_LSB_FIRST;
395 retval = spi_setup(spi);
396 if (retval < 0)
397 spi->mode = save;
398 else
399 dev_dbg(&spi->dev, "%csb first\n",
400 tmp ? 'l' : 'm');
401 }
402 break;
403 case SPI_IOC_WR_BITS_PER_WORD:
404 retval = __get_user(tmp, (__u8 __user *)arg);
405 if (retval == 0) {
406 u8 save = spi->bits_per_word;
407
408 spi->bits_per_word = tmp;
409 retval = spi_setup(spi);
410 if (retval < 0)
411 spi->bits_per_word = save;
412 else
413 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
414 }
415 break;
416 case SPI_IOC_WR_MAX_SPEED_HZ:
417 retval = __get_user(tmp, (__u32 __user *)arg);
418 if (retval == 0) {
419 u32 save = spi->max_speed_hz;
420
421 spi->max_speed_hz = tmp;
422 retval = spi_setup(spi);
423 if (retval < 0)
424 spi->max_speed_hz = save;
425 else
426 dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
427 }
428 break;
429
430 default:
431 /* segmented and/or full-duplex I/O request */
432 if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
David Brownell25d5cb42008-05-23 13:05:03 -0700433 || _IOC_DIR(cmd) != _IOC_WRITE) {
434 retval = -ENOTTY;
435 break;
436 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700437
438 tmp = _IOC_SIZE(cmd);
439 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) {
440 retval = -EINVAL;
441 break;
442 }
443 n_ioc = tmp / sizeof(struct spi_ioc_transfer);
444 if (n_ioc == 0)
445 break;
446
447 /* copy into scratch area */
448 ioc = kmalloc(tmp, GFP_KERNEL);
449 if (!ioc) {
450 retval = -ENOMEM;
451 break;
452 }
453 if (__copy_from_user(ioc, (void __user *)arg, tmp)) {
Florin Malita9bea3f22007-05-23 13:57:45 -0700454 kfree(ioc);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700455 retval = -EFAULT;
456 break;
457 }
458
459 /* translate to spi_message, execute */
460 retval = spidev_message(spidev, ioc, n_ioc);
461 kfree(ioc);
462 break;
463 }
Alan Cox4ef754b2008-07-23 21:29:55 -0700464
465 mutex_unlock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700466 spi_dev_put(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700467 return retval;
468}
469
470static int spidev_open(struct inode *inode, struct file *filp)
471{
472 struct spidev_data *spidev;
473 int status = -ENXIO;
474
Jonathan Corbet609f9e92008-05-16 13:46:14 -0600475 lock_kernel();
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700476 mutex_lock(&device_list_lock);
477
478 list_for_each_entry(spidev, &device_list, device_entry) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700479 if (spidev->devt == inode->i_rdev) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700480 status = 0;
481 break;
482 }
483 }
484 if (status == 0) {
485 if (!spidev->buffer) {
486 spidev->buffer = kmalloc(bufsiz, GFP_KERNEL);
487 if (!spidev->buffer) {
488 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
489 status = -ENOMEM;
490 }
491 }
492 if (status == 0) {
493 spidev->users++;
494 filp->private_data = spidev;
495 nonseekable_open(inode, filp);
496 }
497 } else
498 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
499
500 mutex_unlock(&device_list_lock);
Jonathan Corbet609f9e92008-05-16 13:46:14 -0600501 unlock_kernel();
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700502 return status;
503}
504
505static int spidev_release(struct inode *inode, struct file *filp)
506{
507 struct spidev_data *spidev;
508 int status = 0;
509
510 mutex_lock(&device_list_lock);
511 spidev = filp->private_data;
512 filp->private_data = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700513
514 /* last close? */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700515 spidev->users--;
516 if (!spidev->users) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700517 int dofree;
518
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700519 kfree(spidev->buffer);
520 spidev->buffer = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700521
522 /* ... after we unbound from the underlying device? */
523 spin_lock_irq(&spidev->spi_lock);
524 dofree = (spidev->spi == NULL);
525 spin_unlock_irq(&spidev->spi_lock);
526
527 if (dofree)
528 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700529 }
530 mutex_unlock(&device_list_lock);
531
532 return status;
533}
534
535static struct file_operations spidev_fops = {
536 .owner = THIS_MODULE,
537 /* REVISIT switch to aio primitives, so that userspace
538 * gets more complete API coverage. It'll simplify things
539 * too, except for the locking.
540 */
541 .write = spidev_write,
542 .read = spidev_read,
Alan Cox4ef754b2008-07-23 21:29:55 -0700543 .unlocked_ioctl = spidev_ioctl,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700544 .open = spidev_open,
545 .release = spidev_release,
546};
547
548/*-------------------------------------------------------------------------*/
549
550/* The main reason to have this class is to make mdev/udev create the
551 * /dev/spidevB.C character device nodes exposing our userspace API.
552 * It also simplifies memory management.
553 */
554
David Brownellb2c8dad2008-06-05 22:45:50 -0700555static struct class *spidev_class;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700556
557/*-------------------------------------------------------------------------*/
558
559static int spidev_probe(struct spi_device *spi)
560{
561 struct spidev_data *spidev;
562 int status;
563 unsigned long minor;
564
565 /* Allocate driver data */
566 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
567 if (!spidev)
568 return -ENOMEM;
569
570 /* Initialize the driver data */
571 spidev->spi = spi;
David Brownell25d5cb42008-05-23 13:05:03 -0700572 spin_lock_init(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700573 mutex_init(&spidev->buf_lock);
574
575 INIT_LIST_HEAD(&spidev->device_entry);
576
577 /* If we can allocate a minor number, hook up this device.
578 * Reusing minors is fine so long as udev or mdev is working.
579 */
580 mutex_lock(&device_list_lock);
Domen Puncer0a4dd772007-05-15 23:57:05 -0700581 minor = find_first_zero_bit(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700582 if (minor < N_SPI_MINORS) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700583 struct device *dev;
584
585 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
Greg Kroah-Hartmana9b12612008-07-21 20:03:34 -0700586 dev = device_create(spidev_class, &spi->dev, spidev->devt,
587 spidev, "spidev%d.%d",
588 spi->master->bus_num, spi->chip_select);
David Brownellb2c8dad2008-06-05 22:45:50 -0700589 status = IS_ERR(dev) ? PTR_ERR(dev) : 0;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700590 } else {
591 dev_dbg(&spi->dev, "no minor number available!\n");
592 status = -ENODEV;
593 }
594 if (status == 0) {
595 set_bit(minor, minors);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700596 list_add(&spidev->device_entry, &device_list);
597 }
598 mutex_unlock(&device_list_lock);
599
Wolfgang Ockeraaacf4b2008-12-01 13:13:52 -0800600 if (status == 0)
601 spi_set_drvdata(spi, spidev);
602 else
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700603 kfree(spidev);
604
605 return status;
606}
607
608static int spidev_remove(struct spi_device *spi)
609{
David Brownellb2c8dad2008-06-05 22:45:50 -0700610 struct spidev_data *spidev = spi_get_drvdata(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700611
David Brownell25d5cb42008-05-23 13:05:03 -0700612 /* make sure ops on existing fds can abort cleanly */
613 spin_lock_irq(&spidev->spi_lock);
614 spidev->spi = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700615 spi_set_drvdata(spi, NULL);
David Brownell25d5cb42008-05-23 13:05:03 -0700616 spin_unlock_irq(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700617
David Brownell25d5cb42008-05-23 13:05:03 -0700618 /* prevent new opens */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700619 mutex_lock(&device_list_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700620 list_del(&spidev->device_entry);
David Brownellb2c8dad2008-06-05 22:45:50 -0700621 device_destroy(spidev_class, spidev->devt);
622 clear_bit(MINOR(spidev->devt), minors);
623 if (spidev->users == 0)
624 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700625 mutex_unlock(&device_list_lock);
626
627 return 0;
628}
629
630static struct spi_driver spidev_spi = {
631 .driver = {
632 .name = "spidev",
633 .owner = THIS_MODULE,
634 },
635 .probe = spidev_probe,
636 .remove = __devexit_p(spidev_remove),
637
638 /* NOTE: suspend/resume methods are not necessary here.
639 * We don't do anything except pass the requests to/from
640 * the underlying controller. The refrigerator handles
641 * most issues; the controller driver handles the rest.
642 */
643};
644
645/*-------------------------------------------------------------------------*/
646
647static int __init spidev_init(void)
648{
649 int status;
650
651 /* Claim our 256 reserved device numbers. Then register a class
652 * that will key udev/mdev to add/remove /dev nodes. Last, register
653 * the driver which manages those device numbers.
654 */
655 BUILD_BUG_ON(N_SPI_MINORS > 256);
656 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
657 if (status < 0)
658 return status;
659
David Brownellb2c8dad2008-06-05 22:45:50 -0700660 spidev_class = class_create(THIS_MODULE, "spidev");
661 if (IS_ERR(spidev_class)) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700662 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
David Brownellb2c8dad2008-06-05 22:45:50 -0700663 return PTR_ERR(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700664 }
665
666 status = spi_register_driver(&spidev_spi);
667 if (status < 0) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700668 class_destroy(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700669 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
670 }
671 return status;
672}
673module_init(spidev_init);
674
675static void __exit spidev_exit(void)
676{
677 spi_unregister_driver(&spidev_spi);
David Brownellb2c8dad2008-06-05 22:45:50 -0700678 class_destroy(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700679 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
680}
681module_exit(spidev_exit);
682
683MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
684MODULE_DESCRIPTION("User mode SPI device interface");
685MODULE_LICENSE("GPL");