Commit | Line | Data |
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814a8d50 AP |
1 | /* |
2 | * spidev.c -- simple synchronous userspace interface to SPI devices | |
3 | * | |
4 | * Copyright (C) 2006 SWAPP | |
5 | * Andrea Paterniani <a.paterniani@swapp-eng.it> | |
6 | * Copyright (C) 2007 David Brownell (simplification, cleanup) | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | */ | |
22 | ||
23 | #include <linux/init.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/ioctl.h> | |
26 | #include <linux/fs.h> | |
27 | #include <linux/device.h> | |
28 | #include <linux/list.h> | |
29 | #include <linux/errno.h> | |
30 | #include <linux/mutex.h> | |
31 | #include <linux/slab.h> | |
32 | ||
33 | #include <linux/spi/spi.h> | |
34 | #include <linux/spi/spidev.h> | |
35 | ||
36 | #include <asm/uaccess.h> | |
37 | ||
38 | ||
39 | /* | |
40 | * This supports acccess to SPI devices using normal userspace I/O calls. | |
41 | * Note that while traditional UNIX/POSIX I/O semantics are half duplex, | |
42 | * and often mask message boundaries, full SPI support requires full duplex | |
43 | * transfers. There are several kinds of of internal message boundaries to | |
44 | * handle chipselect management and other protocol options. | |
45 | * | |
46 | * SPI has a character major number assigned. We allocate minor numbers | |
47 | * dynamically using a bitmask. You must use hotplug tools, such as udev | |
48 | * (or mdev with busybox) to create and destroy the /dev/spidevB.C device | |
49 | * nodes, since there is no fixed association of minor numbers with any | |
50 | * particular SPI bus or device. | |
51 | */ | |
52 | #define SPIDEV_MAJOR 153 /* assigned */ | |
53 | #define N_SPI_MINORS 32 /* ... up to 256 */ | |
54 | ||
55 | static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG]; | |
56 | ||
57 | ||
6f166e38 AV |
58 | /* Bit masks for spi_device.mode management. Note that incorrect |
59 | * settings for CS_HIGH and 3WIRE can cause *lots* of trouble for other | |
60 | * devices on a shared bus: CS_HIGH, because this device will be | |
61 | * active when it shouldn't be; 3WIRE, because when active it won't | |
62 | * behave as it should. | |
63 | * | |
64 | * REVISIT should changing those two modes be privileged? | |
65 | */ | |
66 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | |
67 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP) | |
814a8d50 AP |
68 | |
69 | struct spidev_data { | |
70 | struct device dev; | |
25d5cb4b | 71 | spinlock_t spi_lock; |
814a8d50 AP |
72 | struct spi_device *spi; |
73 | struct list_head device_entry; | |
74 | ||
75 | struct mutex buf_lock; | |
76 | unsigned users; | |
77 | u8 *buffer; | |
78 | }; | |
79 | ||
80 | static LIST_HEAD(device_list); | |
81 | static DEFINE_MUTEX(device_list_lock); | |
82 | ||
83 | static unsigned bufsiz = 4096; | |
84 | module_param(bufsiz, uint, S_IRUGO); | |
85 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
86 | ||
87 | /*-------------------------------------------------------------------------*/ | |
88 | ||
25d5cb4b DB |
89 | /* |
90 | * We can't use the standard synchronous wrappers for file I/O; we | |
91 | * need to protect against async removal of the underlying spi_device. | |
92 | */ | |
93 | static void spidev_complete(void *arg) | |
94 | { | |
95 | complete(arg); | |
96 | } | |
97 | ||
98 | static ssize_t | |
99 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
100 | { | |
101 | DECLARE_COMPLETION_ONSTACK(done); | |
102 | int status; | |
103 | ||
104 | message->complete = spidev_complete; | |
105 | message->context = &done; | |
106 | ||
107 | spin_lock_irq(&spidev->spi_lock); | |
108 | if (spidev->spi == NULL) | |
109 | status = -ESHUTDOWN; | |
110 | else | |
111 | status = spi_async(spidev->spi, message); | |
112 | spin_unlock_irq(&spidev->spi_lock); | |
113 | ||
114 | if (status == 0) { | |
115 | wait_for_completion(&done); | |
116 | status = message->status; | |
117 | if (status == 0) | |
118 | status = message->actual_length; | |
119 | } | |
120 | return status; | |
121 | } | |
122 | ||
123 | static inline ssize_t | |
124 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
125 | { | |
126 | struct spi_transfer t = { | |
127 | .tx_buf = spidev->buffer, | |
128 | .len = len, | |
129 | }; | |
130 | struct spi_message m; | |
131 | ||
132 | spi_message_init(&m); | |
133 | spi_message_add_tail(&t, &m); | |
134 | return spidev_sync(spidev, &m); | |
135 | } | |
136 | ||
137 | static inline ssize_t | |
138 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
139 | { | |
140 | struct spi_transfer t = { | |
141 | .rx_buf = spidev->buffer, | |
142 | .len = len, | |
143 | }; | |
144 | struct spi_message m; | |
145 | ||
146 | spi_message_init(&m); | |
147 | spi_message_add_tail(&t, &m); | |
148 | return spidev_sync(spidev, &m); | |
149 | } | |
150 | ||
151 | /*-------------------------------------------------------------------------*/ | |
152 | ||
814a8d50 AP |
153 | /* Read-only message with current device setup */ |
154 | static ssize_t | |
155 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
156 | { | |
157 | struct spidev_data *spidev; | |
814a8d50 AP |
158 | ssize_t status = 0; |
159 | ||
160 | /* chipselect only toggles at start or end of operation */ | |
161 | if (count > bufsiz) | |
162 | return -EMSGSIZE; | |
163 | ||
164 | spidev = filp->private_data; | |
814a8d50 AP |
165 | |
166 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 167 | status = spidev_sync_read(spidev, count); |
814a8d50 AP |
168 | if (status == 0) { |
169 | unsigned long missing; | |
170 | ||
171 | missing = copy_to_user(buf, spidev->buffer, count); | |
172 | if (count && missing == count) | |
173 | status = -EFAULT; | |
174 | else | |
175 | status = count - missing; | |
176 | } | |
177 | mutex_unlock(&spidev->buf_lock); | |
178 | ||
179 | return status; | |
180 | } | |
181 | ||
182 | /* Write-only message with current device setup */ | |
183 | static ssize_t | |
184 | spidev_write(struct file *filp, const char __user *buf, | |
185 | size_t count, loff_t *f_pos) | |
186 | { | |
187 | struct spidev_data *spidev; | |
814a8d50 AP |
188 | ssize_t status = 0; |
189 | unsigned long missing; | |
190 | ||
191 | /* chipselect only toggles at start or end of operation */ | |
192 | if (count > bufsiz) | |
193 | return -EMSGSIZE; | |
194 | ||
195 | spidev = filp->private_data; | |
814a8d50 AP |
196 | |
197 | mutex_lock(&spidev->buf_lock); | |
198 | missing = copy_from_user(spidev->buffer, buf, count); | |
199 | if (missing == 0) { | |
25d5cb4b | 200 | status = spidev_sync_write(spidev, count); |
814a8d50 AP |
201 | if (status == 0) |
202 | status = count; | |
203 | } else | |
204 | status = -EFAULT; | |
205 | mutex_unlock(&spidev->buf_lock); | |
206 | ||
207 | return status; | |
208 | } | |
209 | ||
210 | static int spidev_message(struct spidev_data *spidev, | |
211 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
212 | { | |
213 | struct spi_message msg; | |
214 | struct spi_transfer *k_xfers; | |
215 | struct spi_transfer *k_tmp; | |
216 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 AP |
217 | unsigned n, total; |
218 | u8 *buf; | |
219 | int status = -EFAULT; | |
220 | ||
221 | spi_message_init(&msg); | |
222 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
223 | if (k_xfers == NULL) | |
224 | return -ENOMEM; | |
225 | ||
226 | /* Construct spi_message, copying any tx data to bounce buffer. | |
227 | * We walk the array of user-provided transfers, using each one | |
228 | * to initialize a kernel version of the same transfer. | |
229 | */ | |
230 | mutex_lock(&spidev->buf_lock); | |
231 | buf = spidev->buffer; | |
232 | total = 0; | |
233 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
234 | n; | |
235 | n--, k_tmp++, u_tmp++) { | |
236 | k_tmp->len = u_tmp->len; | |
237 | ||
da90fa8f DP |
238 | total += k_tmp->len; |
239 | if (total > bufsiz) { | |
240 | status = -EMSGSIZE; | |
241 | goto done; | |
242 | } | |
243 | ||
814a8d50 AP |
244 | if (u_tmp->rx_buf) { |
245 | k_tmp->rx_buf = buf; | |
96ddbf50 | 246 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 247 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 248 | u_tmp->len)) |
814a8d50 AP |
249 | goto done; |
250 | } | |
251 | if (u_tmp->tx_buf) { | |
252 | k_tmp->tx_buf = buf; | |
4917d927 | 253 | if (copy_from_user(buf, (const u8 __user *) |
142956af | 254 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
255 | u_tmp->len)) |
256 | goto done; | |
257 | } | |
814a8d50 AP |
258 | buf += k_tmp->len; |
259 | ||
260 | k_tmp->cs_change = !!u_tmp->cs_change; | |
261 | k_tmp->bits_per_word = u_tmp->bits_per_word; | |
262 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
263 | k_tmp->speed_hz = u_tmp->speed_hz; | |
264 | #ifdef VERBOSE | |
265 | dev_dbg(&spi->dev, | |
266 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", | |
267 | u_tmp->len, | |
268 | u_tmp->rx_buf ? "rx " : "", | |
269 | u_tmp->tx_buf ? "tx " : "", | |
270 | u_tmp->cs_change ? "cs " : "", | |
271 | u_tmp->bits_per_word ? : spi->bits_per_word, | |
272 | u_tmp->delay_usecs, | |
273 | u_tmp->speed_hz ? : spi->max_speed_hz); | |
274 | #endif | |
275 | spi_message_add_tail(k_tmp, &msg); | |
276 | } | |
277 | ||
25d5cb4b | 278 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
279 | if (status < 0) |
280 | goto done; | |
281 | ||
282 | /* copy any rx data out of bounce buffer */ | |
283 | buf = spidev->buffer; | |
284 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { | |
285 | if (u_tmp->rx_buf) { | |
4917d927 | 286 | if (__copy_to_user((u8 __user *) |
142956af | 287 | (uintptr_t) u_tmp->rx_buf, buf, |
814a8d50 AP |
288 | u_tmp->len)) { |
289 | status = -EFAULT; | |
290 | goto done; | |
291 | } | |
292 | } | |
293 | buf += u_tmp->len; | |
294 | } | |
295 | status = total; | |
296 | ||
297 | done: | |
298 | mutex_unlock(&spidev->buf_lock); | |
299 | kfree(k_xfers); | |
300 | return status; | |
301 | } | |
302 | ||
303 | static int | |
304 | spidev_ioctl(struct inode *inode, struct file *filp, | |
305 | unsigned int cmd, unsigned long arg) | |
306 | { | |
307 | int err = 0; | |
308 | int retval = 0; | |
309 | struct spidev_data *spidev; | |
310 | struct spi_device *spi; | |
311 | u32 tmp; | |
312 | unsigned n_ioc; | |
313 | struct spi_ioc_transfer *ioc; | |
314 | ||
315 | /* Check type and command number */ | |
316 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
317 | return -ENOTTY; | |
318 | ||
319 | /* Check access direction once here; don't repeat below. | |
320 | * IOC_DIR is from the user perspective, while access_ok is | |
321 | * from the kernel perspective; so they look reversed. | |
322 | */ | |
323 | if (_IOC_DIR(cmd) & _IOC_READ) | |
324 | err = !access_ok(VERIFY_WRITE, | |
325 | (void __user *)arg, _IOC_SIZE(cmd)); | |
326 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
327 | err = !access_ok(VERIFY_READ, | |
328 | (void __user *)arg, _IOC_SIZE(cmd)); | |
329 | if (err) | |
330 | return -EFAULT; | |
331 | ||
25d5cb4b DB |
332 | /* guard against device removal before, or while, |
333 | * we issue this ioctl. | |
334 | */ | |
814a8d50 | 335 | spidev = filp->private_data; |
25d5cb4b DB |
336 | spin_lock_irq(&spidev->spi_lock); |
337 | spi = spi_dev_get(spidev->spi); | |
338 | spin_unlock_irq(&spidev->spi_lock); | |
339 | ||
340 | if (spi == NULL) | |
341 | return -ESHUTDOWN; | |
814a8d50 AP |
342 | |
343 | switch (cmd) { | |
344 | /* read requests */ | |
345 | case SPI_IOC_RD_MODE: | |
346 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
347 | (__u8 __user *)arg); | |
348 | break; | |
349 | case SPI_IOC_RD_LSB_FIRST: | |
350 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
351 | (__u8 __user *)arg); | |
352 | break; | |
353 | case SPI_IOC_RD_BITS_PER_WORD: | |
354 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
355 | break; | |
356 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
357 | retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg); | |
358 | break; | |
359 | ||
360 | /* write requests */ | |
361 | case SPI_IOC_WR_MODE: | |
362 | retval = __get_user(tmp, (u8 __user *)arg); | |
363 | if (retval == 0) { | |
364 | u8 save = spi->mode; | |
365 | ||
366 | if (tmp & ~SPI_MODE_MASK) { | |
367 | retval = -EINVAL; | |
368 | break; | |
369 | } | |
370 | ||
371 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
372 | spi->mode = (u8)tmp; | |
373 | retval = spi_setup(spi); | |
374 | if (retval < 0) | |
375 | spi->mode = save; | |
376 | else | |
377 | dev_dbg(&spi->dev, "spi mode %02x\n", tmp); | |
378 | } | |
379 | break; | |
380 | case SPI_IOC_WR_LSB_FIRST: | |
381 | retval = __get_user(tmp, (__u8 __user *)arg); | |
382 | if (retval == 0) { | |
383 | u8 save = spi->mode; | |
384 | ||
385 | if (tmp) | |
386 | spi->mode |= SPI_LSB_FIRST; | |
387 | else | |
388 | spi->mode &= ~SPI_LSB_FIRST; | |
389 | retval = spi_setup(spi); | |
390 | if (retval < 0) | |
391 | spi->mode = save; | |
392 | else | |
393 | dev_dbg(&spi->dev, "%csb first\n", | |
394 | tmp ? 'l' : 'm'); | |
395 | } | |
396 | break; | |
397 | case SPI_IOC_WR_BITS_PER_WORD: | |
398 | retval = __get_user(tmp, (__u8 __user *)arg); | |
399 | if (retval == 0) { | |
400 | u8 save = spi->bits_per_word; | |
401 | ||
402 | spi->bits_per_word = tmp; | |
403 | retval = spi_setup(spi); | |
404 | if (retval < 0) | |
405 | spi->bits_per_word = save; | |
406 | else | |
407 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
408 | } | |
409 | break; | |
410 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
411 | retval = __get_user(tmp, (__u32 __user *)arg); | |
412 | if (retval == 0) { | |
413 | u32 save = spi->max_speed_hz; | |
414 | ||
415 | spi->max_speed_hz = tmp; | |
416 | retval = spi_setup(spi); | |
417 | if (retval < 0) | |
418 | spi->max_speed_hz = save; | |
419 | else | |
420 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
421 | } | |
422 | break; | |
423 | ||
424 | default: | |
425 | /* segmented and/or full-duplex I/O request */ | |
426 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
25d5cb4b DB |
427 | || _IOC_DIR(cmd) != _IOC_WRITE) { |
428 | retval = -ENOTTY; | |
429 | break; | |
430 | } | |
814a8d50 AP |
431 | |
432 | tmp = _IOC_SIZE(cmd); | |
433 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { | |
434 | retval = -EINVAL; | |
435 | break; | |
436 | } | |
437 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
438 | if (n_ioc == 0) | |
439 | break; | |
440 | ||
441 | /* copy into scratch area */ | |
442 | ioc = kmalloc(tmp, GFP_KERNEL); | |
443 | if (!ioc) { | |
444 | retval = -ENOMEM; | |
445 | break; | |
446 | } | |
447 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { | |
9bea3f29 | 448 | kfree(ioc); |
814a8d50 AP |
449 | retval = -EFAULT; |
450 | break; | |
451 | } | |
452 | ||
453 | /* translate to spi_message, execute */ | |
454 | retval = spidev_message(spidev, ioc, n_ioc); | |
455 | kfree(ioc); | |
456 | break; | |
457 | } | |
25d5cb4b | 458 | spi_dev_put(spi); |
814a8d50 AP |
459 | return retval; |
460 | } | |
461 | ||
462 | static int spidev_open(struct inode *inode, struct file *filp) | |
463 | { | |
464 | struct spidev_data *spidev; | |
465 | int status = -ENXIO; | |
466 | ||
467 | mutex_lock(&device_list_lock); | |
468 | ||
469 | list_for_each_entry(spidev, &device_list, device_entry) { | |
470 | if (spidev->dev.devt == inode->i_rdev) { | |
471 | status = 0; | |
472 | break; | |
473 | } | |
474 | } | |
475 | if (status == 0) { | |
476 | if (!spidev->buffer) { | |
477 | spidev->buffer = kmalloc(bufsiz, GFP_KERNEL); | |
478 | if (!spidev->buffer) { | |
479 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
480 | status = -ENOMEM; | |
481 | } | |
482 | } | |
483 | if (status == 0) { | |
484 | spidev->users++; | |
485 | filp->private_data = spidev; | |
486 | nonseekable_open(inode, filp); | |
487 | } | |
488 | } else | |
489 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
490 | ||
491 | mutex_unlock(&device_list_lock); | |
492 | return status; | |
493 | } | |
494 | ||
495 | static int spidev_release(struct inode *inode, struct file *filp) | |
496 | { | |
497 | struct spidev_data *spidev; | |
498 | int status = 0; | |
499 | ||
500 | mutex_lock(&device_list_lock); | |
501 | spidev = filp->private_data; | |
502 | filp->private_data = NULL; | |
503 | spidev->users--; | |
504 | if (!spidev->users) { | |
505 | kfree(spidev->buffer); | |
506 | spidev->buffer = NULL; | |
507 | } | |
508 | mutex_unlock(&device_list_lock); | |
509 | ||
510 | return status; | |
511 | } | |
512 | ||
513 | static struct file_operations spidev_fops = { | |
514 | .owner = THIS_MODULE, | |
515 | /* REVISIT switch to aio primitives, so that userspace | |
516 | * gets more complete API coverage. It'll simplify things | |
517 | * too, except for the locking. | |
518 | */ | |
519 | .write = spidev_write, | |
520 | .read = spidev_read, | |
521 | .ioctl = spidev_ioctl, | |
522 | .open = spidev_open, | |
523 | .release = spidev_release, | |
524 | }; | |
525 | ||
526 | /*-------------------------------------------------------------------------*/ | |
527 | ||
528 | /* The main reason to have this class is to make mdev/udev create the | |
529 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
530 | * It also simplifies memory management. | |
531 | */ | |
532 | ||
533 | static void spidev_classdev_release(struct device *dev) | |
534 | { | |
535 | struct spidev_data *spidev; | |
536 | ||
537 | spidev = container_of(dev, struct spidev_data, dev); | |
538 | kfree(spidev); | |
539 | } | |
540 | ||
541 | static struct class spidev_class = { | |
542 | .name = "spidev", | |
543 | .owner = THIS_MODULE, | |
544 | .dev_release = spidev_classdev_release, | |
545 | }; | |
546 | ||
547 | /*-------------------------------------------------------------------------*/ | |
548 | ||
549 | static int spidev_probe(struct spi_device *spi) | |
550 | { | |
551 | struct spidev_data *spidev; | |
552 | int status; | |
553 | unsigned long minor; | |
554 | ||
555 | /* Allocate driver data */ | |
556 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
557 | if (!spidev) | |
558 | return -ENOMEM; | |
559 | ||
560 | /* Initialize the driver data */ | |
561 | spidev->spi = spi; | |
25d5cb4b | 562 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
563 | mutex_init(&spidev->buf_lock); |
564 | ||
565 | INIT_LIST_HEAD(&spidev->device_entry); | |
566 | ||
567 | /* If we can allocate a minor number, hook up this device. | |
568 | * Reusing minors is fine so long as udev or mdev is working. | |
569 | */ | |
570 | mutex_lock(&device_list_lock); | |
0a4dd778 | 571 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 AP |
572 | if (minor < N_SPI_MINORS) { |
573 | spidev->dev.parent = &spi->dev; | |
574 | spidev->dev.class = &spidev_class; | |
575 | spidev->dev.devt = MKDEV(SPIDEV_MAJOR, minor); | |
576 | snprintf(spidev->dev.bus_id, sizeof spidev->dev.bus_id, | |
577 | "spidev%d.%d", | |
578 | spi->master->bus_num, spi->chip_select); | |
579 | status = device_register(&spidev->dev); | |
580 | } else { | |
581 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
582 | status = -ENODEV; | |
583 | } | |
584 | if (status == 0) { | |
585 | set_bit(minor, minors); | |
586 | dev_set_drvdata(&spi->dev, spidev); | |
587 | list_add(&spidev->device_entry, &device_list); | |
588 | } | |
589 | mutex_unlock(&device_list_lock); | |
590 | ||
591 | if (status != 0) | |
592 | kfree(spidev); | |
593 | ||
594 | return status; | |
595 | } | |
596 | ||
597 | static int spidev_remove(struct spi_device *spi) | |
598 | { | |
599 | struct spidev_data *spidev = dev_get_drvdata(&spi->dev); | |
600 | ||
25d5cb4b DB |
601 | /* make sure ops on existing fds can abort cleanly */ |
602 | spin_lock_irq(&spidev->spi_lock); | |
603 | spidev->spi = NULL; | |
604 | spin_unlock_irq(&spidev->spi_lock); | |
814a8d50 | 605 | |
25d5cb4b DB |
606 | /* prevent new opens */ |
607 | mutex_lock(&device_list_lock); | |
814a8d50 AP |
608 | list_del(&spidev->device_entry); |
609 | dev_set_drvdata(&spi->dev, NULL); | |
610 | clear_bit(MINOR(spidev->dev.devt), minors); | |
611 | device_unregister(&spidev->dev); | |
814a8d50 AP |
612 | mutex_unlock(&device_list_lock); |
613 | ||
614 | return 0; | |
615 | } | |
616 | ||
617 | static struct spi_driver spidev_spi = { | |
618 | .driver = { | |
619 | .name = "spidev", | |
620 | .owner = THIS_MODULE, | |
621 | }, | |
622 | .probe = spidev_probe, | |
623 | .remove = __devexit_p(spidev_remove), | |
624 | ||
625 | /* NOTE: suspend/resume methods are not necessary here. | |
626 | * We don't do anything except pass the requests to/from | |
627 | * the underlying controller. The refrigerator handles | |
628 | * most issues; the controller driver handles the rest. | |
629 | */ | |
630 | }; | |
631 | ||
632 | /*-------------------------------------------------------------------------*/ | |
633 | ||
634 | static int __init spidev_init(void) | |
635 | { | |
636 | int status; | |
637 | ||
638 | /* Claim our 256 reserved device numbers. Then register a class | |
639 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
640 | * the driver which manages those device numbers. | |
641 | */ | |
642 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
643 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
644 | if (status < 0) | |
645 | return status; | |
646 | ||
647 | status = class_register(&spidev_class); | |
648 | if (status < 0) { | |
649 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); | |
650 | return status; | |
651 | } | |
652 | ||
653 | status = spi_register_driver(&spidev_spi); | |
654 | if (status < 0) { | |
655 | class_unregister(&spidev_class); | |
656 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); | |
657 | } | |
658 | return status; | |
659 | } | |
660 | module_init(spidev_init); | |
661 | ||
662 | static void __exit spidev_exit(void) | |
663 | { | |
664 | spi_unregister_driver(&spidev_spi); | |
665 | class_unregister(&spidev_class); | |
666 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); | |
667 | } | |
668 | module_exit(spidev_exit); | |
669 | ||
670 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
671 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
672 | MODULE_LICENSE("GPL"); |