1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Simple synchronous userspace interface to SPI devices
4 *
5 * Copyright (C) 2006 SWAPP
6 * Andrea Paterniani <a.paterniani@swapp-eng.it>
7 * Copyright (C) 2007 David Brownell (simplification, cleanup)
8 */
9
10 #include <linux/init.h>
11 #include <linux/ioctl.h>
12 #include <linux/fs.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/list.h>
16 #include <linux/errno.h>
17 #include <linux/mod_devicetable.h>
18 #include <linux/module.h>
19 #include <linux/mutex.h>
20 #include <linux/property.h>
21 #include <linux/slab.h>
22 #include <linux/compat.h>
23
24 #include <linux/spi/spi.h>
25 #include <linux/spi/spidev.h>
26
27 #include <linux/uaccess.h>
28
29
30 /*
31 * This supports access to SPI devices using normal userspace I/O calls.
32 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
33 * and often mask message boundaries, full SPI support requires full duplex
34 * transfers. There are several kinds of internal message boundaries to
35 * handle chipselect management and other protocol options.
36 *
37 * SPI has a character major number assigned. We allocate minor numbers
38 * dynamically using a bitmask. You must use hotplug tools, such as udev
39 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
40 * nodes, since there is no fixed association of minor numbers with any
41 * particular SPI bus or device.
42 */
43 #define SPIDEV_MAJOR 153 /* assigned */
44 #define N_SPI_MINORS 32 /* ... up to 256 */
45
46 static DECLARE_BITMAP(minors, N_SPI_MINORS);
47
48 static_assert(N_SPI_MINORS > 0 && N_SPI_MINORS <= 256);
49
50 /* Bit masks for spi_device.mode management. Note that incorrect
51 * settings for some settings can cause *lots* of trouble for other
52 * devices on a shared bus:
53 *
54 * - CS_HIGH ... this device will be active when it shouldn't be
55 * - 3WIRE ... when active, it won't behave as it should
56 * - NO_CS ... there will be no explicit message boundaries; this
57 * is completely incompatible with the shared bus model
58 * - READY ... transfers may proceed when they shouldn't.
59 *
60 * REVISIT should changing those flags be privileged?
61 */
62 #define SPI_MODE_MASK (SPI_MODE_X_MASK | SPI_CS_HIGH \
63 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
64 | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
65 | SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL \
66 | SPI_RX_QUAD | SPI_RX_OCTAL \
67 | SPI_RX_CPHA_FLIP | SPI_3WIRE_HIZ \
68 | SPI_MOSI_IDLE_LOW)
69
70 struct spidev_data {
71 dev_t devt;
72 struct mutex spi_lock;
73 struct spi_device *spi;
74 struct list_head device_entry;
75
76 /* TX/RX buffers are NULL unless this device is open (users > 0) */
77 unsigned users;
78 u8 *tx_buffer;
79 u8 *rx_buffer;
80 u32 speed_hz;
81 };
82
83 static LIST_HEAD(device_list);
84 static DEFINE_MUTEX(device_list_lock);
85
86 static unsigned bufsiz = 4096;
87 module_param(bufsiz, uint, S_IRUGO);
88 MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
89
90 /*-------------------------------------------------------------------------*/
91
92 static ssize_t
spidev_sync_unlocked(struct spi_device * spi,struct spi_message * message)93 spidev_sync_unlocked(struct spi_device *spi, struct spi_message *message)
94 {
95 ssize_t status;
96
97 status = spi_sync(spi, message);
98 if (status == 0)
99 status = message->actual_length;
100
101 return status;
102 }
103
104 static inline ssize_t
spidev_sync_write(struct spidev_data * spidev,size_t len)105 spidev_sync_write(struct spidev_data *spidev, size_t len)
106 {
107 struct spi_transfer t = {
108 .tx_buf = spidev->tx_buffer,
109 .len = len,
110 .speed_hz = spidev->speed_hz,
111 };
112 struct spi_message m;
113
114 spi_message_init(&m);
115 spi_message_add_tail(&t, &m);
116
117 return spidev_sync_unlocked(spidev->spi, &m);
118 }
119
120 static inline ssize_t
spidev_sync_read(struct spidev_data * spidev,size_t len)121 spidev_sync_read(struct spidev_data *spidev, size_t len)
122 {
123 struct spi_transfer t = {
124 .rx_buf = spidev->rx_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
133 return spidev_sync_unlocked(spidev->spi, &m);
134 }
135
136 /*-------------------------------------------------------------------------*/
137
138 /* Read-only message with current device setup */
139 static ssize_t
spidev_read(struct file * filp,char __user * buf,size_t count,loff_t * f_pos)140 spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
141 {
142 struct spidev_data *spidev;
143 ssize_t status = -ESHUTDOWN;
144
145 /* chipselect only toggles at start or end of operation */
146 if (count > bufsiz)
147 return -EMSGSIZE;
148
149 spidev = filp->private_data;
150
151 mutex_lock(&spidev->spi_lock);
152
153 if (spidev->spi == NULL)
154 goto err_spi_removed;
155
156 status = spidev_sync_read(spidev, count);
157 if (status > 0) {
158 unsigned long missing;
159
160 missing = copy_to_user(buf, spidev->rx_buffer, status);
161 if (missing == status)
162 status = -EFAULT;
163 else
164 status = status - missing;
165 }
166
167 err_spi_removed:
168 mutex_unlock(&spidev->spi_lock);
169
170 return status;
171 }
172
173 /* Write-only message with current device setup */
174 static ssize_t
spidev_write(struct file * filp,const char __user * buf,size_t count,loff_t * f_pos)175 spidev_write(struct file *filp, const char __user *buf,
176 size_t count, loff_t *f_pos)
177 {
178 struct spidev_data *spidev;
179 ssize_t status = -ESHUTDOWN;
180 unsigned long missing;
181
182 /* chipselect only toggles at start or end of operation */
183 if (count > bufsiz)
184 return -EMSGSIZE;
185
186 spidev = filp->private_data;
187
188 mutex_lock(&spidev->spi_lock);
189
190 if (spidev->spi == NULL)
191 goto err_spi_removed;
192
193 missing = copy_from_user(spidev->tx_buffer, buf, count);
194 if (missing == 0)
195 status = spidev_sync_write(spidev, count);
196 else
197 status = -EFAULT;
198
199 err_spi_removed:
200 mutex_unlock(&spidev->spi_lock);
201
202 return status;
203 }
204
spidev_message(struct spidev_data * spidev,struct spi_ioc_transfer * u_xfers,unsigned n_xfers)205 static int spidev_message(struct spidev_data *spidev,
206 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
207 {
208 struct spi_message msg;
209 struct spi_transfer *k_xfers;
210 struct spi_transfer *k_tmp;
211 struct spi_ioc_transfer *u_tmp;
212 unsigned n, total, tx_total, rx_total;
213 u8 *tx_buf, *rx_buf;
214 int status = -EFAULT;
215
216 spi_message_init(&msg);
217 k_xfers = kzalloc_objs(*k_tmp, n_xfers);
218 if (k_xfers == NULL)
219 return -ENOMEM;
220
221 /* Construct spi_message, copying any tx data to bounce buffer.
222 * We walk the array of user-provided transfers, using each one
223 * to initialize a kernel version of the same transfer.
224 */
225 tx_buf = spidev->tx_buffer;
226 rx_buf = spidev->rx_buffer;
227 total = 0;
228 tx_total = 0;
229 rx_total = 0;
230 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
231 n;
232 n--, k_tmp++, u_tmp++) {
233 /* Ensure that also following allocations from rx_buf/tx_buf will meet
234 * DMA alignment requirements.
235 */
236 unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_DMA_MINALIGN);
237
238 k_tmp->len = u_tmp->len;
239
240 total += k_tmp->len;
241 /* Since the function returns the total length of transfers
242 * on success, restrict the total to positive int values to
243 * avoid the return value looking like an error. Also check
244 * each transfer length to avoid arithmetic overflow.
245 */
246 if (total > INT_MAX || k_tmp->len > INT_MAX) {
247 status = -EMSGSIZE;
248 goto done;
249 }
250
251 if (u_tmp->rx_buf) {
252 /* this transfer needs space in RX bounce buffer */
253 rx_total += len_aligned;
254 if (rx_total > bufsiz) {
255 status = -EMSGSIZE;
256 goto done;
257 }
258 k_tmp->rx_buf = rx_buf;
259 rx_buf += len_aligned;
260 }
261 if (u_tmp->tx_buf) {
262 /* this transfer needs space in TX bounce buffer */
263 tx_total += len_aligned;
264 if (tx_total > bufsiz) {
265 status = -EMSGSIZE;
266 goto done;
267 }
268 k_tmp->tx_buf = tx_buf;
269 if (copy_from_user(tx_buf, (const u8 __user *)
270 (uintptr_t) u_tmp->tx_buf,
271 u_tmp->len))
272 goto done;
273 tx_buf += len_aligned;
274 }
275
276 k_tmp->cs_change = !!u_tmp->cs_change;
277 k_tmp->tx_nbits = u_tmp->tx_nbits;
278 k_tmp->rx_nbits = u_tmp->rx_nbits;
279 k_tmp->bits_per_word = u_tmp->bits_per_word;
280 k_tmp->delay.value = u_tmp->delay_usecs;
281 k_tmp->delay.unit = SPI_DELAY_UNIT_USECS;
282 k_tmp->speed_hz = u_tmp->speed_hz;
283 k_tmp->word_delay.value = u_tmp->word_delay_usecs;
284 k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
285 if (!k_tmp->speed_hz)
286 k_tmp->speed_hz = spidev->speed_hz;
287 #ifdef VERBOSE
288 dev_dbg(&spidev->spi->dev,
289 " xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n",
290 k_tmp->len,
291 k_tmp->rx_buf ? "rx " : "",
292 k_tmp->tx_buf ? "tx " : "",
293 k_tmp->cs_change ? "cs " : "",
294 k_tmp->bits_per_word ? : spidev->spi->bits_per_word,
295 k_tmp->delay.value,
296 k_tmp->word_delay.value,
297 k_tmp->speed_hz ? : spidev->spi->max_speed_hz);
298 #endif
299 spi_message_add_tail(k_tmp, &msg);
300 }
301
302 status = spidev_sync_unlocked(spidev->spi, &msg);
303 if (status < 0)
304 goto done;
305
306 /* copy any rx data out of bounce buffer */
307 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
308 n;
309 n--, k_tmp++, u_tmp++) {
310 if (u_tmp->rx_buf) {
311 if (copy_to_user((u8 __user *)
312 (uintptr_t) u_tmp->rx_buf, k_tmp->rx_buf,
313 u_tmp->len)) {
314 status = -EFAULT;
315 goto done;
316 }
317 }
318 }
319 status = total;
320
321 done:
322 kfree(k_xfers);
323 return status;
324 }
325
326 static struct spi_ioc_transfer *
spidev_get_ioc_message(unsigned int cmd,struct spi_ioc_transfer __user * u_ioc,unsigned * n_ioc)327 spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
328 unsigned *n_ioc)
329 {
330 u32 tmp;
331
332 /* Check type, command number and direction */
333 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC
334 || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
335 || _IOC_DIR(cmd) != _IOC_WRITE)
336 return ERR_PTR(-ENOTTY);
337
338 tmp = _IOC_SIZE(cmd);
339 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0)
340 return ERR_PTR(-EINVAL);
341 *n_ioc = tmp / sizeof(struct spi_ioc_transfer);
342 if (*n_ioc == 0)
343 return NULL;
344
345 /* copy into scratch area */
346 return memdup_user(u_ioc, tmp);
347 }
348
349 static long
spidev_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)350 spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
351 {
352 int retval = 0;
353 struct spidev_data *spidev;
354 struct spi_device *spi;
355 struct spi_controller *ctlr;
356 u32 tmp;
357 unsigned n_ioc;
358 struct spi_ioc_transfer *ioc;
359
360 /* Check type and command number */
361 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
362 return -ENOTTY;
363
364 /* guard against device removal before, or while,
365 * we issue this ioctl.
366 */
367 spidev = filp->private_data;
368 mutex_lock(&spidev->spi_lock);
369 spi = spi_dev_get(spidev->spi);
370 if (spi == NULL) {
371 mutex_unlock(&spidev->spi_lock);
372 return -ESHUTDOWN;
373 }
374
375 ctlr = spi->controller;
376
377 switch (cmd) {
378 /* read requests */
379 case SPI_IOC_RD_MODE:
380 case SPI_IOC_RD_MODE32:
381 tmp = spi->mode & SPI_MODE_MASK;
382
383 if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0))
384 tmp &= ~SPI_CS_HIGH;
385
386 if (cmd == SPI_IOC_RD_MODE)
387 retval = put_user(tmp, (__u8 __user *)arg);
388 else
389 retval = put_user(tmp, (__u32 __user *)arg);
390 break;
391 case SPI_IOC_RD_LSB_FIRST:
392 retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
393 (__u8 __user *)arg);
394 break;
395 case SPI_IOC_RD_BITS_PER_WORD:
396 retval = put_user(spi->bits_per_word, (__u8 __user *)arg);
397 break;
398 case SPI_IOC_RD_MAX_SPEED_HZ:
399 retval = put_user(spidev->speed_hz, (__u32 __user *)arg);
400 break;
401
402 /* write requests */
403 case SPI_IOC_WR_MODE:
404 case SPI_IOC_WR_MODE32:
405 if (cmd == SPI_IOC_WR_MODE)
406 retval = get_user(tmp, (u8 __user *)arg);
407 else
408 retval = get_user(tmp, (u32 __user *)arg);
409 if (retval == 0) {
410 u32 save = spi->mode;
411
412 if (tmp & ~SPI_MODE_MASK) {
413 retval = -EINVAL;
414 break;
415 }
416
417 if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0))
418 tmp |= SPI_CS_HIGH;
419
420 tmp |= spi->mode & ~SPI_MODE_MASK;
421 spi->mode = tmp & SPI_MODE_USER_MASK;
422 retval = spi_setup(spi);
423 if (retval < 0)
424 spi->mode = save;
425 else
426 dev_dbg(&spi->dev, "spi mode %x\n", tmp);
427 }
428 break;
429 case SPI_IOC_WR_LSB_FIRST:
430 retval = get_user(tmp, (__u8 __user *)arg);
431 if (retval == 0) {
432 u32 save = spi->mode;
433
434 if (tmp)
435 spi->mode |= SPI_LSB_FIRST;
436 else
437 spi->mode &= ~SPI_LSB_FIRST;
438 retval = spi_setup(spi);
439 if (retval < 0)
440 spi->mode = save;
441 else
442 dev_dbg(&spi->dev, "%csb first\n",
443 tmp ? 'l' : 'm');
444 }
445 break;
446 case SPI_IOC_WR_BITS_PER_WORD:
447 retval = get_user(tmp, (__u8 __user *)arg);
448 if (retval == 0) {
449 u8 save = spi->bits_per_word;
450
451 spi->bits_per_word = tmp;
452 retval = spi_setup(spi);
453 if (retval < 0)
454 spi->bits_per_word = save;
455 else
456 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
457 }
458 break;
459 case SPI_IOC_WR_MAX_SPEED_HZ: {
460 u32 save;
461
462 retval = get_user(tmp, (__u32 __user *)arg);
463 if (retval)
464 break;
465 if (tmp == 0) {
466 retval = -EINVAL;
467 break;
468 }
469
470 save = spi->max_speed_hz;
471
472 spi->max_speed_hz = tmp;
473 retval = spi_setup(spi);
474 if (retval == 0) {
475 spidev->speed_hz = tmp;
476 dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz);
477 }
478
479 spi->max_speed_hz = save;
480 break;
481 }
482 default:
483 /* segmented and/or full-duplex I/O request */
484 /* Check message and copy into scratch area */
485 ioc = spidev_get_ioc_message(cmd,
486 (struct spi_ioc_transfer __user *)arg, &n_ioc);
487 if (IS_ERR(ioc)) {
488 retval = PTR_ERR(ioc);
489 break;
490 }
491 if (!ioc)
492 break; /* n_ioc is also 0 */
493
494 /* translate to spi_message, execute */
495 retval = spidev_message(spidev, ioc, n_ioc);
496 kfree(ioc);
497 break;
498 }
499
500 spi_dev_put(spi);
501 mutex_unlock(&spidev->spi_lock);
502 return retval;
503 }
504
505 #ifdef CONFIG_COMPAT
506 static long
spidev_compat_ioc_message(struct file * filp,unsigned int cmd,unsigned long arg)507 spidev_compat_ioc_message(struct file *filp, unsigned int cmd,
508 unsigned long arg)
509 {
510 struct spi_ioc_transfer __user *u_ioc;
511 int retval = 0;
512 struct spidev_data *spidev;
513 struct spi_device *spi;
514 unsigned n_ioc, n;
515 struct spi_ioc_transfer *ioc;
516
517 u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg);
518
519 /* guard against device removal before, or while,
520 * we issue this ioctl.
521 */
522 spidev = filp->private_data;
523 mutex_lock(&spidev->spi_lock);
524 spi = spi_dev_get(spidev->spi);
525 if (spi == NULL) {
526 mutex_unlock(&spidev->spi_lock);
527 return -ESHUTDOWN;
528 }
529
530 /* Check message and copy into scratch area */
531 ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc);
532 if (IS_ERR(ioc)) {
533 retval = PTR_ERR(ioc);
534 goto done;
535 }
536 if (!ioc)
537 goto done; /* n_ioc is also 0 */
538
539 /* Convert buffer pointers */
540 for (n = 0; n < n_ioc; n++) {
541 ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf);
542 ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf);
543 }
544
545 /* translate to spi_message, execute */
546 retval = spidev_message(spidev, ioc, n_ioc);
547 kfree(ioc);
548
549 done:
550 spi_dev_put(spi);
551 mutex_unlock(&spidev->spi_lock);
552 return retval;
553 }
554
555 static long
spidev_compat_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)556 spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
557 {
558 if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC
559 && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0))
560 && _IOC_DIR(cmd) == _IOC_WRITE)
561 return spidev_compat_ioc_message(filp, cmd, arg);
562
563 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
564 }
565 #else
566 #define spidev_compat_ioctl NULL
567 #endif /* CONFIG_COMPAT */
568
spidev_open(struct inode * inode,struct file * filp)569 static int spidev_open(struct inode *inode, struct file *filp)
570 {
571 struct spidev_data *spidev = NULL, *iter;
572 int status = -ENXIO;
573
574 mutex_lock(&device_list_lock);
575
576 list_for_each_entry(iter, &device_list, device_entry) {
577 if (iter->devt == inode->i_rdev) {
578 status = 0;
579 spidev = iter;
580 break;
581 }
582 }
583
584 if (!spidev) {
585 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
586 goto err_find_dev;
587 }
588
589 if (!spidev->tx_buffer) {
590 spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL);
591 if (!spidev->tx_buffer) {
592 status = -ENOMEM;
593 goto err_find_dev;
594 }
595 }
596
597 if (!spidev->rx_buffer) {
598 spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
599 if (!spidev->rx_buffer) {
600 status = -ENOMEM;
601 goto err_alloc_rx_buf;
602 }
603 }
604
605 spidev->users++;
606 filp->private_data = spidev;
607 stream_open(inode, filp);
608
609 mutex_unlock(&device_list_lock);
610 return 0;
611
612 err_alloc_rx_buf:
613 kfree(spidev->tx_buffer);
614 spidev->tx_buffer = NULL;
615 err_find_dev:
616 mutex_unlock(&device_list_lock);
617 return status;
618 }
619
spidev_release(struct inode * inode,struct file * filp)620 static int spidev_release(struct inode *inode, struct file *filp)
621 {
622 struct spidev_data *spidev;
623 int dofree;
624
625 mutex_lock(&device_list_lock);
626 spidev = filp->private_data;
627 filp->private_data = NULL;
628
629 mutex_lock(&spidev->spi_lock);
630 /* ... after we unbound from the underlying device? */
631 dofree = (spidev->spi == NULL);
632 mutex_unlock(&spidev->spi_lock);
633
634 /* last close? */
635 spidev->users--;
636 if (!spidev->users) {
637
638 kfree(spidev->tx_buffer);
639 spidev->tx_buffer = NULL;
640
641 kfree(spidev->rx_buffer);
642 spidev->rx_buffer = NULL;
643
644 if (dofree)
645 kfree(spidev);
646 else
647 spidev->speed_hz = spidev->spi->max_speed_hz;
648 }
649 #ifdef CONFIG_SPI_SLAVE
650 if (!dofree)
651 spi_target_abort(spidev->spi);
652 #endif
653 mutex_unlock(&device_list_lock);
654
655 return 0;
656 }
657
658 static const struct file_operations spidev_fops = {
659 .owner = THIS_MODULE,
660 /* REVISIT switch to aio primitives, so that userspace
661 * gets more complete API coverage. It'll simplify things
662 * too, except for the locking.
663 */
664 .write = spidev_write,
665 .read = spidev_read,
666 .unlocked_ioctl = spidev_ioctl,
667 .compat_ioctl = spidev_compat_ioctl,
668 .open = spidev_open,
669 .release = spidev_release,
670 };
671
672 /*-------------------------------------------------------------------------*/
673
674 /* The main reason to have this class is to make mdev/udev create the
675 * /dev/spidevB.C character device nodes exposing our userspace API.
676 * It also simplifies memory management.
677 */
678
679 static const struct class spidev_class = {
680 .name = "spidev",
681 };
682
683 /*
684 * The spi device ids are expected to match the device names of the
685 * spidev_dt_ids array below. Both arrays are kept in the same ordering.
686 */
687 static const struct spi_device_id spidev_spi_ids[] = {
688 { .name = /* abb */ "spi-sensor" },
689 { .name = /* arduino */ "unoq-mcu" },
690 { .name = /* cisco */ "spi-petra" },
691 { .name = /* dh */ "dhcom-board" },
692 { .name = /* elgin */ "jg10309-01" },
693 { .name = /* gocontroll */ "moduline-module-slot"},
694 { .name = /* lineartechnology */ "ltc2488" },
695 { .name = /* lwn */ "bk4" },
696 { .name = /* lwn */ "bk4-spi" },
697 { .name = /* menlo */ "m53cpld" },
698 { .name = /* micron */ "spi-authenta" },
699 { .name = /* rohm */ "bh2228fv" },
700 { .name = /* rohm */ "dh2228fv" },
701 { .name = /* semtech */ "sx1301" },
702 { .name = /* silabs */ "em3581" },
703 { .name = /* silabs */ "si3210" },
704 {},
705 };
706 MODULE_DEVICE_TABLE(spi, spidev_spi_ids);
707
708 /*
709 * spidev should never be referenced in DT without a specific compatible string,
710 * it is a Linux implementation thing rather than a description of the hardware.
711 */
spidev_of_check(struct device * dev)712 static int spidev_of_check(struct device *dev)
713 {
714 if (device_property_match_string(dev, "compatible", "spidev") < 0)
715 return 0;
716
717 dev_err(dev, "spidev listed directly in DT is not supported\n");
718 return -EINVAL;
719 }
720
721 static const struct of_device_id spidev_dt_ids[] = {
722 { .compatible = "abb,spi-sensor", .data = &spidev_of_check },
723 { .compatible = "arduino,unoq-mcu", .data = &spidev_of_check },
724 { .compatible = "cisco,spi-petra", .data = &spidev_of_check },
725 { .compatible = "dh,dhcom-board", .data = &spidev_of_check },
726 { .compatible = "elgin,jg10309-01", .data = &spidev_of_check },
727 { .compatible = "gocontroll,moduline-module-slot", .data = &spidev_of_check},
728 { .compatible = "lineartechnology,ltc2488", .data = &spidev_of_check },
729 { .compatible = "lwn,bk4", .data = &spidev_of_check },
730 { .compatible = "lwn,bk4-spi", .data = &spidev_of_check },
731 { .compatible = "menlo,m53cpld", .data = &spidev_of_check },
732 { .compatible = "micron,spi-authenta", .data = &spidev_of_check },
733 { .compatible = "rohm,bh2228fv", .data = &spidev_of_check },
734 { .compatible = "rohm,dh2228fv", .data = &spidev_of_check },
735 { .compatible = "semtech,sx1301", .data = &spidev_of_check },
736 { .compatible = "silabs,em3581", .data = &spidev_of_check },
737 { .compatible = "silabs,si3210", .data = &spidev_of_check },
738 {},
739 };
740 MODULE_DEVICE_TABLE(of, spidev_dt_ids);
741
742 /* Dummy SPI devices not to be used in production systems */
spidev_acpi_check(struct device * dev)743 static int spidev_acpi_check(struct device *dev)
744 {
745 dev_warn(dev, "do not use this driver in production systems!\n");
746 return 0;
747 }
748
749 static const struct acpi_device_id spidev_acpi_ids[] = {
750 /*
751 * The ACPI SPT000* devices are only meant for development and
752 * testing. Systems used in production should have a proper ACPI
753 * description of the connected peripheral and they should also use
754 * a proper driver instead of poking directly to the SPI bus.
755 */
756 { "SPT0001", (kernel_ulong_t)&spidev_acpi_check },
757 { "SPT0002", (kernel_ulong_t)&spidev_acpi_check },
758 { "SPT0003", (kernel_ulong_t)&spidev_acpi_check },
759 {},
760 };
761 MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids);
762
763 /*-------------------------------------------------------------------------*/
764
spidev_probe(struct spi_device * spi)765 static int spidev_probe(struct spi_device *spi)
766 {
767 int (*match)(struct device *dev);
768 struct spidev_data *spidev;
769 int status;
770 unsigned long minor;
771
772 match = device_get_match_data(&spi->dev);
773 if (match) {
774 status = match(&spi->dev);
775 if (status)
776 return status;
777 }
778
779 /* Allocate driver data */
780 spidev = kzalloc_obj(*spidev);
781 if (!spidev)
782 return -ENOMEM;
783
784 /* Initialize the driver data */
785 spidev->spi = spi;
786 mutex_init(&spidev->spi_lock);
787
788 INIT_LIST_HEAD(&spidev->device_entry);
789
790 /* If we can allocate a minor number, hook up this device.
791 * Reusing minors is fine so long as udev or mdev is working.
792 */
793 mutex_lock(&device_list_lock);
794 minor = find_first_zero_bit(minors, N_SPI_MINORS);
795 if (minor < N_SPI_MINORS) {
796 struct device *dev;
797
798 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
799 dev = device_create(&spidev_class, &spi->dev, spidev->devt,
800 spidev, "spidev%d.%d",
801 spi->controller->bus_num, spi_get_chipselect(spi, 0));
802 status = PTR_ERR_OR_ZERO(dev);
803 } else {
804 dev_dbg(&spi->dev, "no minor number available!\n");
805 status = -ENODEV;
806 }
807 if (status == 0) {
808 set_bit(minor, minors);
809 list_add(&spidev->device_entry, &device_list);
810 }
811 mutex_unlock(&device_list_lock);
812
813 spidev->speed_hz = spi->max_speed_hz;
814
815 if (status == 0)
816 spi_set_drvdata(spi, spidev);
817 else
818 kfree(spidev);
819
820 return status;
821 }
822
spidev_remove(struct spi_device * spi)823 static void spidev_remove(struct spi_device *spi)
824 {
825 struct spidev_data *spidev = spi_get_drvdata(spi);
826
827 /* prevent new opens */
828 mutex_lock(&device_list_lock);
829 /* make sure ops on existing fds can abort cleanly */
830 mutex_lock(&spidev->spi_lock);
831 spidev->spi = NULL;
832 mutex_unlock(&spidev->spi_lock);
833
834 list_del(&spidev->device_entry);
835 device_destroy(&spidev_class, spidev->devt);
836 clear_bit(MINOR(spidev->devt), minors);
837 if (spidev->users == 0)
838 kfree(spidev);
839 mutex_unlock(&device_list_lock);
840 }
841
842 static struct spi_driver spidev_spi_driver = {
843 .driver = {
844 .name = "spidev",
845 .of_match_table = spidev_dt_ids,
846 .acpi_match_table = spidev_acpi_ids,
847 },
848 .probe = spidev_probe,
849 .remove = spidev_remove,
850 .id_table = spidev_spi_ids,
851
852 /* NOTE: suspend/resume methods are not necessary here.
853 * We don't do anything except pass the requests to/from
854 * the underlying controller. The refrigerator handles
855 * most issues; the controller driver handles the rest.
856 */
857 };
858
859 /*-------------------------------------------------------------------------*/
860
spidev_init(void)861 static int __init spidev_init(void)
862 {
863 int status;
864
865 /* Claim our 256 reserved device numbers. Then register a class
866 * that will key udev/mdev to add/remove /dev nodes. Last, register
867 * the driver which manages those device numbers.
868 */
869 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
870 if (status < 0)
871 return status;
872
873 status = class_register(&spidev_class);
874 if (status) {
875 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
876 return status;
877 }
878
879 status = spi_register_driver(&spidev_spi_driver);
880 if (status < 0) {
881 class_unregister(&spidev_class);
882 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
883 }
884 return status;
885 }
886 module_init(spidev_init);
887
spidev_exit(void)888 static void __exit spidev_exit(void)
889 {
890 spi_unregister_driver(&spidev_spi_driver);
891 class_unregister(&spidev_class);
892 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
893 }
894 module_exit(spidev_exit);
895
896 MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
897 MODULE_DESCRIPTION("User mode SPI device interface");
898 MODULE_LICENSE("GPL");
899 MODULE_ALIAS("spi:spidev");
900