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> | |
b2c8dadd | 28 | #include <linux/err.h> |
814a8d50 AP |
29 | #include <linux/list.h> |
30 | #include <linux/errno.h> | |
31 | #include <linux/mutex.h> | |
32 | #include <linux/slab.h> | |
33 | ||
34 | #include <linux/spi/spi.h> | |
35 | #include <linux/spi/spidev.h> | |
36 | ||
37 | #include <asm/uaccess.h> | |
38 | ||
39 | ||
40 | /* | |
41 | * This supports acccess 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 of internal message boundaries to | |
45 | * handle chipselect management and other protocol options. | |
46 | * | |
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. | |
52 | */ | |
53 | #define SPIDEV_MAJOR 153 /* assigned */ | |
54 | #define N_SPI_MINORS 32 /* ... up to 256 */ | |
55 | ||
56 | static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG]; | |
57 | ||
58 | ||
6f166e38 AV |
59 | /* Bit masks for spi_device.mode management. Note that incorrect |
60 | * settings for CS_HIGH and 3WIRE can cause *lots* of trouble for other | |
61 | * devices on a shared bus: CS_HIGH, because this device will be | |
62 | * active when it shouldn't be; 3WIRE, because when active it won't | |
63 | * behave as it should. | |
64 | * | |
65 | * REVISIT should changing those two modes be privileged? | |
66 | */ | |
67 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | |
68 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP) | |
814a8d50 AP |
69 | |
70 | struct spidev_data { | |
b2c8dadd | 71 | dev_t devt; |
25d5cb4b | 72 | spinlock_t spi_lock; |
814a8d50 AP |
73 | struct spi_device *spi; |
74 | struct list_head device_entry; | |
75 | ||
b2c8dadd | 76 | /* buffer is NULL unless this device is open (users > 0) */ |
814a8d50 AP |
77 | struct mutex buf_lock; |
78 | unsigned users; | |
79 | u8 *buffer; | |
80 | }; | |
81 | ||
82 | static LIST_HEAD(device_list); | |
83 | static DEFINE_MUTEX(device_list_lock); | |
84 | ||
85 | static unsigned bufsiz = 4096; | |
86 | module_param(bufsiz, uint, S_IRUGO); | |
87 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
88 | ||
89 | /*-------------------------------------------------------------------------*/ | |
90 | ||
25d5cb4b DB |
91 | /* |
92 | * We can't use the standard synchronous wrappers for file I/O; we | |
93 | * need to protect against async removal of the underlying spi_device. | |
94 | */ | |
95 | static void spidev_complete(void *arg) | |
96 | { | |
97 | complete(arg); | |
98 | } | |
99 | ||
100 | static ssize_t | |
101 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
102 | { | |
103 | DECLARE_COMPLETION_ONSTACK(done); | |
104 | int status; | |
105 | ||
106 | message->complete = spidev_complete; | |
107 | message->context = &done; | |
108 | ||
109 | spin_lock_irq(&spidev->spi_lock); | |
110 | if (spidev->spi == NULL) | |
111 | status = -ESHUTDOWN; | |
112 | else | |
113 | status = spi_async(spidev->spi, message); | |
114 | spin_unlock_irq(&spidev->spi_lock); | |
115 | ||
116 | if (status == 0) { | |
117 | wait_for_completion(&done); | |
118 | status = message->status; | |
119 | if (status == 0) | |
120 | status = message->actual_length; | |
121 | } | |
122 | return status; | |
123 | } | |
124 | ||
125 | static inline ssize_t | |
126 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
127 | { | |
128 | struct spi_transfer t = { | |
129 | .tx_buf = spidev->buffer, | |
130 | .len = len, | |
131 | }; | |
132 | struct spi_message m; | |
133 | ||
134 | spi_message_init(&m); | |
135 | spi_message_add_tail(&t, &m); | |
136 | return spidev_sync(spidev, &m); | |
137 | } | |
138 | ||
139 | static inline ssize_t | |
140 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
141 | { | |
142 | struct spi_transfer t = { | |
143 | .rx_buf = spidev->buffer, | |
144 | .len = len, | |
145 | }; | |
146 | struct spi_message m; | |
147 | ||
148 | spi_message_init(&m); | |
149 | spi_message_add_tail(&t, &m); | |
150 | return spidev_sync(spidev, &m); | |
151 | } | |
152 | ||
153 | /*-------------------------------------------------------------------------*/ | |
154 | ||
814a8d50 AP |
155 | /* Read-only message with current device setup */ |
156 | static ssize_t | |
157 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
158 | { | |
159 | struct spidev_data *spidev; | |
814a8d50 AP |
160 | ssize_t status = 0; |
161 | ||
162 | /* chipselect only toggles at start or end of operation */ | |
163 | if (count > bufsiz) | |
164 | return -EMSGSIZE; | |
165 | ||
166 | spidev = filp->private_data; | |
814a8d50 AP |
167 | |
168 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 169 | status = spidev_sync_read(spidev, count); |
814a8d50 AP |
170 | if (status == 0) { |
171 | unsigned long missing; | |
172 | ||
173 | missing = copy_to_user(buf, spidev->buffer, count); | |
174 | if (count && missing == count) | |
175 | status = -EFAULT; | |
176 | else | |
177 | status = count - missing; | |
178 | } | |
179 | mutex_unlock(&spidev->buf_lock); | |
180 | ||
181 | return status; | |
182 | } | |
183 | ||
184 | /* Write-only message with current device setup */ | |
185 | static ssize_t | |
186 | spidev_write(struct file *filp, const char __user *buf, | |
187 | size_t count, loff_t *f_pos) | |
188 | { | |
189 | struct spidev_data *spidev; | |
814a8d50 AP |
190 | ssize_t status = 0; |
191 | unsigned long missing; | |
192 | ||
193 | /* chipselect only toggles at start or end of operation */ | |
194 | if (count > bufsiz) | |
195 | return -EMSGSIZE; | |
196 | ||
197 | spidev = filp->private_data; | |
814a8d50 AP |
198 | |
199 | mutex_lock(&spidev->buf_lock); | |
200 | missing = copy_from_user(spidev->buffer, buf, count); | |
201 | if (missing == 0) { | |
25d5cb4b | 202 | status = spidev_sync_write(spidev, count); |
814a8d50 AP |
203 | if (status == 0) |
204 | status = count; | |
205 | } else | |
206 | status = -EFAULT; | |
207 | mutex_unlock(&spidev->buf_lock); | |
208 | ||
209 | return status; | |
210 | } | |
211 | ||
212 | static int spidev_message(struct spidev_data *spidev, | |
213 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
214 | { | |
215 | struct spi_message msg; | |
216 | struct spi_transfer *k_xfers; | |
217 | struct spi_transfer *k_tmp; | |
218 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 AP |
219 | unsigned n, total; |
220 | u8 *buf; | |
221 | int status = -EFAULT; | |
222 | ||
223 | spi_message_init(&msg); | |
224 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
225 | if (k_xfers == NULL) | |
226 | return -ENOMEM; | |
227 | ||
228 | /* Construct spi_message, copying any tx data to bounce buffer. | |
229 | * We walk the array of user-provided transfers, using each one | |
230 | * to initialize a kernel version of the same transfer. | |
231 | */ | |
232 | mutex_lock(&spidev->buf_lock); | |
233 | buf = spidev->buffer; | |
234 | total = 0; | |
235 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
236 | n; | |
237 | n--, k_tmp++, u_tmp++) { | |
238 | k_tmp->len = u_tmp->len; | |
239 | ||
da90fa8f DP |
240 | total += k_tmp->len; |
241 | if (total > bufsiz) { | |
242 | status = -EMSGSIZE; | |
243 | goto done; | |
244 | } | |
245 | ||
814a8d50 AP |
246 | if (u_tmp->rx_buf) { |
247 | k_tmp->rx_buf = buf; | |
96ddbf50 | 248 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 249 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 250 | u_tmp->len)) |
814a8d50 AP |
251 | goto done; |
252 | } | |
253 | if (u_tmp->tx_buf) { | |
254 | k_tmp->tx_buf = buf; | |
4917d927 | 255 | if (copy_from_user(buf, (const u8 __user *) |
142956af | 256 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
257 | u_tmp->len)) |
258 | goto done; | |
259 | } | |
814a8d50 AP |
260 | buf += k_tmp->len; |
261 | ||
262 | k_tmp->cs_change = !!u_tmp->cs_change; | |
263 | k_tmp->bits_per_word = u_tmp->bits_per_word; | |
264 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
265 | k_tmp->speed_hz = u_tmp->speed_hz; | |
266 | #ifdef VERBOSE | |
267 | dev_dbg(&spi->dev, | |
268 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", | |
269 | u_tmp->len, | |
270 | u_tmp->rx_buf ? "rx " : "", | |
271 | u_tmp->tx_buf ? "tx " : "", | |
272 | u_tmp->cs_change ? "cs " : "", | |
273 | u_tmp->bits_per_word ? : spi->bits_per_word, | |
274 | u_tmp->delay_usecs, | |
275 | u_tmp->speed_hz ? : spi->max_speed_hz); | |
276 | #endif | |
277 | spi_message_add_tail(k_tmp, &msg); | |
278 | } | |
279 | ||
25d5cb4b | 280 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
281 | if (status < 0) |
282 | goto done; | |
283 | ||
284 | /* copy any rx data out of bounce buffer */ | |
285 | buf = spidev->buffer; | |
286 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { | |
287 | if (u_tmp->rx_buf) { | |
4917d927 | 288 | if (__copy_to_user((u8 __user *) |
142956af | 289 | (uintptr_t) u_tmp->rx_buf, buf, |
814a8d50 AP |
290 | u_tmp->len)) { |
291 | status = -EFAULT; | |
292 | goto done; | |
293 | } | |
294 | } | |
295 | buf += u_tmp->len; | |
296 | } | |
297 | status = total; | |
298 | ||
299 | done: | |
300 | mutex_unlock(&spidev->buf_lock); | |
301 | kfree(k_xfers); | |
302 | return status; | |
303 | } | |
304 | ||
305 | static int | |
306 | spidev_ioctl(struct inode *inode, struct file *filp, | |
307 | unsigned int cmd, unsigned long arg) | |
308 | { | |
309 | int err = 0; | |
310 | int retval = 0; | |
311 | struct spidev_data *spidev; | |
312 | struct spi_device *spi; | |
313 | u32 tmp; | |
314 | unsigned n_ioc; | |
315 | struct spi_ioc_transfer *ioc; | |
316 | ||
317 | /* Check type and command number */ | |
318 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
319 | return -ENOTTY; | |
320 | ||
321 | /* Check access direction once here; don't repeat below. | |
322 | * IOC_DIR is from the user perspective, while access_ok is | |
323 | * from the kernel perspective; so they look reversed. | |
324 | */ | |
325 | if (_IOC_DIR(cmd) & _IOC_READ) | |
326 | err = !access_ok(VERIFY_WRITE, | |
327 | (void __user *)arg, _IOC_SIZE(cmd)); | |
328 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
329 | err = !access_ok(VERIFY_READ, | |
330 | (void __user *)arg, _IOC_SIZE(cmd)); | |
331 | if (err) | |
332 | return -EFAULT; | |
333 | ||
25d5cb4b DB |
334 | /* guard against device removal before, or while, |
335 | * we issue this ioctl. | |
336 | */ | |
814a8d50 | 337 | spidev = filp->private_data; |
25d5cb4b DB |
338 | spin_lock_irq(&spidev->spi_lock); |
339 | spi = spi_dev_get(spidev->spi); | |
340 | spin_unlock_irq(&spidev->spi_lock); | |
341 | ||
342 | if (spi == NULL) | |
343 | return -ESHUTDOWN; | |
814a8d50 AP |
344 | |
345 | switch (cmd) { | |
346 | /* read requests */ | |
347 | case SPI_IOC_RD_MODE: | |
348 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
349 | (__u8 __user *)arg); | |
350 | break; | |
351 | case SPI_IOC_RD_LSB_FIRST: | |
352 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
353 | (__u8 __user *)arg); | |
354 | break; | |
355 | case SPI_IOC_RD_BITS_PER_WORD: | |
356 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
357 | break; | |
358 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
359 | retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg); | |
360 | break; | |
361 | ||
362 | /* write requests */ | |
363 | case SPI_IOC_WR_MODE: | |
364 | retval = __get_user(tmp, (u8 __user *)arg); | |
365 | if (retval == 0) { | |
366 | u8 save = spi->mode; | |
367 | ||
368 | if (tmp & ~SPI_MODE_MASK) { | |
369 | retval = -EINVAL; | |
370 | break; | |
371 | } | |
372 | ||
373 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
374 | spi->mode = (u8)tmp; | |
375 | retval = spi_setup(spi); | |
376 | if (retval < 0) | |
377 | spi->mode = save; | |
378 | else | |
379 | dev_dbg(&spi->dev, "spi mode %02x\n", tmp); | |
380 | } | |
381 | break; | |
382 | case SPI_IOC_WR_LSB_FIRST: | |
383 | retval = __get_user(tmp, (__u8 __user *)arg); | |
384 | if (retval == 0) { | |
385 | u8 save = spi->mode; | |
386 | ||
387 | if (tmp) | |
388 | spi->mode |= SPI_LSB_FIRST; | |
389 | else | |
390 | spi->mode &= ~SPI_LSB_FIRST; | |
391 | retval = spi_setup(spi); | |
392 | if (retval < 0) | |
393 | spi->mode = save; | |
394 | else | |
395 | dev_dbg(&spi->dev, "%csb first\n", | |
396 | tmp ? 'l' : 'm'); | |
397 | } | |
398 | break; | |
399 | case SPI_IOC_WR_BITS_PER_WORD: | |
400 | retval = __get_user(tmp, (__u8 __user *)arg); | |
401 | if (retval == 0) { | |
402 | u8 save = spi->bits_per_word; | |
403 | ||
404 | spi->bits_per_word = tmp; | |
405 | retval = spi_setup(spi); | |
406 | if (retval < 0) | |
407 | spi->bits_per_word = save; | |
408 | else | |
409 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
410 | } | |
411 | break; | |
412 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
413 | retval = __get_user(tmp, (__u32 __user *)arg); | |
414 | if (retval == 0) { | |
415 | u32 save = spi->max_speed_hz; | |
416 | ||
417 | spi->max_speed_hz = tmp; | |
418 | retval = spi_setup(spi); | |
419 | if (retval < 0) | |
420 | spi->max_speed_hz = save; | |
421 | else | |
422 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
423 | } | |
424 | break; | |
425 | ||
426 | default: | |
427 | /* segmented and/or full-duplex I/O request */ | |
428 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
25d5cb4b DB |
429 | || _IOC_DIR(cmd) != _IOC_WRITE) { |
430 | retval = -ENOTTY; | |
431 | break; | |
432 | } | |
814a8d50 AP |
433 | |
434 | tmp = _IOC_SIZE(cmd); | |
435 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { | |
436 | retval = -EINVAL; | |
437 | break; | |
438 | } | |
439 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
440 | if (n_ioc == 0) | |
441 | break; | |
442 | ||
443 | /* copy into scratch area */ | |
444 | ioc = kmalloc(tmp, GFP_KERNEL); | |
445 | if (!ioc) { | |
446 | retval = -ENOMEM; | |
447 | break; | |
448 | } | |
449 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { | |
9bea3f29 | 450 | kfree(ioc); |
814a8d50 AP |
451 | retval = -EFAULT; |
452 | break; | |
453 | } | |
454 | ||
455 | /* translate to spi_message, execute */ | |
456 | retval = spidev_message(spidev, ioc, n_ioc); | |
457 | kfree(ioc); | |
458 | break; | |
459 | } | |
25d5cb4b | 460 | spi_dev_put(spi); |
814a8d50 AP |
461 | return retval; |
462 | } | |
463 | ||
464 | static int spidev_open(struct inode *inode, struct file *filp) | |
465 | { | |
466 | struct spidev_data *spidev; | |
467 | int status = -ENXIO; | |
468 | ||
469 | mutex_lock(&device_list_lock); | |
470 | ||
471 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 472 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
473 | status = 0; |
474 | break; | |
475 | } | |
476 | } | |
477 | if (status == 0) { | |
478 | if (!spidev->buffer) { | |
479 | spidev->buffer = kmalloc(bufsiz, GFP_KERNEL); | |
480 | if (!spidev->buffer) { | |
481 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
482 | status = -ENOMEM; | |
483 | } | |
484 | } | |
485 | if (status == 0) { | |
486 | spidev->users++; | |
487 | filp->private_data = spidev; | |
488 | nonseekable_open(inode, filp); | |
489 | } | |
490 | } else | |
491 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
492 | ||
493 | mutex_unlock(&device_list_lock); | |
494 | return status; | |
495 | } | |
496 | ||
497 | static int spidev_release(struct inode *inode, struct file *filp) | |
498 | { | |
499 | struct spidev_data *spidev; | |
500 | int status = 0; | |
501 | ||
502 | mutex_lock(&device_list_lock); | |
503 | spidev = filp->private_data; | |
504 | filp->private_data = NULL; | |
b2c8dadd DB |
505 | |
506 | /* last close? */ | |
814a8d50 AP |
507 | spidev->users--; |
508 | if (!spidev->users) { | |
b2c8dadd DB |
509 | int dofree; |
510 | ||
814a8d50 AP |
511 | kfree(spidev->buffer); |
512 | spidev->buffer = NULL; | |
b2c8dadd DB |
513 | |
514 | /* ... after we unbound from the underlying device? */ | |
515 | spin_lock_irq(&spidev->spi_lock); | |
516 | dofree = (spidev->spi == NULL); | |
517 | spin_unlock_irq(&spidev->spi_lock); | |
518 | ||
519 | if (dofree) | |
520 | kfree(spidev); | |
814a8d50 AP |
521 | } |
522 | mutex_unlock(&device_list_lock); | |
523 | ||
524 | return status; | |
525 | } | |
526 | ||
527 | static struct file_operations spidev_fops = { | |
528 | .owner = THIS_MODULE, | |
529 | /* REVISIT switch to aio primitives, so that userspace | |
530 | * gets more complete API coverage. It'll simplify things | |
531 | * too, except for the locking. | |
532 | */ | |
533 | .write = spidev_write, | |
534 | .read = spidev_read, | |
535 | .ioctl = spidev_ioctl, | |
536 | .open = spidev_open, | |
537 | .release = spidev_release, | |
538 | }; | |
539 | ||
540 | /*-------------------------------------------------------------------------*/ | |
541 | ||
542 | /* The main reason to have this class is to make mdev/udev create the | |
543 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
544 | * It also simplifies memory management. | |
545 | */ | |
546 | ||
b2c8dadd | 547 | static struct class *spidev_class; |
814a8d50 AP |
548 | |
549 | /*-------------------------------------------------------------------------*/ | |
550 | ||
551 | static int spidev_probe(struct spi_device *spi) | |
552 | { | |
553 | struct spidev_data *spidev; | |
554 | int status; | |
555 | unsigned long minor; | |
556 | ||
557 | /* Allocate driver data */ | |
558 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
559 | if (!spidev) | |
560 | return -ENOMEM; | |
561 | ||
562 | /* Initialize the driver data */ | |
563 | spidev->spi = spi; | |
25d5cb4b | 564 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
565 | mutex_init(&spidev->buf_lock); |
566 | ||
567 | INIT_LIST_HEAD(&spidev->device_entry); | |
568 | ||
569 | /* If we can allocate a minor number, hook up this device. | |
570 | * Reusing minors is fine so long as udev or mdev is working. | |
571 | */ | |
572 | mutex_lock(&device_list_lock); | |
0a4dd778 | 573 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 574 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
575 | struct device *dev; |
576 | ||
577 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
578 | dev = device_create(spidev_class, &spi->dev, spidev->devt, | |
814a8d50 AP |
579 | "spidev%d.%d", |
580 | spi->master->bus_num, spi->chip_select); | |
b2c8dadd | 581 | status = IS_ERR(dev) ? PTR_ERR(dev) : 0; |
814a8d50 AP |
582 | } else { |
583 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
584 | status = -ENODEV; | |
585 | } | |
586 | if (status == 0) { | |
587 | set_bit(minor, minors); | |
b2c8dadd | 588 | spi_set_drvdata(spi, spidev); |
814a8d50 AP |
589 | list_add(&spidev->device_entry, &device_list); |
590 | } | |
591 | mutex_unlock(&device_list_lock); | |
592 | ||
593 | if (status != 0) | |
594 | kfree(spidev); | |
595 | ||
596 | return status; | |
597 | } | |
598 | ||
599 | static int spidev_remove(struct spi_device *spi) | |
600 | { | |
b2c8dadd | 601 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 602 | |
25d5cb4b DB |
603 | /* make sure ops on existing fds can abort cleanly */ |
604 | spin_lock_irq(&spidev->spi_lock); | |
605 | spidev->spi = NULL; | |
b2c8dadd | 606 | spi_set_drvdata(spi, NULL); |
25d5cb4b | 607 | spin_unlock_irq(&spidev->spi_lock); |
814a8d50 | 608 | |
25d5cb4b DB |
609 | /* prevent new opens */ |
610 | mutex_lock(&device_list_lock); | |
814a8d50 | 611 | list_del(&spidev->device_entry); |
b2c8dadd DB |
612 | device_destroy(spidev_class, spidev->devt); |
613 | clear_bit(MINOR(spidev->devt), minors); | |
614 | if (spidev->users == 0) | |
615 | kfree(spidev); | |
814a8d50 AP |
616 | mutex_unlock(&device_list_lock); |
617 | ||
618 | return 0; | |
619 | } | |
620 | ||
621 | static struct spi_driver spidev_spi = { | |
622 | .driver = { | |
623 | .name = "spidev", | |
624 | .owner = THIS_MODULE, | |
625 | }, | |
626 | .probe = spidev_probe, | |
627 | .remove = __devexit_p(spidev_remove), | |
628 | ||
629 | /* NOTE: suspend/resume methods are not necessary here. | |
630 | * We don't do anything except pass the requests to/from | |
631 | * the underlying controller. The refrigerator handles | |
632 | * most issues; the controller driver handles the rest. | |
633 | */ | |
634 | }; | |
635 | ||
636 | /*-------------------------------------------------------------------------*/ | |
637 | ||
638 | static int __init spidev_init(void) | |
639 | { | |
640 | int status; | |
641 | ||
642 | /* Claim our 256 reserved device numbers. Then register a class | |
643 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
644 | * the driver which manages those device numbers. | |
645 | */ | |
646 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
647 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
648 | if (status < 0) | |
649 | return status; | |
650 | ||
b2c8dadd DB |
651 | spidev_class = class_create(THIS_MODULE, "spidev"); |
652 | if (IS_ERR(spidev_class)) { | |
814a8d50 | 653 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
b2c8dadd | 654 | return PTR_ERR(spidev_class); |
814a8d50 AP |
655 | } |
656 | ||
657 | status = spi_register_driver(&spidev_spi); | |
658 | if (status < 0) { | |
b2c8dadd | 659 | class_destroy(spidev_class); |
814a8d50 AP |
660 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
661 | } | |
662 | return status; | |
663 | } | |
664 | module_init(spidev_init); | |
665 | ||
666 | static void __exit spidev_exit(void) | |
667 | { | |
668 | spi_unregister_driver(&spidev_spi); | |
b2c8dadd | 669 | class_destroy(spidev_class); |
814a8d50 AP |
670 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
671 | } | |
672 | module_exit(spidev_exit); | |
673 | ||
674 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
675 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
676 | MODULE_LICENSE("GPL"); |