Commit | Line | Data |
---|---|---|
814a8d50 | 1 | /* |
ca632f55 | 2 | * Simple synchronous userspace interface to SPI devices |
814a8d50 AP |
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> | |
7d48ec36 | 33 | #include <linux/compat.h> |
880cfd43 MR |
34 | #include <linux/of.h> |
35 | #include <linux/of_device.h> | |
814a8d50 AP |
36 | |
37 | #include <linux/spi/spi.h> | |
38 | #include <linux/spi/spidev.h> | |
39 | ||
40 | #include <asm/uaccess.h> | |
41 | ||
42 | ||
43 | /* | |
b595076a | 44 | * This supports access to SPI devices using normal userspace I/O calls. |
814a8d50 AP |
45 | * Note that while traditional UNIX/POSIX I/O semantics are half duplex, |
46 | * and often mask message boundaries, full SPI support requires full duplex | |
137f1188 | 47 | * transfers. There are several kinds of internal message boundaries to |
814a8d50 AP |
48 | * handle chipselect management and other protocol options. |
49 | * | |
50 | * SPI has a character major number assigned. We allocate minor numbers | |
51 | * dynamically using a bitmask. You must use hotplug tools, such as udev | |
52 | * (or mdev with busybox) to create and destroy the /dev/spidevB.C device | |
53 | * nodes, since there is no fixed association of minor numbers with any | |
54 | * particular SPI bus or device. | |
55 | */ | |
56 | #define SPIDEV_MAJOR 153 /* assigned */ | |
57 | #define N_SPI_MINORS 32 /* ... up to 256 */ | |
58 | ||
8ae1c924 | 59 | static DECLARE_BITMAP(minors, N_SPI_MINORS); |
814a8d50 AP |
60 | |
61 | ||
6f166e38 | 62 | /* Bit masks for spi_device.mode management. Note that incorrect |
b55f627f DB |
63 | * settings for some settings can cause *lots* of trouble for other |
64 | * devices on a shared bus: | |
6f166e38 | 65 | * |
b55f627f DB |
66 | * - CS_HIGH ... this device will be active when it shouldn't be |
67 | * - 3WIRE ... when active, it won't behave as it should | |
68 | * - NO_CS ... there will be no explicit message boundaries; this | |
69 | * is completely incompatible with the shared bus model | |
70 | * - READY ... transfers may proceed when they shouldn't. | |
71 | * | |
72 | * REVISIT should changing those flags be privileged? | |
6f166e38 AV |
73 | */ |
74 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | |
b55f627f DB |
75 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ |
76 | | SPI_NO_CS | SPI_READY) | |
814a8d50 AP |
77 | |
78 | struct spidev_data { | |
b2c8dadd | 79 | dev_t devt; |
25d5cb4b | 80 | spinlock_t spi_lock; |
814a8d50 AP |
81 | struct spi_device *spi; |
82 | struct list_head device_entry; | |
83 | ||
b2c8dadd | 84 | /* buffer is NULL unless this device is open (users > 0) */ |
814a8d50 AP |
85 | struct mutex buf_lock; |
86 | unsigned users; | |
87 | u8 *buffer; | |
88 | }; | |
89 | ||
90 | static LIST_HEAD(device_list); | |
91 | static DEFINE_MUTEX(device_list_lock); | |
92 | ||
93 | static unsigned bufsiz = 4096; | |
94 | module_param(bufsiz, uint, S_IRUGO); | |
95 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
96 | ||
97 | /*-------------------------------------------------------------------------*/ | |
98 | ||
25d5cb4b DB |
99 | /* |
100 | * We can't use the standard synchronous wrappers for file I/O; we | |
101 | * need to protect against async removal of the underlying spi_device. | |
102 | */ | |
103 | static void spidev_complete(void *arg) | |
104 | { | |
105 | complete(arg); | |
106 | } | |
107 | ||
108 | static ssize_t | |
109 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
110 | { | |
111 | DECLARE_COMPLETION_ONSTACK(done); | |
112 | int status; | |
113 | ||
114 | message->complete = spidev_complete; | |
115 | message->context = &done; | |
116 | ||
117 | spin_lock_irq(&spidev->spi_lock); | |
118 | if (spidev->spi == NULL) | |
119 | status = -ESHUTDOWN; | |
120 | else | |
121 | status = spi_async(spidev->spi, message); | |
122 | spin_unlock_irq(&spidev->spi_lock); | |
123 | ||
124 | if (status == 0) { | |
125 | wait_for_completion(&done); | |
126 | status = message->status; | |
127 | if (status == 0) | |
128 | status = message->actual_length; | |
129 | } | |
130 | return status; | |
131 | } | |
132 | ||
133 | static inline ssize_t | |
134 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
135 | { | |
136 | struct spi_transfer t = { | |
137 | .tx_buf = spidev->buffer, | |
138 | .len = len, | |
139 | }; | |
140 | struct spi_message m; | |
141 | ||
142 | spi_message_init(&m); | |
143 | spi_message_add_tail(&t, &m); | |
144 | return spidev_sync(spidev, &m); | |
145 | } | |
146 | ||
147 | static inline ssize_t | |
148 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
149 | { | |
150 | struct spi_transfer t = { | |
151 | .rx_buf = spidev->buffer, | |
152 | .len = len, | |
153 | }; | |
154 | struct spi_message m; | |
155 | ||
156 | spi_message_init(&m); | |
157 | spi_message_add_tail(&t, &m); | |
158 | return spidev_sync(spidev, &m); | |
159 | } | |
160 | ||
161 | /*-------------------------------------------------------------------------*/ | |
162 | ||
814a8d50 AP |
163 | /* Read-only message with current device setup */ |
164 | static ssize_t | |
165 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
166 | { | |
167 | struct spidev_data *spidev; | |
814a8d50 AP |
168 | ssize_t status = 0; |
169 | ||
170 | /* chipselect only toggles at start or end of operation */ | |
171 | if (count > bufsiz) | |
172 | return -EMSGSIZE; | |
173 | ||
174 | spidev = filp->private_data; | |
814a8d50 AP |
175 | |
176 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 177 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 178 | if (status > 0) { |
814a8d50 AP |
179 | unsigned long missing; |
180 | ||
4b1295b0 SS |
181 | missing = copy_to_user(buf, spidev->buffer, status); |
182 | if (missing == status) | |
814a8d50 AP |
183 | status = -EFAULT; |
184 | else | |
4b1295b0 | 185 | status = status - missing; |
814a8d50 AP |
186 | } |
187 | mutex_unlock(&spidev->buf_lock); | |
188 | ||
189 | return status; | |
190 | } | |
191 | ||
192 | /* Write-only message with current device setup */ | |
193 | static ssize_t | |
194 | spidev_write(struct file *filp, const char __user *buf, | |
195 | size_t count, loff_t *f_pos) | |
196 | { | |
197 | struct spidev_data *spidev; | |
814a8d50 AP |
198 | ssize_t status = 0; |
199 | unsigned long missing; | |
200 | ||
201 | /* chipselect only toggles at start or end of operation */ | |
202 | if (count > bufsiz) | |
203 | return -EMSGSIZE; | |
204 | ||
205 | spidev = filp->private_data; | |
814a8d50 AP |
206 | |
207 | mutex_lock(&spidev->buf_lock); | |
208 | missing = copy_from_user(spidev->buffer, buf, count); | |
209 | if (missing == 0) { | |
25d5cb4b | 210 | status = spidev_sync_write(spidev, count); |
814a8d50 AP |
211 | } else |
212 | status = -EFAULT; | |
213 | mutex_unlock(&spidev->buf_lock); | |
214 | ||
215 | return status; | |
216 | } | |
217 | ||
218 | static int spidev_message(struct spidev_data *spidev, | |
219 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
220 | { | |
221 | struct spi_message msg; | |
222 | struct spi_transfer *k_xfers; | |
223 | struct spi_transfer *k_tmp; | |
224 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 AP |
225 | unsigned n, total; |
226 | u8 *buf; | |
227 | int status = -EFAULT; | |
228 | ||
229 | spi_message_init(&msg); | |
230 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
231 | if (k_xfers == NULL) | |
232 | return -ENOMEM; | |
233 | ||
234 | /* Construct spi_message, copying any tx data to bounce buffer. | |
235 | * We walk the array of user-provided transfers, using each one | |
236 | * to initialize a kernel version of the same transfer. | |
237 | */ | |
814a8d50 AP |
238 | buf = spidev->buffer; |
239 | total = 0; | |
240 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
241 | n; | |
242 | n--, k_tmp++, u_tmp++) { | |
243 | k_tmp->len = u_tmp->len; | |
244 | ||
da90fa8f | 245 | total += k_tmp->len; |
14a1fe5d IA |
246 | /* Check total length of transfers. Also check each |
247 | * transfer length to avoid arithmetic overflow. | |
248 | */ | |
249 | if (total > bufsiz || k_tmp->len > bufsiz) { | |
da90fa8f DP |
250 | status = -EMSGSIZE; |
251 | goto done; | |
252 | } | |
253 | ||
814a8d50 AP |
254 | if (u_tmp->rx_buf) { |
255 | k_tmp->rx_buf = buf; | |
96ddbf50 | 256 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 257 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 258 | u_tmp->len)) |
814a8d50 AP |
259 | goto done; |
260 | } | |
261 | if (u_tmp->tx_buf) { | |
262 | k_tmp->tx_buf = buf; | |
4917d927 | 263 | if (copy_from_user(buf, (const u8 __user *) |
142956af | 264 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
265 | u_tmp->len)) |
266 | goto done; | |
267 | } | |
814a8d50 AP |
268 | buf += k_tmp->len; |
269 | ||
270 | k_tmp->cs_change = !!u_tmp->cs_change; | |
271 | k_tmp->bits_per_word = u_tmp->bits_per_word; | |
272 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
273 | k_tmp->speed_hz = u_tmp->speed_hz; | |
274 | #ifdef VERBOSE | |
41df70d9 | 275 | dev_dbg(&spidev->spi->dev, |
814a8d50 AP |
276 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", |
277 | u_tmp->len, | |
278 | u_tmp->rx_buf ? "rx " : "", | |
279 | u_tmp->tx_buf ? "tx " : "", | |
280 | u_tmp->cs_change ? "cs " : "", | |
41df70d9 | 281 | u_tmp->bits_per_word ? : spidev->spi->bits_per_word, |
814a8d50 | 282 | u_tmp->delay_usecs, |
41df70d9 | 283 | u_tmp->speed_hz ? : spidev->spi->max_speed_hz); |
814a8d50 AP |
284 | #endif |
285 | spi_message_add_tail(k_tmp, &msg); | |
286 | } | |
287 | ||
25d5cb4b | 288 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
289 | if (status < 0) |
290 | goto done; | |
291 | ||
292 | /* copy any rx data out of bounce buffer */ | |
293 | buf = spidev->buffer; | |
294 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { | |
295 | if (u_tmp->rx_buf) { | |
4917d927 | 296 | if (__copy_to_user((u8 __user *) |
142956af | 297 | (uintptr_t) u_tmp->rx_buf, buf, |
814a8d50 AP |
298 | u_tmp->len)) { |
299 | status = -EFAULT; | |
300 | goto done; | |
301 | } | |
302 | } | |
303 | buf += u_tmp->len; | |
304 | } | |
305 | status = total; | |
306 | ||
307 | done: | |
814a8d50 AP |
308 | kfree(k_xfers); |
309 | return status; | |
310 | } | |
311 | ||
4ef754b7 AC |
312 | static long |
313 | spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
814a8d50 AP |
314 | { |
315 | int err = 0; | |
316 | int retval = 0; | |
317 | struct spidev_data *spidev; | |
318 | struct spi_device *spi; | |
319 | u32 tmp; | |
320 | unsigned n_ioc; | |
321 | struct spi_ioc_transfer *ioc; | |
322 | ||
323 | /* Check type and command number */ | |
324 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
325 | return -ENOTTY; | |
326 | ||
327 | /* Check access direction once here; don't repeat below. | |
328 | * IOC_DIR is from the user perspective, while access_ok is | |
329 | * from the kernel perspective; so they look reversed. | |
330 | */ | |
331 | if (_IOC_DIR(cmd) & _IOC_READ) | |
332 | err = !access_ok(VERIFY_WRITE, | |
333 | (void __user *)arg, _IOC_SIZE(cmd)); | |
334 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
335 | err = !access_ok(VERIFY_READ, | |
336 | (void __user *)arg, _IOC_SIZE(cmd)); | |
337 | if (err) | |
338 | return -EFAULT; | |
339 | ||
25d5cb4b DB |
340 | /* guard against device removal before, or while, |
341 | * we issue this ioctl. | |
342 | */ | |
814a8d50 | 343 | spidev = filp->private_data; |
25d5cb4b DB |
344 | spin_lock_irq(&spidev->spi_lock); |
345 | spi = spi_dev_get(spidev->spi); | |
346 | spin_unlock_irq(&spidev->spi_lock); | |
347 | ||
348 | if (spi == NULL) | |
349 | return -ESHUTDOWN; | |
814a8d50 | 350 | |
4ef754b7 AC |
351 | /* use the buffer lock here for triple duty: |
352 | * - prevent I/O (from us) so calling spi_setup() is safe; | |
353 | * - prevent concurrent SPI_IOC_WR_* from morphing | |
354 | * data fields while SPI_IOC_RD_* reads them; | |
355 | * - SPI_IOC_MESSAGE needs the buffer locked "normally". | |
356 | */ | |
357 | mutex_lock(&spidev->buf_lock); | |
358 | ||
814a8d50 AP |
359 | switch (cmd) { |
360 | /* read requests */ | |
361 | case SPI_IOC_RD_MODE: | |
362 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
363 | (__u8 __user *)arg); | |
364 | break; | |
365 | case SPI_IOC_RD_LSB_FIRST: | |
366 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
367 | (__u8 __user *)arg); | |
368 | break; | |
369 | case SPI_IOC_RD_BITS_PER_WORD: | |
370 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
371 | break; | |
372 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
373 | retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg); | |
374 | break; | |
375 | ||
376 | /* write requests */ | |
377 | case SPI_IOC_WR_MODE: | |
378 | retval = __get_user(tmp, (u8 __user *)arg); | |
379 | if (retval == 0) { | |
380 | u8 save = spi->mode; | |
381 | ||
382 | if (tmp & ~SPI_MODE_MASK) { | |
383 | retval = -EINVAL; | |
384 | break; | |
385 | } | |
386 | ||
387 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
388 | spi->mode = (u8)tmp; | |
389 | retval = spi_setup(spi); | |
390 | if (retval < 0) | |
391 | spi->mode = save; | |
392 | else | |
393 | dev_dbg(&spi->dev, "spi mode %02x\n", tmp); | |
394 | } | |
395 | break; | |
396 | case SPI_IOC_WR_LSB_FIRST: | |
397 | retval = __get_user(tmp, (__u8 __user *)arg); | |
398 | if (retval == 0) { | |
399 | u8 save = spi->mode; | |
400 | ||
401 | if (tmp) | |
402 | spi->mode |= SPI_LSB_FIRST; | |
403 | else | |
404 | spi->mode &= ~SPI_LSB_FIRST; | |
405 | retval = spi_setup(spi); | |
406 | if (retval < 0) | |
407 | spi->mode = save; | |
408 | else | |
409 | dev_dbg(&spi->dev, "%csb first\n", | |
410 | tmp ? 'l' : 'm'); | |
411 | } | |
412 | break; | |
413 | case SPI_IOC_WR_BITS_PER_WORD: | |
414 | retval = __get_user(tmp, (__u8 __user *)arg); | |
415 | if (retval == 0) { | |
416 | u8 save = spi->bits_per_word; | |
417 | ||
418 | spi->bits_per_word = tmp; | |
419 | retval = spi_setup(spi); | |
420 | if (retval < 0) | |
421 | spi->bits_per_word = save; | |
422 | else | |
423 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
424 | } | |
425 | break; | |
426 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
427 | retval = __get_user(tmp, (__u32 __user *)arg); | |
428 | if (retval == 0) { | |
429 | u32 save = spi->max_speed_hz; | |
430 | ||
431 | spi->max_speed_hz = tmp; | |
432 | retval = spi_setup(spi); | |
433 | if (retval < 0) | |
434 | spi->max_speed_hz = save; | |
435 | else | |
436 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
437 | } | |
438 | break; | |
439 | ||
440 | default: | |
441 | /* segmented and/or full-duplex I/O request */ | |
442 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
25d5cb4b DB |
443 | || _IOC_DIR(cmd) != _IOC_WRITE) { |
444 | retval = -ENOTTY; | |
445 | break; | |
446 | } | |
814a8d50 AP |
447 | |
448 | tmp = _IOC_SIZE(cmd); | |
449 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { | |
450 | retval = -EINVAL; | |
451 | break; | |
452 | } | |
453 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
454 | if (n_ioc == 0) | |
455 | break; | |
456 | ||
457 | /* copy into scratch area */ | |
458 | ioc = kmalloc(tmp, GFP_KERNEL); | |
459 | if (!ioc) { | |
460 | retval = -ENOMEM; | |
461 | break; | |
462 | } | |
463 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { | |
9bea3f29 | 464 | kfree(ioc); |
814a8d50 AP |
465 | retval = -EFAULT; |
466 | break; | |
467 | } | |
468 | ||
469 | /* translate to spi_message, execute */ | |
470 | retval = spidev_message(spidev, ioc, n_ioc); | |
471 | kfree(ioc); | |
472 | break; | |
473 | } | |
4ef754b7 AC |
474 | |
475 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 476 | spi_dev_put(spi); |
814a8d50 AP |
477 | return retval; |
478 | } | |
479 | ||
7d48ec36 BW |
480 | #ifdef CONFIG_COMPAT |
481 | static long | |
482 | spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
483 | { | |
484 | return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); | |
485 | } | |
486 | #else | |
487 | #define spidev_compat_ioctl NULL | |
488 | #endif /* CONFIG_COMPAT */ | |
489 | ||
814a8d50 AP |
490 | static int spidev_open(struct inode *inode, struct file *filp) |
491 | { | |
492 | struct spidev_data *spidev; | |
493 | int status = -ENXIO; | |
494 | ||
495 | mutex_lock(&device_list_lock); | |
496 | ||
497 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 498 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
499 | status = 0; |
500 | break; | |
501 | } | |
502 | } | |
503 | if (status == 0) { | |
504 | if (!spidev->buffer) { | |
505 | spidev->buffer = kmalloc(bufsiz, GFP_KERNEL); | |
506 | if (!spidev->buffer) { | |
507 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
508 | status = -ENOMEM; | |
509 | } | |
510 | } | |
511 | if (status == 0) { | |
512 | spidev->users++; | |
513 | filp->private_data = spidev; | |
514 | nonseekable_open(inode, filp); | |
515 | } | |
516 | } else | |
517 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
518 | ||
519 | mutex_unlock(&device_list_lock); | |
520 | return status; | |
521 | } | |
522 | ||
523 | static int spidev_release(struct inode *inode, struct file *filp) | |
524 | { | |
525 | struct spidev_data *spidev; | |
526 | int status = 0; | |
527 | ||
528 | mutex_lock(&device_list_lock); | |
529 | spidev = filp->private_data; | |
530 | filp->private_data = NULL; | |
b2c8dadd DB |
531 | |
532 | /* last close? */ | |
814a8d50 AP |
533 | spidev->users--; |
534 | if (!spidev->users) { | |
b2c8dadd DB |
535 | int dofree; |
536 | ||
814a8d50 AP |
537 | kfree(spidev->buffer); |
538 | spidev->buffer = NULL; | |
b2c8dadd DB |
539 | |
540 | /* ... after we unbound from the underlying device? */ | |
541 | spin_lock_irq(&spidev->spi_lock); | |
542 | dofree = (spidev->spi == NULL); | |
543 | spin_unlock_irq(&spidev->spi_lock); | |
544 | ||
545 | if (dofree) | |
546 | kfree(spidev); | |
814a8d50 AP |
547 | } |
548 | mutex_unlock(&device_list_lock); | |
549 | ||
550 | return status; | |
551 | } | |
552 | ||
828c0950 | 553 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
554 | .owner = THIS_MODULE, |
555 | /* REVISIT switch to aio primitives, so that userspace | |
556 | * gets more complete API coverage. It'll simplify things | |
557 | * too, except for the locking. | |
558 | */ | |
559 | .write = spidev_write, | |
560 | .read = spidev_read, | |
4ef754b7 | 561 | .unlocked_ioctl = spidev_ioctl, |
7d48ec36 | 562 | .compat_ioctl = spidev_compat_ioctl, |
814a8d50 AP |
563 | .open = spidev_open, |
564 | .release = spidev_release, | |
6038f373 | 565 | .llseek = no_llseek, |
814a8d50 AP |
566 | }; |
567 | ||
568 | /*-------------------------------------------------------------------------*/ | |
569 | ||
570 | /* The main reason to have this class is to make mdev/udev create the | |
571 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
572 | * It also simplifies memory management. | |
573 | */ | |
574 | ||
b2c8dadd | 575 | static struct class *spidev_class; |
814a8d50 AP |
576 | |
577 | /*-------------------------------------------------------------------------*/ | |
578 | ||
fd4a319b | 579 | static int spidev_probe(struct spi_device *spi) |
814a8d50 AP |
580 | { |
581 | struct spidev_data *spidev; | |
582 | int status; | |
583 | unsigned long minor; | |
584 | ||
585 | /* Allocate driver data */ | |
586 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
587 | if (!spidev) | |
588 | return -ENOMEM; | |
589 | ||
590 | /* Initialize the driver data */ | |
591 | spidev->spi = spi; | |
25d5cb4b | 592 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
593 | mutex_init(&spidev->buf_lock); |
594 | ||
595 | INIT_LIST_HEAD(&spidev->device_entry); | |
596 | ||
597 | /* If we can allocate a minor number, hook up this device. | |
598 | * Reusing minors is fine so long as udev or mdev is working. | |
599 | */ | |
600 | mutex_lock(&device_list_lock); | |
0a4dd778 | 601 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 602 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
603 | struct device *dev; |
604 | ||
605 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
606 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
607 | spidev, "spidev%d.%d", | |
608 | spi->master->bus_num, spi->chip_select); | |
8179bb26 | 609 | status = PTR_RET(dev); |
814a8d50 AP |
610 | } else { |
611 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
612 | status = -ENODEV; | |
613 | } | |
614 | if (status == 0) { | |
615 | set_bit(minor, minors); | |
814a8d50 AP |
616 | list_add(&spidev->device_entry, &device_list); |
617 | } | |
618 | mutex_unlock(&device_list_lock); | |
619 | ||
aaacf4bb WO |
620 | if (status == 0) |
621 | spi_set_drvdata(spi, spidev); | |
622 | else | |
814a8d50 AP |
623 | kfree(spidev); |
624 | ||
625 | return status; | |
626 | } | |
627 | ||
fd4a319b | 628 | static int spidev_remove(struct spi_device *spi) |
814a8d50 | 629 | { |
b2c8dadd | 630 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 631 | |
25d5cb4b DB |
632 | /* make sure ops on existing fds can abort cleanly */ |
633 | spin_lock_irq(&spidev->spi_lock); | |
634 | spidev->spi = NULL; | |
b2c8dadd | 635 | spi_set_drvdata(spi, NULL); |
25d5cb4b | 636 | spin_unlock_irq(&spidev->spi_lock); |
814a8d50 | 637 | |
25d5cb4b DB |
638 | /* prevent new opens */ |
639 | mutex_lock(&device_list_lock); | |
814a8d50 | 640 | list_del(&spidev->device_entry); |
b2c8dadd DB |
641 | device_destroy(spidev_class, spidev->devt); |
642 | clear_bit(MINOR(spidev->devt), minors); | |
643 | if (spidev->users == 0) | |
644 | kfree(spidev); | |
814a8d50 AP |
645 | mutex_unlock(&device_list_lock); |
646 | ||
647 | return 0; | |
648 | } | |
649 | ||
880cfd43 | 650 | static const struct of_device_id spidev_dt_ids[] = { |
8fad805b | 651 | { .compatible = "rohm,dh2228fv" }, |
880cfd43 MR |
652 | {}, |
653 | }; | |
654 | ||
655 | MODULE_DEVICE_TABLE(of, spidev_dt_ids); | |
656 | ||
db389b61 | 657 | static struct spi_driver spidev_spi_driver = { |
814a8d50 AP |
658 | .driver = { |
659 | .name = "spidev", | |
660 | .owner = THIS_MODULE, | |
880cfd43 | 661 | .of_match_table = of_match_ptr(spidev_dt_ids), |
814a8d50 AP |
662 | }, |
663 | .probe = spidev_probe, | |
fd4a319b | 664 | .remove = spidev_remove, |
814a8d50 AP |
665 | |
666 | /* NOTE: suspend/resume methods are not necessary here. | |
667 | * We don't do anything except pass the requests to/from | |
668 | * the underlying controller. The refrigerator handles | |
669 | * most issues; the controller driver handles the rest. | |
670 | */ | |
671 | }; | |
672 | ||
673 | /*-------------------------------------------------------------------------*/ | |
674 | ||
675 | static int __init spidev_init(void) | |
676 | { | |
677 | int status; | |
678 | ||
679 | /* Claim our 256 reserved device numbers. Then register a class | |
680 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
681 | * the driver which manages those device numbers. | |
682 | */ | |
683 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
684 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
685 | if (status < 0) | |
686 | return status; | |
687 | ||
b2c8dadd DB |
688 | spidev_class = class_create(THIS_MODULE, "spidev"); |
689 | if (IS_ERR(spidev_class)) { | |
db389b61 | 690 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
b2c8dadd | 691 | return PTR_ERR(spidev_class); |
814a8d50 AP |
692 | } |
693 | ||
db389b61 | 694 | status = spi_register_driver(&spidev_spi_driver); |
814a8d50 | 695 | if (status < 0) { |
b2c8dadd | 696 | class_destroy(spidev_class); |
db389b61 | 697 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
698 | } |
699 | return status; | |
700 | } | |
701 | module_init(spidev_init); | |
702 | ||
703 | static void __exit spidev_exit(void) | |
704 | { | |
db389b61 | 705 | spi_unregister_driver(&spidev_spi_driver); |
b2c8dadd | 706 | class_destroy(spidev_class); |
db389b61 | 707 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
708 | } |
709 | module_exit(spidev_exit); | |
710 | ||
711 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
712 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
713 | MODULE_LICENSE("GPL"); | |
e0626e38 | 714 | MODULE_ALIAS("spi:spidev"); |