Merge tag 'trace-v5.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[linux/fpc-iii.git] / drivers / spi / spidev.c
blob859910ec8d9f6b649a9de491d830f6b718d82f1e
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Simple synchronous userspace interface to SPI devices
5 * Copyright (C) 2006 SWAPP
6 * Andrea Paterniani <a.paterniani@swapp-eng.it>
7 * Copyright (C) 2007 David Brownell (simplification, cleanup)
8 */
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/ioctl.h>
13 #include <linux/fs.h>
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/list.h>
17 #include <linux/errno.h>
18 #include <linux/mutex.h>
19 #include <linux/slab.h>
20 #include <linux/compat.h>
21 #include <linux/of.h>
22 #include <linux/of_device.h>
23 #include <linux/acpi.h>
25 #include <linux/spi/spi.h>
26 #include <linux/spi/spidev.h>
28 #include <linux/uaccess.h>
32 * This supports access to SPI devices using normal userspace I/O calls.
33 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
34 * and often mask message boundaries, full SPI support requires full duplex
35 * transfers. There are several kinds of internal message boundaries to
36 * handle chipselect management and other protocol options.
38 * SPI has a character major number assigned. We allocate minor numbers
39 * dynamically using a bitmask. You must use hotplug tools, such as udev
40 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
41 * nodes, since there is no fixed association of minor numbers with any
42 * particular SPI bus or device.
44 #define SPIDEV_MAJOR 153 /* assigned */
45 #define N_SPI_MINORS 32 /* ... up to 256 */
47 static DECLARE_BITMAP(minors, N_SPI_MINORS);
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:
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.
60 * REVISIT should changing those flags be privileged?
62 #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | 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)
68 struct spidev_data {
69 dev_t devt;
70 spinlock_t spi_lock;
71 struct spi_device *spi;
72 struct list_head device_entry;
74 /* TX/RX buffers are NULL unless this device is open (users > 0) */
75 struct mutex buf_lock;
76 unsigned users;
77 u8 *tx_buffer;
78 u8 *rx_buffer;
79 u32 speed_hz;
82 static LIST_HEAD(device_list);
83 static DEFINE_MUTEX(device_list_lock);
85 static unsigned bufsiz = 4096;
86 module_param(bufsiz, uint, S_IRUGO);
87 MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
89 /*-------------------------------------------------------------------------*/
91 static ssize_t
92 spidev_sync(struct spidev_data *spidev, struct spi_message *message)
94 int status;
95 struct spi_device *spi;
97 spin_lock_irq(&spidev->spi_lock);
98 spi = spidev->spi;
99 spin_unlock_irq(&spidev->spi_lock);
101 if (spi == NULL)
102 status = -ESHUTDOWN;
103 else
104 status = spi_sync(spi, message);
106 if (status == 0)
107 status = message->actual_length;
109 return status;
112 static inline ssize_t
113 spidev_sync_write(struct spidev_data *spidev, size_t len)
115 struct spi_transfer t = {
116 .tx_buf = spidev->tx_buffer,
117 .len = len,
118 .speed_hz = spidev->speed_hz,
120 struct spi_message m;
122 spi_message_init(&m);
123 spi_message_add_tail(&t, &m);
124 return spidev_sync(spidev, &m);
127 static inline ssize_t
128 spidev_sync_read(struct spidev_data *spidev, size_t len)
130 struct spi_transfer t = {
131 .rx_buf = spidev->rx_buffer,
132 .len = len,
133 .speed_hz = spidev->speed_hz,
135 struct spi_message m;
137 spi_message_init(&m);
138 spi_message_add_tail(&t, &m);
139 return spidev_sync(spidev, &m);
142 /*-------------------------------------------------------------------------*/
144 /* Read-only message with current device setup */
145 static ssize_t
146 spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
148 struct spidev_data *spidev;
149 ssize_t status;
151 /* chipselect only toggles at start or end of operation */
152 if (count > bufsiz)
153 return -EMSGSIZE;
155 spidev = filp->private_data;
157 mutex_lock(&spidev->buf_lock);
158 status = spidev_sync_read(spidev, count);
159 if (status > 0) {
160 unsigned long missing;
162 missing = copy_to_user(buf, spidev->rx_buffer, status);
163 if (missing == status)
164 status = -EFAULT;
165 else
166 status = status - missing;
168 mutex_unlock(&spidev->buf_lock);
170 return status;
173 /* Write-only message with current device setup */
174 static ssize_t
175 spidev_write(struct file *filp, const char __user *buf,
176 size_t count, loff_t *f_pos)
178 struct spidev_data *spidev;
179 ssize_t status;
180 unsigned long missing;
182 /* chipselect only toggles at start or end of operation */
183 if (count > bufsiz)
184 return -EMSGSIZE;
186 spidev = filp->private_data;
188 mutex_lock(&spidev->buf_lock);
189 missing = copy_from_user(spidev->tx_buffer, buf, count);
190 if (missing == 0)
191 status = spidev_sync_write(spidev, count);
192 else
193 status = -EFAULT;
194 mutex_unlock(&spidev->buf_lock);
196 return status;
199 static int spidev_message(struct spidev_data *spidev,
200 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
202 struct spi_message msg;
203 struct spi_transfer *k_xfers;
204 struct spi_transfer *k_tmp;
205 struct spi_ioc_transfer *u_tmp;
206 unsigned n, total, tx_total, rx_total;
207 u8 *tx_buf, *rx_buf;
208 int status = -EFAULT;
210 spi_message_init(&msg);
211 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
212 if (k_xfers == NULL)
213 return -ENOMEM;
215 /* Construct spi_message, copying any tx data to bounce buffer.
216 * We walk the array of user-provided transfers, using each one
217 * to initialize a kernel version of the same transfer.
219 tx_buf = spidev->tx_buffer;
220 rx_buf = spidev->rx_buffer;
221 total = 0;
222 tx_total = 0;
223 rx_total = 0;
224 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
226 n--, k_tmp++, u_tmp++) {
227 /* Ensure that also following allocations from rx_buf/tx_buf will meet
228 * DMA alignment requirements.
230 unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_KMALLOC_MINALIGN);
232 k_tmp->len = u_tmp->len;
234 total += k_tmp->len;
235 /* Since the function returns the total length of transfers
236 * on success, restrict the total to positive int values to
237 * avoid the return value looking like an error. Also check
238 * each transfer length to avoid arithmetic overflow.
240 if (total > INT_MAX || k_tmp->len > INT_MAX) {
241 status = -EMSGSIZE;
242 goto done;
245 if (u_tmp->rx_buf) {
246 /* this transfer needs space in RX bounce buffer */
247 rx_total += len_aligned;
248 if (rx_total > bufsiz) {
249 status = -EMSGSIZE;
250 goto done;
252 k_tmp->rx_buf = rx_buf;
253 rx_buf += len_aligned;
255 if (u_tmp->tx_buf) {
256 /* this transfer needs space in TX bounce buffer */
257 tx_total += len_aligned;
258 if (tx_total > bufsiz) {
259 status = -EMSGSIZE;
260 goto done;
262 k_tmp->tx_buf = tx_buf;
263 if (copy_from_user(tx_buf, (const u8 __user *)
264 (uintptr_t) u_tmp->tx_buf,
265 u_tmp->len))
266 goto done;
267 tx_buf += len_aligned;
270 k_tmp->cs_change = !!u_tmp->cs_change;
271 k_tmp->tx_nbits = u_tmp->tx_nbits;
272 k_tmp->rx_nbits = u_tmp->rx_nbits;
273 k_tmp->bits_per_word = u_tmp->bits_per_word;
274 k_tmp->delay.value = u_tmp->delay_usecs;
275 k_tmp->delay.unit = SPI_DELAY_UNIT_USECS;
276 k_tmp->speed_hz = u_tmp->speed_hz;
277 k_tmp->word_delay.value = u_tmp->word_delay_usecs;
278 k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
279 if (!k_tmp->speed_hz)
280 k_tmp->speed_hz = spidev->speed_hz;
281 #ifdef VERBOSE
282 dev_dbg(&spidev->spi->dev,
283 " xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n",
284 k_tmp->len,
285 k_tmp->rx_buf ? "rx " : "",
286 k_tmp->tx_buf ? "tx " : "",
287 k_tmp->cs_change ? "cs " : "",
288 k_tmp->bits_per_word ? : spidev->spi->bits_per_word,
289 k_tmp->delay.value,
290 k_tmp->word_delay.value,
291 k_tmp->speed_hz ? : spidev->spi->max_speed_hz);
292 #endif
293 spi_message_add_tail(k_tmp, &msg);
296 status = spidev_sync(spidev, &msg);
297 if (status < 0)
298 goto done;
300 /* copy any rx data out of bounce buffer */
301 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
303 n--, k_tmp++, u_tmp++) {
304 if (u_tmp->rx_buf) {
305 if (copy_to_user((u8 __user *)
306 (uintptr_t) u_tmp->rx_buf, k_tmp->rx_buf,
307 u_tmp->len)) {
308 status = -EFAULT;
309 goto done;
313 status = total;
315 done:
316 kfree(k_xfers);
317 return status;
320 static struct spi_ioc_transfer *
321 spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
322 unsigned *n_ioc)
324 u32 tmp;
326 /* Check type, command number and direction */
327 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC
328 || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
329 || _IOC_DIR(cmd) != _IOC_WRITE)
330 return ERR_PTR(-ENOTTY);
332 tmp = _IOC_SIZE(cmd);
333 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0)
334 return ERR_PTR(-EINVAL);
335 *n_ioc = tmp / sizeof(struct spi_ioc_transfer);
336 if (*n_ioc == 0)
337 return NULL;
339 /* copy into scratch area */
340 return memdup_user(u_ioc, tmp);
343 static long
344 spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
346 int retval = 0;
347 struct spidev_data *spidev;
348 struct spi_device *spi;
349 u32 tmp;
350 unsigned n_ioc;
351 struct spi_ioc_transfer *ioc;
353 /* Check type and command number */
354 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
355 return -ENOTTY;
357 /* guard against device removal before, or while,
358 * we issue this ioctl.
360 spidev = filp->private_data;
361 spin_lock_irq(&spidev->spi_lock);
362 spi = spi_dev_get(spidev->spi);
363 spin_unlock_irq(&spidev->spi_lock);
365 if (spi == NULL)
366 return -ESHUTDOWN;
368 /* use the buffer lock here for triple duty:
369 * - prevent I/O (from us) so calling spi_setup() is safe;
370 * - prevent concurrent SPI_IOC_WR_* from morphing
371 * data fields while SPI_IOC_RD_* reads them;
372 * - SPI_IOC_MESSAGE needs the buffer locked "normally".
374 mutex_lock(&spidev->buf_lock);
376 switch (cmd) {
377 /* read requests */
378 case SPI_IOC_RD_MODE:
379 retval = put_user(spi->mode & SPI_MODE_MASK,
380 (__u8 __user *)arg);
381 break;
382 case SPI_IOC_RD_MODE32:
383 retval = put_user(spi->mode & SPI_MODE_MASK,
384 (__u32 __user *)arg);
385 break;
386 case SPI_IOC_RD_LSB_FIRST:
387 retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
388 (__u8 __user *)arg);
389 break;
390 case SPI_IOC_RD_BITS_PER_WORD:
391 retval = put_user(spi->bits_per_word, (__u8 __user *)arg);
392 break;
393 case SPI_IOC_RD_MAX_SPEED_HZ:
394 retval = put_user(spidev->speed_hz, (__u32 __user *)arg);
395 break;
397 /* write requests */
398 case SPI_IOC_WR_MODE:
399 case SPI_IOC_WR_MODE32:
400 if (cmd == SPI_IOC_WR_MODE)
401 retval = get_user(tmp, (u8 __user *)arg);
402 else
403 retval = get_user(tmp, (u32 __user *)arg);
404 if (retval == 0) {
405 struct spi_controller *ctlr = spi->controller;
406 u32 save = spi->mode;
408 if (tmp & ~SPI_MODE_MASK) {
409 retval = -EINVAL;
410 break;
413 if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods &&
414 ctlr->cs_gpiods[spi->chip_select])
415 tmp |= SPI_CS_HIGH;
417 tmp |= spi->mode & ~SPI_MODE_MASK;
418 spi->mode = (u16)tmp;
419 retval = spi_setup(spi);
420 if (retval < 0)
421 spi->mode = save;
422 else
423 dev_dbg(&spi->dev, "spi mode %x\n", tmp);
425 break;
426 case SPI_IOC_WR_LSB_FIRST:
427 retval = get_user(tmp, (__u8 __user *)arg);
428 if (retval == 0) {
429 u32 save = spi->mode;
431 if (tmp)
432 spi->mode |= SPI_LSB_FIRST;
433 else
434 spi->mode &= ~SPI_LSB_FIRST;
435 retval = spi_setup(spi);
436 if (retval < 0)
437 spi->mode = save;
438 else
439 dev_dbg(&spi->dev, "%csb first\n",
440 tmp ? 'l' : 'm');
442 break;
443 case SPI_IOC_WR_BITS_PER_WORD:
444 retval = get_user(tmp, (__u8 __user *)arg);
445 if (retval == 0) {
446 u8 save = spi->bits_per_word;
448 spi->bits_per_word = tmp;
449 retval = spi_setup(spi);
450 if (retval < 0)
451 spi->bits_per_word = save;
452 else
453 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
455 break;
456 case SPI_IOC_WR_MAX_SPEED_HZ:
457 retval = get_user(tmp, (__u32 __user *)arg);
458 if (retval == 0) {
459 u32 save = spi->max_speed_hz;
461 spi->max_speed_hz = tmp;
462 retval = spi_setup(spi);
463 if (retval == 0) {
464 spidev->speed_hz = tmp;
465 dev_dbg(&spi->dev, "%d Hz (max)\n",
466 spidev->speed_hz);
468 spi->max_speed_hz = save;
470 break;
472 default:
473 /* segmented and/or full-duplex I/O request */
474 /* Check message and copy into scratch area */
475 ioc = spidev_get_ioc_message(cmd,
476 (struct spi_ioc_transfer __user *)arg, &n_ioc);
477 if (IS_ERR(ioc)) {
478 retval = PTR_ERR(ioc);
479 break;
481 if (!ioc)
482 break; /* n_ioc is also 0 */
484 /* translate to spi_message, execute */
485 retval = spidev_message(spidev, ioc, n_ioc);
486 kfree(ioc);
487 break;
490 mutex_unlock(&spidev->buf_lock);
491 spi_dev_put(spi);
492 return retval;
495 #ifdef CONFIG_COMPAT
496 static long
497 spidev_compat_ioc_message(struct file *filp, unsigned int cmd,
498 unsigned long arg)
500 struct spi_ioc_transfer __user *u_ioc;
501 int retval = 0;
502 struct spidev_data *spidev;
503 struct spi_device *spi;
504 unsigned n_ioc, n;
505 struct spi_ioc_transfer *ioc;
507 u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg);
509 /* guard against device removal before, or while,
510 * we issue this ioctl.
512 spidev = filp->private_data;
513 spin_lock_irq(&spidev->spi_lock);
514 spi = spi_dev_get(spidev->spi);
515 spin_unlock_irq(&spidev->spi_lock);
517 if (spi == NULL)
518 return -ESHUTDOWN;
520 /* SPI_IOC_MESSAGE needs the buffer locked "normally" */
521 mutex_lock(&spidev->buf_lock);
523 /* Check message and copy into scratch area */
524 ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc);
525 if (IS_ERR(ioc)) {
526 retval = PTR_ERR(ioc);
527 goto done;
529 if (!ioc)
530 goto done; /* n_ioc is also 0 */
532 /* Convert buffer pointers */
533 for (n = 0; n < n_ioc; n++) {
534 ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf);
535 ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf);
538 /* translate to spi_message, execute */
539 retval = spidev_message(spidev, ioc, n_ioc);
540 kfree(ioc);
542 done:
543 mutex_unlock(&spidev->buf_lock);
544 spi_dev_put(spi);
545 return retval;
548 static long
549 spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
551 if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC
552 && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0))
553 && _IOC_DIR(cmd) == _IOC_WRITE)
554 return spidev_compat_ioc_message(filp, cmd, arg);
556 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
558 #else
559 #define spidev_compat_ioctl NULL
560 #endif /* CONFIG_COMPAT */
562 static int spidev_open(struct inode *inode, struct file *filp)
564 struct spidev_data *spidev;
565 int status = -ENXIO;
567 mutex_lock(&device_list_lock);
569 list_for_each_entry(spidev, &device_list, device_entry) {
570 if (spidev->devt == inode->i_rdev) {
571 status = 0;
572 break;
576 if (status) {
577 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
578 goto err_find_dev;
581 if (!spidev->tx_buffer) {
582 spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL);
583 if (!spidev->tx_buffer) {
584 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
585 status = -ENOMEM;
586 goto err_find_dev;
590 if (!spidev->rx_buffer) {
591 spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
592 if (!spidev->rx_buffer) {
593 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
594 status = -ENOMEM;
595 goto err_alloc_rx_buf;
599 spidev->users++;
600 filp->private_data = spidev;
601 stream_open(inode, filp);
603 mutex_unlock(&device_list_lock);
604 return 0;
606 err_alloc_rx_buf:
607 kfree(spidev->tx_buffer);
608 spidev->tx_buffer = NULL;
609 err_find_dev:
610 mutex_unlock(&device_list_lock);
611 return status;
614 static int spidev_release(struct inode *inode, struct file *filp)
616 struct spidev_data *spidev;
617 int dofree;
619 mutex_lock(&device_list_lock);
620 spidev = filp->private_data;
621 filp->private_data = NULL;
623 spin_lock_irq(&spidev->spi_lock);
624 /* ... after we unbound from the underlying device? */
625 dofree = (spidev->spi == NULL);
626 spin_unlock_irq(&spidev->spi_lock);
628 /* last close? */
629 spidev->users--;
630 if (!spidev->users) {
632 kfree(spidev->tx_buffer);
633 spidev->tx_buffer = NULL;
635 kfree(spidev->rx_buffer);
636 spidev->rx_buffer = NULL;
638 if (dofree)
639 kfree(spidev);
640 else
641 spidev->speed_hz = spidev->spi->max_speed_hz;
643 #ifdef CONFIG_SPI_SLAVE
644 if (!dofree)
645 spi_slave_abort(spidev->spi);
646 #endif
647 mutex_unlock(&device_list_lock);
649 return 0;
652 static const struct file_operations spidev_fops = {
653 .owner = THIS_MODULE,
654 /* REVISIT switch to aio primitives, so that userspace
655 * gets more complete API coverage. It'll simplify things
656 * too, except for the locking.
658 .write = spidev_write,
659 .read = spidev_read,
660 .unlocked_ioctl = spidev_ioctl,
661 .compat_ioctl = spidev_compat_ioctl,
662 .open = spidev_open,
663 .release = spidev_release,
664 .llseek = no_llseek,
667 /*-------------------------------------------------------------------------*/
669 /* The main reason to have this class is to make mdev/udev create the
670 * /dev/spidevB.C character device nodes exposing our userspace API.
671 * It also simplifies memory management.
674 static struct class *spidev_class;
676 #ifdef CONFIG_OF
677 static const struct of_device_id spidev_dt_ids[] = {
678 { .compatible = "rohm,dh2228fv" },
679 { .compatible = "lineartechnology,ltc2488" },
680 { .compatible = "ge,achc" },
681 { .compatible = "semtech,sx1301" },
682 { .compatible = "lwn,bk4" },
683 { .compatible = "dh,dhcom-board" },
684 { .compatible = "menlo,m53cpld" },
687 MODULE_DEVICE_TABLE(of, spidev_dt_ids);
688 #endif
690 #ifdef CONFIG_ACPI
692 /* Dummy SPI devices not to be used in production systems */
693 #define SPIDEV_ACPI_DUMMY 1
695 static const struct acpi_device_id spidev_acpi_ids[] = {
697 * The ACPI SPT000* devices are only meant for development and
698 * testing. Systems used in production should have a proper ACPI
699 * description of the connected peripheral and they should also use
700 * a proper driver instead of poking directly to the SPI bus.
702 { "SPT0001", SPIDEV_ACPI_DUMMY },
703 { "SPT0002", SPIDEV_ACPI_DUMMY },
704 { "SPT0003", SPIDEV_ACPI_DUMMY },
707 MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids);
709 static void spidev_probe_acpi(struct spi_device *spi)
711 const struct acpi_device_id *id;
713 if (!has_acpi_companion(&spi->dev))
714 return;
716 id = acpi_match_device(spidev_acpi_ids, &spi->dev);
717 if (WARN_ON(!id))
718 return;
720 if (id->driver_data == SPIDEV_ACPI_DUMMY)
721 dev_warn(&spi->dev, "do not use this driver in production systems!\n");
723 #else
724 static inline void spidev_probe_acpi(struct spi_device *spi) {}
725 #endif
727 /*-------------------------------------------------------------------------*/
729 static int spidev_probe(struct spi_device *spi)
731 struct spidev_data *spidev;
732 int status;
733 unsigned long minor;
736 * spidev should never be referenced in DT without a specific
737 * compatible string, it is a Linux implementation thing
738 * rather than a description of the hardware.
740 WARN(spi->dev.of_node &&
741 of_device_is_compatible(spi->dev.of_node, "spidev"),
742 "%pOF: buggy DT: spidev listed directly in DT\n", spi->dev.of_node);
744 spidev_probe_acpi(spi);
746 /* Allocate driver data */
747 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
748 if (!spidev)
749 return -ENOMEM;
751 /* Initialize the driver data */
752 spidev->spi = spi;
753 spin_lock_init(&spidev->spi_lock);
754 mutex_init(&spidev->buf_lock);
756 INIT_LIST_HEAD(&spidev->device_entry);
758 /* If we can allocate a minor number, hook up this device.
759 * Reusing minors is fine so long as udev or mdev is working.
761 mutex_lock(&device_list_lock);
762 minor = find_first_zero_bit(minors, N_SPI_MINORS);
763 if (minor < N_SPI_MINORS) {
764 struct device *dev;
766 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
767 dev = device_create(spidev_class, &spi->dev, spidev->devt,
768 spidev, "spidev%d.%d",
769 spi->master->bus_num, spi->chip_select);
770 status = PTR_ERR_OR_ZERO(dev);
771 } else {
772 dev_dbg(&spi->dev, "no minor number available!\n");
773 status = -ENODEV;
775 if (status == 0) {
776 set_bit(minor, minors);
777 list_add(&spidev->device_entry, &device_list);
779 mutex_unlock(&device_list_lock);
781 spidev->speed_hz = spi->max_speed_hz;
783 if (status == 0)
784 spi_set_drvdata(spi, spidev);
785 else
786 kfree(spidev);
788 return status;
791 static int spidev_remove(struct spi_device *spi)
793 struct spidev_data *spidev = spi_get_drvdata(spi);
795 /* prevent new opens */
796 mutex_lock(&device_list_lock);
797 /* make sure ops on existing fds can abort cleanly */
798 spin_lock_irq(&spidev->spi_lock);
799 spidev->spi = NULL;
800 spin_unlock_irq(&spidev->spi_lock);
802 list_del(&spidev->device_entry);
803 device_destroy(spidev_class, spidev->devt);
804 clear_bit(MINOR(spidev->devt), minors);
805 if (spidev->users == 0)
806 kfree(spidev);
807 mutex_unlock(&device_list_lock);
809 return 0;
812 static struct spi_driver spidev_spi_driver = {
813 .driver = {
814 .name = "spidev",
815 .of_match_table = of_match_ptr(spidev_dt_ids),
816 .acpi_match_table = ACPI_PTR(spidev_acpi_ids),
818 .probe = spidev_probe,
819 .remove = spidev_remove,
821 /* NOTE: suspend/resume methods are not necessary here.
822 * We don't do anything except pass the requests to/from
823 * the underlying controller. The refrigerator handles
824 * most issues; the controller driver handles the rest.
828 /*-------------------------------------------------------------------------*/
830 static int __init spidev_init(void)
832 int status;
834 /* Claim our 256 reserved device numbers. Then register a class
835 * that will key udev/mdev to add/remove /dev nodes. Last, register
836 * the driver which manages those device numbers.
838 BUILD_BUG_ON(N_SPI_MINORS > 256);
839 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
840 if (status < 0)
841 return status;
843 spidev_class = class_create(THIS_MODULE, "spidev");
844 if (IS_ERR(spidev_class)) {
845 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
846 return PTR_ERR(spidev_class);
849 status = spi_register_driver(&spidev_spi_driver);
850 if (status < 0) {
851 class_destroy(spidev_class);
852 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
854 return status;
856 module_init(spidev_init);
858 static void __exit spidev_exit(void)
860 spi_unregister_driver(&spidev_spi_driver);
861 class_destroy(spidev_class);
862 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
864 module_exit(spidev_exit);
866 MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
867 MODULE_DESCRIPTION("User mode SPI device interface");
868 MODULE_LICENSE("GPL");
869 MODULE_ALIAS("spi:spidev");