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Commit | Line | Data |
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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 | ||
865f6d19 | 85 | /* TX/RX buffers are NULL unless this device is open (users > 0) */ |
814a8d50 AP |
86 | struct mutex buf_lock; |
87 | unsigned users; | |
865f6d19 RJ |
88 | u8 *tx_buffer; |
89 | u8 *rx_buffer; | |
91690516 | 90 | u32 speed_hz; |
814a8d50 AP |
91 | }; |
92 | ||
93 | static LIST_HEAD(device_list); | |
94 | static DEFINE_MUTEX(device_list_lock); | |
95 | ||
96 | static unsigned bufsiz = 4096; | |
97 | module_param(bufsiz, uint, S_IRUGO); | |
98 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
99 | ||
100 | /*-------------------------------------------------------------------------*/ | |
101 | ||
25d5cb4b DB |
102 | /* |
103 | * We can't use the standard synchronous wrappers for file I/O; we | |
104 | * need to protect against async removal of the underlying spi_device. | |
105 | */ | |
106 | static void spidev_complete(void *arg) | |
107 | { | |
108 | complete(arg); | |
109 | } | |
110 | ||
111 | static ssize_t | |
112 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
113 | { | |
114 | DECLARE_COMPLETION_ONSTACK(done); | |
115 | int status; | |
116 | ||
117 | message->complete = spidev_complete; | |
118 | message->context = &done; | |
119 | ||
120 | spin_lock_irq(&spidev->spi_lock); | |
121 | if (spidev->spi == NULL) | |
122 | status = -ESHUTDOWN; | |
123 | else | |
124 | status = spi_async(spidev->spi, message); | |
125 | spin_unlock_irq(&spidev->spi_lock); | |
126 | ||
127 | if (status == 0) { | |
128 | wait_for_completion(&done); | |
129 | status = message->status; | |
130 | if (status == 0) | |
131 | status = message->actual_length; | |
132 | } | |
133 | return status; | |
134 | } | |
135 | ||
136 | static inline ssize_t | |
137 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
138 | { | |
139 | struct spi_transfer t = { | |
865f6d19 | 140 | .tx_buf = spidev->tx_buffer, |
25d5cb4b | 141 | .len = len, |
91690516 | 142 | .speed_hz = spidev->speed_hz, |
25d5cb4b DB |
143 | }; |
144 | struct spi_message m; | |
145 | ||
146 | spi_message_init(&m); | |
147 | spi_message_add_tail(&t, &m); | |
148 | return spidev_sync(spidev, &m); | |
149 | } | |
150 | ||
151 | static inline ssize_t | |
152 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
153 | { | |
154 | struct spi_transfer t = { | |
865f6d19 | 155 | .rx_buf = spidev->rx_buffer, |
25d5cb4b | 156 | .len = len, |
91690516 | 157 | .speed_hz = spidev->speed_hz, |
25d5cb4b DB |
158 | }; |
159 | struct spi_message m; | |
160 | ||
161 | spi_message_init(&m); | |
162 | spi_message_add_tail(&t, &m); | |
163 | return spidev_sync(spidev, &m); | |
164 | } | |
165 | ||
166 | /*-------------------------------------------------------------------------*/ | |
167 | ||
814a8d50 AP |
168 | /* Read-only message with current device setup */ |
169 | static ssize_t | |
170 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
171 | { | |
172 | struct spidev_data *spidev; | |
814a8d50 AP |
173 | ssize_t status = 0; |
174 | ||
175 | /* chipselect only toggles at start or end of operation */ | |
176 | if (count > bufsiz) | |
177 | return -EMSGSIZE; | |
178 | ||
179 | spidev = filp->private_data; | |
814a8d50 AP |
180 | |
181 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 182 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 183 | if (status > 0) { |
814a8d50 AP |
184 | unsigned long missing; |
185 | ||
865f6d19 | 186 | missing = copy_to_user(buf, spidev->rx_buffer, status); |
4b1295b0 | 187 | if (missing == status) |
814a8d50 AP |
188 | status = -EFAULT; |
189 | else | |
4b1295b0 | 190 | status = status - missing; |
814a8d50 AP |
191 | } |
192 | mutex_unlock(&spidev->buf_lock); | |
193 | ||
194 | return status; | |
195 | } | |
196 | ||
197 | /* Write-only message with current device setup */ | |
198 | static ssize_t | |
199 | spidev_write(struct file *filp, const char __user *buf, | |
200 | size_t count, loff_t *f_pos) | |
201 | { | |
202 | struct spidev_data *spidev; | |
814a8d50 AP |
203 | ssize_t status = 0; |
204 | unsigned long missing; | |
205 | ||
206 | /* chipselect only toggles at start or end of operation */ | |
207 | if (count > bufsiz) | |
208 | return -EMSGSIZE; | |
209 | ||
210 | spidev = filp->private_data; | |
814a8d50 AP |
211 | |
212 | mutex_lock(&spidev->buf_lock); | |
865f6d19 | 213 | missing = copy_from_user(spidev->tx_buffer, buf, count); |
95c63cfb | 214 | if (missing == 0) |
25d5cb4b | 215 | status = spidev_sync_write(spidev, count); |
95c63cfb | 216 | else |
814a8d50 AP |
217 | status = -EFAULT; |
218 | mutex_unlock(&spidev->buf_lock); | |
219 | ||
220 | return status; | |
221 | } | |
222 | ||
223 | static int spidev_message(struct spidev_data *spidev, | |
224 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
225 | { | |
226 | struct spi_message msg; | |
227 | struct spi_transfer *k_xfers; | |
228 | struct spi_transfer *k_tmp; | |
229 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 | 230 | unsigned n, total; |
865f6d19 | 231 | u8 *tx_buf, *rx_buf; |
814a8d50 AP |
232 | int status = -EFAULT; |
233 | ||
234 | spi_message_init(&msg); | |
235 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
236 | if (k_xfers == NULL) | |
237 | return -ENOMEM; | |
238 | ||
239 | /* Construct spi_message, copying any tx data to bounce buffer. | |
240 | * We walk the array of user-provided transfers, using each one | |
241 | * to initialize a kernel version of the same transfer. | |
242 | */ | |
865f6d19 RJ |
243 | tx_buf = spidev->tx_buffer; |
244 | rx_buf = spidev->rx_buffer; | |
814a8d50 AP |
245 | total = 0; |
246 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
247 | n; | |
248 | n--, k_tmp++, u_tmp++) { | |
249 | k_tmp->len = u_tmp->len; | |
250 | ||
da90fa8f DP |
251 | total += k_tmp->len; |
252 | if (total > bufsiz) { | |
253 | status = -EMSGSIZE; | |
254 | goto done; | |
255 | } | |
256 | ||
814a8d50 | 257 | if (u_tmp->rx_buf) { |
865f6d19 | 258 | k_tmp->rx_buf = rx_buf; |
96ddbf50 | 259 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 260 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 261 | u_tmp->len)) |
814a8d50 AP |
262 | goto done; |
263 | } | |
264 | if (u_tmp->tx_buf) { | |
865f6d19 RJ |
265 | k_tmp->tx_buf = tx_buf; |
266 | if (copy_from_user(tx_buf, (const u8 __user *) | |
142956af | 267 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
268 | u_tmp->len)) |
269 | goto done; | |
270 | } | |
865f6d19 RJ |
271 | tx_buf += k_tmp->len; |
272 | rx_buf += k_tmp->len; | |
814a8d50 AP |
273 | |
274 | k_tmp->cs_change = !!u_tmp->cs_change; | |
dc64d39b GU |
275 | k_tmp->tx_nbits = u_tmp->tx_nbits; |
276 | k_tmp->rx_nbits = u_tmp->rx_nbits; | |
814a8d50 AP |
277 | k_tmp->bits_per_word = u_tmp->bits_per_word; |
278 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
279 | k_tmp->speed_hz = u_tmp->speed_hz; | |
91690516 MB |
280 | if (!k_tmp->speed_hz) |
281 | k_tmp->speed_hz = spidev->speed_hz; | |
814a8d50 | 282 | #ifdef VERBOSE |
41df70d9 | 283 | dev_dbg(&spidev->spi->dev, |
814a8d50 AP |
284 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", |
285 | u_tmp->len, | |
286 | u_tmp->rx_buf ? "rx " : "", | |
287 | u_tmp->tx_buf ? "tx " : "", | |
288 | u_tmp->cs_change ? "cs " : "", | |
41df70d9 | 289 | u_tmp->bits_per_word ? : spidev->spi->bits_per_word, |
814a8d50 | 290 | u_tmp->delay_usecs, |
41df70d9 | 291 | u_tmp->speed_hz ? : spidev->spi->max_speed_hz); |
814a8d50 AP |
292 | #endif |
293 | spi_message_add_tail(k_tmp, &msg); | |
294 | } | |
295 | ||
25d5cb4b | 296 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
297 | if (status < 0) |
298 | goto done; | |
299 | ||
300 | /* copy any rx data out of bounce buffer */ | |
865f6d19 | 301 | rx_buf = spidev->rx_buffer; |
814a8d50 AP |
302 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { |
303 | if (u_tmp->rx_buf) { | |
4917d927 | 304 | if (__copy_to_user((u8 __user *) |
865f6d19 | 305 | (uintptr_t) u_tmp->rx_buf, rx_buf, |
814a8d50 AP |
306 | u_tmp->len)) { |
307 | status = -EFAULT; | |
308 | goto done; | |
309 | } | |
310 | } | |
865f6d19 | 311 | rx_buf += u_tmp->len; |
814a8d50 AP |
312 | } |
313 | status = total; | |
314 | ||
315 | done: | |
814a8d50 AP |
316 | kfree(k_xfers); |
317 | return status; | |
318 | } | |
319 | ||
4ef754b7 AC |
320 | static long |
321 | spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
814a8d50 AP |
322 | { |
323 | int err = 0; | |
324 | int retval = 0; | |
325 | struct spidev_data *spidev; | |
326 | struct spi_device *spi; | |
327 | u32 tmp; | |
328 | unsigned n_ioc; | |
329 | struct spi_ioc_transfer *ioc; | |
330 | ||
331 | /* Check type and command number */ | |
332 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
333 | return -ENOTTY; | |
334 | ||
335 | /* Check access direction once here; don't repeat below. | |
336 | * IOC_DIR is from the user perspective, while access_ok is | |
337 | * from the kernel perspective; so they look reversed. | |
338 | */ | |
339 | if (_IOC_DIR(cmd) & _IOC_READ) | |
340 | err = !access_ok(VERIFY_WRITE, | |
341 | (void __user *)arg, _IOC_SIZE(cmd)); | |
342 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
343 | err = !access_ok(VERIFY_READ, | |
344 | (void __user *)arg, _IOC_SIZE(cmd)); | |
345 | if (err) | |
346 | return -EFAULT; | |
347 | ||
25d5cb4b DB |
348 | /* guard against device removal before, or while, |
349 | * we issue this ioctl. | |
350 | */ | |
814a8d50 | 351 | spidev = filp->private_data; |
25d5cb4b DB |
352 | spin_lock_irq(&spidev->spi_lock); |
353 | spi = spi_dev_get(spidev->spi); | |
354 | spin_unlock_irq(&spidev->spi_lock); | |
355 | ||
356 | if (spi == NULL) | |
357 | return -ESHUTDOWN; | |
814a8d50 | 358 | |
4ef754b7 AC |
359 | /* use the buffer lock here for triple duty: |
360 | * - prevent I/O (from us) so calling spi_setup() is safe; | |
361 | * - prevent concurrent SPI_IOC_WR_* from morphing | |
362 | * data fields while SPI_IOC_RD_* reads them; | |
363 | * - SPI_IOC_MESSAGE needs the buffer locked "normally". | |
364 | */ | |
365 | mutex_lock(&spidev->buf_lock); | |
366 | ||
814a8d50 AP |
367 | switch (cmd) { |
368 | /* read requests */ | |
369 | case SPI_IOC_RD_MODE: | |
370 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
371 | (__u8 __user *)arg); | |
372 | break; | |
dc64d39b GU |
373 | case SPI_IOC_RD_MODE32: |
374 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
375 | (__u32 __user *)arg); | |
376 | break; | |
814a8d50 AP |
377 | case SPI_IOC_RD_LSB_FIRST: |
378 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
379 | (__u8 __user *)arg); | |
380 | break; | |
381 | case SPI_IOC_RD_BITS_PER_WORD: | |
382 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
383 | break; | |
384 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
91690516 | 385 | retval = __put_user(spidev->speed_hz, (__u32 __user *)arg); |
814a8d50 AP |
386 | break; |
387 | ||
388 | /* write requests */ | |
389 | case SPI_IOC_WR_MODE: | |
dc64d39b GU |
390 | case SPI_IOC_WR_MODE32: |
391 | if (cmd == SPI_IOC_WR_MODE) | |
392 | retval = __get_user(tmp, (u8 __user *)arg); | |
393 | else | |
394 | retval = __get_user(tmp, (u32 __user *)arg); | |
814a8d50 | 395 | if (retval == 0) { |
e6456186 | 396 | u32 save = spi->mode; |
814a8d50 AP |
397 | |
398 | if (tmp & ~SPI_MODE_MASK) { | |
399 | retval = -EINVAL; | |
400 | break; | |
401 | } | |
402 | ||
403 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
dc64d39b | 404 | spi->mode = (u16)tmp; |
814a8d50 AP |
405 | retval = spi_setup(spi); |
406 | if (retval < 0) | |
407 | spi->mode = save; | |
408 | else | |
dc64d39b | 409 | dev_dbg(&spi->dev, "spi mode %x\n", tmp); |
814a8d50 AP |
410 | } |
411 | break; | |
412 | case SPI_IOC_WR_LSB_FIRST: | |
413 | retval = __get_user(tmp, (__u8 __user *)arg); | |
414 | if (retval == 0) { | |
e6456186 | 415 | u32 save = spi->mode; |
814a8d50 AP |
416 | |
417 | if (tmp) | |
418 | spi->mode |= SPI_LSB_FIRST; | |
419 | else | |
420 | spi->mode &= ~SPI_LSB_FIRST; | |
421 | retval = spi_setup(spi); | |
422 | if (retval < 0) | |
423 | spi->mode = save; | |
424 | else | |
425 | dev_dbg(&spi->dev, "%csb first\n", | |
426 | tmp ? 'l' : 'm'); | |
427 | } | |
428 | break; | |
429 | case SPI_IOC_WR_BITS_PER_WORD: | |
430 | retval = __get_user(tmp, (__u8 __user *)arg); | |
431 | if (retval == 0) { | |
432 | u8 save = spi->bits_per_word; | |
433 | ||
434 | spi->bits_per_word = tmp; | |
435 | retval = spi_setup(spi); | |
436 | if (retval < 0) | |
437 | spi->bits_per_word = save; | |
438 | else | |
439 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
440 | } | |
441 | break; | |
442 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
443 | retval = __get_user(tmp, (__u32 __user *)arg); | |
444 | if (retval == 0) { | |
445 | u32 save = spi->max_speed_hz; | |
446 | ||
447 | spi->max_speed_hz = tmp; | |
448 | retval = spi_setup(spi); | |
91690516 MB |
449 | if (retval >= 0) |
450 | spidev->speed_hz = tmp; | |
814a8d50 AP |
451 | else |
452 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
91690516 | 453 | spi->max_speed_hz = save; |
814a8d50 AP |
454 | } |
455 | break; | |
456 | ||
457 | default: | |
458 | /* segmented and/or full-duplex I/O request */ | |
459 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
25d5cb4b DB |
460 | || _IOC_DIR(cmd) != _IOC_WRITE) { |
461 | retval = -ENOTTY; | |
462 | break; | |
463 | } | |
814a8d50 AP |
464 | |
465 | tmp = _IOC_SIZE(cmd); | |
466 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { | |
467 | retval = -EINVAL; | |
468 | break; | |
469 | } | |
470 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
471 | if (n_ioc == 0) | |
472 | break; | |
473 | ||
474 | /* copy into scratch area */ | |
475 | ioc = kmalloc(tmp, GFP_KERNEL); | |
476 | if (!ioc) { | |
477 | retval = -ENOMEM; | |
478 | break; | |
479 | } | |
480 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { | |
9bea3f29 | 481 | kfree(ioc); |
814a8d50 AP |
482 | retval = -EFAULT; |
483 | break; | |
484 | } | |
485 | ||
486 | /* translate to spi_message, execute */ | |
487 | retval = spidev_message(spidev, ioc, n_ioc); | |
488 | kfree(ioc); | |
489 | break; | |
490 | } | |
4ef754b7 AC |
491 | |
492 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 493 | spi_dev_put(spi); |
814a8d50 AP |
494 | return retval; |
495 | } | |
496 | ||
7d48ec36 BW |
497 | #ifdef CONFIG_COMPAT |
498 | static long | |
499 | spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
500 | { | |
501 | return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); | |
502 | } | |
503 | #else | |
504 | #define spidev_compat_ioctl NULL | |
505 | #endif /* CONFIG_COMPAT */ | |
506 | ||
814a8d50 AP |
507 | static int spidev_open(struct inode *inode, struct file *filp) |
508 | { | |
509 | struct spidev_data *spidev; | |
510 | int status = -ENXIO; | |
511 | ||
512 | mutex_lock(&device_list_lock); | |
513 | ||
514 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 515 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
516 | status = 0; |
517 | break; | |
518 | } | |
519 | } | |
865f6d19 RJ |
520 | |
521 | if (status) { | |
522 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
523 | goto err_find_dev; | |
524 | } | |
525 | ||
526 | if (!spidev->tx_buffer) { | |
527 | spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
528 | if (!spidev->tx_buffer) { | |
814a8d50 AP |
529 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); |
530 | status = -ENOMEM; | |
865f6d19 | 531 | goto err_find_dev; |
814a8d50 AP |
532 | } |
533 | } | |
865f6d19 RJ |
534 | |
535 | if (!spidev->rx_buffer) { | |
536 | spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
537 | if (!spidev->rx_buffer) { | |
538 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
539 | status = -ENOMEM; | |
540 | goto err_alloc_rx_buf; | |
814a8d50 | 541 | } |
865f6d19 RJ |
542 | } |
543 | ||
544 | spidev->users++; | |
545 | filp->private_data = spidev; | |
546 | nonseekable_open(inode, filp); | |
814a8d50 | 547 | |
865f6d19 RJ |
548 | mutex_unlock(&device_list_lock); |
549 | return 0; | |
550 | ||
551 | err_alloc_rx_buf: | |
552 | kfree(spidev->tx_buffer); | |
553 | spidev->tx_buffer = NULL; | |
554 | err_find_dev: | |
814a8d50 AP |
555 | mutex_unlock(&device_list_lock); |
556 | return status; | |
557 | } | |
558 | ||
559 | static int spidev_release(struct inode *inode, struct file *filp) | |
560 | { | |
561 | struct spidev_data *spidev; | |
562 | int status = 0; | |
563 | ||
564 | mutex_lock(&device_list_lock); | |
565 | spidev = filp->private_data; | |
566 | filp->private_data = NULL; | |
b2c8dadd DB |
567 | |
568 | /* last close? */ | |
814a8d50 AP |
569 | spidev->users--; |
570 | if (!spidev->users) { | |
b2c8dadd DB |
571 | int dofree; |
572 | ||
865f6d19 RJ |
573 | kfree(spidev->tx_buffer); |
574 | spidev->tx_buffer = NULL; | |
575 | ||
576 | kfree(spidev->rx_buffer); | |
577 | spidev->rx_buffer = NULL; | |
b2c8dadd | 578 | |
91690516 MB |
579 | spidev->speed_hz = spidev->spi->max_speed_hz; |
580 | ||
b2c8dadd DB |
581 | /* ... after we unbound from the underlying device? */ |
582 | spin_lock_irq(&spidev->spi_lock); | |
583 | dofree = (spidev->spi == NULL); | |
584 | spin_unlock_irq(&spidev->spi_lock); | |
585 | ||
586 | if (dofree) | |
587 | kfree(spidev); | |
814a8d50 AP |
588 | } |
589 | mutex_unlock(&device_list_lock); | |
590 | ||
591 | return status; | |
592 | } | |
593 | ||
828c0950 | 594 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
595 | .owner = THIS_MODULE, |
596 | /* REVISIT switch to aio primitives, so that userspace | |
597 | * gets more complete API coverage. It'll simplify things | |
598 | * too, except for the locking. | |
599 | */ | |
600 | .write = spidev_write, | |
601 | .read = spidev_read, | |
4ef754b7 | 602 | .unlocked_ioctl = spidev_ioctl, |
7d48ec36 | 603 | .compat_ioctl = spidev_compat_ioctl, |
814a8d50 AP |
604 | .open = spidev_open, |
605 | .release = spidev_release, | |
6038f373 | 606 | .llseek = no_llseek, |
814a8d50 AP |
607 | }; |
608 | ||
609 | /*-------------------------------------------------------------------------*/ | |
610 | ||
611 | /* The main reason to have this class is to make mdev/udev create the | |
612 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
613 | * It also simplifies memory management. | |
614 | */ | |
615 | ||
b2c8dadd | 616 | static struct class *spidev_class; |
814a8d50 AP |
617 | |
618 | /*-------------------------------------------------------------------------*/ | |
619 | ||
fd4a319b | 620 | static int spidev_probe(struct spi_device *spi) |
814a8d50 AP |
621 | { |
622 | struct spidev_data *spidev; | |
623 | int status; | |
624 | unsigned long minor; | |
625 | ||
626 | /* Allocate driver data */ | |
627 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
628 | if (!spidev) | |
629 | return -ENOMEM; | |
630 | ||
631 | /* Initialize the driver data */ | |
632 | spidev->spi = spi; | |
25d5cb4b | 633 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
634 | mutex_init(&spidev->buf_lock); |
635 | ||
636 | INIT_LIST_HEAD(&spidev->device_entry); | |
637 | ||
638 | /* If we can allocate a minor number, hook up this device. | |
639 | * Reusing minors is fine so long as udev or mdev is working. | |
640 | */ | |
641 | mutex_lock(&device_list_lock); | |
0a4dd778 | 642 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 643 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
644 | struct device *dev; |
645 | ||
646 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
647 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
648 | spidev, "spidev%d.%d", | |
649 | spi->master->bus_num, spi->chip_select); | |
8c6ffba0 | 650 | status = PTR_ERR_OR_ZERO(dev); |
814a8d50 AP |
651 | } else { |
652 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
653 | status = -ENODEV; | |
654 | } | |
655 | if (status == 0) { | |
656 | set_bit(minor, minors); | |
814a8d50 AP |
657 | list_add(&spidev->device_entry, &device_list); |
658 | } | |
659 | mutex_unlock(&device_list_lock); | |
660 | ||
91690516 MB |
661 | spidev->speed_hz = spi->max_speed_hz; |
662 | ||
aaacf4bb WO |
663 | if (status == 0) |
664 | spi_set_drvdata(spi, spidev); | |
665 | else | |
814a8d50 AP |
666 | kfree(spidev); |
667 | ||
668 | return status; | |
669 | } | |
670 | ||
fd4a319b | 671 | static int spidev_remove(struct spi_device *spi) |
814a8d50 | 672 | { |
b2c8dadd | 673 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 674 | |
25d5cb4b DB |
675 | /* make sure ops on existing fds can abort cleanly */ |
676 | spin_lock_irq(&spidev->spi_lock); | |
677 | spidev->spi = NULL; | |
678 | spin_unlock_irq(&spidev->spi_lock); | |
814a8d50 | 679 | |
25d5cb4b DB |
680 | /* prevent new opens */ |
681 | mutex_lock(&device_list_lock); | |
814a8d50 | 682 | list_del(&spidev->device_entry); |
b2c8dadd DB |
683 | device_destroy(spidev_class, spidev->devt); |
684 | clear_bit(MINOR(spidev->devt), minors); | |
685 | if (spidev->users == 0) | |
686 | kfree(spidev); | |
814a8d50 AP |
687 | mutex_unlock(&device_list_lock); |
688 | ||
689 | return 0; | |
690 | } | |
691 | ||
880cfd43 | 692 | static const struct of_device_id spidev_dt_ids[] = { |
8fad805b | 693 | { .compatible = "rohm,dh2228fv" }, |
880cfd43 MR |
694 | {}, |
695 | }; | |
696 | ||
697 | MODULE_DEVICE_TABLE(of, spidev_dt_ids); | |
698 | ||
db389b61 | 699 | static struct spi_driver spidev_spi_driver = { |
814a8d50 AP |
700 | .driver = { |
701 | .name = "spidev", | |
702 | .owner = THIS_MODULE, | |
880cfd43 | 703 | .of_match_table = of_match_ptr(spidev_dt_ids), |
814a8d50 AP |
704 | }, |
705 | .probe = spidev_probe, | |
fd4a319b | 706 | .remove = spidev_remove, |
814a8d50 AP |
707 | |
708 | /* NOTE: suspend/resume methods are not necessary here. | |
709 | * We don't do anything except pass the requests to/from | |
710 | * the underlying controller. The refrigerator handles | |
711 | * most issues; the controller driver handles the rest. | |
712 | */ | |
713 | }; | |
714 | ||
715 | /*-------------------------------------------------------------------------*/ | |
716 | ||
717 | static int __init spidev_init(void) | |
718 | { | |
719 | int status; | |
720 | ||
721 | /* Claim our 256 reserved device numbers. Then register a class | |
722 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
723 | * the driver which manages those device numbers. | |
724 | */ | |
725 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
726 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
727 | if (status < 0) | |
728 | return status; | |
729 | ||
b2c8dadd DB |
730 | spidev_class = class_create(THIS_MODULE, "spidev"); |
731 | if (IS_ERR(spidev_class)) { | |
db389b61 | 732 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
b2c8dadd | 733 | return PTR_ERR(spidev_class); |
814a8d50 AP |
734 | } |
735 | ||
db389b61 | 736 | status = spi_register_driver(&spidev_spi_driver); |
814a8d50 | 737 | if (status < 0) { |
b2c8dadd | 738 | class_destroy(spidev_class); |
db389b61 | 739 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
740 | } |
741 | return status; | |
742 | } | |
743 | module_init(spidev_init); | |
744 | ||
745 | static void __exit spidev_exit(void) | |
746 | { | |
db389b61 | 747 | spi_unregister_driver(&spidev_spi_driver); |
b2c8dadd | 748 | class_destroy(spidev_class); |
db389b61 | 749 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
750 | } |
751 | module_exit(spidev_exit); | |
752 | ||
753 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
754 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
755 | MODULE_LICENSE("GPL"); | |
e0626e38 | 756 | MODULE_ALIAS("spi:spidev"); |