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 | ||
95c63cfb | 40 | #include <linux/uaccess.h> |
814a8d50 AP |
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 | 75 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ |
dc64d39b GU |
76 | | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \ |
77 | | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD) | |
814a8d50 AP |
78 | |
79 | struct spidev_data { | |
b2c8dadd | 80 | dev_t devt; |
25d5cb4b | 81 | spinlock_t spi_lock; |
814a8d50 AP |
82 | struct spi_device *spi; |
83 | struct list_head device_entry; | |
84 | ||
b2c8dadd | 85 | /* buffer is NULL unless this device is open (users > 0) */ |
814a8d50 AP |
86 | struct mutex buf_lock; |
87 | unsigned users; | |
88 | u8 *buffer; | |
89 | }; | |
90 | ||
91 | static LIST_HEAD(device_list); | |
92 | static DEFINE_MUTEX(device_list_lock); | |
93 | ||
94 | static unsigned bufsiz = 4096; | |
95 | module_param(bufsiz, uint, S_IRUGO); | |
96 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
97 | ||
98 | /*-------------------------------------------------------------------------*/ | |
99 | ||
25d5cb4b DB |
100 | /* |
101 | * We can't use the standard synchronous wrappers for file I/O; we | |
102 | * need to protect against async removal of the underlying spi_device. | |
103 | */ | |
104 | static void spidev_complete(void *arg) | |
105 | { | |
106 | complete(arg); | |
107 | } | |
108 | ||
109 | static ssize_t | |
110 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
111 | { | |
112 | DECLARE_COMPLETION_ONSTACK(done); | |
113 | int status; | |
114 | ||
115 | message->complete = spidev_complete; | |
116 | message->context = &done; | |
117 | ||
118 | spin_lock_irq(&spidev->spi_lock); | |
119 | if (spidev->spi == NULL) | |
120 | status = -ESHUTDOWN; | |
121 | else | |
122 | status = spi_async(spidev->spi, message); | |
123 | spin_unlock_irq(&spidev->spi_lock); | |
124 | ||
125 | if (status == 0) { | |
126 | wait_for_completion(&done); | |
127 | status = message->status; | |
128 | if (status == 0) | |
129 | status = message->actual_length; | |
130 | } | |
131 | return status; | |
132 | } | |
133 | ||
134 | static inline ssize_t | |
135 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
136 | { | |
137 | struct spi_transfer t = { | |
138 | .tx_buf = spidev->buffer, | |
139 | .len = len, | |
140 | }; | |
141 | struct spi_message m; | |
142 | ||
143 | spi_message_init(&m); | |
144 | spi_message_add_tail(&t, &m); | |
145 | return spidev_sync(spidev, &m); | |
146 | } | |
147 | ||
148 | static inline ssize_t | |
149 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
150 | { | |
151 | struct spi_transfer t = { | |
152 | .rx_buf = spidev->buffer, | |
153 | .len = len, | |
154 | }; | |
155 | struct spi_message m; | |
156 | ||
157 | spi_message_init(&m); | |
158 | spi_message_add_tail(&t, &m); | |
159 | return spidev_sync(spidev, &m); | |
160 | } | |
161 | ||
162 | /*-------------------------------------------------------------------------*/ | |
163 | ||
814a8d50 AP |
164 | /* Read-only message with current device setup */ |
165 | static ssize_t | |
166 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
167 | { | |
168 | struct spidev_data *spidev; | |
814a8d50 AP |
169 | ssize_t status = 0; |
170 | ||
171 | /* chipselect only toggles at start or end of operation */ | |
172 | if (count > bufsiz) | |
173 | return -EMSGSIZE; | |
174 | ||
175 | spidev = filp->private_data; | |
814a8d50 AP |
176 | |
177 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 178 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 179 | if (status > 0) { |
814a8d50 AP |
180 | unsigned long missing; |
181 | ||
4b1295b0 SS |
182 | missing = copy_to_user(buf, spidev->buffer, status); |
183 | if (missing == status) | |
814a8d50 AP |
184 | status = -EFAULT; |
185 | else | |
4b1295b0 | 186 | status = status - missing; |
814a8d50 AP |
187 | } |
188 | mutex_unlock(&spidev->buf_lock); | |
189 | ||
190 | return status; | |
191 | } | |
192 | ||
193 | /* Write-only message with current device setup */ | |
194 | static ssize_t | |
195 | spidev_write(struct file *filp, const char __user *buf, | |
196 | size_t count, loff_t *f_pos) | |
197 | { | |
198 | struct spidev_data *spidev; | |
814a8d50 AP |
199 | ssize_t status = 0; |
200 | unsigned long missing; | |
201 | ||
202 | /* chipselect only toggles at start or end of operation */ | |
203 | if (count > bufsiz) | |
204 | return -EMSGSIZE; | |
205 | ||
206 | spidev = filp->private_data; | |
814a8d50 AP |
207 | |
208 | mutex_lock(&spidev->buf_lock); | |
209 | missing = copy_from_user(spidev->buffer, buf, count); | |
95c63cfb | 210 | if (missing == 0) |
25d5cb4b | 211 | status = spidev_sync_write(spidev, count); |
95c63cfb | 212 | else |
814a8d50 AP |
213 | status = -EFAULT; |
214 | mutex_unlock(&spidev->buf_lock); | |
215 | ||
216 | return status; | |
217 | } | |
218 | ||
219 | static int spidev_message(struct spidev_data *spidev, | |
220 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
221 | { | |
222 | struct spi_message msg; | |
223 | struct spi_transfer *k_xfers; | |
224 | struct spi_transfer *k_tmp; | |
225 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 AP |
226 | unsigned n, total; |
227 | u8 *buf; | |
228 | int status = -EFAULT; | |
229 | ||
230 | spi_message_init(&msg); | |
231 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
232 | if (k_xfers == NULL) | |
233 | return -ENOMEM; | |
234 | ||
235 | /* Construct spi_message, copying any tx data to bounce buffer. | |
236 | * We walk the array of user-provided transfers, using each one | |
237 | * to initialize a kernel version of the same transfer. | |
238 | */ | |
814a8d50 AP |
239 | buf = spidev->buffer; |
240 | total = 0; | |
241 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
242 | n; | |
243 | n--, k_tmp++, u_tmp++) { | |
244 | k_tmp->len = u_tmp->len; | |
245 | ||
da90fa8f DP |
246 | total += k_tmp->len; |
247 | if (total > bufsiz) { | |
248 | status = -EMSGSIZE; | |
249 | goto done; | |
250 | } | |
251 | ||
814a8d50 AP |
252 | if (u_tmp->rx_buf) { |
253 | k_tmp->rx_buf = buf; | |
96ddbf50 | 254 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 255 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 256 | u_tmp->len)) |
814a8d50 AP |
257 | goto done; |
258 | } | |
259 | if (u_tmp->tx_buf) { | |
260 | k_tmp->tx_buf = buf; | |
4917d927 | 261 | if (copy_from_user(buf, (const u8 __user *) |
142956af | 262 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
263 | u_tmp->len)) |
264 | goto done; | |
265 | } | |
814a8d50 AP |
266 | buf += k_tmp->len; |
267 | ||
268 | k_tmp->cs_change = !!u_tmp->cs_change; | |
dc64d39b GU |
269 | k_tmp->tx_nbits = u_tmp->tx_nbits; |
270 | k_tmp->rx_nbits = u_tmp->rx_nbits; | |
814a8d50 AP |
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; | |
dc64d39b GU |
365 | case SPI_IOC_RD_MODE32: |
366 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
367 | (__u32 __user *)arg); | |
368 | break; | |
814a8d50 AP |
369 | case SPI_IOC_RD_LSB_FIRST: |
370 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
371 | (__u8 __user *)arg); | |
372 | break; | |
373 | case SPI_IOC_RD_BITS_PER_WORD: | |
374 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
375 | break; | |
376 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
377 | retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg); | |
378 | break; | |
379 | ||
380 | /* write requests */ | |
381 | case SPI_IOC_WR_MODE: | |
dc64d39b GU |
382 | case SPI_IOC_WR_MODE32: |
383 | if (cmd == SPI_IOC_WR_MODE) | |
384 | retval = __get_user(tmp, (u8 __user *)arg); | |
385 | else | |
386 | retval = __get_user(tmp, (u32 __user *)arg); | |
814a8d50 | 387 | if (retval == 0) { |
e6456186 | 388 | u32 save = spi->mode; |
814a8d50 AP |
389 | |
390 | if (tmp & ~SPI_MODE_MASK) { | |
391 | retval = -EINVAL; | |
392 | break; | |
393 | } | |
394 | ||
395 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
dc64d39b | 396 | spi->mode = (u16)tmp; |
814a8d50 AP |
397 | retval = spi_setup(spi); |
398 | if (retval < 0) | |
399 | spi->mode = save; | |
400 | else | |
dc64d39b | 401 | dev_dbg(&spi->dev, "spi mode %x\n", tmp); |
814a8d50 AP |
402 | } |
403 | break; | |
404 | case SPI_IOC_WR_LSB_FIRST: | |
405 | retval = __get_user(tmp, (__u8 __user *)arg); | |
406 | if (retval == 0) { | |
e6456186 | 407 | u32 save = spi->mode; |
814a8d50 AP |
408 | |
409 | if (tmp) | |
410 | spi->mode |= SPI_LSB_FIRST; | |
411 | else | |
412 | spi->mode &= ~SPI_LSB_FIRST; | |
413 | retval = spi_setup(spi); | |
414 | if (retval < 0) | |
415 | spi->mode = save; | |
416 | else | |
417 | dev_dbg(&spi->dev, "%csb first\n", | |
418 | tmp ? 'l' : 'm'); | |
419 | } | |
420 | break; | |
421 | case SPI_IOC_WR_BITS_PER_WORD: | |
422 | retval = __get_user(tmp, (__u8 __user *)arg); | |
423 | if (retval == 0) { | |
424 | u8 save = spi->bits_per_word; | |
425 | ||
426 | spi->bits_per_word = tmp; | |
427 | retval = spi_setup(spi); | |
428 | if (retval < 0) | |
429 | spi->bits_per_word = save; | |
430 | else | |
431 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
432 | } | |
433 | break; | |
434 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
435 | retval = __get_user(tmp, (__u32 __user *)arg); | |
436 | if (retval == 0) { | |
437 | u32 save = spi->max_speed_hz; | |
438 | ||
439 | spi->max_speed_hz = tmp; | |
440 | retval = spi_setup(spi); | |
441 | if (retval < 0) | |
442 | spi->max_speed_hz = save; | |
443 | else | |
444 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
445 | } | |
446 | break; | |
447 | ||
448 | default: | |
449 | /* segmented and/or full-duplex I/O request */ | |
450 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
25d5cb4b DB |
451 | || _IOC_DIR(cmd) != _IOC_WRITE) { |
452 | retval = -ENOTTY; | |
453 | break; | |
454 | } | |
814a8d50 AP |
455 | |
456 | tmp = _IOC_SIZE(cmd); | |
457 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { | |
458 | retval = -EINVAL; | |
459 | break; | |
460 | } | |
461 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
462 | if (n_ioc == 0) | |
463 | break; | |
464 | ||
465 | /* copy into scratch area */ | |
466 | ioc = kmalloc(tmp, GFP_KERNEL); | |
467 | if (!ioc) { | |
468 | retval = -ENOMEM; | |
469 | break; | |
470 | } | |
471 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { | |
9bea3f29 | 472 | kfree(ioc); |
814a8d50 AP |
473 | retval = -EFAULT; |
474 | break; | |
475 | } | |
476 | ||
477 | /* translate to spi_message, execute */ | |
478 | retval = spidev_message(spidev, ioc, n_ioc); | |
479 | kfree(ioc); | |
480 | break; | |
481 | } | |
4ef754b7 AC |
482 | |
483 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 484 | spi_dev_put(spi); |
814a8d50 AP |
485 | return retval; |
486 | } | |
487 | ||
7d48ec36 BW |
488 | #ifdef CONFIG_COMPAT |
489 | static long | |
490 | spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
491 | { | |
492 | return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); | |
493 | } | |
494 | #else | |
495 | #define spidev_compat_ioctl NULL | |
496 | #endif /* CONFIG_COMPAT */ | |
497 | ||
814a8d50 AP |
498 | static int spidev_open(struct inode *inode, struct file *filp) |
499 | { | |
500 | struct spidev_data *spidev; | |
501 | int status = -ENXIO; | |
502 | ||
503 | mutex_lock(&device_list_lock); | |
504 | ||
505 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 506 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
507 | status = 0; |
508 | break; | |
509 | } | |
510 | } | |
511 | if (status == 0) { | |
512 | if (!spidev->buffer) { | |
513 | spidev->buffer = kmalloc(bufsiz, GFP_KERNEL); | |
514 | if (!spidev->buffer) { | |
515 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
516 | status = -ENOMEM; | |
517 | } | |
518 | } | |
519 | if (status == 0) { | |
520 | spidev->users++; | |
521 | filp->private_data = spidev; | |
522 | nonseekable_open(inode, filp); | |
523 | } | |
524 | } else | |
525 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
526 | ||
527 | mutex_unlock(&device_list_lock); | |
528 | return status; | |
529 | } | |
530 | ||
531 | static int spidev_release(struct inode *inode, struct file *filp) | |
532 | { | |
533 | struct spidev_data *spidev; | |
534 | int status = 0; | |
535 | ||
536 | mutex_lock(&device_list_lock); | |
537 | spidev = filp->private_data; | |
538 | filp->private_data = NULL; | |
b2c8dadd DB |
539 | |
540 | /* last close? */ | |
814a8d50 AP |
541 | spidev->users--; |
542 | if (!spidev->users) { | |
b2c8dadd DB |
543 | int dofree; |
544 | ||
814a8d50 AP |
545 | kfree(spidev->buffer); |
546 | spidev->buffer = NULL; | |
b2c8dadd DB |
547 | |
548 | /* ... after we unbound from the underlying device? */ | |
549 | spin_lock_irq(&spidev->spi_lock); | |
550 | dofree = (spidev->spi == NULL); | |
551 | spin_unlock_irq(&spidev->spi_lock); | |
552 | ||
553 | if (dofree) | |
554 | kfree(spidev); | |
814a8d50 AP |
555 | } |
556 | mutex_unlock(&device_list_lock); | |
557 | ||
558 | return status; | |
559 | } | |
560 | ||
828c0950 | 561 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
562 | .owner = THIS_MODULE, |
563 | /* REVISIT switch to aio primitives, so that userspace | |
564 | * gets more complete API coverage. It'll simplify things | |
565 | * too, except for the locking. | |
566 | */ | |
567 | .write = spidev_write, | |
568 | .read = spidev_read, | |
4ef754b7 | 569 | .unlocked_ioctl = spidev_ioctl, |
7d48ec36 | 570 | .compat_ioctl = spidev_compat_ioctl, |
814a8d50 AP |
571 | .open = spidev_open, |
572 | .release = spidev_release, | |
6038f373 | 573 | .llseek = no_llseek, |
814a8d50 AP |
574 | }; |
575 | ||
576 | /*-------------------------------------------------------------------------*/ | |
577 | ||
578 | /* The main reason to have this class is to make mdev/udev create the | |
579 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
580 | * It also simplifies memory management. | |
581 | */ | |
582 | ||
b2c8dadd | 583 | static struct class *spidev_class; |
814a8d50 AP |
584 | |
585 | /*-------------------------------------------------------------------------*/ | |
586 | ||
fd4a319b | 587 | static int spidev_probe(struct spi_device *spi) |
814a8d50 AP |
588 | { |
589 | struct spidev_data *spidev; | |
590 | int status; | |
591 | unsigned long minor; | |
592 | ||
593 | /* Allocate driver data */ | |
594 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
595 | if (!spidev) | |
596 | return -ENOMEM; | |
597 | ||
598 | /* Initialize the driver data */ | |
599 | spidev->spi = spi; | |
25d5cb4b | 600 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
601 | mutex_init(&spidev->buf_lock); |
602 | ||
603 | INIT_LIST_HEAD(&spidev->device_entry); | |
604 | ||
605 | /* If we can allocate a minor number, hook up this device. | |
606 | * Reusing minors is fine so long as udev or mdev is working. | |
607 | */ | |
608 | mutex_lock(&device_list_lock); | |
0a4dd778 | 609 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 610 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
611 | struct device *dev; |
612 | ||
613 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
614 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
615 | spidev, "spidev%d.%d", | |
616 | spi->master->bus_num, spi->chip_select); | |
8c6ffba0 | 617 | status = PTR_ERR_OR_ZERO(dev); |
814a8d50 AP |
618 | } else { |
619 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
620 | status = -ENODEV; | |
621 | } | |
622 | if (status == 0) { | |
623 | set_bit(minor, minors); | |
814a8d50 AP |
624 | list_add(&spidev->device_entry, &device_list); |
625 | } | |
626 | mutex_unlock(&device_list_lock); | |
627 | ||
aaacf4bb WO |
628 | if (status == 0) |
629 | spi_set_drvdata(spi, spidev); | |
630 | else | |
814a8d50 AP |
631 | kfree(spidev); |
632 | ||
633 | return status; | |
634 | } | |
635 | ||
fd4a319b | 636 | static int spidev_remove(struct spi_device *spi) |
814a8d50 | 637 | { |
b2c8dadd | 638 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 639 | |
25d5cb4b DB |
640 | /* make sure ops on existing fds can abort cleanly */ |
641 | spin_lock_irq(&spidev->spi_lock); | |
642 | spidev->spi = NULL; | |
643 | spin_unlock_irq(&spidev->spi_lock); | |
814a8d50 | 644 | |
25d5cb4b DB |
645 | /* prevent new opens */ |
646 | mutex_lock(&device_list_lock); | |
814a8d50 | 647 | list_del(&spidev->device_entry); |
b2c8dadd DB |
648 | device_destroy(spidev_class, spidev->devt); |
649 | clear_bit(MINOR(spidev->devt), minors); | |
650 | if (spidev->users == 0) | |
651 | kfree(spidev); | |
814a8d50 AP |
652 | mutex_unlock(&device_list_lock); |
653 | ||
654 | return 0; | |
655 | } | |
656 | ||
880cfd43 | 657 | static const struct of_device_id spidev_dt_ids[] = { |
8fad805b | 658 | { .compatible = "rohm,dh2228fv" }, |
880cfd43 MR |
659 | {}, |
660 | }; | |
661 | ||
662 | MODULE_DEVICE_TABLE(of, spidev_dt_ids); | |
663 | ||
db389b61 | 664 | static struct spi_driver spidev_spi_driver = { |
814a8d50 AP |
665 | .driver = { |
666 | .name = "spidev", | |
667 | .owner = THIS_MODULE, | |
880cfd43 | 668 | .of_match_table = of_match_ptr(spidev_dt_ids), |
814a8d50 AP |
669 | }, |
670 | .probe = spidev_probe, | |
fd4a319b | 671 | .remove = spidev_remove, |
814a8d50 AP |
672 | |
673 | /* NOTE: suspend/resume methods are not necessary here. | |
674 | * We don't do anything except pass the requests to/from | |
675 | * the underlying controller. The refrigerator handles | |
676 | * most issues; the controller driver handles the rest. | |
677 | */ | |
678 | }; | |
679 | ||
680 | /*-------------------------------------------------------------------------*/ | |
681 | ||
682 | static int __init spidev_init(void) | |
683 | { | |
684 | int status; | |
685 | ||
686 | /* Claim our 256 reserved device numbers. Then register a class | |
687 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
688 | * the driver which manages those device numbers. | |
689 | */ | |
690 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
691 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
692 | if (status < 0) | |
693 | return status; | |
694 | ||
b2c8dadd DB |
695 | spidev_class = class_create(THIS_MODULE, "spidev"); |
696 | if (IS_ERR(spidev_class)) { | |
db389b61 | 697 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
b2c8dadd | 698 | return PTR_ERR(spidev_class); |
814a8d50 AP |
699 | } |
700 | ||
db389b61 | 701 | status = spi_register_driver(&spidev_spi_driver); |
814a8d50 | 702 | if (status < 0) { |
b2c8dadd | 703 | class_destroy(spidev_class); |
db389b61 | 704 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
705 | } |
706 | return status; | |
707 | } | |
708 | module_init(spidev_init); | |
709 | ||
710 | static void __exit spidev_exit(void) | |
711 | { | |
db389b61 | 712 | spi_unregister_driver(&spidev_spi_driver); |
b2c8dadd | 713 | class_destroy(spidev_class); |
db389b61 | 714 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
715 | } |
716 | module_exit(spidev_exit); | |
717 | ||
718 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
719 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
720 | MODULE_LICENSE("GPL"); | |
e0626e38 | 721 | MODULE_ALIAS("spi:spidev"); |