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. | |
814a8d50 AP |
17 | */ |
18 | ||
19 | #include <linux/init.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/ioctl.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/device.h> | |
b2c8dadd | 24 | #include <linux/err.h> |
814a8d50 AP |
25 | #include <linux/list.h> |
26 | #include <linux/errno.h> | |
27 | #include <linux/mutex.h> | |
28 | #include <linux/slab.h> | |
7d48ec36 | 29 | #include <linux/compat.h> |
880cfd43 MR |
30 | #include <linux/of.h> |
31 | #include <linux/of_device.h> | |
cf9f4327 | 32 | #include <linux/acpi.h> |
814a8d50 AP |
33 | |
34 | #include <linux/spi/spi.h> | |
35 | #include <linux/spi/spidev.h> | |
36 | ||
95c63cfb | 37 | #include <linux/uaccess.h> |
814a8d50 AP |
38 | |
39 | ||
40 | /* | |
b595076a | 41 | * This supports access to SPI devices using normal userspace I/O calls. |
814a8d50 AP |
42 | * Note that while traditional UNIX/POSIX I/O semantics are half duplex, |
43 | * and often mask message boundaries, full SPI support requires full duplex | |
137f1188 | 44 | * transfers. There are several kinds of internal message boundaries to |
814a8d50 AP |
45 | * handle chipselect management and other protocol options. |
46 | * | |
47 | * SPI has a character major number assigned. We allocate minor numbers | |
48 | * dynamically using a bitmask. You must use hotplug tools, such as udev | |
49 | * (or mdev with busybox) to create and destroy the /dev/spidevB.C device | |
50 | * nodes, since there is no fixed association of minor numbers with any | |
51 | * particular SPI bus or device. | |
52 | */ | |
53 | #define SPIDEV_MAJOR 153 /* assigned */ | |
54 | #define N_SPI_MINORS 32 /* ... up to 256 */ | |
55 | ||
8ae1c924 | 56 | static DECLARE_BITMAP(minors, N_SPI_MINORS); |
814a8d50 AP |
57 | |
58 | ||
6f166e38 | 59 | /* Bit masks for spi_device.mode management. Note that incorrect |
b55f627f DB |
60 | * settings for some settings can cause *lots* of trouble for other |
61 | * devices on a shared bus: | |
6f166e38 | 62 | * |
b55f627f DB |
63 | * - CS_HIGH ... this device will be active when it shouldn't be |
64 | * - 3WIRE ... when active, it won't behave as it should | |
65 | * - NO_CS ... there will be no explicit message boundaries; this | |
66 | * is completely incompatible with the shared bus model | |
67 | * - READY ... transfers may proceed when they shouldn't. | |
68 | * | |
69 | * REVISIT should changing those flags be privileged? | |
6f166e38 AV |
70 | */ |
71 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | |
b55f627f | 72 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ |
dc64d39b GU |
73 | | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \ |
74 | | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD) | |
814a8d50 AP |
75 | |
76 | struct spidev_data { | |
b2c8dadd | 77 | dev_t devt; |
25d5cb4b | 78 | spinlock_t spi_lock; |
814a8d50 AP |
79 | struct spi_device *spi; |
80 | struct list_head device_entry; | |
81 | ||
865f6d19 | 82 | /* TX/RX buffers are NULL unless this device is open (users > 0) */ |
814a8d50 AP |
83 | struct mutex buf_lock; |
84 | unsigned users; | |
865f6d19 RJ |
85 | u8 *tx_buffer; |
86 | u8 *rx_buffer; | |
91690516 | 87 | u32 speed_hz; |
814a8d50 AP |
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 | static ssize_t |
100 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
101 | { | |
102 | DECLARE_COMPLETION_ONSTACK(done); | |
103 | int status; | |
98d6f479 | 104 | struct spi_device *spi; |
25d5cb4b DB |
105 | |
106 | spin_lock_irq(&spidev->spi_lock); | |
98d6f479 MS |
107 | spi = spidev->spi; |
108 | spin_unlock_irq(&spidev->spi_lock); | |
109 | ||
110 | if (spi == NULL) | |
25d5cb4b DB |
111 | status = -ESHUTDOWN; |
112 | else | |
98d6f479 MS |
113 | status = spi_sync(spi, message); |
114 | ||
115 | if (status == 0) | |
116 | status = message->actual_length; | |
25d5cb4b | 117 | |
25d5cb4b DB |
118 | return status; |
119 | } | |
120 | ||
121 | static inline ssize_t | |
122 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
123 | { | |
124 | struct spi_transfer t = { | |
865f6d19 | 125 | .tx_buf = spidev->tx_buffer, |
25d5cb4b | 126 | .len = len, |
91690516 | 127 | .speed_hz = spidev->speed_hz, |
25d5cb4b DB |
128 | }; |
129 | struct spi_message m; | |
130 | ||
131 | spi_message_init(&m); | |
132 | spi_message_add_tail(&t, &m); | |
133 | return spidev_sync(spidev, &m); | |
134 | } | |
135 | ||
136 | static inline ssize_t | |
137 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
138 | { | |
139 | struct spi_transfer t = { | |
865f6d19 | 140 | .rx_buf = spidev->rx_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 | /*-------------------------------------------------------------------------*/ | |
152 | ||
814a8d50 AP |
153 | /* Read-only message with current device setup */ |
154 | static ssize_t | |
155 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
156 | { | |
157 | struct spidev_data *spidev; | |
814a8d50 AP |
158 | ssize_t status = 0; |
159 | ||
160 | /* chipselect only toggles at start or end of operation */ | |
161 | if (count > bufsiz) | |
162 | return -EMSGSIZE; | |
163 | ||
164 | spidev = filp->private_data; | |
814a8d50 AP |
165 | |
166 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 167 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 168 | if (status > 0) { |
814a8d50 AP |
169 | unsigned long missing; |
170 | ||
865f6d19 | 171 | missing = copy_to_user(buf, spidev->rx_buffer, status); |
4b1295b0 | 172 | if (missing == status) |
814a8d50 AP |
173 | status = -EFAULT; |
174 | else | |
4b1295b0 | 175 | status = status - missing; |
814a8d50 AP |
176 | } |
177 | mutex_unlock(&spidev->buf_lock); | |
178 | ||
179 | return status; | |
180 | } | |
181 | ||
182 | /* Write-only message with current device setup */ | |
183 | static ssize_t | |
184 | spidev_write(struct file *filp, const char __user *buf, | |
185 | size_t count, loff_t *f_pos) | |
186 | { | |
187 | struct spidev_data *spidev; | |
814a8d50 AP |
188 | ssize_t status = 0; |
189 | unsigned long missing; | |
190 | ||
191 | /* chipselect only toggles at start or end of operation */ | |
192 | if (count > bufsiz) | |
193 | return -EMSGSIZE; | |
194 | ||
195 | spidev = filp->private_data; | |
814a8d50 AP |
196 | |
197 | mutex_lock(&spidev->buf_lock); | |
865f6d19 | 198 | missing = copy_from_user(spidev->tx_buffer, buf, count); |
95c63cfb | 199 | if (missing == 0) |
25d5cb4b | 200 | status = spidev_sync_write(spidev, count); |
95c63cfb | 201 | else |
814a8d50 AP |
202 | status = -EFAULT; |
203 | mutex_unlock(&spidev->buf_lock); | |
204 | ||
205 | return status; | |
206 | } | |
207 | ||
208 | static int spidev_message(struct spidev_data *spidev, | |
209 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
210 | { | |
211 | struct spi_message msg; | |
212 | struct spi_transfer *k_xfers; | |
213 | struct spi_transfer *k_tmp; | |
214 | struct spi_ioc_transfer *u_tmp; | |
9a12bff7 | 215 | unsigned n, total, tx_total, rx_total; |
865f6d19 | 216 | u8 *tx_buf, *rx_buf; |
814a8d50 AP |
217 | int status = -EFAULT; |
218 | ||
219 | spi_message_init(&msg); | |
220 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
221 | if (k_xfers == NULL) | |
222 | return -ENOMEM; | |
223 | ||
224 | /* Construct spi_message, copying any tx data to bounce buffer. | |
225 | * We walk the array of user-provided transfers, using each one | |
226 | * to initialize a kernel version of the same transfer. | |
227 | */ | |
865f6d19 RJ |
228 | tx_buf = spidev->tx_buffer; |
229 | rx_buf = spidev->rx_buffer; | |
814a8d50 | 230 | total = 0; |
9a12bff7 IA |
231 | tx_total = 0; |
232 | rx_total = 0; | |
814a8d50 AP |
233 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; |
234 | n; | |
235 | n--, k_tmp++, u_tmp++) { | |
236 | k_tmp->len = u_tmp->len; | |
237 | ||
da90fa8f | 238 | total += k_tmp->len; |
9a12bff7 IA |
239 | /* Since the function returns the total length of transfers |
240 | * on success, restrict the total to positive int values to | |
f20fbaad IA |
241 | * avoid the return value looking like an error. Also check |
242 | * each transfer length to avoid arithmetic overflow. | |
9a12bff7 | 243 | */ |
f20fbaad | 244 | if (total > INT_MAX || k_tmp->len > INT_MAX) { |
da90fa8f DP |
245 | status = -EMSGSIZE; |
246 | goto done; | |
247 | } | |
248 | ||
814a8d50 | 249 | if (u_tmp->rx_buf) { |
9a12bff7 IA |
250 | /* this transfer needs space in RX bounce buffer */ |
251 | rx_total += k_tmp->len; | |
252 | if (rx_total > bufsiz) { | |
253 | status = -EMSGSIZE; | |
254 | goto done; | |
255 | } | |
865f6d19 | 256 | k_tmp->rx_buf = rx_buf; |
96ddbf50 | 257 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 258 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 259 | u_tmp->len)) |
814a8d50 | 260 | goto done; |
9a12bff7 | 261 | rx_buf += k_tmp->len; |
814a8d50 AP |
262 | } |
263 | if (u_tmp->tx_buf) { | |
9a12bff7 IA |
264 | /* this transfer needs space in TX bounce buffer */ |
265 | tx_total += k_tmp->len; | |
266 | if (tx_total > bufsiz) { | |
267 | status = -EMSGSIZE; | |
268 | goto done; | |
269 | } | |
865f6d19 RJ |
270 | k_tmp->tx_buf = tx_buf; |
271 | if (copy_from_user(tx_buf, (const u8 __user *) | |
142956af | 272 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
273 | u_tmp->len)) |
274 | goto done; | |
9a12bff7 | 275 | tx_buf += k_tmp->len; |
814a8d50 | 276 | } |
814a8d50 AP |
277 | |
278 | k_tmp->cs_change = !!u_tmp->cs_change; | |
dc64d39b GU |
279 | k_tmp->tx_nbits = u_tmp->tx_nbits; |
280 | k_tmp->rx_nbits = u_tmp->rx_nbits; | |
814a8d50 AP |
281 | k_tmp->bits_per_word = u_tmp->bits_per_word; |
282 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
283 | k_tmp->speed_hz = u_tmp->speed_hz; | |
91690516 MB |
284 | if (!k_tmp->speed_hz) |
285 | k_tmp->speed_hz = spidev->speed_hz; | |
814a8d50 | 286 | #ifdef VERBOSE |
41df70d9 | 287 | dev_dbg(&spidev->spi->dev, |
f15c5841 | 288 | " xfer len %u %s%s%s%dbits %u usec %uHz\n", |
814a8d50 AP |
289 | u_tmp->len, |
290 | u_tmp->rx_buf ? "rx " : "", | |
291 | u_tmp->tx_buf ? "tx " : "", | |
292 | u_tmp->cs_change ? "cs " : "", | |
41df70d9 | 293 | u_tmp->bits_per_word ? : spidev->spi->bits_per_word, |
814a8d50 | 294 | u_tmp->delay_usecs, |
41df70d9 | 295 | u_tmp->speed_hz ? : spidev->spi->max_speed_hz); |
814a8d50 AP |
296 | #endif |
297 | spi_message_add_tail(k_tmp, &msg); | |
298 | } | |
299 | ||
25d5cb4b | 300 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
301 | if (status < 0) |
302 | goto done; | |
303 | ||
304 | /* copy any rx data out of bounce buffer */ | |
865f6d19 | 305 | rx_buf = spidev->rx_buffer; |
814a8d50 AP |
306 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { |
307 | if (u_tmp->rx_buf) { | |
4917d927 | 308 | if (__copy_to_user((u8 __user *) |
865f6d19 | 309 | (uintptr_t) u_tmp->rx_buf, rx_buf, |
814a8d50 AP |
310 | u_tmp->len)) { |
311 | status = -EFAULT; | |
312 | goto done; | |
313 | } | |
9a12bff7 | 314 | rx_buf += u_tmp->len; |
814a8d50 | 315 | } |
814a8d50 AP |
316 | } |
317 | status = total; | |
318 | ||
319 | done: | |
814a8d50 AP |
320 | kfree(k_xfers); |
321 | return status; | |
322 | } | |
323 | ||
7782a1a9 IA |
324 | static struct spi_ioc_transfer * |
325 | spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc, | |
326 | unsigned *n_ioc) | |
327 | { | |
328 | struct spi_ioc_transfer *ioc; | |
329 | u32 tmp; | |
330 | ||
331 | /* Check type, command number and direction */ | |
332 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC | |
333 | || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
334 | || _IOC_DIR(cmd) != _IOC_WRITE) | |
335 | return ERR_PTR(-ENOTTY); | |
336 | ||
337 | tmp = _IOC_SIZE(cmd); | |
338 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) | |
339 | return ERR_PTR(-EINVAL); | |
340 | *n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
341 | if (*n_ioc == 0) | |
342 | return NULL; | |
343 | ||
344 | /* copy into scratch area */ | |
345 | ioc = kmalloc(tmp, GFP_KERNEL); | |
346 | if (!ioc) | |
347 | return ERR_PTR(-ENOMEM); | |
348 | if (__copy_from_user(ioc, u_ioc, tmp)) { | |
349 | kfree(ioc); | |
350 | return ERR_PTR(-EFAULT); | |
351 | } | |
352 | return ioc; | |
353 | } | |
354 | ||
4ef754b7 AC |
355 | static long |
356 | spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
814a8d50 AP |
357 | { |
358 | int err = 0; | |
359 | int retval = 0; | |
360 | struct spidev_data *spidev; | |
361 | struct spi_device *spi; | |
362 | u32 tmp; | |
363 | unsigned n_ioc; | |
364 | struct spi_ioc_transfer *ioc; | |
365 | ||
366 | /* Check type and command number */ | |
367 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
368 | return -ENOTTY; | |
369 | ||
370 | /* Check access direction once here; don't repeat below. | |
371 | * IOC_DIR is from the user perspective, while access_ok is | |
372 | * from the kernel perspective; so they look reversed. | |
373 | */ | |
374 | if (_IOC_DIR(cmd) & _IOC_READ) | |
375 | err = !access_ok(VERIFY_WRITE, | |
376 | (void __user *)arg, _IOC_SIZE(cmd)); | |
377 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
378 | err = !access_ok(VERIFY_READ, | |
379 | (void __user *)arg, _IOC_SIZE(cmd)); | |
380 | if (err) | |
381 | return -EFAULT; | |
382 | ||
25d5cb4b DB |
383 | /* guard against device removal before, or while, |
384 | * we issue this ioctl. | |
385 | */ | |
814a8d50 | 386 | spidev = filp->private_data; |
25d5cb4b DB |
387 | spin_lock_irq(&spidev->spi_lock); |
388 | spi = spi_dev_get(spidev->spi); | |
389 | spin_unlock_irq(&spidev->spi_lock); | |
390 | ||
391 | if (spi == NULL) | |
392 | return -ESHUTDOWN; | |
814a8d50 | 393 | |
4ef754b7 AC |
394 | /* use the buffer lock here for triple duty: |
395 | * - prevent I/O (from us) so calling spi_setup() is safe; | |
396 | * - prevent concurrent SPI_IOC_WR_* from morphing | |
397 | * data fields while SPI_IOC_RD_* reads them; | |
398 | * - SPI_IOC_MESSAGE needs the buffer locked "normally". | |
399 | */ | |
400 | mutex_lock(&spidev->buf_lock); | |
401 | ||
814a8d50 AP |
402 | switch (cmd) { |
403 | /* read requests */ | |
404 | case SPI_IOC_RD_MODE: | |
405 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
406 | (__u8 __user *)arg); | |
407 | break; | |
dc64d39b GU |
408 | case SPI_IOC_RD_MODE32: |
409 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
410 | (__u32 __user *)arg); | |
411 | break; | |
814a8d50 AP |
412 | case SPI_IOC_RD_LSB_FIRST: |
413 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
414 | (__u8 __user *)arg); | |
415 | break; | |
416 | case SPI_IOC_RD_BITS_PER_WORD: | |
417 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
418 | break; | |
419 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
91690516 | 420 | retval = __put_user(spidev->speed_hz, (__u32 __user *)arg); |
814a8d50 AP |
421 | break; |
422 | ||
423 | /* write requests */ | |
424 | case SPI_IOC_WR_MODE: | |
dc64d39b GU |
425 | case SPI_IOC_WR_MODE32: |
426 | if (cmd == SPI_IOC_WR_MODE) | |
427 | retval = __get_user(tmp, (u8 __user *)arg); | |
428 | else | |
429 | retval = __get_user(tmp, (u32 __user *)arg); | |
814a8d50 | 430 | if (retval == 0) { |
e6456186 | 431 | u32 save = spi->mode; |
814a8d50 AP |
432 | |
433 | if (tmp & ~SPI_MODE_MASK) { | |
434 | retval = -EINVAL; | |
435 | break; | |
436 | } | |
437 | ||
438 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
dc64d39b | 439 | spi->mode = (u16)tmp; |
814a8d50 AP |
440 | retval = spi_setup(spi); |
441 | if (retval < 0) | |
442 | spi->mode = save; | |
443 | else | |
dc64d39b | 444 | dev_dbg(&spi->dev, "spi mode %x\n", tmp); |
814a8d50 AP |
445 | } |
446 | break; | |
447 | case SPI_IOC_WR_LSB_FIRST: | |
448 | retval = __get_user(tmp, (__u8 __user *)arg); | |
449 | if (retval == 0) { | |
e6456186 | 450 | u32 save = spi->mode; |
814a8d50 AP |
451 | |
452 | if (tmp) | |
453 | spi->mode |= SPI_LSB_FIRST; | |
454 | else | |
455 | spi->mode &= ~SPI_LSB_FIRST; | |
456 | retval = spi_setup(spi); | |
457 | if (retval < 0) | |
458 | spi->mode = save; | |
459 | else | |
460 | dev_dbg(&spi->dev, "%csb first\n", | |
461 | tmp ? 'l' : 'm'); | |
462 | } | |
463 | break; | |
464 | case SPI_IOC_WR_BITS_PER_WORD: | |
465 | retval = __get_user(tmp, (__u8 __user *)arg); | |
466 | if (retval == 0) { | |
467 | u8 save = spi->bits_per_word; | |
468 | ||
469 | spi->bits_per_word = tmp; | |
470 | retval = spi_setup(spi); | |
471 | if (retval < 0) | |
472 | spi->bits_per_word = save; | |
473 | else | |
474 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
475 | } | |
476 | break; | |
477 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
478 | retval = __get_user(tmp, (__u32 __user *)arg); | |
479 | if (retval == 0) { | |
480 | u32 save = spi->max_speed_hz; | |
481 | ||
482 | spi->max_speed_hz = tmp; | |
483 | retval = spi_setup(spi); | |
91690516 MB |
484 | if (retval >= 0) |
485 | spidev->speed_hz = tmp; | |
814a8d50 AP |
486 | else |
487 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
91690516 | 488 | spi->max_speed_hz = save; |
814a8d50 AP |
489 | } |
490 | break; | |
491 | ||
492 | default: | |
493 | /* segmented and/or full-duplex I/O request */ | |
7782a1a9 IA |
494 | /* Check message and copy into scratch area */ |
495 | ioc = spidev_get_ioc_message(cmd, | |
496 | (struct spi_ioc_transfer __user *)arg, &n_ioc); | |
497 | if (IS_ERR(ioc)) { | |
498 | retval = PTR_ERR(ioc); | |
814a8d50 AP |
499 | break; |
500 | } | |
7782a1a9 IA |
501 | if (!ioc) |
502 | break; /* n_ioc is also 0 */ | |
814a8d50 AP |
503 | |
504 | /* translate to spi_message, execute */ | |
505 | retval = spidev_message(spidev, ioc, n_ioc); | |
506 | kfree(ioc); | |
507 | break; | |
508 | } | |
4ef754b7 AC |
509 | |
510 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 511 | spi_dev_put(spi); |
814a8d50 AP |
512 | return retval; |
513 | } | |
514 | ||
7d48ec36 | 515 | #ifdef CONFIG_COMPAT |
7782a1a9 IA |
516 | static long |
517 | spidev_compat_ioc_message(struct file *filp, unsigned int cmd, | |
518 | unsigned long arg) | |
519 | { | |
520 | struct spi_ioc_transfer __user *u_ioc; | |
521 | int retval = 0; | |
522 | struct spidev_data *spidev; | |
523 | struct spi_device *spi; | |
524 | unsigned n_ioc, n; | |
525 | struct spi_ioc_transfer *ioc; | |
526 | ||
527 | u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg); | |
528 | if (!access_ok(VERIFY_READ, u_ioc, _IOC_SIZE(cmd))) | |
529 | return -EFAULT; | |
530 | ||
531 | /* guard against device removal before, or while, | |
532 | * we issue this ioctl. | |
533 | */ | |
534 | spidev = filp->private_data; | |
535 | spin_lock_irq(&spidev->spi_lock); | |
536 | spi = spi_dev_get(spidev->spi); | |
537 | spin_unlock_irq(&spidev->spi_lock); | |
538 | ||
539 | if (spi == NULL) | |
540 | return -ESHUTDOWN; | |
541 | ||
542 | /* SPI_IOC_MESSAGE needs the buffer locked "normally" */ | |
543 | mutex_lock(&spidev->buf_lock); | |
544 | ||
545 | /* Check message and copy into scratch area */ | |
546 | ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc); | |
547 | if (IS_ERR(ioc)) { | |
548 | retval = PTR_ERR(ioc); | |
549 | goto done; | |
550 | } | |
551 | if (!ioc) | |
552 | goto done; /* n_ioc is also 0 */ | |
553 | ||
554 | /* Convert buffer pointers */ | |
555 | for (n = 0; n < n_ioc; n++) { | |
556 | ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf); | |
557 | ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf); | |
558 | } | |
559 | ||
560 | /* translate to spi_message, execute */ | |
561 | retval = spidev_message(spidev, ioc, n_ioc); | |
562 | kfree(ioc); | |
563 | ||
564 | done: | |
565 | mutex_unlock(&spidev->buf_lock); | |
566 | spi_dev_put(spi); | |
567 | return retval; | |
568 | } | |
569 | ||
7d48ec36 BW |
570 | static long |
571 | spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
572 | { | |
7782a1a9 IA |
573 | if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC |
574 | && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) | |
575 | && _IOC_DIR(cmd) == _IOC_WRITE) | |
576 | return spidev_compat_ioc_message(filp, cmd, arg); | |
577 | ||
7d48ec36 BW |
578 | return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); |
579 | } | |
580 | #else | |
581 | #define spidev_compat_ioctl NULL | |
582 | #endif /* CONFIG_COMPAT */ | |
583 | ||
814a8d50 AP |
584 | static int spidev_open(struct inode *inode, struct file *filp) |
585 | { | |
586 | struct spidev_data *spidev; | |
587 | int status = -ENXIO; | |
588 | ||
589 | mutex_lock(&device_list_lock); | |
590 | ||
591 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 592 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
593 | status = 0; |
594 | break; | |
595 | } | |
596 | } | |
865f6d19 RJ |
597 | |
598 | if (status) { | |
599 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
600 | goto err_find_dev; | |
601 | } | |
602 | ||
603 | if (!spidev->tx_buffer) { | |
604 | spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
605 | if (!spidev->tx_buffer) { | |
89a63566 CIK |
606 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); |
607 | status = -ENOMEM; | |
865f6d19 | 608 | goto err_find_dev; |
814a8d50 | 609 | } |
89a63566 | 610 | } |
865f6d19 RJ |
611 | |
612 | if (!spidev->rx_buffer) { | |
613 | spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
614 | if (!spidev->rx_buffer) { | |
615 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
616 | status = -ENOMEM; | |
617 | goto err_alloc_rx_buf; | |
814a8d50 | 618 | } |
865f6d19 RJ |
619 | } |
620 | ||
621 | spidev->users++; | |
622 | filp->private_data = spidev; | |
623 | nonseekable_open(inode, filp); | |
814a8d50 | 624 | |
865f6d19 RJ |
625 | mutex_unlock(&device_list_lock); |
626 | return 0; | |
627 | ||
628 | err_alloc_rx_buf: | |
629 | kfree(spidev->tx_buffer); | |
630 | spidev->tx_buffer = NULL; | |
631 | err_find_dev: | |
814a8d50 AP |
632 | mutex_unlock(&device_list_lock); |
633 | return status; | |
634 | } | |
635 | ||
636 | static int spidev_release(struct inode *inode, struct file *filp) | |
637 | { | |
638 | struct spidev_data *spidev; | |
814a8d50 AP |
639 | |
640 | mutex_lock(&device_list_lock); | |
641 | spidev = filp->private_data; | |
642 | filp->private_data = NULL; | |
b2c8dadd DB |
643 | |
644 | /* last close? */ | |
814a8d50 AP |
645 | spidev->users--; |
646 | if (!spidev->users) { | |
b2c8dadd DB |
647 | int dofree; |
648 | ||
865f6d19 RJ |
649 | kfree(spidev->tx_buffer); |
650 | spidev->tx_buffer = NULL; | |
651 | ||
652 | kfree(spidev->rx_buffer); | |
653 | spidev->rx_buffer = NULL; | |
b2c8dadd | 654 | |
56ea1075 | 655 | spin_lock_irq(&spidev->spi_lock); |
dd85ebf6 SM |
656 | if (spidev->spi) |
657 | spidev->speed_hz = spidev->spi->max_speed_hz; | |
91690516 | 658 | |
b2c8dadd | 659 | /* ... after we unbound from the underlying device? */ |
b2c8dadd DB |
660 | dofree = (spidev->spi == NULL); |
661 | spin_unlock_irq(&spidev->spi_lock); | |
662 | ||
663 | if (dofree) | |
664 | kfree(spidev); | |
814a8d50 AP |
665 | } |
666 | mutex_unlock(&device_list_lock); | |
667 | ||
99472cc0 | 668 | return 0; |
814a8d50 AP |
669 | } |
670 | ||
828c0950 | 671 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
672 | .owner = THIS_MODULE, |
673 | /* REVISIT switch to aio primitives, so that userspace | |
674 | * gets more complete API coverage. It'll simplify things | |
675 | * too, except for the locking. | |
676 | */ | |
677 | .write = spidev_write, | |
678 | .read = spidev_read, | |
4ef754b7 | 679 | .unlocked_ioctl = spidev_ioctl, |
7d48ec36 | 680 | .compat_ioctl = spidev_compat_ioctl, |
814a8d50 AP |
681 | .open = spidev_open, |
682 | .release = spidev_release, | |
6038f373 | 683 | .llseek = no_llseek, |
814a8d50 AP |
684 | }; |
685 | ||
686 | /*-------------------------------------------------------------------------*/ | |
687 | ||
688 | /* The main reason to have this class is to make mdev/udev create the | |
689 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
690 | * It also simplifies memory management. | |
691 | */ | |
692 | ||
b2c8dadd | 693 | static struct class *spidev_class; |
814a8d50 | 694 | |
956b200a MB |
695 | #ifdef CONFIG_OF |
696 | static const struct of_device_id spidev_dt_ids[] = { | |
697 | { .compatible = "rohm,dh2228fv" }, | |
6fec919b | 698 | { .compatible = "lineartechnology,ltc2488" }, |
956b200a MB |
699 | {}, |
700 | }; | |
701 | MODULE_DEVICE_TABLE(of, spidev_dt_ids); | |
702 | #endif | |
703 | ||
cf9f4327 MW |
704 | #ifdef CONFIG_ACPI |
705 | ||
706 | /* Dummy SPI devices not to be used in production systems */ | |
707 | #define SPIDEV_ACPI_DUMMY 1 | |
708 | ||
709 | static const struct acpi_device_id spidev_acpi_ids[] = { | |
710 | /* | |
711 | * The ACPI SPT000* devices are only meant for development and | |
712 | * testing. Systems used in production should have a proper ACPI | |
713 | * description of the connected peripheral and they should also use | |
714 | * a proper driver instead of poking directly to the SPI bus. | |
715 | */ | |
716 | { "SPT0001", SPIDEV_ACPI_DUMMY }, | |
717 | { "SPT0002", SPIDEV_ACPI_DUMMY }, | |
718 | { "SPT0003", SPIDEV_ACPI_DUMMY }, | |
719 | {}, | |
720 | }; | |
721 | MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids); | |
722 | ||
723 | static void spidev_probe_acpi(struct spi_device *spi) | |
724 | { | |
725 | const struct acpi_device_id *id; | |
726 | ||
727 | if (!has_acpi_companion(&spi->dev)) | |
728 | return; | |
729 | ||
730 | id = acpi_match_device(spidev_acpi_ids, &spi->dev); | |
731 | if (WARN_ON(!id)) | |
732 | return; | |
733 | ||
734 | if (id->driver_data == SPIDEV_ACPI_DUMMY) | |
735 | dev_warn(&spi->dev, "do not use this driver in production systems!\n"); | |
736 | } | |
737 | #else | |
738 | static inline void spidev_probe_acpi(struct spi_device *spi) {} | |
739 | #endif | |
740 | ||
814a8d50 AP |
741 | /*-------------------------------------------------------------------------*/ |
742 | ||
fd4a319b | 743 | static int spidev_probe(struct spi_device *spi) |
814a8d50 AP |
744 | { |
745 | struct spidev_data *spidev; | |
746 | int status; | |
747 | unsigned long minor; | |
748 | ||
956b200a MB |
749 | /* |
750 | * spidev should never be referenced in DT without a specific | |
ffe22888 | 751 | * compatible string, it is a Linux implementation thing |
956b200a MB |
752 | * rather than a description of the hardware. |
753 | */ | |
754 | if (spi->dev.of_node && !of_match_device(spidev_dt_ids, &spi->dev)) { | |
755 | dev_err(&spi->dev, "buggy DT: spidev listed directly in DT\n"); | |
756 | WARN_ON(spi->dev.of_node && | |
757 | !of_match_device(spidev_dt_ids, &spi->dev)); | |
758 | } | |
759 | ||
cf9f4327 MW |
760 | spidev_probe_acpi(spi); |
761 | ||
814a8d50 AP |
762 | /* Allocate driver data */ |
763 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
764 | if (!spidev) | |
765 | return -ENOMEM; | |
766 | ||
767 | /* Initialize the driver data */ | |
768 | spidev->spi = spi; | |
25d5cb4b | 769 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
770 | mutex_init(&spidev->buf_lock); |
771 | ||
772 | INIT_LIST_HEAD(&spidev->device_entry); | |
773 | ||
774 | /* If we can allocate a minor number, hook up this device. | |
775 | * Reusing minors is fine so long as udev or mdev is working. | |
776 | */ | |
777 | mutex_lock(&device_list_lock); | |
0a4dd778 | 778 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 779 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
780 | struct device *dev; |
781 | ||
782 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
783 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
784 | spidev, "spidev%d.%d", | |
785 | spi->master->bus_num, spi->chip_select); | |
8c6ffba0 | 786 | status = PTR_ERR_OR_ZERO(dev); |
814a8d50 AP |
787 | } else { |
788 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
789 | status = -ENODEV; | |
790 | } | |
791 | if (status == 0) { | |
792 | set_bit(minor, minors); | |
814a8d50 AP |
793 | list_add(&spidev->device_entry, &device_list); |
794 | } | |
795 | mutex_unlock(&device_list_lock); | |
796 | ||
91690516 MB |
797 | spidev->speed_hz = spi->max_speed_hz; |
798 | ||
aaacf4bb WO |
799 | if (status == 0) |
800 | spi_set_drvdata(spi, spidev); | |
801 | else | |
814a8d50 AP |
802 | kfree(spidev); |
803 | ||
804 | return status; | |
805 | } | |
806 | ||
fd4a319b | 807 | static int spidev_remove(struct spi_device *spi) |
814a8d50 | 808 | { |
b2c8dadd | 809 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 810 | |
25d5cb4b DB |
811 | /* make sure ops on existing fds can abort cleanly */ |
812 | spin_lock_irq(&spidev->spi_lock); | |
813 | spidev->spi = NULL; | |
814 | spin_unlock_irq(&spidev->spi_lock); | |
814a8d50 | 815 | |
25d5cb4b DB |
816 | /* prevent new opens */ |
817 | mutex_lock(&device_list_lock); | |
814a8d50 | 818 | list_del(&spidev->device_entry); |
b2c8dadd DB |
819 | device_destroy(spidev_class, spidev->devt); |
820 | clear_bit(MINOR(spidev->devt), minors); | |
821 | if (spidev->users == 0) | |
822 | kfree(spidev); | |
814a8d50 AP |
823 | mutex_unlock(&device_list_lock); |
824 | ||
825 | return 0; | |
826 | } | |
827 | ||
db389b61 | 828 | static struct spi_driver spidev_spi_driver = { |
814a8d50 AP |
829 | .driver = { |
830 | .name = "spidev", | |
880cfd43 | 831 | .of_match_table = of_match_ptr(spidev_dt_ids), |
cf9f4327 | 832 | .acpi_match_table = ACPI_PTR(spidev_acpi_ids), |
814a8d50 AP |
833 | }, |
834 | .probe = spidev_probe, | |
fd4a319b | 835 | .remove = spidev_remove, |
814a8d50 AP |
836 | |
837 | /* NOTE: suspend/resume methods are not necessary here. | |
838 | * We don't do anything except pass the requests to/from | |
839 | * the underlying controller. The refrigerator handles | |
840 | * most issues; the controller driver handles the rest. | |
841 | */ | |
842 | }; | |
843 | ||
844 | /*-------------------------------------------------------------------------*/ | |
845 | ||
846 | static int __init spidev_init(void) | |
847 | { | |
848 | int status; | |
849 | ||
850 | /* Claim our 256 reserved device numbers. Then register a class | |
851 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
852 | * the driver which manages those device numbers. | |
853 | */ | |
854 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
855 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
856 | if (status < 0) | |
857 | return status; | |
858 | ||
b2c8dadd DB |
859 | spidev_class = class_create(THIS_MODULE, "spidev"); |
860 | if (IS_ERR(spidev_class)) { | |
db389b61 | 861 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
b2c8dadd | 862 | return PTR_ERR(spidev_class); |
814a8d50 AP |
863 | } |
864 | ||
db389b61 | 865 | status = spi_register_driver(&spidev_spi_driver); |
814a8d50 | 866 | if (status < 0) { |
b2c8dadd | 867 | class_destroy(spidev_class); |
db389b61 | 868 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
869 | } |
870 | return status; | |
871 | } | |
872 | module_init(spidev_init); | |
873 | ||
874 | static void __exit spidev_exit(void) | |
875 | { | |
db389b61 | 876 | spi_unregister_driver(&spidev_spi_driver); |
b2c8dadd | 877 | class_destroy(spidev_class); |
db389b61 | 878 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
879 | } |
880 | module_exit(spidev_exit); | |
881 | ||
882 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
883 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
884 | MODULE_LICENSE("GPL"); | |
e0626e38 | 885 | MODULE_ALIAS("spi:spidev"); |