blob: ea1bec3c9a13359a4058a762e9f2f8de7755cc36 [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>
33
34#include <linux/spi/spi.h>
35#include <linux/spi/spidev.h>
36
37#include <asm/uaccess.h>
38
39
40/*
41 * This supports acccess to SPI devices using normal userspace I/O calls.
42 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
43 * and often mask message boundaries, full SPI support requires full duplex
Thadeu Lima de Souza Cascardo137f1182009-10-22 17:34:29 -020044 * transfers. There are several kinds of internal message boundaries to
Andrea Paterniani814a8d52007-05-08 00:32:15 -070045 * handle chipselect management and other protocol options.
46 *
47 * SPI has a character major number assigned. We allocate minor numbers
48 * dynamically using a bitmask. You must use hotplug tools, such as udev
49 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
50 * nodes, since there is no fixed association of minor numbers with any
51 * particular SPI bus or device.
52 */
53#define SPIDEV_MAJOR 153 /* assigned */
54#define N_SPI_MINORS 32 /* ... up to 256 */
55
Thadeu Lima de Souza Cascardo8ae1c922009-12-14 14:20:23 -080056static DECLARE_BITMAP(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -070057
58
Anton Vorontsov6f166e32007-07-31 00:38:43 -070059/* Bit masks for spi_device.mode management. Note that incorrect
David Brownellb55f6272009-06-30 11:41:26 -070060 * settings for some settings can cause *lots* of trouble for other
61 * devices on a shared bus:
Anton Vorontsov6f166e32007-07-31 00:38:43 -070062 *
David Brownellb55f6272009-06-30 11:41:26 -070063 * - CS_HIGH ... this device will be active when it shouldn't be
64 * - 3WIRE ... when active, it won't behave as it should
65 * - NO_CS ... there will be no explicit message boundaries; this
66 * is completely incompatible with the shared bus model
67 * - READY ... transfers may proceed when they shouldn't.
68 *
69 * REVISIT should changing those flags be privileged?
Anton Vorontsov6f166e32007-07-31 00:38:43 -070070 */
71#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
David Brownellb55f6272009-06-30 11:41:26 -070072 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
73 | SPI_NO_CS | SPI_READY)
Andrea Paterniani814a8d52007-05-08 00:32:15 -070074
75struct spidev_data {
David Brownellb2c8dad2008-06-05 22:45:50 -070076 dev_t devt;
David Brownell25d5cb42008-05-23 13:05:03 -070077 spinlock_t spi_lock;
Andrea Paterniani814a8d52007-05-08 00:32:15 -070078 struct spi_device *spi;
79 struct list_head device_entry;
80
David Brownellb2c8dad2008-06-05 22:45:50 -070081 /* buffer is NULL unless this device is open (users > 0) */
Andrea Paterniani814a8d52007-05-08 00:32:15 -070082 struct mutex buf_lock;
83 unsigned users;
84 u8 *buffer;
85};
86
87static LIST_HEAD(device_list);
88static DEFINE_MUTEX(device_list_lock);
89
90static unsigned bufsiz = 4096;
91module_param(bufsiz, uint, S_IRUGO);
92MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
93
94/*-------------------------------------------------------------------------*/
95
David Brownell25d5cb42008-05-23 13:05:03 -070096/*
97 * We can't use the standard synchronous wrappers for file I/O; we
98 * need to protect against async removal of the underlying spi_device.
99 */
100static void spidev_complete(void *arg)
101{
102 complete(arg);
103}
104
105static ssize_t
106spidev_sync(struct spidev_data *spidev, struct spi_message *message)
107{
108 DECLARE_COMPLETION_ONSTACK(done);
109 int status;
110
111 message->complete = spidev_complete;
112 message->context = &done;
113
114 spin_lock_irq(&spidev->spi_lock);
115 if (spidev->spi == NULL)
116 status = -ESHUTDOWN;
117 else
118 status = spi_async(spidev->spi, message);
119 spin_unlock_irq(&spidev->spi_lock);
120
121 if (status == 0) {
122 wait_for_completion(&done);
123 status = message->status;
124 if (status == 0)
125 status = message->actual_length;
126 }
127 return status;
128}
129
130static inline ssize_t
131spidev_sync_write(struct spidev_data *spidev, size_t len)
132{
133 struct spi_transfer t = {
134 .tx_buf = spidev->buffer,
135 .len = len,
136 };
137 struct spi_message m;
138
139 spi_message_init(&m);
140 spi_message_add_tail(&t, &m);
141 return spidev_sync(spidev, &m);
142}
143
144static inline ssize_t
145spidev_sync_read(struct spidev_data *spidev, size_t len)
146{
147 struct spi_transfer t = {
148 .rx_buf = spidev->buffer,
149 .len = len,
150 };
151 struct spi_message m;
152
153 spi_message_init(&m);
154 spi_message_add_tail(&t, &m);
155 return spidev_sync(spidev, &m);
156}
157
158/*-------------------------------------------------------------------------*/
159
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700160/* Read-only message with current device setup */
161static ssize_t
162spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
163{
164 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700165 ssize_t status = 0;
166
167 /* chipselect only toggles at start or end of operation */
168 if (count > bufsiz)
169 return -EMSGSIZE;
170
171 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700172
173 mutex_lock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700174 status = spidev_sync_read(spidev, count);
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700175 if (status > 0) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700176 unsigned long missing;
177
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700178 missing = copy_to_user(buf, spidev->buffer, status);
179 if (missing == status)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700180 status = -EFAULT;
181 else
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700182 status = status - missing;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700183 }
184 mutex_unlock(&spidev->buf_lock);
185
186 return status;
187}
188
189/* Write-only message with current device setup */
190static ssize_t
191spidev_write(struct file *filp, const char __user *buf,
192 size_t count, loff_t *f_pos)
193{
194 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700195 ssize_t status = 0;
196 unsigned long missing;
197
198 /* chipselect only toggles at start or end of operation */
199 if (count > bufsiz)
200 return -EMSGSIZE;
201
202 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700203
204 mutex_lock(&spidev->buf_lock);
205 missing = copy_from_user(spidev->buffer, buf, count);
206 if (missing == 0) {
David Brownell25d5cb42008-05-23 13:05:03 -0700207 status = spidev_sync_write(spidev, count);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700208 } else
209 status = -EFAULT;
210 mutex_unlock(&spidev->buf_lock);
211
212 return status;
213}
214
215static int spidev_message(struct spidev_data *spidev,
216 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
217{
218 struct spi_message msg;
219 struct spi_transfer *k_xfers;
220 struct spi_transfer *k_tmp;
221 struct spi_ioc_transfer *u_tmp;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700222 unsigned n, total;
223 u8 *buf;
224 int status = -EFAULT;
225
226 spi_message_init(&msg);
227 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
228 if (k_xfers == NULL)
229 return -ENOMEM;
230
231 /* Construct spi_message, copying any tx data to bounce buffer.
232 * We walk the array of user-provided transfers, using each one
233 * to initialize a kernel version of the same transfer.
234 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700235 buf = spidev->buffer;
236 total = 0;
237 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
238 n;
239 n--, k_tmp++, u_tmp++) {
240 k_tmp->len = u_tmp->len;
241
Domen Puncerda90fa82007-05-23 13:57:39 -0700242 total += k_tmp->len;
243 if (total > bufsiz) {
244 status = -EMSGSIZE;
245 goto done;
246 }
247
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700248 if (u_tmp->rx_buf) {
249 k_tmp->rx_buf = buf;
David Brownell96ddbf52007-08-10 13:01:09 -0700250 if (!access_ok(VERIFY_WRITE, (u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000251 (uintptr_t) u_tmp->rx_buf,
David Brownell96ddbf52007-08-10 13:01:09 -0700252 u_tmp->len))
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700253 goto done;
254 }
255 if (u_tmp->tx_buf) {
256 k_tmp->tx_buf = buf;
David Brownell4917d922007-07-17 04:04:04 -0700257 if (copy_from_user(buf, (const u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000258 (uintptr_t) u_tmp->tx_buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700259 u_tmp->len))
260 goto done;
261 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700262 buf += k_tmp->len;
263
264 k_tmp->cs_change = !!u_tmp->cs_change;
265 k_tmp->bits_per_word = u_tmp->bits_per_word;
266 k_tmp->delay_usecs = u_tmp->delay_usecs;
267 k_tmp->speed_hz = u_tmp->speed_hz;
268#ifdef VERBOSE
Florian Fainelli41df70d2009-12-07 14:28:43 +0000269 dev_dbg(&spidev->spi->dev,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700270 " xfer len %zd %s%s%s%dbits %u usec %uHz\n",
271 u_tmp->len,
272 u_tmp->rx_buf ? "rx " : "",
273 u_tmp->tx_buf ? "tx " : "",
274 u_tmp->cs_change ? "cs " : "",
Florian Fainelli41df70d2009-12-07 14:28:43 +0000275 u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700276 u_tmp->delay_usecs,
Florian Fainelli41df70d2009-12-07 14:28:43 +0000277 u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700278#endif
279 spi_message_add_tail(k_tmp, &msg);
280 }
281
David Brownell25d5cb42008-05-23 13:05:03 -0700282 status = spidev_sync(spidev, &msg);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700283 if (status < 0)
284 goto done;
285
286 /* copy any rx data out of bounce buffer */
287 buf = spidev->buffer;
288 for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
289 if (u_tmp->rx_buf) {
David Brownell4917d922007-07-17 04:04:04 -0700290 if (__copy_to_user((u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000291 (uintptr_t) u_tmp->rx_buf, buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700292 u_tmp->len)) {
293 status = -EFAULT;
294 goto done;
295 }
296 }
297 buf += u_tmp->len;
298 }
299 status = total;
300
301done:
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700302 kfree(k_xfers);
303 return status;
304}
305
Alan Cox4ef754b2008-07-23 21:29:55 -0700306static long
307spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700308{
309 int err = 0;
310 int retval = 0;
311 struct spidev_data *spidev;
312 struct spi_device *spi;
313 u32 tmp;
314 unsigned n_ioc;
315 struct spi_ioc_transfer *ioc;
316
317 /* Check type and command number */
318 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
319 return -ENOTTY;
320
321 /* Check access direction once here; don't repeat below.
322 * IOC_DIR is from the user perspective, while access_ok is
323 * from the kernel perspective; so they look reversed.
324 */
325 if (_IOC_DIR(cmd) & _IOC_READ)
326 err = !access_ok(VERIFY_WRITE,
327 (void __user *)arg, _IOC_SIZE(cmd));
328 if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
329 err = !access_ok(VERIFY_READ,
330 (void __user *)arg, _IOC_SIZE(cmd));
331 if (err)
332 return -EFAULT;
333
David Brownell25d5cb42008-05-23 13:05:03 -0700334 /* guard against device removal before, or while,
335 * we issue this ioctl.
336 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700337 spidev = filp->private_data;
David Brownell25d5cb42008-05-23 13:05:03 -0700338 spin_lock_irq(&spidev->spi_lock);
339 spi = spi_dev_get(spidev->spi);
340 spin_unlock_irq(&spidev->spi_lock);
341
342 if (spi == NULL)
343 return -ESHUTDOWN;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700344
Alan Cox4ef754b2008-07-23 21:29:55 -0700345 /* use the buffer lock here for triple duty:
346 * - prevent I/O (from us) so calling spi_setup() is safe;
347 * - prevent concurrent SPI_IOC_WR_* from morphing
348 * data fields while SPI_IOC_RD_* reads them;
349 * - SPI_IOC_MESSAGE needs the buffer locked "normally".
350 */
351 mutex_lock(&spidev->buf_lock);
352
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700353 switch (cmd) {
354 /* read requests */
355 case SPI_IOC_RD_MODE:
356 retval = __put_user(spi->mode & SPI_MODE_MASK,
357 (__u8 __user *)arg);
358 break;
359 case SPI_IOC_RD_LSB_FIRST:
360 retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
361 (__u8 __user *)arg);
362 break;
363 case SPI_IOC_RD_BITS_PER_WORD:
364 retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
365 break;
366 case SPI_IOC_RD_MAX_SPEED_HZ:
367 retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg);
368 break;
369
370 /* write requests */
371 case SPI_IOC_WR_MODE:
372 retval = __get_user(tmp, (u8 __user *)arg);
373 if (retval == 0) {
374 u8 save = spi->mode;
375
376 if (tmp & ~SPI_MODE_MASK) {
377 retval = -EINVAL;
378 break;
379 }
380
381 tmp |= spi->mode & ~SPI_MODE_MASK;
382 spi->mode = (u8)tmp;
383 retval = spi_setup(spi);
384 if (retval < 0)
385 spi->mode = save;
386 else
387 dev_dbg(&spi->dev, "spi mode %02x\n", tmp);
388 }
389 break;
390 case SPI_IOC_WR_LSB_FIRST:
391 retval = __get_user(tmp, (__u8 __user *)arg);
392 if (retval == 0) {
393 u8 save = spi->mode;
394
395 if (tmp)
396 spi->mode |= SPI_LSB_FIRST;
397 else
398 spi->mode &= ~SPI_LSB_FIRST;
399 retval = spi_setup(spi);
400 if (retval < 0)
401 spi->mode = save;
402 else
403 dev_dbg(&spi->dev, "%csb first\n",
404 tmp ? 'l' : 'm');
405 }
406 break;
407 case SPI_IOC_WR_BITS_PER_WORD:
408 retval = __get_user(tmp, (__u8 __user *)arg);
409 if (retval == 0) {
410 u8 save = spi->bits_per_word;
411
412 spi->bits_per_word = tmp;
413 retval = spi_setup(spi);
414 if (retval < 0)
415 spi->bits_per_word = save;
416 else
417 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
418 }
419 break;
420 case SPI_IOC_WR_MAX_SPEED_HZ:
421 retval = __get_user(tmp, (__u32 __user *)arg);
422 if (retval == 0) {
423 u32 save = spi->max_speed_hz;
424
425 spi->max_speed_hz = tmp;
426 retval = spi_setup(spi);
427 if (retval < 0)
428 spi->max_speed_hz = save;
429 else
430 dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
431 }
432 break;
433
434 default:
435 /* segmented and/or full-duplex I/O request */
436 if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
David Brownell25d5cb42008-05-23 13:05:03 -0700437 || _IOC_DIR(cmd) != _IOC_WRITE) {
438 retval = -ENOTTY;
439 break;
440 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700441
442 tmp = _IOC_SIZE(cmd);
443 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) {
444 retval = -EINVAL;
445 break;
446 }
447 n_ioc = tmp / sizeof(struct spi_ioc_transfer);
448 if (n_ioc == 0)
449 break;
450
451 /* copy into scratch area */
452 ioc = kmalloc(tmp, GFP_KERNEL);
453 if (!ioc) {
454 retval = -ENOMEM;
455 break;
456 }
457 if (__copy_from_user(ioc, (void __user *)arg, tmp)) {
Florin Malita9bea3f22007-05-23 13:57:45 -0700458 kfree(ioc);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700459 retval = -EFAULT;
460 break;
461 }
462
463 /* translate to spi_message, execute */
464 retval = spidev_message(spidev, ioc, n_ioc);
465 kfree(ioc);
466 break;
467 }
Alan Cox4ef754b2008-07-23 21:29:55 -0700468
469 mutex_unlock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700470 spi_dev_put(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700471 return retval;
472}
473
474static int spidev_open(struct inode *inode, struct file *filp)
475{
476 struct spidev_data *spidev;
477 int status = -ENXIO;
478
479 mutex_lock(&device_list_lock);
480
481 list_for_each_entry(spidev, &device_list, device_entry) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700482 if (spidev->devt == inode->i_rdev) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700483 status = 0;
484 break;
485 }
486 }
487 if (status == 0) {
488 if (!spidev->buffer) {
489 spidev->buffer = kmalloc(bufsiz, GFP_KERNEL);
490 if (!spidev->buffer) {
491 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
492 status = -ENOMEM;
493 }
494 }
495 if (status == 0) {
496 spidev->users++;
497 filp->private_data = spidev;
498 nonseekable_open(inode, filp);
499 }
500 } else
501 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
502
503 mutex_unlock(&device_list_lock);
504 return status;
505}
506
507static int spidev_release(struct inode *inode, struct file *filp)
508{
509 struct spidev_data *spidev;
510 int status = 0;
511
512 mutex_lock(&device_list_lock);
513 spidev = filp->private_data;
514 filp->private_data = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700515
516 /* last close? */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700517 spidev->users--;
518 if (!spidev->users) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700519 int dofree;
520
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700521 kfree(spidev->buffer);
522 spidev->buffer = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700523
524 /* ... after we unbound from the underlying device? */
525 spin_lock_irq(&spidev->spi_lock);
526 dofree = (spidev->spi == NULL);
527 spin_unlock_irq(&spidev->spi_lock);
528
529 if (dofree)
530 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700531 }
532 mutex_unlock(&device_list_lock);
533
534 return status;
535}
536
Alexey Dobriyan828c0952009-10-01 15:43:56 -0700537static const struct file_operations spidev_fops = {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700538 .owner = THIS_MODULE,
539 /* REVISIT switch to aio primitives, so that userspace
540 * gets more complete API coverage. It'll simplify things
541 * too, except for the locking.
542 */
543 .write = spidev_write,
544 .read = spidev_read,
Alan Cox4ef754b2008-07-23 21:29:55 -0700545 .unlocked_ioctl = spidev_ioctl,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700546 .open = spidev_open,
547 .release = spidev_release,
548};
549
550/*-------------------------------------------------------------------------*/
551
552/* The main reason to have this class is to make mdev/udev create the
553 * /dev/spidevB.C character device nodes exposing our userspace API.
554 * It also simplifies memory management.
555 */
556
David Brownellb2c8dad2008-06-05 22:45:50 -0700557static struct class *spidev_class;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700558
559/*-------------------------------------------------------------------------*/
560
Mike Frysingerdb389b62009-12-14 14:20:22 -0800561static int __devinit spidev_probe(struct spi_device *spi)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700562{
563 struct spidev_data *spidev;
564 int status;
565 unsigned long minor;
566
567 /* Allocate driver data */
568 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
569 if (!spidev)
570 return -ENOMEM;
571
572 /* Initialize the driver data */
573 spidev->spi = spi;
David Brownell25d5cb42008-05-23 13:05:03 -0700574 spin_lock_init(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700575 mutex_init(&spidev->buf_lock);
576
577 INIT_LIST_HEAD(&spidev->device_entry);
578
579 /* If we can allocate a minor number, hook up this device.
580 * Reusing minors is fine so long as udev or mdev is working.
581 */
582 mutex_lock(&device_list_lock);
Domen Puncer0a4dd772007-05-15 23:57:05 -0700583 minor = find_first_zero_bit(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700584 if (minor < N_SPI_MINORS) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700585 struct device *dev;
586
587 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
Greg Kroah-Hartmana9b12612008-07-21 20:03:34 -0700588 dev = device_create(spidev_class, &spi->dev, spidev->devt,
589 spidev, "spidev%d.%d",
590 spi->master->bus_num, spi->chip_select);
David Brownellb2c8dad2008-06-05 22:45:50 -0700591 status = IS_ERR(dev) ? PTR_ERR(dev) : 0;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700592 } else {
593 dev_dbg(&spi->dev, "no minor number available!\n");
594 status = -ENODEV;
595 }
596 if (status == 0) {
597 set_bit(minor, minors);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700598 list_add(&spidev->device_entry, &device_list);
599 }
600 mutex_unlock(&device_list_lock);
601
Wolfgang Ockeraaacf4b2008-12-01 13:13:52 -0800602 if (status == 0)
603 spi_set_drvdata(spi, spidev);
604 else
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700605 kfree(spidev);
606
607 return status;
608}
609
Mike Frysingerdb389b62009-12-14 14:20:22 -0800610static int __devexit spidev_remove(struct spi_device *spi)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700611{
David Brownellb2c8dad2008-06-05 22:45:50 -0700612 struct spidev_data *spidev = spi_get_drvdata(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700613
David Brownell25d5cb42008-05-23 13:05:03 -0700614 /* make sure ops on existing fds can abort cleanly */
615 spin_lock_irq(&spidev->spi_lock);
616 spidev->spi = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700617 spi_set_drvdata(spi, NULL);
David Brownell25d5cb42008-05-23 13:05:03 -0700618 spin_unlock_irq(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700619
David Brownell25d5cb42008-05-23 13:05:03 -0700620 /* prevent new opens */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700621 mutex_lock(&device_list_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700622 list_del(&spidev->device_entry);
David Brownellb2c8dad2008-06-05 22:45:50 -0700623 device_destroy(spidev_class, spidev->devt);
624 clear_bit(MINOR(spidev->devt), minors);
625 if (spidev->users == 0)
626 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700627 mutex_unlock(&device_list_lock);
628
629 return 0;
630}
631
Mike Frysingerdb389b62009-12-14 14:20:22 -0800632static struct spi_driver spidev_spi_driver = {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700633 .driver = {
634 .name = "spidev",
635 .owner = THIS_MODULE,
636 },
637 .probe = spidev_probe,
638 .remove = __devexit_p(spidev_remove),
639
640 /* NOTE: suspend/resume methods are not necessary here.
641 * We don't do anything except pass the requests to/from
642 * the underlying controller. The refrigerator handles
643 * most issues; the controller driver handles the rest.
644 */
645};
646
647/*-------------------------------------------------------------------------*/
648
649static int __init spidev_init(void)
650{
651 int status;
652
653 /* Claim our 256 reserved device numbers. Then register a class
654 * that will key udev/mdev to add/remove /dev nodes. Last, register
655 * the driver which manages those device numbers.
656 */
657 BUILD_BUG_ON(N_SPI_MINORS > 256);
658 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
659 if (status < 0)
660 return status;
661
David Brownellb2c8dad2008-06-05 22:45:50 -0700662 spidev_class = class_create(THIS_MODULE, "spidev");
663 if (IS_ERR(spidev_class)) {
Mike Frysingerdb389b62009-12-14 14:20:22 -0800664 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
David Brownellb2c8dad2008-06-05 22:45:50 -0700665 return PTR_ERR(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700666 }
667
Mike Frysingerdb389b62009-12-14 14:20:22 -0800668 status = spi_register_driver(&spidev_spi_driver);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700669 if (status < 0) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700670 class_destroy(spidev_class);
Mike Frysingerdb389b62009-12-14 14:20:22 -0800671 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700672 }
673 return status;
674}
675module_init(spidev_init);
676
677static void __exit spidev_exit(void)
678{
Mike Frysingerdb389b62009-12-14 14:20:22 -0800679 spi_unregister_driver(&spidev_spi_driver);
David Brownellb2c8dad2008-06-05 22:45:50 -0700680 class_destroy(spidev_class);
Mike Frysingerdb389b62009-12-14 14:20:22 -0800681 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700682}
683module_exit(spidev_exit);
684
685MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
686MODULE_DESCRIPTION("User mode SPI device interface");
687MODULE_LICENSE("GPL");
Anton Vorontsove0626e32009-09-22 16:46:08 -0700688MODULE_ALIAS("spi:spidev");