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Andrea Paterniani814a8d52007-05-08 00:32:15 -07001/*
Grant Likelyca632f52011-06-06 01:16:30 -06002 * Simple synchronous userspace interface to SPI devices
Andrea Paterniani814a8d52007-05-08 00:32:15 -07003 *
4 * Copyright (C) 2006 SWAPP
5 * Andrea Paterniani <a.paterniani@swapp-eng.it>
6 * Copyright (C) 2007 David Brownell (simplification, cleanup)
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#include <linux/init.h>
24#include <linux/module.h>
25#include <linux/ioctl.h>
26#include <linux/fs.h>
27#include <linux/device.h>
David Brownellb2c8dad2008-06-05 22:45:50 -070028#include <linux/err.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070029#include <linux/list.h>
30#include <linux/errno.h>
31#include <linux/mutex.h>
32#include <linux/slab.h>
Bernhard Walle7d48ec32011-02-03 09:37:18 +010033#include <linux/compat.h>
Maxime Ripard880cfd42012-10-31 11:30:08 +010034#include <linux/of.h>
35#include <linux/of_device.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070036
37#include <linux/spi/spi.h>
38#include <linux/spi/spidev.h>
39
Jingoo Han95c63cf2013-10-14 10:36:54 +090040#include <linux/uaccess.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070041
42
43/*
Uwe Kleine-Königb5950762010-11-01 15:38:34 -040044 * This supports access to SPI devices using normal userspace I/O calls.
Andrea Paterniani814a8d52007-05-08 00:32:15 -070045 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
46 * and often mask message boundaries, full SPI support requires full duplex
Thadeu Lima de Souza Cascardo137f1182009-10-22 17:34:29 -020047 * transfers. There are several kinds of internal message boundaries to
Andrea Paterniani814a8d52007-05-08 00:32:15 -070048 * handle chipselect management and other protocol options.
49 *
50 * SPI has a character major number assigned. We allocate minor numbers
51 * dynamically using a bitmask. You must use hotplug tools, such as udev
52 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
53 * nodes, since there is no fixed association of minor numbers with any
54 * particular SPI bus or device.
55 */
56#define SPIDEV_MAJOR 153 /* assigned */
57#define N_SPI_MINORS 32 /* ... up to 256 */
58
Thadeu Lima de Souza Cascardo8ae1c922009-12-14 14:20:23 -080059static DECLARE_BITMAP(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -070060
61
Anton Vorontsov6f166e32007-07-31 00:38:43 -070062/* Bit masks for spi_device.mode management. Note that incorrect
David Brownellb55f6272009-06-30 11:41:26 -070063 * settings for some settings can cause *lots* of trouble for other
64 * devices on a shared bus:
Anton Vorontsov6f166e32007-07-31 00:38:43 -070065 *
David Brownellb55f6272009-06-30 11:41:26 -070066 * - CS_HIGH ... this device will be active when it shouldn't be
67 * - 3WIRE ... when active, it won't behave as it should
68 * - NO_CS ... there will be no explicit message boundaries; this
69 * is completely incompatible with the shared bus model
70 * - READY ... transfers may proceed when they shouldn't.
71 *
72 * REVISIT should changing those flags be privileged?
Anton Vorontsov6f166e32007-07-31 00:38:43 -070073 */
74#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
David Brownellb55f6272009-06-30 11:41:26 -070075 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
76 | SPI_NO_CS | SPI_READY)
Andrea Paterniani814a8d52007-05-08 00:32:15 -070077
78struct spidev_data {
David Brownellb2c8dad2008-06-05 22:45:50 -070079 dev_t devt;
David Brownell25d5cb42008-05-23 13:05:03 -070080 spinlock_t spi_lock;
Andrea Paterniani814a8d52007-05-08 00:32:15 -070081 struct spi_device *spi;
82 struct list_head device_entry;
83
David Brownellb2c8dad2008-06-05 22:45:50 -070084 /* buffer is NULL unless this device is open (users > 0) */
Andrea Paterniani814a8d52007-05-08 00:32:15 -070085 struct mutex buf_lock;
86 unsigned users;
87 u8 *buffer;
88};
89
90static LIST_HEAD(device_list);
91static DEFINE_MUTEX(device_list_lock);
92
93static unsigned bufsiz = 4096;
94module_param(bufsiz, uint, S_IRUGO);
95MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
96
97/*-------------------------------------------------------------------------*/
98
David Brownell25d5cb42008-05-23 13:05:03 -070099/*
100 * We can't use the standard synchronous wrappers for file I/O; we
101 * need to protect against async removal of the underlying spi_device.
102 */
103static void spidev_complete(void *arg)
104{
105 complete(arg);
106}
107
108static ssize_t
109spidev_sync(struct spidev_data *spidev, struct spi_message *message)
110{
111 DECLARE_COMPLETION_ONSTACK(done);
112 int status;
113
114 message->complete = spidev_complete;
115 message->context = &done;
116
117 spin_lock_irq(&spidev->spi_lock);
118 if (spidev->spi == NULL)
119 status = -ESHUTDOWN;
120 else
121 status = spi_async(spidev->spi, message);
122 spin_unlock_irq(&spidev->spi_lock);
123
124 if (status == 0) {
125 wait_for_completion(&done);
126 status = message->status;
127 if (status == 0)
128 status = message->actual_length;
129 }
130 return status;
131}
132
133static inline ssize_t
134spidev_sync_write(struct spidev_data *spidev, size_t len)
135{
136 struct spi_transfer t = {
137 .tx_buf = spidev->buffer,
138 .len = len,
139 };
140 struct spi_message m;
141
142 spi_message_init(&m);
143 spi_message_add_tail(&t, &m);
144 return spidev_sync(spidev, &m);
145}
146
147static inline ssize_t
148spidev_sync_read(struct spidev_data *spidev, size_t len)
149{
150 struct spi_transfer t = {
151 .rx_buf = spidev->buffer,
152 .len = len,
153 };
154 struct spi_message m;
155
156 spi_message_init(&m);
157 spi_message_add_tail(&t, &m);
158 return spidev_sync(spidev, &m);
159}
160
161/*-------------------------------------------------------------------------*/
162
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700163/* Read-only message with current device setup */
164static ssize_t
165spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
166{
167 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700168 ssize_t status = 0;
169
170 /* chipselect only toggles at start or end of operation */
171 if (count > bufsiz)
172 return -EMSGSIZE;
173
174 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700175
176 mutex_lock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700177 status = spidev_sync_read(spidev, count);
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700178 if (status > 0) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700179 unsigned long missing;
180
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700181 missing = copy_to_user(buf, spidev->buffer, status);
182 if (missing == status)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700183 status = -EFAULT;
184 else
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700185 status = status - missing;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700186 }
187 mutex_unlock(&spidev->buf_lock);
188
189 return status;
190}
191
192/* Write-only message with current device setup */
193static ssize_t
194spidev_write(struct file *filp, const char __user *buf,
195 size_t count, loff_t *f_pos)
196{
197 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700198 ssize_t status = 0;
199 unsigned long missing;
200
201 /* chipselect only toggles at start or end of operation */
202 if (count > bufsiz)
203 return -EMSGSIZE;
204
205 spidev = filp->private_data;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700206
207 mutex_lock(&spidev->buf_lock);
208 missing = copy_from_user(spidev->buffer, buf, count);
Jingoo Han95c63cf2013-10-14 10:36:54 +0900209 if (missing == 0)
David Brownell25d5cb42008-05-23 13:05:03 -0700210 status = spidev_sync_write(spidev, count);
Jingoo Han95c63cf2013-10-14 10:36:54 +0900211 else
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700212 status = -EFAULT;
213 mutex_unlock(&spidev->buf_lock);
214
215 return status;
216}
217
218static int spidev_message(struct spidev_data *spidev,
219 struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
220{
221 struct spi_message msg;
222 struct spi_transfer *k_xfers;
223 struct spi_transfer *k_tmp;
224 struct spi_ioc_transfer *u_tmp;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700225 unsigned n, total;
226 u8 *buf;
227 int status = -EFAULT;
228
229 spi_message_init(&msg);
230 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
231 if (k_xfers == NULL)
232 return -ENOMEM;
233
234 /* Construct spi_message, copying any tx data to bounce buffer.
235 * We walk the array of user-provided transfers, using each one
236 * to initialize a kernel version of the same transfer.
237 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700238 buf = spidev->buffer;
239 total = 0;
240 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
241 n;
242 n--, k_tmp++, u_tmp++) {
243 k_tmp->len = u_tmp->len;
244
Domen Puncerda90fa82007-05-23 13:57:39 -0700245 total += k_tmp->len;
246 if (total > bufsiz) {
247 status = -EMSGSIZE;
248 goto done;
249 }
250
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700251 if (u_tmp->rx_buf) {
252 k_tmp->rx_buf = buf;
David Brownell96ddbf52007-08-10 13:01:09 -0700253 if (!access_ok(VERIFY_WRITE, (u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000254 (uintptr_t) u_tmp->rx_buf,
David Brownell96ddbf52007-08-10 13:01:09 -0700255 u_tmp->len))
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700256 goto done;
257 }
258 if (u_tmp->tx_buf) {
259 k_tmp->tx_buf = buf;
David Brownell4917d922007-07-17 04:04:04 -0700260 if (copy_from_user(buf, (const u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000261 (uintptr_t) u_tmp->tx_buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700262 u_tmp->len))
263 goto done;
264 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700265 buf += k_tmp->len;
266
267 k_tmp->cs_change = !!u_tmp->cs_change;
268 k_tmp->bits_per_word = u_tmp->bits_per_word;
269 k_tmp->delay_usecs = u_tmp->delay_usecs;
270 k_tmp->speed_hz = u_tmp->speed_hz;
271#ifdef VERBOSE
Florian Fainelli41df70d2009-12-07 14:28:43 +0000272 dev_dbg(&spidev->spi->dev,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700273 " xfer len %zd %s%s%s%dbits %u usec %uHz\n",
274 u_tmp->len,
275 u_tmp->rx_buf ? "rx " : "",
276 u_tmp->tx_buf ? "tx " : "",
277 u_tmp->cs_change ? "cs " : "",
Florian Fainelli41df70d2009-12-07 14:28:43 +0000278 u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700279 u_tmp->delay_usecs,
Florian Fainelli41df70d2009-12-07 14:28:43 +0000280 u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700281#endif
282 spi_message_add_tail(k_tmp, &msg);
283 }
284
David Brownell25d5cb42008-05-23 13:05:03 -0700285 status = spidev_sync(spidev, &msg);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700286 if (status < 0)
287 goto done;
288
289 /* copy any rx data out of bounce buffer */
290 buf = spidev->buffer;
291 for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
292 if (u_tmp->rx_buf) {
David Brownell4917d922007-07-17 04:04:04 -0700293 if (__copy_to_user((u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000294 (uintptr_t) u_tmp->rx_buf, buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700295 u_tmp->len)) {
296 status = -EFAULT;
297 goto done;
298 }
299 }
300 buf += u_tmp->len;
301 }
302 status = total;
303
304done:
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700305 kfree(k_xfers);
306 return status;
307}
308
Alan Cox4ef754b2008-07-23 21:29:55 -0700309static long
310spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700311{
312 int err = 0;
313 int retval = 0;
314 struct spidev_data *spidev;
315 struct spi_device *spi;
316 u32 tmp;
317 unsigned n_ioc;
318 struct spi_ioc_transfer *ioc;
319
320 /* Check type and command number */
321 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
322 return -ENOTTY;
323
324 /* Check access direction once here; don't repeat below.
325 * IOC_DIR is from the user perspective, while access_ok is
326 * from the kernel perspective; so they look reversed.
327 */
328 if (_IOC_DIR(cmd) & _IOC_READ)
329 err = !access_ok(VERIFY_WRITE,
330 (void __user *)arg, _IOC_SIZE(cmd));
331 if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
332 err = !access_ok(VERIFY_READ,
333 (void __user *)arg, _IOC_SIZE(cmd));
334 if (err)
335 return -EFAULT;
336
David Brownell25d5cb42008-05-23 13:05:03 -0700337 /* guard against device removal before, or while,
338 * we issue this ioctl.
339 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700340 spidev = filp->private_data;
David Brownell25d5cb42008-05-23 13:05:03 -0700341 spin_lock_irq(&spidev->spi_lock);
342 spi = spi_dev_get(spidev->spi);
343 spin_unlock_irq(&spidev->spi_lock);
344
345 if (spi == NULL)
346 return -ESHUTDOWN;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700347
Alan Cox4ef754b2008-07-23 21:29:55 -0700348 /* use the buffer lock here for triple duty:
349 * - prevent I/O (from us) so calling spi_setup() is safe;
350 * - prevent concurrent SPI_IOC_WR_* from morphing
351 * data fields while SPI_IOC_RD_* reads them;
352 * - SPI_IOC_MESSAGE needs the buffer locked "normally".
353 */
354 mutex_lock(&spidev->buf_lock);
355
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700356 switch (cmd) {
357 /* read requests */
358 case SPI_IOC_RD_MODE:
359 retval = __put_user(spi->mode & SPI_MODE_MASK,
360 (__u8 __user *)arg);
361 break;
362 case SPI_IOC_RD_LSB_FIRST:
363 retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
364 (__u8 __user *)arg);
365 break;
366 case SPI_IOC_RD_BITS_PER_WORD:
367 retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
368 break;
369 case SPI_IOC_RD_MAX_SPEED_HZ:
370 retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg);
371 break;
372
373 /* write requests */
374 case SPI_IOC_WR_MODE:
375 retval = __get_user(tmp, (u8 __user *)arg);
376 if (retval == 0) {
377 u8 save = spi->mode;
378
379 if (tmp & ~SPI_MODE_MASK) {
380 retval = -EINVAL;
381 break;
382 }
383
384 tmp |= spi->mode & ~SPI_MODE_MASK;
385 spi->mode = (u8)tmp;
386 retval = spi_setup(spi);
387 if (retval < 0)
388 spi->mode = save;
389 else
390 dev_dbg(&spi->dev, "spi mode %02x\n", tmp);
391 }
392 break;
393 case SPI_IOC_WR_LSB_FIRST:
394 retval = __get_user(tmp, (__u8 __user *)arg);
395 if (retval == 0) {
396 u8 save = spi->mode;
397
398 if (tmp)
399 spi->mode |= SPI_LSB_FIRST;
400 else
401 spi->mode &= ~SPI_LSB_FIRST;
402 retval = spi_setup(spi);
403 if (retval < 0)
404 spi->mode = save;
405 else
406 dev_dbg(&spi->dev, "%csb first\n",
407 tmp ? 'l' : 'm');
408 }
409 break;
410 case SPI_IOC_WR_BITS_PER_WORD:
411 retval = __get_user(tmp, (__u8 __user *)arg);
412 if (retval == 0) {
413 u8 save = spi->bits_per_word;
414
415 spi->bits_per_word = tmp;
416 retval = spi_setup(spi);
417 if (retval < 0)
418 spi->bits_per_word = save;
419 else
420 dev_dbg(&spi->dev, "%d bits per word\n", tmp);
421 }
422 break;
423 case SPI_IOC_WR_MAX_SPEED_HZ:
424 retval = __get_user(tmp, (__u32 __user *)arg);
425 if (retval == 0) {
426 u32 save = spi->max_speed_hz;
427
428 spi->max_speed_hz = tmp;
429 retval = spi_setup(spi);
430 if (retval < 0)
431 spi->max_speed_hz = save;
432 else
433 dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
434 }
435 break;
436
437 default:
438 /* segmented and/or full-duplex I/O request */
439 if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
David Brownell25d5cb42008-05-23 13:05:03 -0700440 || _IOC_DIR(cmd) != _IOC_WRITE) {
441 retval = -ENOTTY;
442 break;
443 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700444
445 tmp = _IOC_SIZE(cmd);
446 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) {
447 retval = -EINVAL;
448 break;
449 }
450 n_ioc = tmp / sizeof(struct spi_ioc_transfer);
451 if (n_ioc == 0)
452 break;
453
454 /* copy into scratch area */
455 ioc = kmalloc(tmp, GFP_KERNEL);
456 if (!ioc) {
457 retval = -ENOMEM;
458 break;
459 }
460 if (__copy_from_user(ioc, (void __user *)arg, tmp)) {
Florin Malita9bea3f22007-05-23 13:57:45 -0700461 kfree(ioc);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700462 retval = -EFAULT;
463 break;
464 }
465
466 /* translate to spi_message, execute */
467 retval = spidev_message(spidev, ioc, n_ioc);
468 kfree(ioc);
469 break;
470 }
Alan Cox4ef754b2008-07-23 21:29:55 -0700471
472 mutex_unlock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700473 spi_dev_put(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700474 return retval;
475}
476
Bernhard Walle7d48ec32011-02-03 09:37:18 +0100477#ifdef CONFIG_COMPAT
478static long
479spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
480{
481 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
482}
483#else
484#define spidev_compat_ioctl NULL
485#endif /* CONFIG_COMPAT */
486
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700487static int spidev_open(struct inode *inode, struct file *filp)
488{
489 struct spidev_data *spidev;
490 int status = -ENXIO;
491
492 mutex_lock(&device_list_lock);
493
494 list_for_each_entry(spidev, &device_list, device_entry) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700495 if (spidev->devt == inode->i_rdev) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700496 status = 0;
497 break;
498 }
499 }
500 if (status == 0) {
501 if (!spidev->buffer) {
502 spidev->buffer = kmalloc(bufsiz, GFP_KERNEL);
503 if (!spidev->buffer) {
504 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
505 status = -ENOMEM;
506 }
507 }
508 if (status == 0) {
509 spidev->users++;
510 filp->private_data = spidev;
511 nonseekable_open(inode, filp);
512 }
513 } else
514 pr_debug("spidev: nothing for minor %d\n", iminor(inode));
515
516 mutex_unlock(&device_list_lock);
517 return status;
518}
519
520static int spidev_release(struct inode *inode, struct file *filp)
521{
522 struct spidev_data *spidev;
523 int status = 0;
524
525 mutex_lock(&device_list_lock);
526 spidev = filp->private_data;
527 filp->private_data = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700528
529 /* last close? */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700530 spidev->users--;
531 if (!spidev->users) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700532 int dofree;
533
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700534 kfree(spidev->buffer);
535 spidev->buffer = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700536
537 /* ... after we unbound from the underlying device? */
538 spin_lock_irq(&spidev->spi_lock);
539 dofree = (spidev->spi == NULL);
540 spin_unlock_irq(&spidev->spi_lock);
541
542 if (dofree)
543 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700544 }
545 mutex_unlock(&device_list_lock);
546
547 return status;
548}
549
Alexey Dobriyan828c0952009-10-01 15:43:56 -0700550static const struct file_operations spidev_fops = {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700551 .owner = THIS_MODULE,
552 /* REVISIT switch to aio primitives, so that userspace
553 * gets more complete API coverage. It'll simplify things
554 * too, except for the locking.
555 */
556 .write = spidev_write,
557 .read = spidev_read,
Alan Cox4ef754b2008-07-23 21:29:55 -0700558 .unlocked_ioctl = spidev_ioctl,
Bernhard Walle7d48ec32011-02-03 09:37:18 +0100559 .compat_ioctl = spidev_compat_ioctl,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700560 .open = spidev_open,
561 .release = spidev_release,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200562 .llseek = no_llseek,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700563};
564
565/*-------------------------------------------------------------------------*/
566
567/* The main reason to have this class is to make mdev/udev create the
568 * /dev/spidevB.C character device nodes exposing our userspace API.
569 * It also simplifies memory management.
570 */
571
David Brownellb2c8dad2008-06-05 22:45:50 -0700572static struct class *spidev_class;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700573
574/*-------------------------------------------------------------------------*/
575
Grant Likelyfd4a3192012-12-07 16:57:14 +0000576static int spidev_probe(struct spi_device *spi)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700577{
578 struct spidev_data *spidev;
579 int status;
580 unsigned long minor;
581
582 /* Allocate driver data */
583 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
584 if (!spidev)
585 return -ENOMEM;
586
587 /* Initialize the driver data */
588 spidev->spi = spi;
David Brownell25d5cb42008-05-23 13:05:03 -0700589 spin_lock_init(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700590 mutex_init(&spidev->buf_lock);
591
592 INIT_LIST_HEAD(&spidev->device_entry);
593
594 /* If we can allocate a minor number, hook up this device.
595 * Reusing minors is fine so long as udev or mdev is working.
596 */
597 mutex_lock(&device_list_lock);
Domen Puncer0a4dd772007-05-15 23:57:05 -0700598 minor = find_first_zero_bit(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700599 if (minor < N_SPI_MINORS) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700600 struct device *dev;
601
602 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
Greg Kroah-Hartmana9b12612008-07-21 20:03:34 -0700603 dev = device_create(spidev_class, &spi->dev, spidev->devt,
604 spidev, "spidev%d.%d",
605 spi->master->bus_num, spi->chip_select);
Rusty Russell8c6ffba2013-07-15 11:20:32 +0930606 status = PTR_ERR_OR_ZERO(dev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700607 } else {
608 dev_dbg(&spi->dev, "no minor number available!\n");
609 status = -ENODEV;
610 }
611 if (status == 0) {
612 set_bit(minor, minors);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700613 list_add(&spidev->device_entry, &device_list);
614 }
615 mutex_unlock(&device_list_lock);
616
Wolfgang Ockeraaacf4b2008-12-01 13:13:52 -0800617 if (status == 0)
618 spi_set_drvdata(spi, spidev);
619 else
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700620 kfree(spidev);
621
622 return status;
623}
624
Grant Likelyfd4a3192012-12-07 16:57:14 +0000625static int spidev_remove(struct spi_device *spi)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700626{
David Brownellb2c8dad2008-06-05 22:45:50 -0700627 struct spidev_data *spidev = spi_get_drvdata(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700628
David Brownell25d5cb42008-05-23 13:05:03 -0700629 /* make sure ops on existing fds can abort cleanly */
630 spin_lock_irq(&spidev->spi_lock);
631 spidev->spi = NULL;
632 spin_unlock_irq(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700633
David Brownell25d5cb42008-05-23 13:05:03 -0700634 /* prevent new opens */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700635 mutex_lock(&device_list_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700636 list_del(&spidev->device_entry);
David Brownellb2c8dad2008-06-05 22:45:50 -0700637 device_destroy(spidev_class, spidev->devt);
638 clear_bit(MINOR(spidev->devt), minors);
639 if (spidev->users == 0)
640 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700641 mutex_unlock(&device_list_lock);
642
643 return 0;
644}
645
Maxime Ripard880cfd42012-10-31 11:30:08 +0100646static const struct of_device_id spidev_dt_ids[] = {
Maxime Ripard8fad8052012-10-31 11:30:09 +0100647 { .compatible = "rohm,dh2228fv" },
Maxime Ripard880cfd42012-10-31 11:30:08 +0100648 {},
649};
650
651MODULE_DEVICE_TABLE(of, spidev_dt_ids);
652
Mike Frysingerdb389b62009-12-14 14:20:22 -0800653static struct spi_driver spidev_spi_driver = {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700654 .driver = {
655 .name = "spidev",
656 .owner = THIS_MODULE,
Maxime Ripard880cfd42012-10-31 11:30:08 +0100657 .of_match_table = of_match_ptr(spidev_dt_ids),
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700658 },
659 .probe = spidev_probe,
Grant Likelyfd4a3192012-12-07 16:57:14 +0000660 .remove = spidev_remove,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700661
662 /* NOTE: suspend/resume methods are not necessary here.
663 * We don't do anything except pass the requests to/from
664 * the underlying controller. The refrigerator handles
665 * most issues; the controller driver handles the rest.
666 */
667};
668
669/*-------------------------------------------------------------------------*/
670
671static int __init spidev_init(void)
672{
673 int status;
674
675 /* Claim our 256 reserved device numbers. Then register a class
676 * that will key udev/mdev to add/remove /dev nodes. Last, register
677 * the driver which manages those device numbers.
678 */
679 BUILD_BUG_ON(N_SPI_MINORS > 256);
680 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
681 if (status < 0)
682 return status;
683
David Brownellb2c8dad2008-06-05 22:45:50 -0700684 spidev_class = class_create(THIS_MODULE, "spidev");
685 if (IS_ERR(spidev_class)) {
Mike Frysingerdb389b62009-12-14 14:20:22 -0800686 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
David Brownellb2c8dad2008-06-05 22:45:50 -0700687 return PTR_ERR(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700688 }
689
Mike Frysingerdb389b62009-12-14 14:20:22 -0800690 status = spi_register_driver(&spidev_spi_driver);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700691 if (status < 0) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700692 class_destroy(spidev_class);
Mike Frysingerdb389b62009-12-14 14:20:22 -0800693 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700694 }
695 return status;
696}
697module_init(spidev_init);
698
699static void __exit spidev_exit(void)
700{
Mike Frysingerdb389b62009-12-14 14:20:22 -0800701 spi_unregister_driver(&spidev_spi_driver);
David Brownellb2c8dad2008-06-05 22:45:50 -0700702 class_destroy(spidev_class);
Mike Frysingerdb389b62009-12-14 14:20:22 -0800703 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700704}
705module_exit(spidev_exit);
706
707MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
708MODULE_DESCRIPTION("User mode SPI device interface");
709MODULE_LICENSE("GPL");
Anton Vorontsove0626e32009-09-22 16:46:08 -0700710MODULE_ALIAS("spi:spidev");