2 * Simple synchronous userspace interface to SPI devices
4 * Copyright (C) 2006 SWAPP
5 * Andrea Paterniani <a.paterniani@swapp-eng.it>
6 * Copyright (C) 2007 David Brownell (simplification, cleanup)
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.
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.
19 #include <linux/init.h>
20 #include <linux/module.h>
21 #include <linux/ioctl.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>
31 #include <linux/of_device.h>
32 #include <linux/acpi.h>
34 #include <linux/spi/spi.h>
35 #include <linux/spi/spidev.h>
37 #include <linux/uaccess.h>
41 * This supports access to SPI devices using normal userspace I/O calls.
42 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
43 * and often mask message boundaries, full SPI support requires full duplex
44 * transfers. There are several kinds of internal message boundaries to
45 * handle chipselect management and other protocol options.
47 * SPI has a character major number assigned. We allocate minor numbers
48 * dynamically using a bitmask. You must use hotplug tools, such as udev
49 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
50 * nodes, since there is no fixed association of minor numbers with any
51 * particular SPI bus or device.
53 #define SPIDEV_MAJOR 153 /* assigned */
54 #define N_SPI_MINORS 32 /* ... up to 256 */
56 static DECLARE_BITMAP(minors
, N_SPI_MINORS
);
59 /* Bit masks for spi_device.mode management. Note that incorrect
60 * settings for some settings can cause *lots* of trouble for other
61 * devices on a shared bus:
63 * - CS_HIGH ... this device will be active when it shouldn't be
64 * - 3WIRE ... when active, it won't behave as it should
65 * - NO_CS ... there will be no explicit message boundaries; this
66 * is completely incompatible with the shared bus model
67 * - READY ... transfers may proceed when they shouldn't.
69 * REVISIT should changing those flags be privileged?
71 #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
72 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
73 | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
74 | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)
79 struct spi_device
*spi
;
80 struct list_head device_entry
;
82 /* TX/RX buffers are NULL unless this device is open (users > 0) */
83 struct mutex buf_lock
;
90 static LIST_HEAD(device_list
);
91 static DEFINE_MUTEX(device_list_lock
);
93 static unsigned bufsiz
= 4096;
94 module_param(bufsiz
, uint
, S_IRUGO
);
95 MODULE_PARM_DESC(bufsiz
, "data bytes in biggest supported SPI message");
97 /*-------------------------------------------------------------------------*/
100 spidev_sync(struct spidev_data
*spidev
, struct spi_message
*message
)
102 DECLARE_COMPLETION_ONSTACK(done
);
104 struct spi_device
*spi
;
106 spin_lock_irq(&spidev
->spi_lock
);
108 spin_unlock_irq(&spidev
->spi_lock
);
113 status
= spi_sync(spi
, message
);
116 status
= message
->actual_length
;
121 static inline ssize_t
122 spidev_sync_write(struct spidev_data
*spidev
, size_t len
)
124 struct spi_transfer t
= {
125 .tx_buf
= spidev
->tx_buffer
,
127 .speed_hz
= spidev
->speed_hz
,
129 struct spi_message m
;
131 spi_message_init(&m
);
132 spi_message_add_tail(&t
, &m
);
133 return spidev_sync(spidev
, &m
);
136 static inline ssize_t
137 spidev_sync_read(struct spidev_data
*spidev
, size_t len
)
139 struct spi_transfer t
= {
140 .rx_buf
= spidev
->rx_buffer
,
142 .speed_hz
= spidev
->speed_hz
,
144 struct spi_message m
;
146 spi_message_init(&m
);
147 spi_message_add_tail(&t
, &m
);
148 return spidev_sync(spidev
, &m
);
151 /*-------------------------------------------------------------------------*/
153 /* Read-only message with current device setup */
155 spidev_read(struct file
*filp
, char __user
*buf
, size_t count
, loff_t
*f_pos
)
157 struct spidev_data
*spidev
;
160 /* chipselect only toggles at start or end of operation */
164 spidev
= filp
->private_data
;
166 mutex_lock(&spidev
->buf_lock
);
167 status
= spidev_sync_read(spidev
, count
);
169 unsigned long missing
;
171 missing
= copy_to_user(buf
, spidev
->rx_buffer
, status
);
172 if (missing
== status
)
175 status
= status
- missing
;
177 mutex_unlock(&spidev
->buf_lock
);
182 /* Write-only message with current device setup */
184 spidev_write(struct file
*filp
, const char __user
*buf
,
185 size_t count
, loff_t
*f_pos
)
187 struct spidev_data
*spidev
;
189 unsigned long missing
;
191 /* chipselect only toggles at start or end of operation */
195 spidev
= filp
->private_data
;
197 mutex_lock(&spidev
->buf_lock
);
198 missing
= copy_from_user(spidev
->tx_buffer
, buf
, count
);
200 status
= spidev_sync_write(spidev
, count
);
203 mutex_unlock(&spidev
->buf_lock
);
208 static int spidev_message(struct spidev_data
*spidev
,
209 struct spi_ioc_transfer
*u_xfers
, unsigned n_xfers
)
211 struct spi_message msg
;
212 struct spi_transfer
*k_xfers
;
213 struct spi_transfer
*k_tmp
;
214 struct spi_ioc_transfer
*u_tmp
;
215 unsigned n
, total
, tx_total
, rx_total
;
217 int status
= -EFAULT
;
219 spi_message_init(&msg
);
220 k_xfers
= kcalloc(n_xfers
, sizeof(*k_tmp
), GFP_KERNEL
);
224 /* Construct spi_message, copying any tx data to bounce buffer.
225 * We walk the array of user-provided transfers, using each one
226 * to initialize a kernel version of the same transfer.
228 tx_buf
= spidev
->tx_buffer
;
229 rx_buf
= spidev
->rx_buffer
;
233 for (n
= n_xfers
, k_tmp
= k_xfers
, u_tmp
= u_xfers
;
235 n
--, k_tmp
++, u_tmp
++) {
236 k_tmp
->len
= u_tmp
->len
;
239 /* Since the function returns the total length of transfers
240 * on success, restrict the total to positive int values to
241 * avoid the return value looking like an error. Also check
242 * each transfer length to avoid arithmetic overflow.
244 if (total
> INT_MAX
|| k_tmp
->len
> INT_MAX
) {
250 /* this transfer needs space in RX bounce buffer */
251 rx_total
+= k_tmp
->len
;
252 if (rx_total
> bufsiz
) {
256 k_tmp
->rx_buf
= rx_buf
;
257 if (!access_ok(VERIFY_WRITE
, (u8 __user
*)
258 (uintptr_t) u_tmp
->rx_buf
,
261 rx_buf
+= k_tmp
->len
;
264 /* this transfer needs space in TX bounce buffer */
265 tx_total
+= k_tmp
->len
;
266 if (tx_total
> bufsiz
) {
270 k_tmp
->tx_buf
= tx_buf
;
271 if (copy_from_user(tx_buf
, (const u8 __user
*)
272 (uintptr_t) u_tmp
->tx_buf
,
275 tx_buf
+= k_tmp
->len
;
278 k_tmp
->cs_change
= !!u_tmp
->cs_change
;
279 k_tmp
->tx_nbits
= u_tmp
->tx_nbits
;
280 k_tmp
->rx_nbits
= u_tmp
->rx_nbits
;
281 k_tmp
->bits_per_word
= u_tmp
->bits_per_word
;
282 k_tmp
->delay_usecs
= u_tmp
->delay_usecs
;
283 k_tmp
->speed_hz
= u_tmp
->speed_hz
;
284 if (!k_tmp
->speed_hz
)
285 k_tmp
->speed_hz
= spidev
->speed_hz
;
287 dev_dbg(&spidev
->spi
->dev
,
288 " xfer len %u %s%s%s%dbits %u usec %uHz\n",
290 u_tmp
->rx_buf
? "rx " : "",
291 u_tmp
->tx_buf
? "tx " : "",
292 u_tmp
->cs_change
? "cs " : "",
293 u_tmp
->bits_per_word
? : spidev
->spi
->bits_per_word
,
295 u_tmp
->speed_hz
? : spidev
->spi
->max_speed_hz
);
297 spi_message_add_tail(k_tmp
, &msg
);
300 status
= spidev_sync(spidev
, &msg
);
304 /* copy any rx data out of bounce buffer */
305 rx_buf
= spidev
->rx_buffer
;
306 for (n
= n_xfers
, u_tmp
= u_xfers
; n
; n
--, u_tmp
++) {
308 if (__copy_to_user((u8 __user
*)
309 (uintptr_t) u_tmp
->rx_buf
, rx_buf
,
314 rx_buf
+= u_tmp
->len
;
324 static struct spi_ioc_transfer
*
325 spidev_get_ioc_message(unsigned int cmd
, struct spi_ioc_transfer __user
*u_ioc
,
328 struct spi_ioc_transfer
*ioc
;
331 /* Check type, command number and direction */
332 if (_IOC_TYPE(cmd
) != SPI_IOC_MAGIC
333 || _IOC_NR(cmd
) != _IOC_NR(SPI_IOC_MESSAGE(0))
334 || _IOC_DIR(cmd
) != _IOC_WRITE
)
335 return ERR_PTR(-ENOTTY
);
337 tmp
= _IOC_SIZE(cmd
);
338 if ((tmp
% sizeof(struct spi_ioc_transfer
)) != 0)
339 return ERR_PTR(-EINVAL
);
340 *n_ioc
= tmp
/ sizeof(struct spi_ioc_transfer
);
344 /* copy into scratch area */
345 ioc
= kmalloc(tmp
, GFP_KERNEL
);
347 return ERR_PTR(-ENOMEM
);
348 if (__copy_from_user(ioc
, u_ioc
, tmp
)) {
350 return ERR_PTR(-EFAULT
);
356 spidev_ioctl(struct file
*filp
, unsigned int cmd
, unsigned long arg
)
360 struct spidev_data
*spidev
;
361 struct spi_device
*spi
;
364 struct spi_ioc_transfer
*ioc
;
366 /* Check type and command number */
367 if (_IOC_TYPE(cmd
) != SPI_IOC_MAGIC
)
370 /* Check access direction once here; don't repeat below.
371 * IOC_DIR is from the user perspective, while access_ok is
372 * from the kernel perspective; so they look reversed.
374 if (_IOC_DIR(cmd
) & _IOC_READ
)
375 err
= !access_ok(VERIFY_WRITE
,
376 (void __user
*)arg
, _IOC_SIZE(cmd
));
377 if (err
== 0 && _IOC_DIR(cmd
) & _IOC_WRITE
)
378 err
= !access_ok(VERIFY_READ
,
379 (void __user
*)arg
, _IOC_SIZE(cmd
));
383 /* guard against device removal before, or while,
384 * we issue this ioctl.
386 spidev
= filp
->private_data
;
387 spin_lock_irq(&spidev
->spi_lock
);
388 spi
= spi_dev_get(spidev
->spi
);
389 spin_unlock_irq(&spidev
->spi_lock
);
394 /* use the buffer lock here for triple duty:
395 * - prevent I/O (from us) so calling spi_setup() is safe;
396 * - prevent concurrent SPI_IOC_WR_* from morphing
397 * data fields while SPI_IOC_RD_* reads them;
398 * - SPI_IOC_MESSAGE needs the buffer locked "normally".
400 mutex_lock(&spidev
->buf_lock
);
404 case SPI_IOC_RD_MODE
:
405 retval
= __put_user(spi
->mode
& SPI_MODE_MASK
,
408 case SPI_IOC_RD_MODE32
:
409 retval
= __put_user(spi
->mode
& SPI_MODE_MASK
,
410 (__u32 __user
*)arg
);
412 case SPI_IOC_RD_LSB_FIRST
:
413 retval
= __put_user((spi
->mode
& SPI_LSB_FIRST
) ? 1 : 0,
416 case SPI_IOC_RD_BITS_PER_WORD
:
417 retval
= __put_user(spi
->bits_per_word
, (__u8 __user
*)arg
);
419 case SPI_IOC_RD_MAX_SPEED_HZ
:
420 retval
= __put_user(spidev
->speed_hz
, (__u32 __user
*)arg
);
424 case SPI_IOC_WR_MODE
:
425 case SPI_IOC_WR_MODE32
:
426 if (cmd
== SPI_IOC_WR_MODE
)
427 retval
= __get_user(tmp
, (u8 __user
*)arg
);
429 retval
= __get_user(tmp
, (u32 __user
*)arg
);
431 u32 save
= spi
->mode
;
433 if (tmp
& ~SPI_MODE_MASK
) {
438 tmp
|= spi
->mode
& ~SPI_MODE_MASK
;
439 spi
->mode
= (u16
)tmp
;
440 retval
= spi_setup(spi
);
444 dev_dbg(&spi
->dev
, "spi mode %x\n", tmp
);
447 case SPI_IOC_WR_LSB_FIRST
:
448 retval
= __get_user(tmp
, (__u8 __user
*)arg
);
450 u32 save
= spi
->mode
;
453 spi
->mode
|= SPI_LSB_FIRST
;
455 spi
->mode
&= ~SPI_LSB_FIRST
;
456 retval
= spi_setup(spi
);
460 dev_dbg(&spi
->dev
, "%csb first\n",
464 case SPI_IOC_WR_BITS_PER_WORD
:
465 retval
= __get_user(tmp
, (__u8 __user
*)arg
);
467 u8 save
= spi
->bits_per_word
;
469 spi
->bits_per_word
= tmp
;
470 retval
= spi_setup(spi
);
472 spi
->bits_per_word
= save
;
474 dev_dbg(&spi
->dev
, "%d bits per word\n", tmp
);
477 case SPI_IOC_WR_MAX_SPEED_HZ
:
478 retval
= __get_user(tmp
, (__u32 __user
*)arg
);
480 u32 save
= spi
->max_speed_hz
;
482 spi
->max_speed_hz
= tmp
;
483 retval
= spi_setup(spi
);
485 spidev
->speed_hz
= tmp
;
487 dev_dbg(&spi
->dev
, "%d Hz (max)\n", tmp
);
488 spi
->max_speed_hz
= save
;
493 /* segmented and/or full-duplex I/O request */
494 /* Check message and copy into scratch area */
495 ioc
= spidev_get_ioc_message(cmd
,
496 (struct spi_ioc_transfer __user
*)arg
, &n_ioc
);
498 retval
= PTR_ERR(ioc
);
502 break; /* n_ioc is also 0 */
504 /* translate to spi_message, execute */
505 retval
= spidev_message(spidev
, ioc
, n_ioc
);
510 mutex_unlock(&spidev
->buf_lock
);
517 spidev_compat_ioc_message(struct file
*filp
, unsigned int cmd
,
520 struct spi_ioc_transfer __user
*u_ioc
;
522 struct spidev_data
*spidev
;
523 struct spi_device
*spi
;
525 struct spi_ioc_transfer
*ioc
;
527 u_ioc
= (struct spi_ioc_transfer __user
*) compat_ptr(arg
);
528 if (!access_ok(VERIFY_READ
, u_ioc
, _IOC_SIZE(cmd
)))
531 /* guard against device removal before, or while,
532 * we issue this ioctl.
534 spidev
= filp
->private_data
;
535 spin_lock_irq(&spidev
->spi_lock
);
536 spi
= spi_dev_get(spidev
->spi
);
537 spin_unlock_irq(&spidev
->spi_lock
);
542 /* SPI_IOC_MESSAGE needs the buffer locked "normally" */
543 mutex_lock(&spidev
->buf_lock
);
545 /* Check message and copy into scratch area */
546 ioc
= spidev_get_ioc_message(cmd
, u_ioc
, &n_ioc
);
548 retval
= PTR_ERR(ioc
);
552 goto done
; /* n_ioc is also 0 */
554 /* Convert buffer pointers */
555 for (n
= 0; n
< n_ioc
; n
++) {
556 ioc
[n
].rx_buf
= (uintptr_t) compat_ptr(ioc
[n
].rx_buf
);
557 ioc
[n
].tx_buf
= (uintptr_t) compat_ptr(ioc
[n
].tx_buf
);
560 /* translate to spi_message, execute */
561 retval
= spidev_message(spidev
, ioc
, n_ioc
);
565 mutex_unlock(&spidev
->buf_lock
);
571 spidev_compat_ioctl(struct file
*filp
, unsigned int cmd
, unsigned long arg
)
573 if (_IOC_TYPE(cmd
) == SPI_IOC_MAGIC
574 && _IOC_NR(cmd
) == _IOC_NR(SPI_IOC_MESSAGE(0))
575 && _IOC_DIR(cmd
) == _IOC_WRITE
)
576 return spidev_compat_ioc_message(filp
, cmd
, arg
);
578 return spidev_ioctl(filp
, cmd
, (unsigned long)compat_ptr(arg
));
581 #define spidev_compat_ioctl NULL
582 #endif /* CONFIG_COMPAT */
584 static int spidev_open(struct inode
*inode
, struct file
*filp
)
586 struct spidev_data
*spidev
;
589 mutex_lock(&device_list_lock
);
591 list_for_each_entry(spidev
, &device_list
, device_entry
) {
592 if (spidev
->devt
== inode
->i_rdev
) {
599 pr_debug("spidev: nothing for minor %d\n", iminor(inode
));
603 if (!spidev
->tx_buffer
) {
604 spidev
->tx_buffer
= kmalloc(bufsiz
, GFP_KERNEL
);
605 if (!spidev
->tx_buffer
) {
606 dev_dbg(&spidev
->spi
->dev
, "open/ENOMEM\n");
612 if (!spidev
->rx_buffer
) {
613 spidev
->rx_buffer
= kmalloc(bufsiz
, GFP_KERNEL
);
614 if (!spidev
->rx_buffer
) {
615 dev_dbg(&spidev
->spi
->dev
, "open/ENOMEM\n");
617 goto err_alloc_rx_buf
;
622 filp
->private_data
= spidev
;
623 nonseekable_open(inode
, filp
);
625 mutex_unlock(&device_list_lock
);
629 kfree(spidev
->tx_buffer
);
630 spidev
->tx_buffer
= NULL
;
632 mutex_unlock(&device_list_lock
);
636 static int spidev_release(struct inode
*inode
, struct file
*filp
)
638 struct spidev_data
*spidev
;
640 mutex_lock(&device_list_lock
);
641 spidev
= filp
->private_data
;
642 filp
->private_data
= NULL
;
646 if (!spidev
->users
) {
649 kfree(spidev
->tx_buffer
);
650 spidev
->tx_buffer
= NULL
;
652 kfree(spidev
->rx_buffer
);
653 spidev
->rx_buffer
= NULL
;
655 spin_lock_irq(&spidev
->spi_lock
);
657 spidev
->speed_hz
= spidev
->spi
->max_speed_hz
;
659 /* ... after we unbound from the underlying device? */
660 dofree
= (spidev
->spi
== NULL
);
661 spin_unlock_irq(&spidev
->spi_lock
);
666 mutex_unlock(&device_list_lock
);
671 static const struct file_operations spidev_fops
= {
672 .owner
= THIS_MODULE
,
673 /* REVISIT switch to aio primitives, so that userspace
674 * gets more complete API coverage. It'll simplify things
675 * too, except for the locking.
677 .write
= spidev_write
,
679 .unlocked_ioctl
= spidev_ioctl
,
680 .compat_ioctl
= spidev_compat_ioctl
,
682 .release
= spidev_release
,
686 /*-------------------------------------------------------------------------*/
688 /* The main reason to have this class is to make mdev/udev create the
689 * /dev/spidevB.C character device nodes exposing our userspace API.
690 * It also simplifies memory management.
693 static struct class *spidev_class
;
696 static const struct of_device_id spidev_dt_ids
[] = {
697 { .compatible
= "rohm,dh2228fv" },
698 { .compatible
= "lineartechnology,ltc2488" },
699 { .compatible
= "ge,achc" },
702 MODULE_DEVICE_TABLE(of
, spidev_dt_ids
);
707 /* Dummy SPI devices not to be used in production systems */
708 #define SPIDEV_ACPI_DUMMY 1
710 static const struct acpi_device_id spidev_acpi_ids
[] = {
712 * The ACPI SPT000* devices are only meant for development and
713 * testing. Systems used in production should have a proper ACPI
714 * description of the connected peripheral and they should also use
715 * a proper driver instead of poking directly to the SPI bus.
717 { "SPT0001", SPIDEV_ACPI_DUMMY
},
718 { "SPT0002", SPIDEV_ACPI_DUMMY
},
719 { "SPT0003", SPIDEV_ACPI_DUMMY
},
722 MODULE_DEVICE_TABLE(acpi
, spidev_acpi_ids
);
724 static void spidev_probe_acpi(struct spi_device
*spi
)
726 const struct acpi_device_id
*id
;
728 if (!has_acpi_companion(&spi
->dev
))
731 id
= acpi_match_device(spidev_acpi_ids
, &spi
->dev
);
735 if (id
->driver_data
== SPIDEV_ACPI_DUMMY
)
736 dev_warn(&spi
->dev
, "do not use this driver in production systems!\n");
739 static inline void spidev_probe_acpi(struct spi_device
*spi
) {}
742 /*-------------------------------------------------------------------------*/
744 static int spidev_probe(struct spi_device
*spi
)
746 struct spidev_data
*spidev
;
751 * spidev should never be referenced in DT without a specific
752 * compatible string, it is a Linux implementation thing
753 * rather than a description of the hardware.
755 if (spi
->dev
.of_node
&& !of_match_device(spidev_dt_ids
, &spi
->dev
)) {
756 dev_err(&spi
->dev
, "buggy DT: spidev listed directly in DT\n");
757 WARN_ON(spi
->dev
.of_node
&&
758 !of_match_device(spidev_dt_ids
, &spi
->dev
));
761 spidev_probe_acpi(spi
);
763 /* Allocate driver data */
764 spidev
= kzalloc(sizeof(*spidev
), GFP_KERNEL
);
768 /* Initialize the driver data */
770 spin_lock_init(&spidev
->spi_lock
);
771 mutex_init(&spidev
->buf_lock
);
773 INIT_LIST_HEAD(&spidev
->device_entry
);
775 /* If we can allocate a minor number, hook up this device.
776 * Reusing minors is fine so long as udev or mdev is working.
778 mutex_lock(&device_list_lock
);
779 minor
= find_first_zero_bit(minors
, N_SPI_MINORS
);
780 if (minor
< N_SPI_MINORS
) {
783 spidev
->devt
= MKDEV(SPIDEV_MAJOR
, minor
);
784 dev
= device_create(spidev_class
, &spi
->dev
, spidev
->devt
,
785 spidev
, "spidev%d.%d",
786 spi
->master
->bus_num
, spi
->chip_select
);
787 status
= PTR_ERR_OR_ZERO(dev
);
789 dev_dbg(&spi
->dev
, "no minor number available!\n");
793 set_bit(minor
, minors
);
794 list_add(&spidev
->device_entry
, &device_list
);
796 mutex_unlock(&device_list_lock
);
798 spidev
->speed_hz
= spi
->max_speed_hz
;
801 spi_set_drvdata(spi
, spidev
);
808 static int spidev_remove(struct spi_device
*spi
)
810 struct spidev_data
*spidev
= spi_get_drvdata(spi
);
812 /* make sure ops on existing fds can abort cleanly */
813 spin_lock_irq(&spidev
->spi_lock
);
815 spin_unlock_irq(&spidev
->spi_lock
);
817 /* prevent new opens */
818 mutex_lock(&device_list_lock
);
819 list_del(&spidev
->device_entry
);
820 device_destroy(spidev_class
, spidev
->devt
);
821 clear_bit(MINOR(spidev
->devt
), minors
);
822 if (spidev
->users
== 0)
824 mutex_unlock(&device_list_lock
);
829 static struct spi_driver spidev_spi_driver
= {
832 .of_match_table
= of_match_ptr(spidev_dt_ids
),
833 .acpi_match_table
= ACPI_PTR(spidev_acpi_ids
),
835 .probe
= spidev_probe
,
836 .remove
= spidev_remove
,
838 /* NOTE: suspend/resume methods are not necessary here.
839 * We don't do anything except pass the requests to/from
840 * the underlying controller. The refrigerator handles
841 * most issues; the controller driver handles the rest.
845 /*-------------------------------------------------------------------------*/
847 static int __init
spidev_init(void)
851 /* Claim our 256 reserved device numbers. Then register a class
852 * that will key udev/mdev to add/remove /dev nodes. Last, register
853 * the driver which manages those device numbers.
855 BUILD_BUG_ON(N_SPI_MINORS
> 256);
856 status
= register_chrdev(SPIDEV_MAJOR
, "spi", &spidev_fops
);
860 spidev_class
= class_create(THIS_MODULE
, "spidev");
861 if (IS_ERR(spidev_class
)) {
862 unregister_chrdev(SPIDEV_MAJOR
, spidev_spi_driver
.driver
.name
);
863 return PTR_ERR(spidev_class
);
866 status
= spi_register_driver(&spidev_spi_driver
);
868 class_destroy(spidev_class
);
869 unregister_chrdev(SPIDEV_MAJOR
, spidev_spi_driver
.driver
.name
);
873 module_init(spidev_init
);
875 static void __exit
spidev_exit(void)
877 spi_unregister_driver(&spidev_spi_driver
);
878 class_destroy(spidev_class
);
879 unregister_chrdev(SPIDEV_MAJOR
, spidev_spi_driver
.driver
.name
);
881 module_exit(spidev_exit
);
883 MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
884 MODULE_DESCRIPTION("User mode SPI device interface");
885 MODULE_LICENSE("GPL");
886 MODULE_ALIAS("spi:spidev");