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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 | /* | |
b595076a | 41 | * This supports access to SPI devices using normal userspace I/O calls. |
814a8d50 AP |
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 | |
137f1188 | 44 | * transfers. There are several kinds of internal message boundaries to |
814a8d50 AP |
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 | ||
8ae1c924 | 56 | static DECLARE_BITMAP(minors, N_SPI_MINORS); |
814a8d50 AP |
57 | |
58 | ||
6f166e38 | 59 | /* Bit masks for spi_device.mode management. Note that incorrect |
b55f627f DB |
60 | * settings for some settings can cause *lots* of trouble for other |
61 | * devices on a shared bus: | |
6f166e38 | 62 | * |
b55f627f DB |
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. | |
68 | * | |
69 | * REVISIT should changing those flags be privileged? | |
6f166e38 AV |
70 | */ |
71 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | |
b55f627f DB |
72 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ |
73 | | SPI_NO_CS | SPI_READY) | |
814a8d50 AP |
74 | |
75 | struct spidev_data { | |
b2c8dadd | 76 | dev_t devt; |
25d5cb4b | 77 | spinlock_t spi_lock; |
814a8d50 AP |
78 | struct spi_device *spi; |
79 | struct list_head device_entry; | |
80 | ||
b2c8dadd | 81 | /* buffer is NULL unless this device is open (users > 0) */ |
814a8d50 AP |
82 | struct mutex buf_lock; |
83 | unsigned users; | |
84 | u8 *buffer; | |
85 | }; | |
86 | ||
87 | static LIST_HEAD(device_list); | |
88 | static DEFINE_MUTEX(device_list_lock); | |
89 | ||
90 | static unsigned bufsiz = 4096; | |
91 | module_param(bufsiz, uint, S_IRUGO); | |
92 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
93 | ||
94 | /*-------------------------------------------------------------------------*/ | |
95 | ||
25d5cb4b DB |
96 | /* |
97 | * We can't use the standard synchronous wrappers for file I/O; we | |
98 | * need to protect against async removal of the underlying spi_device. | |
99 | */ | |
100 | static void spidev_complete(void *arg) | |
101 | { | |
102 | complete(arg); | |
103 | } | |
104 | ||
105 | static ssize_t | |
106 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
107 | { | |
108 | DECLARE_COMPLETION_ONSTACK(done); | |
109 | int status; | |
110 | ||
111 | message->complete = spidev_complete; | |
112 | message->context = &done; | |
113 | ||
114 | spin_lock_irq(&spidev->spi_lock); | |
115 | if (spidev->spi == NULL) | |
116 | status = -ESHUTDOWN; | |
117 | else | |
118 | status = spi_async(spidev->spi, message); | |
119 | spin_unlock_irq(&spidev->spi_lock); | |
120 | ||
121 | if (status == 0) { | |
122 | wait_for_completion(&done); | |
123 | status = message->status; | |
124 | if (status == 0) | |
125 | status = message->actual_length; | |
126 | } | |
127 | return status; | |
128 | } | |
129 | ||
130 | static inline ssize_t | |
131 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
132 | { | |
133 | struct spi_transfer t = { | |
134 | .tx_buf = spidev->buffer, | |
135 | .len = len, | |
136 | }; | |
137 | struct spi_message m; | |
138 | ||
139 | spi_message_init(&m); | |
140 | spi_message_add_tail(&t, &m); | |
141 | return spidev_sync(spidev, &m); | |
142 | } | |
143 | ||
144 | static inline ssize_t | |
145 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
146 | { | |
147 | struct spi_transfer t = { | |
148 | .rx_buf = spidev->buffer, | |
149 | .len = len, | |
150 | }; | |
151 | struct spi_message m; | |
152 | ||
153 | spi_message_init(&m); | |
154 | spi_message_add_tail(&t, &m); | |
155 | return spidev_sync(spidev, &m); | |
156 | } | |
157 | ||
158 | /*-------------------------------------------------------------------------*/ | |
159 | ||
814a8d50 AP |
160 | /* Read-only message with current device setup */ |
161 | static ssize_t | |
162 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
163 | { | |
164 | struct spidev_data *spidev; | |
814a8d50 AP |
165 | ssize_t status = 0; |
166 | ||
167 | /* chipselect only toggles at start or end of operation */ | |
168 | if (count > bufsiz) | |
169 | return -EMSGSIZE; | |
170 | ||
171 | spidev = filp->private_data; | |
814a8d50 AP |
172 | |
173 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 174 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 175 | if (status > 0) { |
814a8d50 AP |
176 | unsigned long missing; |
177 | ||
4b1295b0 SS |
178 | missing = copy_to_user(buf, spidev->buffer, status); |
179 | if (missing == status) | |
814a8d50 AP |
180 | status = -EFAULT; |
181 | else | |
4b1295b0 | 182 | status = status - missing; |
814a8d50 AP |
183 | } |
184 | mutex_unlock(&spidev->buf_lock); | |
185 | ||
186 | return status; | |
187 | } | |
188 | ||
189 | /* Write-only message with current device setup */ | |
190 | static ssize_t | |
191 | spidev_write(struct file *filp, const char __user *buf, | |
192 | size_t count, loff_t *f_pos) | |
193 | { | |
194 | struct spidev_data *spidev; | |
814a8d50 AP |
195 | ssize_t status = 0; |
196 | unsigned long missing; | |
197 | ||
198 | /* chipselect only toggles at start or end of operation */ | |
199 | if (count > bufsiz) | |
200 | return -EMSGSIZE; | |
201 | ||
202 | spidev = filp->private_data; | |
814a8d50 AP |
203 | |
204 | mutex_lock(&spidev->buf_lock); | |
205 | missing = copy_from_user(spidev->buffer, buf, count); | |
206 | if (missing == 0) { | |
25d5cb4b | 207 | status = spidev_sync_write(spidev, count); |
814a8d50 AP |
208 | } else |
209 | status = -EFAULT; | |
210 | mutex_unlock(&spidev->buf_lock); | |
211 | ||
212 | return status; | |
213 | } | |
214 | ||
215 | static int spidev_message(struct spidev_data *spidev, | |
216 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
217 | { | |
218 | struct spi_message msg; | |
219 | struct spi_transfer *k_xfers; | |
220 | struct spi_transfer *k_tmp; | |
221 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 AP |
222 | unsigned n, total; |
223 | u8 *buf; | |
224 | int status = -EFAULT; | |
225 | ||
226 | spi_message_init(&msg); | |
227 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
228 | if (k_xfers == NULL) | |
229 | return -ENOMEM; | |
230 | ||
231 | /* Construct spi_message, copying any tx data to bounce buffer. | |
232 | * We walk the array of user-provided transfers, using each one | |
233 | * to initialize a kernel version of the same transfer. | |
234 | */ | |
814a8d50 AP |
235 | buf = spidev->buffer; |
236 | total = 0; | |
237 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
238 | n; | |
239 | n--, k_tmp++, u_tmp++) { | |
240 | k_tmp->len = u_tmp->len; | |
241 | ||
da90fa8f DP |
242 | total += k_tmp->len; |
243 | if (total > bufsiz) { | |
244 | status = -EMSGSIZE; | |
245 | goto done; | |
246 | } | |
247 | ||
814a8d50 AP |
248 | if (u_tmp->rx_buf) { |
249 | k_tmp->rx_buf = buf; | |
96ddbf50 | 250 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 251 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 252 | u_tmp->len)) |
814a8d50 AP |
253 | goto done; |
254 | } | |
255 | if (u_tmp->tx_buf) { | |
256 | k_tmp->tx_buf = buf; | |
4917d927 | 257 | if (copy_from_user(buf, (const u8 __user *) |
142956af | 258 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
259 | u_tmp->len)) |
260 | goto done; | |
261 | } | |
814a8d50 AP |
262 | buf += k_tmp->len; |
263 | ||
264 | k_tmp->cs_change = !!u_tmp->cs_change; | |
265 | k_tmp->bits_per_word = u_tmp->bits_per_word; | |
266 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
267 | k_tmp->speed_hz = u_tmp->speed_hz; | |
268 | #ifdef VERBOSE | |
41df70d9 | 269 | dev_dbg(&spidev->spi->dev, |
814a8d50 AP |
270 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", |
271 | u_tmp->len, | |
272 | u_tmp->rx_buf ? "rx " : "", | |
273 | u_tmp->tx_buf ? "tx " : "", | |
274 | u_tmp->cs_change ? "cs " : "", | |
41df70d9 | 275 | u_tmp->bits_per_word ? : spidev->spi->bits_per_word, |
814a8d50 | 276 | u_tmp->delay_usecs, |
41df70d9 | 277 | u_tmp->speed_hz ? : spidev->spi->max_speed_hz); |
814a8d50 AP |
278 | #endif |
279 | spi_message_add_tail(k_tmp, &msg); | |
280 | } | |
281 | ||
25d5cb4b | 282 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
283 | if (status < 0) |
284 | goto done; | |
285 | ||
286 | /* copy any rx data out of bounce buffer */ | |
287 | buf = spidev->buffer; | |
288 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { | |
289 | if (u_tmp->rx_buf) { | |
4917d927 | 290 | if (__copy_to_user((u8 __user *) |
142956af | 291 | (uintptr_t) u_tmp->rx_buf, buf, |
814a8d50 AP |
292 | u_tmp->len)) { |
293 | status = -EFAULT; | |
294 | goto done; | |
295 | } | |
296 | } | |
297 | buf += u_tmp->len; | |
298 | } | |
299 | status = total; | |
300 | ||
301 | done: | |
814a8d50 AP |
302 | kfree(k_xfers); |
303 | return status; | |
304 | } | |
305 | ||
4ef754b7 AC |
306 | static long |
307 | spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
814a8d50 AP |
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 | 344 | |
4ef754b7 AC |
345 | /* use the buffer lock here for triple duty: |
346 | * - prevent I/O (from us) so calling spi_setup() is safe; | |
347 | * - prevent concurrent SPI_IOC_WR_* from morphing | |
348 | * data fields while SPI_IOC_RD_* reads them; | |
349 | * - SPI_IOC_MESSAGE needs the buffer locked "normally". | |
350 | */ | |
351 | mutex_lock(&spidev->buf_lock); | |
352 | ||
814a8d50 AP |
353 | switch (cmd) { |
354 | /* read requests */ | |
355 | case SPI_IOC_RD_MODE: | |
356 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
357 | (__u8 __user *)arg); | |
358 | break; | |
359 | case SPI_IOC_RD_LSB_FIRST: | |
360 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
361 | (__u8 __user *)arg); | |
362 | break; | |
363 | case SPI_IOC_RD_BITS_PER_WORD: | |
364 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
365 | break; | |
366 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
367 | retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg); | |
368 | break; | |
369 | ||
370 | /* write requests */ | |
371 | case SPI_IOC_WR_MODE: | |
372 | retval = __get_user(tmp, (u8 __user *)arg); | |
373 | if (retval == 0) { | |
374 | u8 save = spi->mode; | |
375 | ||
376 | if (tmp & ~SPI_MODE_MASK) { | |
377 | retval = -EINVAL; | |
378 | break; | |
379 | } | |
380 | ||
381 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
382 | spi->mode = (u8)tmp; | |
383 | retval = spi_setup(spi); | |
384 | if (retval < 0) | |
385 | spi->mode = save; | |
386 | else | |
387 | dev_dbg(&spi->dev, "spi mode %02x\n", tmp); | |
388 | } | |
389 | break; | |
390 | case SPI_IOC_WR_LSB_FIRST: | |
391 | retval = __get_user(tmp, (__u8 __user *)arg); | |
392 | if (retval == 0) { | |
393 | u8 save = spi->mode; | |
394 | ||
395 | if (tmp) | |
396 | spi->mode |= SPI_LSB_FIRST; | |
397 | else | |
398 | spi->mode &= ~SPI_LSB_FIRST; | |
399 | retval = spi_setup(spi); | |
400 | if (retval < 0) | |
401 | spi->mode = save; | |
402 | else | |
403 | dev_dbg(&spi->dev, "%csb first\n", | |
404 | tmp ? 'l' : 'm'); | |
405 | } | |
406 | break; | |
407 | case SPI_IOC_WR_BITS_PER_WORD: | |
408 | retval = __get_user(tmp, (__u8 __user *)arg); | |
409 | if (retval == 0) { | |
410 | u8 save = spi->bits_per_word; | |
411 | ||
412 | spi->bits_per_word = tmp; | |
413 | retval = spi_setup(spi); | |
414 | if (retval < 0) | |
415 | spi->bits_per_word = save; | |
416 | else | |
417 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
418 | } | |
419 | break; | |
420 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
421 | retval = __get_user(tmp, (__u32 __user *)arg); | |
422 | if (retval == 0) { | |
423 | u32 save = spi->max_speed_hz; | |
424 | ||
425 | spi->max_speed_hz = tmp; | |
426 | retval = spi_setup(spi); | |
427 | if (retval < 0) | |
428 | spi->max_speed_hz = save; | |
429 | else | |
430 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
431 | } | |
432 | break; | |
433 | ||
434 | default: | |
435 | /* segmented and/or full-duplex I/O request */ | |
436 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
25d5cb4b DB |
437 | || _IOC_DIR(cmd) != _IOC_WRITE) { |
438 | retval = -ENOTTY; | |
439 | break; | |
440 | } | |
814a8d50 AP |
441 | |
442 | tmp = _IOC_SIZE(cmd); | |
443 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { | |
444 | retval = -EINVAL; | |
445 | break; | |
446 | } | |
447 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
448 | if (n_ioc == 0) | |
449 | break; | |
450 | ||
451 | /* copy into scratch area */ | |
452 | ioc = kmalloc(tmp, GFP_KERNEL); | |
453 | if (!ioc) { | |
454 | retval = -ENOMEM; | |
455 | break; | |
456 | } | |
457 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { | |
9bea3f29 | 458 | kfree(ioc); |
814a8d50 AP |
459 | retval = -EFAULT; |
460 | break; | |
461 | } | |
462 | ||
463 | /* translate to spi_message, execute */ | |
464 | retval = spidev_message(spidev, ioc, n_ioc); | |
465 | kfree(ioc); | |
466 | break; | |
467 | } | |
4ef754b7 AC |
468 | |
469 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 470 | spi_dev_put(spi); |
814a8d50 AP |
471 | return retval; |
472 | } | |
473 | ||
474 | static int spidev_open(struct inode *inode, struct file *filp) | |
475 | { | |
476 | struct spidev_data *spidev; | |
477 | int status = -ENXIO; | |
478 | ||
479 | mutex_lock(&device_list_lock); | |
480 | ||
481 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 482 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
483 | status = 0; |
484 | break; | |
485 | } | |
486 | } | |
487 | if (status == 0) { | |
488 | if (!spidev->buffer) { | |
489 | spidev->buffer = kmalloc(bufsiz, GFP_KERNEL); | |
490 | if (!spidev->buffer) { | |
491 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
492 | status = -ENOMEM; | |
493 | } | |
494 | } | |
495 | if (status == 0) { | |
496 | spidev->users++; | |
497 | filp->private_data = spidev; | |
498 | nonseekable_open(inode, filp); | |
499 | } | |
500 | } else | |
501 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
502 | ||
503 | mutex_unlock(&device_list_lock); | |
504 | return status; | |
505 | } | |
506 | ||
507 | static int spidev_release(struct inode *inode, struct file *filp) | |
508 | { | |
509 | struct spidev_data *spidev; | |
510 | int status = 0; | |
511 | ||
512 | mutex_lock(&device_list_lock); | |
513 | spidev = filp->private_data; | |
514 | filp->private_data = NULL; | |
b2c8dadd DB |
515 | |
516 | /* last close? */ | |
814a8d50 AP |
517 | spidev->users--; |
518 | if (!spidev->users) { | |
b2c8dadd DB |
519 | int dofree; |
520 | ||
814a8d50 AP |
521 | kfree(spidev->buffer); |
522 | spidev->buffer = NULL; | |
b2c8dadd DB |
523 | |
524 | /* ... after we unbound from the underlying device? */ | |
525 | spin_lock_irq(&spidev->spi_lock); | |
526 | dofree = (spidev->spi == NULL); | |
527 | spin_unlock_irq(&spidev->spi_lock); | |
528 | ||
529 | if (dofree) | |
530 | kfree(spidev); | |
814a8d50 AP |
531 | } |
532 | mutex_unlock(&device_list_lock); | |
533 | ||
534 | return status; | |
535 | } | |
536 | ||
828c0950 | 537 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
538 | .owner = THIS_MODULE, |
539 | /* REVISIT switch to aio primitives, so that userspace | |
540 | * gets more complete API coverage. It'll simplify things | |
541 | * too, except for the locking. | |
542 | */ | |
543 | .write = spidev_write, | |
544 | .read = spidev_read, | |
4ef754b7 | 545 | .unlocked_ioctl = spidev_ioctl, |
814a8d50 AP |
546 | .open = spidev_open, |
547 | .release = spidev_release, | |
6038f373 | 548 | .llseek = no_llseek, |
814a8d50 AP |
549 | }; |
550 | ||
551 | /*-------------------------------------------------------------------------*/ | |
552 | ||
553 | /* The main reason to have this class is to make mdev/udev create the | |
554 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
555 | * It also simplifies memory management. | |
556 | */ | |
557 | ||
b2c8dadd | 558 | static struct class *spidev_class; |
814a8d50 AP |
559 | |
560 | /*-------------------------------------------------------------------------*/ | |
561 | ||
db389b61 | 562 | static int __devinit spidev_probe(struct spi_device *spi) |
814a8d50 AP |
563 | { |
564 | struct spidev_data *spidev; | |
565 | int status; | |
566 | unsigned long minor; | |
567 | ||
568 | /* Allocate driver data */ | |
569 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
570 | if (!spidev) | |
571 | return -ENOMEM; | |
572 | ||
573 | /* Initialize the driver data */ | |
574 | spidev->spi = spi; | |
25d5cb4b | 575 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
576 | mutex_init(&spidev->buf_lock); |
577 | ||
578 | INIT_LIST_HEAD(&spidev->device_entry); | |
579 | ||
580 | /* If we can allocate a minor number, hook up this device. | |
581 | * Reusing minors is fine so long as udev or mdev is working. | |
582 | */ | |
583 | mutex_lock(&device_list_lock); | |
0a4dd778 | 584 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 585 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
586 | struct device *dev; |
587 | ||
588 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
589 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
590 | spidev, "spidev%d.%d", | |
591 | spi->master->bus_num, spi->chip_select); | |
b2c8dadd | 592 | status = IS_ERR(dev) ? PTR_ERR(dev) : 0; |
814a8d50 AP |
593 | } else { |
594 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
595 | status = -ENODEV; | |
596 | } | |
597 | if (status == 0) { | |
598 | set_bit(minor, minors); | |
814a8d50 AP |
599 | list_add(&spidev->device_entry, &device_list); |
600 | } | |
601 | mutex_unlock(&device_list_lock); | |
602 | ||
aaacf4bb WO |
603 | if (status == 0) |
604 | spi_set_drvdata(spi, spidev); | |
605 | else | |
814a8d50 AP |
606 | kfree(spidev); |
607 | ||
608 | return status; | |
609 | } | |
610 | ||
db389b61 | 611 | static int __devexit spidev_remove(struct spi_device *spi) |
814a8d50 | 612 | { |
b2c8dadd | 613 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 614 | |
25d5cb4b DB |
615 | /* make sure ops on existing fds can abort cleanly */ |
616 | spin_lock_irq(&spidev->spi_lock); | |
617 | spidev->spi = NULL; | |
b2c8dadd | 618 | spi_set_drvdata(spi, NULL); |
25d5cb4b | 619 | spin_unlock_irq(&spidev->spi_lock); |
814a8d50 | 620 | |
25d5cb4b DB |
621 | /* prevent new opens */ |
622 | mutex_lock(&device_list_lock); | |
814a8d50 | 623 | list_del(&spidev->device_entry); |
b2c8dadd DB |
624 | device_destroy(spidev_class, spidev->devt); |
625 | clear_bit(MINOR(spidev->devt), minors); | |
626 | if (spidev->users == 0) | |
627 | kfree(spidev); | |
814a8d50 AP |
628 | mutex_unlock(&device_list_lock); |
629 | ||
630 | return 0; | |
631 | } | |
632 | ||
db389b61 | 633 | static struct spi_driver spidev_spi_driver = { |
814a8d50 AP |
634 | .driver = { |
635 | .name = "spidev", | |
636 | .owner = THIS_MODULE, | |
637 | }, | |
638 | .probe = spidev_probe, | |
639 | .remove = __devexit_p(spidev_remove), | |
640 | ||
641 | /* NOTE: suspend/resume methods are not necessary here. | |
642 | * We don't do anything except pass the requests to/from | |
643 | * the underlying controller. The refrigerator handles | |
644 | * most issues; the controller driver handles the rest. | |
645 | */ | |
646 | }; | |
647 | ||
648 | /*-------------------------------------------------------------------------*/ | |
649 | ||
650 | static int __init spidev_init(void) | |
651 | { | |
652 | int status; | |
653 | ||
654 | /* Claim our 256 reserved device numbers. Then register a class | |
655 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
656 | * the driver which manages those device numbers. | |
657 | */ | |
658 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
659 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
660 | if (status < 0) | |
661 | return status; | |
662 | ||
b2c8dadd DB |
663 | spidev_class = class_create(THIS_MODULE, "spidev"); |
664 | if (IS_ERR(spidev_class)) { | |
db389b61 | 665 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
b2c8dadd | 666 | return PTR_ERR(spidev_class); |
814a8d50 AP |
667 | } |
668 | ||
db389b61 | 669 | status = spi_register_driver(&spidev_spi_driver); |
814a8d50 | 670 | if (status < 0) { |
b2c8dadd | 671 | class_destroy(spidev_class); |
db389b61 | 672 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
673 | } |
674 | return status; | |
675 | } | |
676 | module_init(spidev_init); | |
677 | ||
678 | static void __exit spidev_exit(void) | |
679 | { | |
db389b61 | 680 | spi_unregister_driver(&spidev_spi_driver); |
b2c8dadd | 681 | class_destroy(spidev_class); |
db389b61 | 682 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
683 | } |
684 | module_exit(spidev_exit); | |
685 | ||
686 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
687 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
688 | MODULE_LICENSE("GPL"); | |
e0626e38 | 689 | MODULE_ALIAS("spi:spidev"); |