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