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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> | |
609f9e92 | 33 | #include <linux/smp_lock.h> |
814a8d50 AP |
34 | |
35 | #include <linux/spi/spi.h> | |
36 | #include <linux/spi/spidev.h> | |
37 | ||
38 | #include <asm/uaccess.h> | |
39 | ||
40 | ||
41 | /* | |
42 | * This supports acccess to SPI devices using normal userspace I/O calls. | |
43 | * Note that while traditional UNIX/POSIX I/O semantics are half duplex, | |
44 | * and often mask message boundaries, full SPI support requires full duplex | |
45 | * transfers. There are several kinds of of internal message boundaries to | |
46 | * handle chipselect management and other protocol options. | |
47 | * | |
48 | * SPI has a character major number assigned. We allocate minor numbers | |
49 | * dynamically using a bitmask. You must use hotplug tools, such as udev | |
50 | * (or mdev with busybox) to create and destroy the /dev/spidevB.C device | |
51 | * nodes, since there is no fixed association of minor numbers with any | |
52 | * particular SPI bus or device. | |
53 | */ | |
54 | #define SPIDEV_MAJOR 153 /* assigned */ | |
55 | #define N_SPI_MINORS 32 /* ... up to 256 */ | |
56 | ||
57 | static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG]; | |
58 | ||
59 | ||
6f166e38 | 60 | /* Bit masks for spi_device.mode management. Note that incorrect |
b55f627f DB |
61 | * settings for some settings can cause *lots* of trouble for other |
62 | * devices on a shared bus: | |
6f166e38 | 63 | * |
b55f627f DB |
64 | * - CS_HIGH ... this device will be active when it shouldn't be |
65 | * - 3WIRE ... when active, it won't behave as it should | |
66 | * - NO_CS ... there will be no explicit message boundaries; this | |
67 | * is completely incompatible with the shared bus model | |
68 | * - READY ... transfers may proceed when they shouldn't. | |
69 | * | |
70 | * REVISIT should changing those flags be privileged? | |
6f166e38 AV |
71 | */ |
72 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | |
b55f627f DB |
73 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ |
74 | | SPI_NO_CS | SPI_READY) | |
814a8d50 AP |
75 | |
76 | struct spidev_data { | |
b2c8dadd | 77 | dev_t devt; |
25d5cb4b | 78 | spinlock_t spi_lock; |
814a8d50 AP |
79 | struct spi_device *spi; |
80 | struct list_head device_entry; | |
81 | ||
b2c8dadd | 82 | /* buffer is NULL unless this device is open (users > 0) */ |
814a8d50 AP |
83 | struct mutex buf_lock; |
84 | unsigned users; | |
85 | u8 *buffer; | |
86 | }; | |
87 | ||
88 | static LIST_HEAD(device_list); | |
89 | static DEFINE_MUTEX(device_list_lock); | |
90 | ||
91 | static unsigned bufsiz = 4096; | |
92 | module_param(bufsiz, uint, S_IRUGO); | |
93 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
94 | ||
95 | /*-------------------------------------------------------------------------*/ | |
96 | ||
25d5cb4b DB |
97 | /* |
98 | * We can't use the standard synchronous wrappers for file I/O; we | |
99 | * need to protect against async removal of the underlying spi_device. | |
100 | */ | |
101 | static void spidev_complete(void *arg) | |
102 | { | |
103 | complete(arg); | |
104 | } | |
105 | ||
106 | static ssize_t | |
107 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
108 | { | |
109 | DECLARE_COMPLETION_ONSTACK(done); | |
110 | int status; | |
111 | ||
112 | message->complete = spidev_complete; | |
113 | message->context = &done; | |
114 | ||
115 | spin_lock_irq(&spidev->spi_lock); | |
116 | if (spidev->spi == NULL) | |
117 | status = -ESHUTDOWN; | |
118 | else | |
119 | status = spi_async(spidev->spi, message); | |
120 | spin_unlock_irq(&spidev->spi_lock); | |
121 | ||
122 | if (status == 0) { | |
123 | wait_for_completion(&done); | |
124 | status = message->status; | |
125 | if (status == 0) | |
126 | status = message->actual_length; | |
127 | } | |
128 | return status; | |
129 | } | |
130 | ||
131 | static inline ssize_t | |
132 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
133 | { | |
134 | struct spi_transfer t = { | |
135 | .tx_buf = spidev->buffer, | |
136 | .len = len, | |
137 | }; | |
138 | struct spi_message m; | |
139 | ||
140 | spi_message_init(&m); | |
141 | spi_message_add_tail(&t, &m); | |
142 | return spidev_sync(spidev, &m); | |
143 | } | |
144 | ||
145 | static inline ssize_t | |
146 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
147 | { | |
148 | struct spi_transfer t = { | |
149 | .rx_buf = spidev->buffer, | |
150 | .len = len, | |
151 | }; | |
152 | struct spi_message m; | |
153 | ||
154 | spi_message_init(&m); | |
155 | spi_message_add_tail(&t, &m); | |
156 | return spidev_sync(spidev, &m); | |
157 | } | |
158 | ||
159 | /*-------------------------------------------------------------------------*/ | |
160 | ||
814a8d50 AP |
161 | /* Read-only message with current device setup */ |
162 | static ssize_t | |
163 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
164 | { | |
165 | struct spidev_data *spidev; | |
814a8d50 AP |
166 | ssize_t status = 0; |
167 | ||
168 | /* chipselect only toggles at start or end of operation */ | |
169 | if (count > bufsiz) | |
170 | return -EMSGSIZE; | |
171 | ||
172 | spidev = filp->private_data; | |
814a8d50 AP |
173 | |
174 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 175 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 176 | if (status > 0) { |
814a8d50 AP |
177 | unsigned long missing; |
178 | ||
4b1295b0 SS |
179 | missing = copy_to_user(buf, spidev->buffer, status); |
180 | if (missing == status) | |
814a8d50 AP |
181 | status = -EFAULT; |
182 | else | |
4b1295b0 | 183 | status = status - missing; |
814a8d50 AP |
184 | } |
185 | mutex_unlock(&spidev->buf_lock); | |
186 | ||
187 | return status; | |
188 | } | |
189 | ||
190 | /* Write-only message with current device setup */ | |
191 | static ssize_t | |
192 | spidev_write(struct file *filp, const char __user *buf, | |
193 | size_t count, loff_t *f_pos) | |
194 | { | |
195 | struct spidev_data *spidev; | |
814a8d50 AP |
196 | ssize_t status = 0; |
197 | unsigned long missing; | |
198 | ||
199 | /* chipselect only toggles at start or end of operation */ | |
200 | if (count > bufsiz) | |
201 | return -EMSGSIZE; | |
202 | ||
203 | spidev = filp->private_data; | |
814a8d50 AP |
204 | |
205 | mutex_lock(&spidev->buf_lock); | |
206 | missing = copy_from_user(spidev->buffer, buf, count); | |
207 | if (missing == 0) { | |
25d5cb4b | 208 | status = spidev_sync_write(spidev, count); |
814a8d50 AP |
209 | } else |
210 | status = -EFAULT; | |
211 | mutex_unlock(&spidev->buf_lock); | |
212 | ||
213 | return status; | |
214 | } | |
215 | ||
216 | static int spidev_message(struct spidev_data *spidev, | |
217 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
218 | { | |
219 | struct spi_message msg; | |
220 | struct spi_transfer *k_xfers; | |
221 | struct spi_transfer *k_tmp; | |
222 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 AP |
223 | unsigned n, total; |
224 | u8 *buf; | |
225 | int status = -EFAULT; | |
226 | ||
227 | spi_message_init(&msg); | |
228 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
229 | if (k_xfers == NULL) | |
230 | return -ENOMEM; | |
231 | ||
232 | /* Construct spi_message, copying any tx data to bounce buffer. | |
233 | * We walk the array of user-provided transfers, using each one | |
234 | * to initialize a kernel version of the same transfer. | |
235 | */ | |
814a8d50 AP |
236 | buf = spidev->buffer; |
237 | total = 0; | |
238 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
239 | n; | |
240 | n--, k_tmp++, u_tmp++) { | |
241 | k_tmp->len = u_tmp->len; | |
242 | ||
da90fa8f DP |
243 | total += k_tmp->len; |
244 | if (total > bufsiz) { | |
245 | status = -EMSGSIZE; | |
246 | goto done; | |
247 | } | |
248 | ||
814a8d50 AP |
249 | if (u_tmp->rx_buf) { |
250 | k_tmp->rx_buf = buf; | |
96ddbf50 | 251 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 252 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 253 | u_tmp->len)) |
814a8d50 AP |
254 | goto done; |
255 | } | |
256 | if (u_tmp->tx_buf) { | |
257 | k_tmp->tx_buf = buf; | |
4917d927 | 258 | if (copy_from_user(buf, (const u8 __user *) |
142956af | 259 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
260 | u_tmp->len)) |
261 | goto done; | |
262 | } | |
814a8d50 AP |
263 | buf += k_tmp->len; |
264 | ||
265 | k_tmp->cs_change = !!u_tmp->cs_change; | |
266 | k_tmp->bits_per_word = u_tmp->bits_per_word; | |
267 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
268 | k_tmp->speed_hz = u_tmp->speed_hz; | |
269 | #ifdef VERBOSE | |
41df70d9 | 270 | dev_dbg(&spidev->spi->dev, |
814a8d50 AP |
271 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", |
272 | u_tmp->len, | |
273 | u_tmp->rx_buf ? "rx " : "", | |
274 | u_tmp->tx_buf ? "tx " : "", | |
275 | u_tmp->cs_change ? "cs " : "", | |
41df70d9 | 276 | u_tmp->bits_per_word ? : spidev->spi->bits_per_word, |
814a8d50 | 277 | u_tmp->delay_usecs, |
41df70d9 | 278 | u_tmp->speed_hz ? : spidev->spi->max_speed_hz); |
814a8d50 AP |
279 | #endif |
280 | spi_message_add_tail(k_tmp, &msg); | |
281 | } | |
282 | ||
25d5cb4b | 283 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
284 | if (status < 0) |
285 | goto done; | |
286 | ||
287 | /* copy any rx data out of bounce buffer */ | |
288 | buf = spidev->buffer; | |
289 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { | |
290 | if (u_tmp->rx_buf) { | |
4917d927 | 291 | if (__copy_to_user((u8 __user *) |
142956af | 292 | (uintptr_t) u_tmp->rx_buf, buf, |
814a8d50 AP |
293 | u_tmp->len)) { |
294 | status = -EFAULT; | |
295 | goto done; | |
296 | } | |
297 | } | |
298 | buf += u_tmp->len; | |
299 | } | |
300 | status = total; | |
301 | ||
302 | done: | |
814a8d50 AP |
303 | kfree(k_xfers); |
304 | return status; | |
305 | } | |
306 | ||
4ef754b7 AC |
307 | static long |
308 | spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
814a8d50 AP |
309 | { |
310 | int err = 0; | |
311 | int retval = 0; | |
312 | struct spidev_data *spidev; | |
313 | struct spi_device *spi; | |
314 | u32 tmp; | |
315 | unsigned n_ioc; | |
316 | struct spi_ioc_transfer *ioc; | |
317 | ||
318 | /* Check type and command number */ | |
319 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
320 | return -ENOTTY; | |
321 | ||
322 | /* Check access direction once here; don't repeat below. | |
323 | * IOC_DIR is from the user perspective, while access_ok is | |
324 | * from the kernel perspective; so they look reversed. | |
325 | */ | |
326 | if (_IOC_DIR(cmd) & _IOC_READ) | |
327 | err = !access_ok(VERIFY_WRITE, | |
328 | (void __user *)arg, _IOC_SIZE(cmd)); | |
329 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
330 | err = !access_ok(VERIFY_READ, | |
331 | (void __user *)arg, _IOC_SIZE(cmd)); | |
332 | if (err) | |
333 | return -EFAULT; | |
334 | ||
25d5cb4b DB |
335 | /* guard against device removal before, or while, |
336 | * we issue this ioctl. | |
337 | */ | |
814a8d50 | 338 | spidev = filp->private_data; |
25d5cb4b DB |
339 | spin_lock_irq(&spidev->spi_lock); |
340 | spi = spi_dev_get(spidev->spi); | |
341 | spin_unlock_irq(&spidev->spi_lock); | |
342 | ||
343 | if (spi == NULL) | |
344 | return -ESHUTDOWN; | |
814a8d50 | 345 | |
4ef754b7 AC |
346 | /* use the buffer lock here for triple duty: |
347 | * - prevent I/O (from us) so calling spi_setup() is safe; | |
348 | * - prevent concurrent SPI_IOC_WR_* from morphing | |
349 | * data fields while SPI_IOC_RD_* reads them; | |
350 | * - SPI_IOC_MESSAGE needs the buffer locked "normally". | |
351 | */ | |
352 | mutex_lock(&spidev->buf_lock); | |
353 | ||
814a8d50 AP |
354 | switch (cmd) { |
355 | /* read requests */ | |
356 | case SPI_IOC_RD_MODE: | |
357 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
358 | (__u8 __user *)arg); | |
359 | break; | |
360 | case SPI_IOC_RD_LSB_FIRST: | |
361 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
362 | (__u8 __user *)arg); | |
363 | break; | |
364 | case SPI_IOC_RD_BITS_PER_WORD: | |
365 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
366 | break; | |
367 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
368 | retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg); | |
369 | break; | |
370 | ||
371 | /* write requests */ | |
372 | case SPI_IOC_WR_MODE: | |
373 | retval = __get_user(tmp, (u8 __user *)arg); | |
374 | if (retval == 0) { | |
375 | u8 save = spi->mode; | |
376 | ||
377 | if (tmp & ~SPI_MODE_MASK) { | |
378 | retval = -EINVAL; | |
379 | break; | |
380 | } | |
381 | ||
382 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
383 | spi->mode = (u8)tmp; | |
384 | retval = spi_setup(spi); | |
385 | if (retval < 0) | |
386 | spi->mode = save; | |
387 | else | |
388 | dev_dbg(&spi->dev, "spi mode %02x\n", tmp); | |
389 | } | |
390 | break; | |
391 | case SPI_IOC_WR_LSB_FIRST: | |
392 | retval = __get_user(tmp, (__u8 __user *)arg); | |
393 | if (retval == 0) { | |
394 | u8 save = spi->mode; | |
395 | ||
396 | if (tmp) | |
397 | spi->mode |= SPI_LSB_FIRST; | |
398 | else | |
399 | spi->mode &= ~SPI_LSB_FIRST; | |
400 | retval = spi_setup(spi); | |
401 | if (retval < 0) | |
402 | spi->mode = save; | |
403 | else | |
404 | dev_dbg(&spi->dev, "%csb first\n", | |
405 | tmp ? 'l' : 'm'); | |
406 | } | |
407 | break; | |
408 | case SPI_IOC_WR_BITS_PER_WORD: | |
409 | retval = __get_user(tmp, (__u8 __user *)arg); | |
410 | if (retval == 0) { | |
411 | u8 save = spi->bits_per_word; | |
412 | ||
413 | spi->bits_per_word = tmp; | |
414 | retval = spi_setup(spi); | |
415 | if (retval < 0) | |
416 | spi->bits_per_word = save; | |
417 | else | |
418 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
419 | } | |
420 | break; | |
421 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
422 | retval = __get_user(tmp, (__u32 __user *)arg); | |
423 | if (retval == 0) { | |
424 | u32 save = spi->max_speed_hz; | |
425 | ||
426 | spi->max_speed_hz = tmp; | |
427 | retval = spi_setup(spi); | |
428 | if (retval < 0) | |
429 | spi->max_speed_hz = save; | |
430 | else | |
431 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
432 | } | |
433 | break; | |
434 | ||
435 | default: | |
436 | /* segmented and/or full-duplex I/O request */ | |
437 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
25d5cb4b DB |
438 | || _IOC_DIR(cmd) != _IOC_WRITE) { |
439 | retval = -ENOTTY; | |
440 | break; | |
441 | } | |
814a8d50 AP |
442 | |
443 | tmp = _IOC_SIZE(cmd); | |
444 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { | |
445 | retval = -EINVAL; | |
446 | break; | |
447 | } | |
448 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
449 | if (n_ioc == 0) | |
450 | break; | |
451 | ||
452 | /* copy into scratch area */ | |
453 | ioc = kmalloc(tmp, GFP_KERNEL); | |
454 | if (!ioc) { | |
455 | retval = -ENOMEM; | |
456 | break; | |
457 | } | |
458 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { | |
9bea3f29 | 459 | kfree(ioc); |
814a8d50 AP |
460 | retval = -EFAULT; |
461 | break; | |
462 | } | |
463 | ||
464 | /* translate to spi_message, execute */ | |
465 | retval = spidev_message(spidev, ioc, n_ioc); | |
466 | kfree(ioc); | |
467 | break; | |
468 | } | |
4ef754b7 AC |
469 | |
470 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 471 | spi_dev_put(spi); |
814a8d50 AP |
472 | return retval; |
473 | } | |
474 | ||
475 | static int spidev_open(struct inode *inode, struct file *filp) | |
476 | { | |
477 | struct spidev_data *spidev; | |
478 | int status = -ENXIO; | |
479 | ||
609f9e92 | 480 | lock_kernel(); |
814a8d50 AP |
481 | mutex_lock(&device_list_lock); |
482 | ||
483 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 484 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
485 | status = 0; |
486 | break; | |
487 | } | |
488 | } | |
489 | if (status == 0) { | |
490 | if (!spidev->buffer) { | |
491 | spidev->buffer = kmalloc(bufsiz, GFP_KERNEL); | |
492 | if (!spidev->buffer) { | |
493 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
494 | status = -ENOMEM; | |
495 | } | |
496 | } | |
497 | if (status == 0) { | |
498 | spidev->users++; | |
499 | filp->private_data = spidev; | |
500 | nonseekable_open(inode, filp); | |
501 | } | |
502 | } else | |
503 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
504 | ||
505 | mutex_unlock(&device_list_lock); | |
609f9e92 | 506 | unlock_kernel(); |
814a8d50 AP |
507 | return status; |
508 | } | |
509 | ||
510 | static int spidev_release(struct inode *inode, struct file *filp) | |
511 | { | |
512 | struct spidev_data *spidev; | |
513 | int status = 0; | |
514 | ||
515 | mutex_lock(&device_list_lock); | |
516 | spidev = filp->private_data; | |
517 | filp->private_data = NULL; | |
b2c8dadd DB |
518 | |
519 | /* last close? */ | |
814a8d50 AP |
520 | spidev->users--; |
521 | if (!spidev->users) { | |
b2c8dadd DB |
522 | int dofree; |
523 | ||
814a8d50 AP |
524 | kfree(spidev->buffer); |
525 | spidev->buffer = NULL; | |
b2c8dadd DB |
526 | |
527 | /* ... after we unbound from the underlying device? */ | |
528 | spin_lock_irq(&spidev->spi_lock); | |
529 | dofree = (spidev->spi == NULL); | |
530 | spin_unlock_irq(&spidev->spi_lock); | |
531 | ||
532 | if (dofree) | |
533 | kfree(spidev); | |
814a8d50 AP |
534 | } |
535 | mutex_unlock(&device_list_lock); | |
536 | ||
537 | return status; | |
538 | } | |
539 | ||
828c0950 | 540 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
541 | .owner = THIS_MODULE, |
542 | /* REVISIT switch to aio primitives, so that userspace | |
543 | * gets more complete API coverage. It'll simplify things | |
544 | * too, except for the locking. | |
545 | */ | |
546 | .write = spidev_write, | |
547 | .read = spidev_read, | |
4ef754b7 | 548 | .unlocked_ioctl = spidev_ioctl, |
814a8d50 AP |
549 | .open = spidev_open, |
550 | .release = spidev_release, | |
551 | }; | |
552 | ||
553 | /*-------------------------------------------------------------------------*/ | |
554 | ||
555 | /* The main reason to have this class is to make mdev/udev create the | |
556 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
557 | * It also simplifies memory management. | |
558 | */ | |
559 | ||
b2c8dadd | 560 | static struct class *spidev_class; |
814a8d50 AP |
561 | |
562 | /*-------------------------------------------------------------------------*/ | |
563 | ||
564 | static int spidev_probe(struct spi_device *spi) | |
565 | { | |
566 | struct spidev_data *spidev; | |
567 | int status; | |
568 | unsigned long minor; | |
569 | ||
570 | /* Allocate driver data */ | |
571 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
572 | if (!spidev) | |
573 | return -ENOMEM; | |
574 | ||
575 | /* Initialize the driver data */ | |
576 | spidev->spi = spi; | |
25d5cb4b | 577 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
578 | mutex_init(&spidev->buf_lock); |
579 | ||
580 | INIT_LIST_HEAD(&spidev->device_entry); | |
581 | ||
582 | /* If we can allocate a minor number, hook up this device. | |
583 | * Reusing minors is fine so long as udev or mdev is working. | |
584 | */ | |
585 | mutex_lock(&device_list_lock); | |
0a4dd778 | 586 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 587 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
588 | struct device *dev; |
589 | ||
590 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
591 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
592 | spidev, "spidev%d.%d", | |
593 | spi->master->bus_num, spi->chip_select); | |
b2c8dadd | 594 | status = IS_ERR(dev) ? PTR_ERR(dev) : 0; |
814a8d50 AP |
595 | } else { |
596 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
597 | status = -ENODEV; | |
598 | } | |
599 | if (status == 0) { | |
600 | set_bit(minor, minors); | |
814a8d50 AP |
601 | list_add(&spidev->device_entry, &device_list); |
602 | } | |
603 | mutex_unlock(&device_list_lock); | |
604 | ||
aaacf4bb WO |
605 | if (status == 0) |
606 | spi_set_drvdata(spi, spidev); | |
607 | else | |
814a8d50 AP |
608 | kfree(spidev); |
609 | ||
610 | return status; | |
611 | } | |
612 | ||
613 | static int spidev_remove(struct spi_device *spi) | |
614 | { | |
b2c8dadd | 615 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 616 | |
25d5cb4b DB |
617 | /* make sure ops on existing fds can abort cleanly */ |
618 | spin_lock_irq(&spidev->spi_lock); | |
619 | spidev->spi = NULL; | |
b2c8dadd | 620 | spi_set_drvdata(spi, NULL); |
25d5cb4b | 621 | spin_unlock_irq(&spidev->spi_lock); |
814a8d50 | 622 | |
25d5cb4b DB |
623 | /* prevent new opens */ |
624 | mutex_lock(&device_list_lock); | |
814a8d50 | 625 | list_del(&spidev->device_entry); |
b2c8dadd DB |
626 | device_destroy(spidev_class, spidev->devt); |
627 | clear_bit(MINOR(spidev->devt), minors); | |
628 | if (spidev->users == 0) | |
629 | kfree(spidev); | |
814a8d50 AP |
630 | mutex_unlock(&device_list_lock); |
631 | ||
632 | return 0; | |
633 | } | |
634 | ||
635 | static struct spi_driver spidev_spi = { | |
636 | .driver = { | |
637 | .name = "spidev", | |
638 | .owner = THIS_MODULE, | |
639 | }, | |
640 | .probe = spidev_probe, | |
641 | .remove = __devexit_p(spidev_remove), | |
642 | ||
643 | /* NOTE: suspend/resume methods are not necessary here. | |
644 | * We don't do anything except pass the requests to/from | |
645 | * the underlying controller. The refrigerator handles | |
646 | * most issues; the controller driver handles the rest. | |
647 | */ | |
648 | }; | |
649 | ||
650 | /*-------------------------------------------------------------------------*/ | |
651 | ||
652 | static int __init spidev_init(void) | |
653 | { | |
654 | int status; | |
655 | ||
656 | /* Claim our 256 reserved device numbers. Then register a class | |
657 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
658 | * the driver which manages those device numbers. | |
659 | */ | |
660 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
661 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
662 | if (status < 0) | |
663 | return status; | |
664 | ||
b2c8dadd DB |
665 | spidev_class = class_create(THIS_MODULE, "spidev"); |
666 | if (IS_ERR(spidev_class)) { | |
814a8d50 | 667 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
b2c8dadd | 668 | return PTR_ERR(spidev_class); |
814a8d50 AP |
669 | } |
670 | ||
671 | status = spi_register_driver(&spidev_spi); | |
672 | if (status < 0) { | |
b2c8dadd | 673 | class_destroy(spidev_class); |
814a8d50 AP |
674 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
675 | } | |
676 | return status; | |
677 | } | |
678 | module_init(spidev_init); | |
679 | ||
680 | static void __exit spidev_exit(void) | |
681 | { | |
682 | spi_unregister_driver(&spidev_spi); | |
b2c8dadd | 683 | class_destroy(spidev_class); |
814a8d50 AP |
684 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
685 | } | |
686 | module_exit(spidev_exit); | |
687 | ||
688 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
689 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
690 | MODULE_LICENSE("GPL"); | |
e0626e38 | 691 | MODULE_ALIAS("spi:spidev"); |