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1/*
2 * 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
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/ioctl.h>
22#include <linux/fs.h>
23#include <linux/device.h>
24#include <linux/err.h>
25#include <linux/list.h>
26#include <linux/errno.h>
27#include <linux/mutex.h>
28#include <linux/slab.h>
29#include <linux/compat.h>
30#include <linux/of.h>
31#include <linux/of_device.h>
32
33#include <linux/spi/spi.h>
34#include <linux/spi/spidev.h>
35
36#include <linux/uaccess.h>
37
38
39/*
40 * This supports access 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 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 DECLARE_BITMAP(minors, N_SPI_MINORS);
56
57
58/* Bit masks for spi_device.mode management. Note that incorrect
59 * settings for some settings can cause *lots* of trouble for other
60 * devices on a shared bus:
61 *
62 * - CS_HIGH ... this device will be active when it shouldn't be
63 * - 3WIRE ... when active, it won't behave as it should
64 * - NO_CS ... there will be no explicit message boundaries; this
65 * is completely incompatible with the shared bus model
66 * - READY ... transfers may proceed when they shouldn't.
67 *
68 * REVISIT should changing those flags be privileged?
69 */
70#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
71 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
72 | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
73 | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)
74
75struct spidev_data {
76 dev_t devt;
77 spinlock_t spi_lock;
78 struct spi_device *spi;
79 struct list_head device_entry;
80
81 /* TX/RX buffers are NULL unless this device is open (users > 0) */
82 struct mutex buf_lock;
83 unsigned users;
84 u8 *tx_buffer;
85 u8 *rx_buffer;
86 u32 speed_hz;
87};
88
89static LIST_HEAD(device_list);
90static DEFINE_MUTEX(device_list_lock);
91
92static unsigned bufsiz = 4096;
93module_param(bufsiz, uint, S_IRUGO);
94MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
95
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 struct spi_device *spi;
104
105 spin_lock_irq(&spidev->spi_lock);
106 spi = spidev->spi;
107 spin_unlock_irq(&spidev->spi_lock);
108
109 if (spi == NULL)
110 status = -ESHUTDOWN;
111 else
112 status = spi_sync(spi, message);
113
114 if (status == 0)
115 status = message->actual_length;
116
117 return status;
118}
119
120static inline ssize_t
121spidev_sync_write(struct spidev_data *spidev, size_t len)
122{
123 struct spi_transfer t = {
124 .tx_buf = spidev->tx_buffer,
125 .len = len,
126 .speed_hz = spidev->speed_hz,
127 };
128 struct spi_message m;
129
130 spi_message_init(&m);
131 spi_message_add_tail(&t, &m);
132 return spidev_sync(spidev, &m);
133}
134
135static inline ssize_t
136spidev_sync_read(struct spidev_data *spidev, size_t len)
137{
138 struct spi_transfer t = {
139 .rx_buf = spidev->rx_buffer,
140 .len = len,
141 .speed_hz = spidev->speed_hz,
142 };
143 struct spi_message m;
144
145 spi_message_init(&m);
146 spi_message_add_tail(&t, &m);
147 return spidev_sync(spidev, &m);
148}
149
150/*-------------------------------------------------------------------------*/
151
152/* Read-only message with current device setup */
153static ssize_t
154spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
155{
156 struct spidev_data *spidev;
157 ssize_t status = 0;
158
159 /* chipselect only toggles at start or end of operation */
160 if (count > bufsiz)
161 return -EMSGSIZE;
162
163 spidev = filp->private_data;
164
165 mutex_lock(&spidev->buf_lock);
166 status = spidev_sync_read(spidev, count);
167 if (status > 0) {
168 unsigned long missing;
169
170 missing = copy_to_user(buf, spidev->rx_buffer, status);
171 if (missing == status)
172 status = -EFAULT;
173 else
174 status = status - missing;
175 }
176 mutex_unlock(&spidev->buf_lock);
177
178 return status;
179}
180
181/* Write-only message with current device setup */
182static ssize_t
183spidev_write(struct file *filp, const char __user *buf,
184 size_t count, loff_t *f_pos)
185{
186 struct spidev_data *spidev;
187 ssize_t status = 0;
188 unsigned long missing;
189
190 /* chipselect only toggles at start or end of operation */
191 if (count > bufsiz)
192 return -EMSGSIZE;
193
194 spidev = filp->private_data;
195
196 mutex_lock(&spidev->buf_lock);
197 missing = copy_from_user(spidev->tx_buffer, buf, count);
198 if (missing == 0)
199 status = spidev_sync_write(spidev, count);
200 else
201 status = -EFAULT;
202 mutex_unlock(&spidev->buf_lock);
203
204 return status;
205}
206
207static int spidev_message(struct spidev_data *spidev,
208 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
209{
210 struct spi_message msg;
211 struct spi_transfer *k_xfers;
212 struct spi_transfer *k_tmp;
213 struct spi_ioc_transfer *u_tmp;
214 unsigned n, total, tx_total, rx_total;
215 u8 *tx_buf, *rx_buf;
216 int status = -EFAULT;
217
218 spi_message_init(&msg);
219 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
220 if (k_xfers == NULL)
221 return -ENOMEM;
222
223 /* Construct spi_message, copying any tx data to bounce buffer.
224 * We walk the array of user-provided transfers, using each one
225 * to initialize a kernel version of the same transfer.
226 */
227 tx_buf = spidev->tx_buffer;
228 rx_buf = spidev->rx_buffer;
229 total = 0;
230 tx_total = 0;
231 rx_total = 0;
232 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
233 n;
234 n--, k_tmp++, u_tmp++) {
235 k_tmp->len = u_tmp->len;
236
237 total += k_tmp->len;
238 /* Since the function returns the total length of transfers
239 * on success, restrict the total to positive int values to
240 * avoid the return value looking like an error. Also check
241 * each transfer length to avoid arithmetic overflow.
242 */
243 if (total > INT_MAX || k_tmp->len > INT_MAX) {
244 status = -EMSGSIZE;
245 goto done;
246 }
247
248 if (u_tmp->rx_buf) {
249 /* this transfer needs space in RX bounce buffer */
250 rx_total += k_tmp->len;
251 if (rx_total > bufsiz) {
252 status = -EMSGSIZE;
253 goto done;
254 }
255 k_tmp->rx_buf = rx_buf;
256 if (!access_ok(VERIFY_WRITE, (u8 __user *)
257 (uintptr_t) u_tmp->rx_buf,
258 u_tmp->len))
259 goto done;
260 rx_buf += k_tmp->len;
261 }
262 if (u_tmp->tx_buf) {
263 /* this transfer needs space in TX bounce buffer */
264 tx_total += k_tmp->len;
265 if (tx_total > bufsiz) {
266 status = -EMSGSIZE;
267 goto done;
268 }
269 k_tmp->tx_buf = tx_buf;
270 if (copy_from_user(tx_buf, (const u8 __user *)
271 (uintptr_t) u_tmp->tx_buf,
272 u_tmp->len))
273 goto done;
274 tx_buf += k_tmp->len;
275 }
276
277 k_tmp->cs_change = !!u_tmp->cs_change;
278 k_tmp->tx_nbits = u_tmp->tx_nbits;
279 k_tmp->rx_nbits = u_tmp->rx_nbits;
280 k_tmp->bits_per_word = u_tmp->bits_per_word;
281 k_tmp->delay_usecs = u_tmp->delay_usecs;
282 k_tmp->speed_hz = u_tmp->speed_hz;
283 if (!k_tmp->speed_hz)
284 k_tmp->speed_hz = spidev->speed_hz;
285#ifdef VERBOSE
286 dev_dbg(&spidev->spi->dev,
287 " xfer len %u %s%s%s%dbits %u usec %uHz\n",
288 u_tmp->len,
289 u_tmp->rx_buf ? "rx " : "",
290 u_tmp->tx_buf ? "tx " : "",
291 u_tmp->cs_change ? "cs " : "",
292 u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
293 u_tmp->delay_usecs,
294 u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
295#endif
296 spi_message_add_tail(k_tmp, &msg);
297 }
298
299 status = spidev_sync(spidev, &msg);
300 if (status < 0)
301 goto done;
302
303 /* copy any rx data out of bounce buffer */
304 rx_buf = spidev->rx_buffer;
305 for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
306 if (u_tmp->rx_buf) {
307 if (__copy_to_user((u8 __user *)
308 (uintptr_t) u_tmp->rx_buf, rx_buf,
309 u_tmp->len)) {
310 status = -EFAULT;
311 goto done;
312 }
313 rx_buf += u_tmp->len;
314 }
315 }
316 status = total;
317
318done:
319 kfree(k_xfers);
320 return status;
321}
322
323static struct spi_ioc_transfer *
324spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
325 unsigned *n_ioc)
326{
327 struct spi_ioc_transfer *ioc;
328 u32 tmp;
329
330 /* Check type, command number and direction */
331 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC
332 || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
333 || _IOC_DIR(cmd) != _IOC_WRITE)
334 return ERR_PTR(-ENOTTY);
335
336 tmp = _IOC_SIZE(cmd);
337 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0)
338 return ERR_PTR(-EINVAL);
339 *n_ioc = tmp / sizeof(struct spi_ioc_transfer);
340 if (*n_ioc == 0)
341 return NULL;
342
343 /* copy into scratch area */
344 ioc = kmalloc(tmp, GFP_KERNEL);
345 if (!ioc)
346 return ERR_PTR(-ENOMEM);
347 if (__copy_from_user(ioc, u_ioc, tmp)) {
348 kfree(ioc);
349 return ERR_PTR(-EFAULT);
350 }
351 return ioc;
352}
353
354static long
355spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
356{
357 int err = 0;
358 int retval = 0;
359 struct spidev_data *spidev;
360 struct spi_device *spi;
361 u32 tmp;
362 unsigned n_ioc;
363 struct spi_ioc_transfer *ioc;
364
365 /* Check type and command number */
366 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
367 return -ENOTTY;
368
369 /* Check access direction once here; don't repeat below.
370 * IOC_DIR is from the user perspective, while access_ok is
371 * from the kernel perspective; so they look reversed.
372 */
373 if (_IOC_DIR(cmd) & _IOC_READ)
374 err = !access_ok(VERIFY_WRITE,
375 (void __user *)arg, _IOC_SIZE(cmd));
376 if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
377 err = !access_ok(VERIFY_READ,
378 (void __user *)arg, _IOC_SIZE(cmd));
379 if (err)
380 return -EFAULT;
381
382 /* guard against device removal before, or while,
383 * we issue this ioctl.
384 */
385 spidev = filp->private_data;
386 spin_lock_irq(&spidev->spi_lock);
387 spi = spi_dev_get(spidev->spi);
388 spin_unlock_irq(&spidev->spi_lock);
389
390 if (spi == NULL)
391 return -ESHUTDOWN;
392
393 /* use the buffer lock here for triple duty:
394 * - prevent I/O (from us) so calling spi_setup() is safe;
395 * - prevent concurrent SPI_IOC_WR_* from morphing
396 * data fields while SPI_IOC_RD_* reads them;
397 * - SPI_IOC_MESSAGE needs the buffer locked "normally".
398 */
399 mutex_lock(&spidev->buf_lock);
400
401 switch (cmd) {
402 /* read requests */
403 case SPI_IOC_RD_MODE:
404 retval = __put_user(spi->mode & SPI_MODE_MASK,
405 (__u8 __user *)arg);
406 break;
407 case SPI_IOC_RD_MODE32:
408 retval = __put_user(spi->mode & SPI_MODE_MASK,
409 (__u32 __user *)arg);
410 break;
411 case SPI_IOC_RD_LSB_FIRST:
412 retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
413 (__u8 __user *)arg);
414 break;
415 case SPI_IOC_RD_BITS_PER_WORD:
416 retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
417 break;
418 case SPI_IOC_RD_MAX_SPEED_HZ:
419 retval = __put_user(spidev->speed_hz, (__u32 __user *)arg);
420 break;
421
422 /* write requests */
423 case SPI_IOC_WR_MODE:
424 case SPI_IOC_WR_MODE32:
425 if (cmd == SPI_IOC_WR_MODE)
426 retval = __get_user(tmp, (u8 __user *)arg);
427 else
428 retval = __get_user(tmp, (u32 __user *)arg);
429 if (retval == 0) {
430 u32 save = spi->mode;
431
432 if (tmp & ~SPI_MODE_MASK) {
433 retval = -EINVAL;
434 break;
435 }
436
437 tmp |= spi->mode & ~SPI_MODE_MASK;
438 spi->mode = (u16)tmp;
439 retval = spi_setup(spi);
440 if (retval < 0)
441 spi->mode = save;
442 else
443 dev_dbg(&spi->dev, "spi mode %x\n", tmp);
444 }
445 break;
446 case SPI_IOC_WR_LSB_FIRST:
447 retval = __get_user(tmp, (__u8 __user *)arg);
448 if (retval == 0) {
449 u32 save = spi->mode;
450
451 if (tmp)
452 spi->mode |= SPI_LSB_FIRST;
453 else
454 spi->mode &= ~SPI_LSB_FIRST;
455 retval = spi_setup(spi);
456 if (retval < 0)
457 spi->mode = save;
458 else
459 dev_dbg(&spi->dev, "%csb first\n",
460 tmp ? 'l' : 'm');
461 }
462 break;
463 case SPI_IOC_WR_BITS_PER_WORD:
464 retval = __get_user(tmp, (__u8 __user *)arg);
465 if (retval == 0) {
466 u8 save = spi->bits_per_word;
467
468 spi->bits_per_word = tmp;
469 retval = spi_setup(spi);
470 if (retval < 0)
471 spi->bits_per_word = save;
472 else
473 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
474 }
475 break;
476 case SPI_IOC_WR_MAX_SPEED_HZ:
477 retval = __get_user(tmp, (__u32 __user *)arg);
478 if (retval == 0) {
479 u32 save = spi->max_speed_hz;
480
481 spi->max_speed_hz = tmp;
482 retval = spi_setup(spi);
483 if (retval >= 0)
484 spidev->speed_hz = tmp;
485 else
486 dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
487 spi->max_speed_hz = save;
488 }
489 break;
490
491 default:
492 /* segmented and/or full-duplex I/O request */
493 /* Check message and copy into scratch area */
494 ioc = spidev_get_ioc_message(cmd,
495 (struct spi_ioc_transfer __user *)arg, &n_ioc);
496 if (IS_ERR(ioc)) {
497 retval = PTR_ERR(ioc);
498 break;
499 }
500 if (!ioc)
501 break; /* n_ioc is also 0 */
502
503 /* translate to spi_message, execute */
504 retval = spidev_message(spidev, ioc, n_ioc);
505 kfree(ioc);
506 break;
507 }
508
509 mutex_unlock(&spidev->buf_lock);
510 spi_dev_put(spi);
511 return retval;
512}
513
514#ifdef CONFIG_COMPAT
515static long
516spidev_compat_ioc_message(struct file *filp, unsigned int cmd,
517 unsigned long arg)
518{
519 struct spi_ioc_transfer __user *u_ioc;
520 int retval = 0;
521 struct spidev_data *spidev;
522 struct spi_device *spi;
523 unsigned n_ioc, n;
524 struct spi_ioc_transfer *ioc;
525
526 u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg);
527 if (!access_ok(VERIFY_READ, u_ioc, _IOC_SIZE(cmd)))
528 return -EFAULT;
529
530 /* guard against device removal before, or while,
531 * we issue this ioctl.
532 */
533 spidev = filp->private_data;
534 spin_lock_irq(&spidev->spi_lock);
535 spi = spi_dev_get(spidev->spi);
536 spin_unlock_irq(&spidev->spi_lock);
537
538 if (spi == NULL)
539 return -ESHUTDOWN;
540
541 /* SPI_IOC_MESSAGE needs the buffer locked "normally" */
542 mutex_lock(&spidev->buf_lock);
543
544 /* Check message and copy into scratch area */
545 ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc);
546 if (IS_ERR(ioc)) {
547 retval = PTR_ERR(ioc);
548 goto done;
549 }
550 if (!ioc)
551 goto done; /* n_ioc is also 0 */
552
553 /* Convert buffer pointers */
554 for (n = 0; n < n_ioc; n++) {
555 ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf);
556 ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf);
557 }
558
559 /* translate to spi_message, execute */
560 retval = spidev_message(spidev, ioc, n_ioc);
561 kfree(ioc);
562
563done:
564 mutex_unlock(&spidev->buf_lock);
565 spi_dev_put(spi);
566 return retval;
567}
568
569static long
570spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
571{
572 if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC
573 && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0))
574 && _IOC_DIR(cmd) == _IOC_WRITE)
575 return spidev_compat_ioc_message(filp, cmd, arg);
576
577 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
578}
579#else
580#define spidev_compat_ioctl NULL
581#endif /* CONFIG_COMPAT */
582
583static int spidev_open(struct inode *inode, struct file *filp)
584{
585 struct spidev_data *spidev;
586 int status = -ENXIO;
587
588 mutex_lock(&device_list_lock);
589
590 list_for_each_entry(spidev, &device_list, device_entry) {
591 if (spidev->devt == inode->i_rdev) {
592 status = 0;
593 break;
594 }
595 }
596
597 if (status) {
598 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
599 goto err_find_dev;
600 }
601
602 if (!spidev->tx_buffer) {
603 spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL);
604 if (!spidev->tx_buffer) {
605 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
606 status = -ENOMEM;
607 goto err_find_dev;
608 }
609 }
610
611 if (!spidev->rx_buffer) {
612 spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
613 if (!spidev->rx_buffer) {
614 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
615 status = -ENOMEM;
616 goto err_alloc_rx_buf;
617 }
618 }
619
620 spidev->users++;
621 filp->private_data = spidev;
622 nonseekable_open(inode, filp);
623
624 mutex_unlock(&device_list_lock);
625 return 0;
626
627err_alloc_rx_buf:
628 kfree(spidev->tx_buffer);
629 spidev->tx_buffer = NULL;
630err_find_dev:
631 mutex_unlock(&device_list_lock);
632 return status;
633}
634
635static int spidev_release(struct inode *inode, struct file *filp)
636{
637 struct spidev_data *spidev;
638
639 mutex_lock(&device_list_lock);
640 spidev = filp->private_data;
641 filp->private_data = NULL;
642
643 /* last close? */
644 spidev->users--;
645 if (!spidev->users) {
646 int dofree;
647
648 kfree(spidev->tx_buffer);
649 spidev->tx_buffer = NULL;
650
651 kfree(spidev->rx_buffer);
652 spidev->rx_buffer = NULL;
653
654 spin_lock_irq(&spidev->spi_lock);
655 if (spidev->spi)
656 spidev->speed_hz = spidev->spi->max_speed_hz;
657
658 /* ... after we unbound from the underlying device? */
659 dofree = (spidev->spi == NULL);
660 spin_unlock_irq(&spidev->spi_lock);
661
662 if (dofree)
663 kfree(spidev);
664 }
665 mutex_unlock(&device_list_lock);
666
667 return 0;
668}
669
670static const struct file_operations spidev_fops = {
671 .owner = THIS_MODULE,
672 /* REVISIT switch to aio primitives, so that userspace
673 * gets more complete API coverage. It'll simplify things
674 * too, except for the locking.
675 */
676 .write = spidev_write,
677 .read = spidev_read,
678 .unlocked_ioctl = spidev_ioctl,
679 .compat_ioctl = spidev_compat_ioctl,
680 .open = spidev_open,
681 .release = spidev_release,
682 .llseek = no_llseek,
683};
684
685/*-------------------------------------------------------------------------*/
686
687/* The main reason to have this class is to make mdev/udev create the
688 * /dev/spidevB.C character device nodes exposing our userspace API.
689 * It also simplifies memory management.
690 */
691
692static struct class *spidev_class;
693
694#ifdef CONFIG_OF
695static const struct of_device_id spidev_dt_ids[] = {
696 { .compatible = "rohm,dh2228fv" },
697 { .compatible = "lineartechnology,ltc2488" },
698 {},
699};
700MODULE_DEVICE_TABLE(of, spidev_dt_ids);
701#endif
702
703/*-------------------------------------------------------------------------*/
704
705static int spidev_probe(struct spi_device *spi)
706{
707 struct spidev_data *spidev;
708 int status;
709 unsigned long minor;
710
711 /*
712 * spidev should never be referenced in DT without a specific
713 * compatible string, it is a Linux implementation thing
714 * rather than a description of the hardware.
715 */
716 if (spi->dev.of_node && !of_match_device(spidev_dt_ids, &spi->dev)) {
717 dev_err(&spi->dev, "buggy DT: spidev listed directly in DT\n");
718 WARN_ON(spi->dev.of_node &&
719 !of_match_device(spidev_dt_ids, &spi->dev));
720 }
721
722 /* Allocate driver data */
723 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
724 if (!spidev)
725 return -ENOMEM;
726
727 /* Initialize the driver data */
728 spidev->spi = spi;
729 spin_lock_init(&spidev->spi_lock);
730 mutex_init(&spidev->buf_lock);
731
732 INIT_LIST_HEAD(&spidev->device_entry);
733
734 /* If we can allocate a minor number, hook up this device.
735 * Reusing minors is fine so long as udev or mdev is working.
736 */
737 mutex_lock(&device_list_lock);
738 minor = find_first_zero_bit(minors, N_SPI_MINORS);
739 if (minor < N_SPI_MINORS) {
740 struct device *dev;
741
742 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
743 dev = device_create(spidev_class, &spi->dev, spidev->devt,
744 spidev, "spidev%d.%d",
745 spi->master->bus_num, spi->chip_select);
746 status = PTR_ERR_OR_ZERO(dev);
747 } else {
748 dev_dbg(&spi->dev, "no minor number available!\n");
749 status = -ENODEV;
750 }
751 if (status == 0) {
752 set_bit(minor, minors);
753 list_add(&spidev->device_entry, &device_list);
754 }
755 mutex_unlock(&device_list_lock);
756
757 spidev->speed_hz = spi->max_speed_hz;
758
759 if (status == 0)
760 spi_set_drvdata(spi, spidev);
761 else
762 kfree(spidev);
763
764 return status;
765}
766
767static int spidev_remove(struct spi_device *spi)
768{
769 struct spidev_data *spidev = spi_get_drvdata(spi);
770
771 /* make sure ops on existing fds can abort cleanly */
772 spin_lock_irq(&spidev->spi_lock);
773 spidev->spi = NULL;
774 spin_unlock_irq(&spidev->spi_lock);
775
776 /* prevent new opens */
777 mutex_lock(&device_list_lock);
778 list_del(&spidev->device_entry);
779 device_destroy(spidev_class, spidev->devt);
780 clear_bit(MINOR(spidev->devt), minors);
781 if (spidev->users == 0)
782 kfree(spidev);
783 mutex_unlock(&device_list_lock);
784
785 return 0;
786}
787
788static struct spi_driver spidev_spi_driver = {
789 .driver = {
790 .name = "spidev",
791 .of_match_table = of_match_ptr(spidev_dt_ids),
792 },
793 .probe = spidev_probe,
794 .remove = spidev_remove,
795
796 /* NOTE: suspend/resume methods are not necessary here.
797 * We don't do anything except pass the requests to/from
798 * the underlying controller. The refrigerator handles
799 * most issues; the controller driver handles the rest.
800 */
801};
802
803/*-------------------------------------------------------------------------*/
804
805static int __init spidev_init(void)
806{
807 int status;
808
809 /* Claim our 256 reserved device numbers. Then register a class
810 * that will key udev/mdev to add/remove /dev nodes. Last, register
811 * the driver which manages those device numbers.
812 */
813 BUILD_BUG_ON(N_SPI_MINORS > 256);
814 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
815 if (status < 0)
816 return status;
817
818 spidev_class = class_create(THIS_MODULE, "spidev");
819 if (IS_ERR(spidev_class)) {
820 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
821 return PTR_ERR(spidev_class);
822 }
823
824 status = spi_register_driver(&spidev_spi_driver);
825 if (status < 0) {
826 class_destroy(spidev_class);
827 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
828 }
829 return status;
830}
831module_init(spidev_init);
832
833static void __exit spidev_exit(void)
834{
835 spi_unregister_driver(&spidev_spi_driver);
836 class_destroy(spidev_class);
837 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
838}
839module_exit(spidev_exit);
840
841MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
842MODULE_DESCRIPTION("User mode SPI device interface");
843MODULE_LICENSE("GPL");
844MODULE_ALIAS("spi:spidev");
1/*
2 * 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/err.h>
29#include <linux/list.h>
30#include <linux/errno.h>
31#include <linux/mutex.h>
32#include <linux/slab.h>
33#include <linux/compat.h>
34
35#include <linux/spi/spi.h>
36#include <linux/spi/spidev.h>
37
38#include <asm/uaccess.h>
39
40
41/*
42 * This supports access 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 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 DECLARE_BITMAP(minors, N_SPI_MINORS);
58
59
60/* Bit masks for spi_device.mode management. Note that incorrect
61 * settings for some settings can cause *lots* of trouble for other
62 * devices on a shared bus:
63 *
64 * - 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?
71 */
72#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
73 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
74 | SPI_NO_CS | SPI_READY)
75
76struct spidev_data {
77 dev_t devt;
78 spinlock_t spi_lock;
79 struct spi_device *spi;
80 struct list_head device_entry;
81
82 /* buffer is NULL unless this device is open (users > 0) */
83 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
97/*
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
161/* 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;
166 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;
173
174 mutex_lock(&spidev->buf_lock);
175 status = spidev_sync_read(spidev, count);
176 if (status > 0) {
177 unsigned long missing;
178
179 missing = copy_to_user(buf, spidev->buffer, status);
180 if (missing == status)
181 status = -EFAULT;
182 else
183 status = status - missing;
184 }
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;
196 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;
204
205 mutex_lock(&spidev->buf_lock);
206 missing = copy_from_user(spidev->buffer, buf, count);
207 if (missing == 0) {
208 status = spidev_sync_write(spidev, count);
209 } 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;
223 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 */
236 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
243 total += k_tmp->len;
244 if (total > bufsiz) {
245 status = -EMSGSIZE;
246 goto done;
247 }
248
249 if (u_tmp->rx_buf) {
250 k_tmp->rx_buf = buf;
251 if (!access_ok(VERIFY_WRITE, (u8 __user *)
252 (uintptr_t) u_tmp->rx_buf,
253 u_tmp->len))
254 goto done;
255 }
256 if (u_tmp->tx_buf) {
257 k_tmp->tx_buf = buf;
258 if (copy_from_user(buf, (const u8 __user *)
259 (uintptr_t) u_tmp->tx_buf,
260 u_tmp->len))
261 goto done;
262 }
263 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(&spidev->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 ? : spidev->spi->bits_per_word,
277 u_tmp->delay_usecs,
278 u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
279#endif
280 spi_message_add_tail(k_tmp, &msg);
281 }
282
283 status = spidev_sync(spidev, &msg);
284 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) {
291 if (__copy_to_user((u8 __user *)
292 (uintptr_t) u_tmp->rx_buf, buf,
293 u_tmp->len)) {
294 status = -EFAULT;
295 goto done;
296 }
297 }
298 buf += u_tmp->len;
299 }
300 status = total;
301
302done:
303 kfree(k_xfers);
304 return status;
305}
306
307static long
308spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
309{
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
335 /* guard against device removal before, or while,
336 * we issue this ioctl.
337 */
338 spidev = filp->private_data;
339 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;
345
346 /* 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
354 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))
438 || _IOC_DIR(cmd) != _IOC_WRITE) {
439 retval = -ENOTTY;
440 break;
441 }
442
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)) {
459 kfree(ioc);
460 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 }
469
470 mutex_unlock(&spidev->buf_lock);
471 spi_dev_put(spi);
472 return retval;
473}
474
475#ifdef CONFIG_COMPAT
476static long
477spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
478{
479 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
480}
481#else
482#define spidev_compat_ioctl NULL
483#endif /* CONFIG_COMPAT */
484
485static int spidev_open(struct inode *inode, struct file *filp)
486{
487 struct spidev_data *spidev;
488 int status = -ENXIO;
489
490 mutex_lock(&device_list_lock);
491
492 list_for_each_entry(spidev, &device_list, device_entry) {
493 if (spidev->devt == inode->i_rdev) {
494 status = 0;
495 break;
496 }
497 }
498 if (status == 0) {
499 if (!spidev->buffer) {
500 spidev->buffer = kmalloc(bufsiz, GFP_KERNEL);
501 if (!spidev->buffer) {
502 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
503 status = -ENOMEM;
504 }
505 }
506 if (status == 0) {
507 spidev->users++;
508 filp->private_data = spidev;
509 nonseekable_open(inode, filp);
510 }
511 } else
512 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
513
514 mutex_unlock(&device_list_lock);
515 return status;
516}
517
518static int spidev_release(struct inode *inode, struct file *filp)
519{
520 struct spidev_data *spidev;
521 int status = 0;
522
523 mutex_lock(&device_list_lock);
524 spidev = filp->private_data;
525 filp->private_data = NULL;
526
527 /* last close? */
528 spidev->users--;
529 if (!spidev->users) {
530 int dofree;
531
532 kfree(spidev->buffer);
533 spidev->buffer = NULL;
534
535 /* ... after we unbound from the underlying device? */
536 spin_lock_irq(&spidev->spi_lock);
537 dofree = (spidev->spi == NULL);
538 spin_unlock_irq(&spidev->spi_lock);
539
540 if (dofree)
541 kfree(spidev);
542 }
543 mutex_unlock(&device_list_lock);
544
545 return status;
546}
547
548static const struct file_operations spidev_fops = {
549 .owner = THIS_MODULE,
550 /* REVISIT switch to aio primitives, so that userspace
551 * gets more complete API coverage. It'll simplify things
552 * too, except for the locking.
553 */
554 .write = spidev_write,
555 .read = spidev_read,
556 .unlocked_ioctl = spidev_ioctl,
557 .compat_ioctl = spidev_compat_ioctl,
558 .open = spidev_open,
559 .release = spidev_release,
560 .llseek = no_llseek,
561};
562
563/*-------------------------------------------------------------------------*/
564
565/* The main reason to have this class is to make mdev/udev create the
566 * /dev/spidevB.C character device nodes exposing our userspace API.
567 * It also simplifies memory management.
568 */
569
570static struct class *spidev_class;
571
572/*-------------------------------------------------------------------------*/
573
574static int __devinit spidev_probe(struct spi_device *spi)
575{
576 struct spidev_data *spidev;
577 int status;
578 unsigned long minor;
579
580 /* Allocate driver data */
581 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
582 if (!spidev)
583 return -ENOMEM;
584
585 /* Initialize the driver data */
586 spidev->spi = spi;
587 spin_lock_init(&spidev->spi_lock);
588 mutex_init(&spidev->buf_lock);
589
590 INIT_LIST_HEAD(&spidev->device_entry);
591
592 /* If we can allocate a minor number, hook up this device.
593 * Reusing minors is fine so long as udev or mdev is working.
594 */
595 mutex_lock(&device_list_lock);
596 minor = find_first_zero_bit(minors, N_SPI_MINORS);
597 if (minor < N_SPI_MINORS) {
598 struct device *dev;
599
600 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
601 dev = device_create(spidev_class, &spi->dev, spidev->devt,
602 spidev, "spidev%d.%d",
603 spi->master->bus_num, spi->chip_select);
604 status = IS_ERR(dev) ? PTR_ERR(dev) : 0;
605 } else {
606 dev_dbg(&spi->dev, "no minor number available!\n");
607 status = -ENODEV;
608 }
609 if (status == 0) {
610 set_bit(minor, minors);
611 list_add(&spidev->device_entry, &device_list);
612 }
613 mutex_unlock(&device_list_lock);
614
615 if (status == 0)
616 spi_set_drvdata(spi, spidev);
617 else
618 kfree(spidev);
619
620 return status;
621}
622
623static int __devexit spidev_remove(struct spi_device *spi)
624{
625 struct spidev_data *spidev = spi_get_drvdata(spi);
626
627 /* make sure ops on existing fds can abort cleanly */
628 spin_lock_irq(&spidev->spi_lock);
629 spidev->spi = NULL;
630 spi_set_drvdata(spi, NULL);
631 spin_unlock_irq(&spidev->spi_lock);
632
633 /* prevent new opens */
634 mutex_lock(&device_list_lock);
635 list_del(&spidev->device_entry);
636 device_destroy(spidev_class, spidev->devt);
637 clear_bit(MINOR(spidev->devt), minors);
638 if (spidev->users == 0)
639 kfree(spidev);
640 mutex_unlock(&device_list_lock);
641
642 return 0;
643}
644
645static struct spi_driver spidev_spi_driver = {
646 .driver = {
647 .name = "spidev",
648 .owner = THIS_MODULE,
649 },
650 .probe = spidev_probe,
651 .remove = __devexit_p(spidev_remove),
652
653 /* NOTE: suspend/resume methods are not necessary here.
654 * We don't do anything except pass the requests to/from
655 * the underlying controller. The refrigerator handles
656 * most issues; the controller driver handles the rest.
657 */
658};
659
660/*-------------------------------------------------------------------------*/
661
662static int __init spidev_init(void)
663{
664 int status;
665
666 /* Claim our 256 reserved device numbers. Then register a class
667 * that will key udev/mdev to add/remove /dev nodes. Last, register
668 * the driver which manages those device numbers.
669 */
670 BUILD_BUG_ON(N_SPI_MINORS > 256);
671 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
672 if (status < 0)
673 return status;
674
675 spidev_class = class_create(THIS_MODULE, "spidev");
676 if (IS_ERR(spidev_class)) {
677 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
678 return PTR_ERR(spidev_class);
679 }
680
681 status = spi_register_driver(&spidev_spi_driver);
682 if (status < 0) {
683 class_destroy(spidev_class);
684 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
685 }
686 return status;
687}
688module_init(spidev_init);
689
690static void __exit spidev_exit(void)
691{
692 spi_unregister_driver(&spidev_spi_driver);
693 class_destroy(spidev_class);
694 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
695}
696module_exit(spidev_exit);
697
698MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
699MODULE_DESCRIPTION("User mode SPI device interface");
700MODULE_LICENSE("GPL");
701MODULE_ALIAS("spi:spidev");