blob: e3bc23bb588340f6856efe33e2d26fc4f6156ea4 [file] [log] [blame]
Andrea Paterniani814a8d52007-05-08 00:32:15 -07001/*
Grant Likelyca632f52011-06-06 01:16:30 -06002 * Simple synchronous userspace interface to SPI devices
Andrea Paterniani814a8d52007-05-08 00:32:15 -07003 *
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>
David Brownellb2c8dad2008-06-05 22:45:50 -070028#include <linux/err.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070029#include <linux/list.h>
30#include <linux/errno.h>
31#include <linux/mutex.h>
32#include <linux/slab.h>
Bernhard Walle7d48ec32011-02-03 09:37:18 +010033#include <linux/compat.h>
Maxime Ripard880cfd42012-10-31 11:30:08 +010034#include <linux/of.h>
35#include <linux/of_device.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070036
37#include <linux/spi/spi.h>
38#include <linux/spi/spidev.h>
39
Jingoo Han95c63cf2013-10-14 10:36:54 +090040#include <linux/uaccess.h>
Andrea Paterniani814a8d52007-05-08 00:32:15 -070041
42
43/*
Uwe Kleine-Königb5950762010-11-01 15:38:34 -040044 * This supports access to SPI devices using normal userspace I/O calls.
Andrea Paterniani814a8d52007-05-08 00:32:15 -070045 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
46 * and often mask message boundaries, full SPI support requires full duplex
Thadeu Lima de Souza Cascardo137f1182009-10-22 17:34:29 -020047 * transfers. There are several kinds of internal message boundaries to
Andrea Paterniani814a8d52007-05-08 00:32:15 -070048 * 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
Thadeu Lima de Souza Cascardo8ae1c922009-12-14 14:20:23 -080059static DECLARE_BITMAP(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -070060
61
Anton Vorontsov6f166e32007-07-31 00:38:43 -070062/* Bit masks for spi_device.mode management. Note that incorrect
David Brownellb55f6272009-06-30 11:41:26 -070063 * settings for some settings can cause *lots* of trouble for other
64 * devices on a shared bus:
Anton Vorontsov6f166e32007-07-31 00:38:43 -070065 *
David Brownellb55f6272009-06-30 11:41:26 -070066 * - 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?
Anton Vorontsov6f166e32007-07-31 00:38:43 -070073 */
74#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
David Brownellb55f6272009-06-30 11:41:26 -070075 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
Geert Uytterhoevendc64d392014-02-25 11:40:17 +010076 | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
77 | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)
Andrea Paterniani814a8d52007-05-08 00:32:15 -070078
79struct spidev_data {
David Brownellb2c8dad2008-06-05 22:45:50 -070080 dev_t devt;
David Brownell25d5cb42008-05-23 13:05:03 -070081 spinlock_t spi_lock;
Andrea Paterniani814a8d52007-05-08 00:32:15 -070082 struct spi_device *spi;
83 struct list_head device_entry;
84
David Brownellb2c8dad2008-06-05 22:45:50 -070085 /* buffer is NULL unless this device is open (users > 0) */
Andrea Paterniani814a8d52007-05-08 00:32:15 -070086 struct mutex buf_lock;
87 unsigned users;
88 u8 *buffer;
89};
90
91static LIST_HEAD(device_list);
92static DEFINE_MUTEX(device_list_lock);
93
94static unsigned bufsiz = 4096;
95module_param(bufsiz, uint, S_IRUGO);
96MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
97
98/*-------------------------------------------------------------------------*/
99
David Brownell25d5cb42008-05-23 13:05:03 -0700100/*
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 */
104static void spidev_complete(void *arg)
105{
106 complete(arg);
107}
108
109static ssize_t
110spidev_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
134static inline ssize_t
135spidev_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
148static inline ssize_t
149spidev_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
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700164/* Read-only message with current device setup */
165static ssize_t
166spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
167{
168 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700169 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;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700176
177 mutex_lock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700178 status = spidev_sync_read(spidev, count);
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700179 if (status > 0) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700180 unsigned long missing;
181
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700182 missing = copy_to_user(buf, spidev->buffer, status);
183 if (missing == status)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700184 status = -EFAULT;
185 else
Sebastian Siewior4b1295b2008-07-04 09:59:56 -0700186 status = status - missing;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700187 }
188 mutex_unlock(&spidev->buf_lock);
189
190 return status;
191}
192
193/* Write-only message with current device setup */
194static ssize_t
195spidev_write(struct file *filp, const char __user *buf,
196 size_t count, loff_t *f_pos)
197{
198 struct spidev_data *spidev;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700199 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;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700207
208 mutex_lock(&spidev->buf_lock);
209 missing = copy_from_user(spidev->buffer, buf, count);
Jingoo Han95c63cf2013-10-14 10:36:54 +0900210 if (missing == 0)
David Brownell25d5cb42008-05-23 13:05:03 -0700211 status = spidev_sync_write(spidev, count);
Jingoo Han95c63cf2013-10-14 10:36:54 +0900212 else
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700213 status = -EFAULT;
214 mutex_unlock(&spidev->buf_lock);
215
216 return status;
217}
218
219static 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;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700226 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 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700239 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
Domen Puncerda90fa82007-05-23 13:57:39 -0700246 total += k_tmp->len;
247 if (total > bufsiz) {
248 status = -EMSGSIZE;
249 goto done;
250 }
251
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700252 if (u_tmp->rx_buf) {
253 k_tmp->rx_buf = buf;
David Brownell96ddbf52007-08-10 13:01:09 -0700254 if (!access_ok(VERIFY_WRITE, (u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000255 (uintptr_t) u_tmp->rx_buf,
David Brownell96ddbf52007-08-10 13:01:09 -0700256 u_tmp->len))
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700257 goto done;
258 }
259 if (u_tmp->tx_buf) {
260 k_tmp->tx_buf = buf;
David Brownell4917d922007-07-17 04:04:04 -0700261 if (copy_from_user(buf, (const u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000262 (uintptr_t) u_tmp->tx_buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700263 u_tmp->len))
264 goto done;
265 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700266 buf += k_tmp->len;
267
268 k_tmp->cs_change = !!u_tmp->cs_change;
Geert Uytterhoevendc64d392014-02-25 11:40:17 +0100269 k_tmp->tx_nbits = u_tmp->tx_nbits;
270 k_tmp->rx_nbits = u_tmp->rx_nbits;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700271 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
Florian Fainelli41df70d2009-12-07 14:28:43 +0000275 dev_dbg(&spidev->spi->dev,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700276 " 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 " : "",
Florian Fainelli41df70d2009-12-07 14:28:43 +0000281 u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700282 u_tmp->delay_usecs,
Florian Fainelli41df70d2009-12-07 14:28:43 +0000283 u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700284#endif
285 spi_message_add_tail(k_tmp, &msg);
286 }
287
David Brownell25d5cb42008-05-23 13:05:03 -0700288 status = spidev_sync(spidev, &msg);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700289 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) {
David Brownell4917d922007-07-17 04:04:04 -0700296 if (__copy_to_user((u8 __user *)
Al Viro142956a2007-10-29 05:11:28 +0000297 (uintptr_t) u_tmp->rx_buf, buf,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700298 u_tmp->len)) {
299 status = -EFAULT;
300 goto done;
301 }
302 }
303 buf += u_tmp->len;
304 }
305 status = total;
306
307done:
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700308 kfree(k_xfers);
309 return status;
310}
311
Alan Cox4ef754b2008-07-23 21:29:55 -0700312static long
313spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700314{
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
David Brownell25d5cb42008-05-23 13:05:03 -0700340 /* guard against device removal before, or while,
341 * we issue this ioctl.
342 */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700343 spidev = filp->private_data;
David Brownell25d5cb42008-05-23 13:05:03 -0700344 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;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700350
Alan Cox4ef754b2008-07-23 21:29:55 -0700351 /* 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
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700359 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;
Geert Uytterhoevendc64d392014-02-25 11:40:17 +0100365 case SPI_IOC_RD_MODE32:
366 retval = __put_user(spi->mode & SPI_MODE_MASK,
367 (__u32 __user *)arg);
368 break;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700369 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:
Geert Uytterhoevendc64d392014-02-25 11:40:17 +0100382 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);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700387 if (retval == 0) {
Geert Uytterhoevene6456182014-02-25 11:40:16 +0100388 u32 save = spi->mode;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700389
390 if (tmp & ~SPI_MODE_MASK) {
391 retval = -EINVAL;
392 break;
393 }
394
395 tmp |= spi->mode & ~SPI_MODE_MASK;
Geert Uytterhoevendc64d392014-02-25 11:40:17 +0100396 spi->mode = (u16)tmp;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700397 retval = spi_setup(spi);
398 if (retval < 0)
399 spi->mode = save;
400 else
Geert Uytterhoevendc64d392014-02-25 11:40:17 +0100401 dev_dbg(&spi->dev, "spi mode %x\n", tmp);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700402 }
403 break;
404 case SPI_IOC_WR_LSB_FIRST:
405 retval = __get_user(tmp, (__u8 __user *)arg);
406 if (retval == 0) {
Geert Uytterhoevene6456182014-02-25 11:40:16 +0100407 u32 save = spi->mode;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700408
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))
David Brownell25d5cb42008-05-23 13:05:03 -0700451 || _IOC_DIR(cmd) != _IOC_WRITE) {
452 retval = -ENOTTY;
453 break;
454 }
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700455
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)) {
Florin Malita9bea3f22007-05-23 13:57:45 -0700472 kfree(ioc);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700473 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 }
Alan Cox4ef754b2008-07-23 21:29:55 -0700482
483 mutex_unlock(&spidev->buf_lock);
David Brownell25d5cb42008-05-23 13:05:03 -0700484 spi_dev_put(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700485 return retval;
486}
487
Bernhard Walle7d48ec32011-02-03 09:37:18 +0100488#ifdef CONFIG_COMPAT
489static long
490spidev_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
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700498static 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) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700506 if (spidev->devt == inode->i_rdev) {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700507 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
531static 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;
David Brownellb2c8dad2008-06-05 22:45:50 -0700539
540 /* last close? */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700541 spidev->users--;
542 if (!spidev->users) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700543 int dofree;
544
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700545 kfree(spidev->buffer);
546 spidev->buffer = NULL;
David Brownellb2c8dad2008-06-05 22:45:50 -0700547
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);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700555 }
556 mutex_unlock(&device_list_lock);
557
558 return status;
559}
560
Alexey Dobriyan828c0952009-10-01 15:43:56 -0700561static const struct file_operations spidev_fops = {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700562 .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,
Alan Cox4ef754b2008-07-23 21:29:55 -0700569 .unlocked_ioctl = spidev_ioctl,
Bernhard Walle7d48ec32011-02-03 09:37:18 +0100570 .compat_ioctl = spidev_compat_ioctl,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700571 .open = spidev_open,
572 .release = spidev_release,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200573 .llseek = no_llseek,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700574};
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
David Brownellb2c8dad2008-06-05 22:45:50 -0700583static struct class *spidev_class;
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700584
585/*-------------------------------------------------------------------------*/
586
Grant Likelyfd4a3192012-12-07 16:57:14 +0000587static int spidev_probe(struct spi_device *spi)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700588{
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;
David Brownell25d5cb42008-05-23 13:05:03 -0700600 spin_lock_init(&spidev->spi_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700601 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);
Domen Puncer0a4dd772007-05-15 23:57:05 -0700609 minor = find_first_zero_bit(minors, N_SPI_MINORS);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700610 if (minor < N_SPI_MINORS) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700611 struct device *dev;
612
613 spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
Greg Kroah-Hartmana9b12612008-07-21 20:03:34 -0700614 dev = device_create(spidev_class, &spi->dev, spidev->devt,
615 spidev, "spidev%d.%d",
616 spi->master->bus_num, spi->chip_select);
Rusty Russell8c6ffba2013-07-15 11:20:32 +0930617 status = PTR_ERR_OR_ZERO(dev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700618 } else {
619 dev_dbg(&spi->dev, "no minor number available!\n");
620 status = -ENODEV;
621 }
622 if (status == 0) {
623 set_bit(minor, minors);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700624 list_add(&spidev->device_entry, &device_list);
625 }
626 mutex_unlock(&device_list_lock);
627
Wolfgang Ockeraaacf4b2008-12-01 13:13:52 -0800628 if (status == 0)
629 spi_set_drvdata(spi, spidev);
630 else
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700631 kfree(spidev);
632
633 return status;
634}
635
Grant Likelyfd4a3192012-12-07 16:57:14 +0000636static int spidev_remove(struct spi_device *spi)
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700637{
David Brownellb2c8dad2008-06-05 22:45:50 -0700638 struct spidev_data *spidev = spi_get_drvdata(spi);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700639
David Brownell25d5cb42008-05-23 13:05:03 -0700640 /* 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);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700644
David Brownell25d5cb42008-05-23 13:05:03 -0700645 /* prevent new opens */
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700646 mutex_lock(&device_list_lock);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700647 list_del(&spidev->device_entry);
David Brownellb2c8dad2008-06-05 22:45:50 -0700648 device_destroy(spidev_class, spidev->devt);
649 clear_bit(MINOR(spidev->devt), minors);
650 if (spidev->users == 0)
651 kfree(spidev);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700652 mutex_unlock(&device_list_lock);
653
654 return 0;
655}
656
Maxime Ripard880cfd42012-10-31 11:30:08 +0100657static const struct of_device_id spidev_dt_ids[] = {
Maxime Ripard8fad8052012-10-31 11:30:09 +0100658 { .compatible = "rohm,dh2228fv" },
Maxime Ripard880cfd42012-10-31 11:30:08 +0100659 {},
660};
661
662MODULE_DEVICE_TABLE(of, spidev_dt_ids);
663
Mike Frysingerdb389b62009-12-14 14:20:22 -0800664static struct spi_driver spidev_spi_driver = {
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700665 .driver = {
666 .name = "spidev",
667 .owner = THIS_MODULE,
Maxime Ripard880cfd42012-10-31 11:30:08 +0100668 .of_match_table = of_match_ptr(spidev_dt_ids),
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700669 },
670 .probe = spidev_probe,
Grant Likelyfd4a3192012-12-07 16:57:14 +0000671 .remove = spidev_remove,
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700672
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
682static 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
David Brownellb2c8dad2008-06-05 22:45:50 -0700695 spidev_class = class_create(THIS_MODULE, "spidev");
696 if (IS_ERR(spidev_class)) {
Mike Frysingerdb389b62009-12-14 14:20:22 -0800697 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
David Brownellb2c8dad2008-06-05 22:45:50 -0700698 return PTR_ERR(spidev_class);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700699 }
700
Mike Frysingerdb389b62009-12-14 14:20:22 -0800701 status = spi_register_driver(&spidev_spi_driver);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700702 if (status < 0) {
David Brownellb2c8dad2008-06-05 22:45:50 -0700703 class_destroy(spidev_class);
Mike Frysingerdb389b62009-12-14 14:20:22 -0800704 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700705 }
706 return status;
707}
708module_init(spidev_init);
709
710static void __exit spidev_exit(void)
711{
Mike Frysingerdb389b62009-12-14 14:20:22 -0800712 spi_unregister_driver(&spidev_spi_driver);
David Brownellb2c8dad2008-06-05 22:45:50 -0700713 class_destroy(spidev_class);
Mike Frysingerdb389b62009-12-14 14:20:22 -0800714 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
Andrea Paterniani814a8d52007-05-08 00:32:15 -0700715}
716module_exit(spidev_exit);
717
718MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
719MODULE_DESCRIPTION("User mode SPI device interface");
720MODULE_LICENSE("GPL");
Anton Vorontsove0626e32009-09-22 16:46:08 -0700721MODULE_ALIAS("spi:spidev");