blob: f921bd1109e1c1ff9a26e851e19a484860b19c08 [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
David Brownellb55f6272009-06-30 11:41:26 -070061 * settings for some settings can cause *lots* of trouble for other
62 * devices on a shared bus:
Anton Vorontsov6f166e32007-07-31 00:38:43 -070063 *
David Brownellb55f6272009-06-30 11:41:26 -070064 * - CS_HIGH ... this device will be active when it shouldn't be
65 * - 3WIRE ... when active, it won't behave as it should
66 * - NO_CS ... there will be no explicit message boundaries; this
67 * is completely incompatible with the shared bus model
68 * - READY ... transfers may proceed when they shouldn't.
69 *
70 * REVISIT should changing those flags be privileged?
Anton Vorontsov6f166e32007-07-31 00:38:43 -070071 */
72#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
David Brownellb55f6272009-06-30 11:41:26 -070073 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
74 | SPI_NO_CS | SPI_READY)
Andrea Paterniani814a8d52007-05-08 00:32:15 -070075
76struct spidev_data {
David Brownellb2c8dad2008-06-05 22:45:50 -070077 dev_t devt;
David Brownell25d5cb42008-05-23 13:05:03 -070078 spinlock_t spi_lock;
Andrea Paterniani814a8d52007-05-08 00:32:15 -070079 struct spi_device *spi;
80 struct list_head device_entry;
81
David Brownellb2c8dad2008-06-05 22:45:50 -070082 /* buffer is NULL unless this device is open (users > 0) */
Andrea Paterniani814a8d52007-05-08 00:32:15 -070083 struct mutex buf_lock;
84 unsigned users;
85 u8 *buffer;
86};
87
88static LIST_HEAD(device_list);
89static DEFINE_MUTEX(device_list_lock);
90
91static unsigned bufsiz = 4096;
92module_param(bufsiz, uint, S_IRUGO);
93MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
94
95/*-------------------------------------------------------------------------*/
96
David Brownell25d5cb42008-05-23 13:05:03 -070097/*
98 * We can't use the standard synchronous wrappers for file I/O; we
99 * need to protect against async removal of the underlying spi_device.
100 */
101static void spidev_complete(void *arg)
102{
103 complete(arg);
104}
105
106static ssize_t
107spidev_sync(struct spidev_data *spidev, struct spi_message *message)
108{
109 DECLARE_COMPLETION_ONSTACK(done);
110 int status;
111
112 message->complete = spidev_complete;
113 message->context = &done;
114
115 spin_lock_irq(&spidev->spi_lock);
116 if (spidev->spi == NULL)
117 status = -ESHUTDOWN;
118 else
119 status = spi_async(spidev->spi, message);
120 spin_unlock_irq(&spidev->spi_lock);
121
122 if (status == 0) {
123 wait_for_completion(&done);
124 status = message->status;
125 if (status == 0)
126 status = message->actual_length;
127 }
128 return status;
129}
130
131static inline ssize_t
132spidev_sync_write(struct spidev_data *spidev, size_t len)
133{
134 struct spi_transfer t = {
135 .tx_buf = spidev->buffer,
136 .len = len,
137 };
138 struct spi_message m;
139
140 spi_message_init(&m);
141 spi_message_add_tail(&t, &m);
142 return spidev_sync(spidev, &m);
143}
144
145static inline ssize_t
146spidev_sync_read(struct spidev_data *spidev, size_t len)
147{
148 struct spi_transfer t = {
149 .rx_buf = spidev->buffer,
150 .len = len,
151 };
152 struct spi_message m;
153
154 spi_message_init(&m);
155 spi_message_add_tail(&t, &m);
156 return spidev_sync(spidev, &m);
157}
158
159/*-------------------------------------------------------------------------*/
160
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700161/* Read-only message with current device setup */
162static ssize_t
163spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
164{
165 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700166 ssize_t status = 0;
167
168 /* chipselect only toggles at start or end of operation */
169 if (count > bufsiz)
170 return -EMSGSIZE;
171
172 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700173
174 mutex_lock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700175 status = spidev_sync_read(spidev, count);
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700176 if (status > 0) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700177 unsigned long missing;
178
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700179 missing = copy_to_user(buf, spidev->buffer, status);
180 if (missing == status)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700181 status = -EFAULT;
182 else
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700183 status = status - missing;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700184 }
185 mutex_unlock(&spidev->buf_lock);
186
187 return status;
188}
189
190/* Write-only message with current device setup */
191static ssize_t
192spidev_write(struct file *filp, const char __user *buf,
193 size_t count, loff_t *f_pos)
194{
195 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700196 ssize_t status = 0;
197 unsigned long missing;
198
199 /* chipselect only toggles at start or end of operation */
200 if (count > bufsiz)
201 return -EMSGSIZE;
202
203 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700204
205 mutex_lock(&spidev->buf_lock);
206 missing = copy_from_user(spidev->buffer, buf, count);
207 if (missing == 0) {
David Brownell25d5cb42008-05-23 13:05:03 -0700208 status = spidev_sync_write(spidev, count);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700209 } else
210 status = -EFAULT;
211 mutex_unlock(&spidev->buf_lock);
212
213 return status;
214}
215
216static int spidev_message(struct spidev_data *spidev,
217 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
218{
219 struct spi_message msg;
220 struct spi_transfer *k_xfers;
221 struct spi_transfer *k_tmp;
222 struct spi_ioc_transfer *u_tmp;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700223 unsigned n, total;
224 u8 *buf;
225 int status = -EFAULT;
226
227 spi_message_init(&msg);
228 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
229 if (k_xfers == NULL)
230 return -ENOMEM;
231
232 /* Construct spi_message, copying any tx data to bounce buffer.
233 * We walk the array of user-provided transfers, using each one
234 * to initialize a kernel version of the same transfer.
235 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700236 buf = spidev->buffer;
237 total = 0;
238 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
239 n;
240 n--, k_tmp++, u_tmp++) {
241 k_tmp->len = u_tmp->len;
242
Domen Puncerda90fa82007-05-23 13:57:39 -0700243 total += k_tmp->len;
244 if (total > bufsiz) {
245 status = -EMSGSIZE;
246 goto done;
247 }
248
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700249 if (u_tmp->rx_buf) {
250 k_tmp->rx_buf = buf;
David Brownell96ddbf52007-08-10 13:01:09 -0700251 if (!access_ok(VERIFY_WRITE, (u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000252 (uintptr_t) u_tmp->rx_buf,
David Brownell96ddbf52007-08-10 13:01:09 -0700253 u_tmp->len))
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700254 goto done;
255 }
256 if (u_tmp->tx_buf) {
257 k_tmp->tx_buf = buf;
David Brownell4917d922007-07-17 04:04:04 -0700258 if (copy_from_user(buf, (const u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000259 (uintptr_t) u_tmp->tx_buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700260 u_tmp->len))
261 goto done;
262 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700263 buf += k_tmp->len;
264
265 k_tmp->cs_change = !!u_tmp->cs_change;
266 k_tmp->bits_per_word = u_tmp->bits_per_word;
267 k_tmp->delay_usecs = u_tmp->delay_usecs;
268 k_tmp->speed_hz = u_tmp->speed_hz;
269#ifdef VERBOSE
270 dev_dbg(&spi->dev,
271 " xfer len %zd %s%s%s%dbits %u usec %uHz\n",
272 u_tmp->len,
273 u_tmp->rx_buf ? "rx " : "",
274 u_tmp->tx_buf ? "tx " : "",
275 u_tmp->cs_change ? "cs " : "",
276 u_tmp->bits_per_word ? : spi->bits_per_word,
277 u_tmp->delay_usecs,
278 u_tmp->speed_hz ? : spi->max_speed_hz);
279#endif
280 spi_message_add_tail(k_tmp, &msg);
281 }
282
David Brownell25d5cb42008-05-23 13:05:03 -0700283 status = spidev_sync(spidev, &msg);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700284 if (status < 0)
285 goto done;
286
287 /* copy any rx data out of bounce buffer */
288 buf = spidev->buffer;
289 for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
290 if (u_tmp->rx_buf) {
David Brownell4917d922007-07-17 04:04:04 -0700291 if (__copy_to_user((u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000292 (uintptr_t) u_tmp->rx_buf, buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700293 u_tmp->len)) {
294 status = -EFAULT;
295 goto done;
296 }
297 }
298 buf += u_tmp->len;
299 }
300 status = total;
301
302done:
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700303 kfree(k_xfers);
304 return status;
305}
306
Alan Cox4ef754b2008-07-23 21:29:55 -0700307static long
308spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700309{
310 int err = 0;
311 int retval = 0;
312 struct spidev_data *spidev;
313 struct spi_device *spi;
314 u32 tmp;
315 unsigned n_ioc;
316 struct spi_ioc_transfer *ioc;
317
318 /* Check type and command number */
319 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
320 return -ENOTTY;
321
322 /* Check access direction once here; don't repeat below.
323 * IOC_DIR is from the user perspective, while access_ok is
324 * from the kernel perspective; so they look reversed.
325 */
326 if (_IOC_DIR(cmd) & _IOC_READ)
327 err = !access_ok(VERIFY_WRITE,
328 (void __user *)arg, _IOC_SIZE(cmd));
329 if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
330 err = !access_ok(VERIFY_READ,
331 (void __user *)arg, _IOC_SIZE(cmd));
332 if (err)
333 return -EFAULT;
334
David Brownell25d5cb42008-05-23 13:05:03 -0700335 /* guard against device removal before, or while,
336 * we issue this ioctl.
337 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700338 spidev = filp->private_data;
David Brownell25d5cb42008-05-23 13:05:03 -0700339 spin_lock_irq(&spidev->spi_lock);
340 spi = spi_dev_get(spidev->spi);
341 spin_unlock_irq(&spidev->spi_lock);
342
343 if (spi == NULL)
344 return -ESHUTDOWN;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700345
Alan Cox4ef754b2008-07-23 21:29:55 -0700346 /* use the buffer lock here for triple duty:
347 * - prevent I/O (from us) so calling spi_setup() is safe;
348 * - prevent concurrent SPI_IOC_WR_* from morphing
349 * data fields while SPI_IOC_RD_* reads them;
350 * - SPI_IOC_MESSAGE needs the buffer locked "normally".
351 */
352 mutex_lock(&spidev->buf_lock);
353
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700354 switch (cmd) {
355 /* read requests */
356 case SPI_IOC_RD_MODE:
357 retval = __put_user(spi->mode & SPI_MODE_MASK,
358 (__u8 __user *)arg);
359 break;
360 case SPI_IOC_RD_LSB_FIRST:
361 retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
362 (__u8 __user *)arg);
363 break;
364 case SPI_IOC_RD_BITS_PER_WORD:
365 retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
366 break;
367 case SPI_IOC_RD_MAX_SPEED_HZ:
368 retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg);
369 break;
370
371 /* write requests */
372 case SPI_IOC_WR_MODE:
373 retval = __get_user(tmp, (u8 __user *)arg);
374 if (retval == 0) {
375 u8 save = spi->mode;
376
377 if (tmp & ~SPI_MODE_MASK) {
378 retval = -EINVAL;
379 break;
380 }
381
382 tmp |= spi->mode & ~SPI_MODE_MASK;
383 spi->mode = (u8)tmp;
384 retval = spi_setup(spi);
385 if (retval < 0)
386 spi->mode = save;
387 else
388 dev_dbg(&spi->dev, "spi mode %02x\n", tmp);
389 }
390 break;
391 case SPI_IOC_WR_LSB_FIRST:
392 retval = __get_user(tmp, (__u8 __user *)arg);
393 if (retval == 0) {
394 u8 save = spi->mode;
395
396 if (tmp)
397 spi->mode |= SPI_LSB_FIRST;
398 else
399 spi->mode &= ~SPI_LSB_FIRST;
400 retval = spi_setup(spi);
401 if (retval < 0)
402 spi->mode = save;
403 else
404 dev_dbg(&spi->dev, "%csb first\n",
405 tmp ? 'l' : 'm');
406 }
407 break;
408 case SPI_IOC_WR_BITS_PER_WORD:
409 retval = __get_user(tmp, (__u8 __user *)arg);
410 if (retval == 0) {
411 u8 save = spi->bits_per_word;
412
413 spi->bits_per_word = tmp;
414 retval = spi_setup(spi);
415 if (retval < 0)
416 spi->bits_per_word = save;
417 else
418 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
419 }
420 break;
421 case SPI_IOC_WR_MAX_SPEED_HZ:
422 retval = __get_user(tmp, (__u32 __user *)arg);
423 if (retval == 0) {
424 u32 save = spi->max_speed_hz;
425
426 spi->max_speed_hz = tmp;
427 retval = spi_setup(spi);
428 if (retval < 0)
429 spi->max_speed_hz = save;
430 else
431 dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
432 }
433 break;
434
435 default:
436 /* segmented and/or full-duplex I/O request */
437 if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
David Brownell25d5cb42008-05-23 13:05:03 -0700438 || _IOC_DIR(cmd) != _IOC_WRITE) {
439 retval = -ENOTTY;
440 break;
441 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700442
443 tmp = _IOC_SIZE(cmd);
444 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) {
445 retval = -EINVAL;
446 break;
447 }
448 n_ioc = tmp / sizeof(struct spi_ioc_transfer);
449 if (n_ioc == 0)
450 break;
451
452 /* copy into scratch area */
453 ioc = kmalloc(tmp, GFP_KERNEL);
454 if (!ioc) {
455 retval = -ENOMEM;
456 break;
457 }
458 if (__copy_from_user(ioc, (void __user *)arg, tmp)) {
Florin Malita9bea3f22007-05-23 13:57:45 -0700459 kfree(ioc);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700460 retval = -EFAULT;
461 break;
462 }
463
464 /* translate to spi_message, execute */
465 retval = spidev_message(spidev, ioc, n_ioc);
466 kfree(ioc);
467 break;
468 }
Alan Cox4ef754b2008-07-23 21:29:55 -0700469
470 mutex_unlock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700471 spi_dev_put(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700472 return retval;
473}
474
475static int spidev_open(struct inode *inode, struct file *filp)
476{
477 struct spidev_data *spidev;
478 int status = -ENXIO;
479
Jonathan Corbet609f9e92008-05-16 13:46:14 -0600480 lock_kernel();
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700481 mutex_lock(&device_list_lock);
482
483 list_for_each_entry(spidev, &device_list, device_entry) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700484 if (spidev->devt == inode->i_rdev) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700485 status = 0;
486 break;
487 }
488 }
489 if (status == 0) {
490 if (!spidev->buffer) {
491 spidev->buffer = kmalloc(bufsiz, GFP_KERNEL);
492 if (!spidev->buffer) {
493 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
494 status = -ENOMEM;
495 }
496 }
497 if (status == 0) {
498 spidev->users++;
499 filp->private_data = spidev;
500 nonseekable_open(inode, filp);
501 }
502 } else
503 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
504
505 mutex_unlock(&device_list_lock);
Jonathan Corbet609f9e92008-05-16 13:46:14 -0600506 unlock_kernel();
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700507 return status;
508}
509
510static int spidev_release(struct inode *inode, struct file *filp)
511{
512 struct spidev_data *spidev;
513 int status = 0;
514
515 mutex_lock(&device_list_lock);
516 spidev = filp->private_data;
517 filp->private_data = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700518
519 /* last close? */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700520 spidev->users--;
521 if (!spidev->users) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700522 int dofree;
523
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700524 kfree(spidev->buffer);
525 spidev->buffer = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700526
527 /* ... after we unbound from the underlying device? */
528 spin_lock_irq(&spidev->spi_lock);
529 dofree = (spidev->spi == NULL);
530 spin_unlock_irq(&spidev->spi_lock);
531
532 if (dofree)
533 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700534 }
535 mutex_unlock(&device_list_lock);
536
537 return status;
538}
539
540static struct file_operations spidev_fops = {
541 .owner = THIS_MODULE,
542 /* REVISIT switch to aio primitives, so that userspace
543 * gets more complete API coverage. It'll simplify things
544 * too, except for the locking.
545 */
546 .write = spidev_write,
547 .read = spidev_read,
Alan Cox4ef754b2008-07-23 21:29:55 -0700548 .unlocked_ioctl = spidev_ioctl,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700549 .open = spidev_open,
550 .release = spidev_release,
551};
552
553/*-------------------------------------------------------------------------*/
554
555/* The main reason to have this class is to make mdev/udev create the
556 * /dev/spidevB.C character device nodes exposing our userspace API.
557 * It also simplifies memory management.
558 */
559
David Brownellb2c8dad2008-06-05 22:45:50 -0700560static struct class *spidev_class;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700561
562/*-------------------------------------------------------------------------*/
563
564static int spidev_probe(struct spi_device *spi)
565{
566 struct spidev_data *spidev;
567 int status;
568 unsigned long minor;
569
570 /* Allocate driver data */
571 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
572 if (!spidev)
573 return -ENOMEM;
574
575 /* Initialize the driver data */
576 spidev->spi = spi;
David Brownell25d5cb42008-05-23 13:05:03 -0700577 spin_lock_init(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700578 mutex_init(&spidev->buf_lock);
579
580 INIT_LIST_HEAD(&spidev->device_entry);
581
582 /* If we can allocate a minor number, hook up this device.
583 * Reusing minors is fine so long as udev or mdev is working.
584 */
585 mutex_lock(&device_list_lock);
Domen Puncer0a4dd772007-05-15 23:57:05 -0700586 minor = find_first_zero_bit(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700587 if (minor < N_SPI_MINORS) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700588 struct device *dev;
589
590 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
Greg Kroah-Hartmana9b12612008-07-21 20:03:34 -0700591 dev = device_create(spidev_class, &spi->dev, spidev->devt,
592 spidev, "spidev%d.%d",
593 spi->master->bus_num, spi->chip_select);
David Brownellb2c8dad2008-06-05 22:45:50 -0700594 status = IS_ERR(dev) ? PTR_ERR(dev) : 0;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700595 } else {
596 dev_dbg(&spi->dev, "no minor number available!\n");
597 status = -ENODEV;
598 }
599 if (status == 0) {
600 set_bit(minor, minors);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700601 list_add(&spidev->device_entry, &device_list);
602 }
603 mutex_unlock(&device_list_lock);
604
Wolfgang Ockeraaacf4b2008-12-01 13:13:52 -0800605 if (status == 0)
606 spi_set_drvdata(spi, spidev);
607 else
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700608 kfree(spidev);
609
610 return status;
611}
612
613static int spidev_remove(struct spi_device *spi)
614{
David Brownellb2c8dad2008-06-05 22:45:50 -0700615 struct spidev_data *spidev = spi_get_drvdata(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700616
David Brownell25d5cb42008-05-23 13:05:03 -0700617 /* make sure ops on existing fds can abort cleanly */
618 spin_lock_irq(&spidev->spi_lock);
619 spidev->spi = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700620 spi_set_drvdata(spi, NULL);
David Brownell25d5cb42008-05-23 13:05:03 -0700621 spin_unlock_irq(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700622
David Brownell25d5cb42008-05-23 13:05:03 -0700623 /* prevent new opens */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700624 mutex_lock(&device_list_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700625 list_del(&spidev->device_entry);
David Brownellb2c8dad2008-06-05 22:45:50 -0700626 device_destroy(spidev_class, spidev->devt);
627 clear_bit(MINOR(spidev->devt), minors);
628 if (spidev->users == 0)
629 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700630 mutex_unlock(&device_list_lock);
631
632 return 0;
633}
634
635static struct spi_driver spidev_spi = {
636 .driver = {
637 .name = "spidev",
638 .owner = THIS_MODULE,
639 },
640 .probe = spidev_probe,
641 .remove = __devexit_p(spidev_remove),
642
643 /* NOTE: suspend/resume methods are not necessary here.
644 * We don't do anything except pass the requests to/from
645 * the underlying controller. The refrigerator handles
646 * most issues; the controller driver handles the rest.
647 */
648};
649
650/*-------------------------------------------------------------------------*/
651
652static int __init spidev_init(void)
653{
654 int status;
655
656 /* Claim our 256 reserved device numbers. Then register a class
657 * that will key udev/mdev to add/remove /dev nodes. Last, register
658 * the driver which manages those device numbers.
659 */
660 BUILD_BUG_ON(N_SPI_MINORS > 256);
661 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
662 if (status < 0)
663 return status;
664
David Brownellb2c8dad2008-06-05 22:45:50 -0700665 spidev_class = class_create(THIS_MODULE, "spidev");
666 if (IS_ERR(spidev_class)) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700667 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
David Brownellb2c8dad2008-06-05 22:45:50 -0700668 return PTR_ERR(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700669 }
670
671 status = spi_register_driver(&spidev_spi);
672 if (status < 0) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700673 class_destroy(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700674 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
675 }
676 return status;
677}
678module_init(spidev_init);
679
680static void __exit spidev_exit(void)
681{
682 spi_unregister_driver(&spidev_spi);
David Brownellb2c8dad2008-06-05 22:45:50 -0700683 class_destroy(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700684 unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name);
685}
686module_exit(spidev_exit);
687
688MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
689MODULE_DESCRIPTION("User mode SPI device interface");
690MODULE_LICENSE("GPL");
Anton Vorontsove0626e32009-09-22 16:46:08 -0700691MODULE_ALIAS("spi:spidev");