1 /* 2 * Simple synchronous userspace interface to SPI devices 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> 28 #include <linux/err.h> 29 #include <linux/list.h> 30 #include <linux/errno.h> 31 #include <linux/mutex.h> 32 #include <linux/slab.h> 33 #include <linux/compat.h> 34 #include <linux/of.h> 35 #include <linux/of_device.h> 36 37 #include <linux/spi/spi.h> 38 #include <linux/spi/spidev.h> 39 40 #include <linux/uaccess.h> 41 42 43 /* 44 * This supports access to SPI devices using normal userspace I/O calls. 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 47 * transfers. There are several kinds of internal message boundaries to 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 59 static DECLARE_BITMAP(minors, N_SPI_MINORS); 60 61 62 /* Bit masks for spi_device.mode management. Note that incorrect 63 * settings for some settings can cause *lots* of trouble for other 64 * devices on a shared bus: 65 * 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? 73 */ 74 #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ 75 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ 76 | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \ 77 | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD) 78 79 struct spidev_data { 80 dev_t devt; 81 spinlock_t spi_lock; 82 struct spi_device *spi; 83 struct list_head device_entry; 84 85 /* TX/RX buffers are NULL unless this device is open (users > 0) */ 86 struct mutex buf_lock; 87 unsigned users; 88 u8 *tx_buffer; 89 u8 *rx_buffer; 90 u32 speed_hz; 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 /*-------------------------------------------------------------------------*/ 101 102 /* 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 = { 140 .tx_buf = spidev->tx_buffer, 141 .len = len, 142 .speed_hz = spidev->speed_hz, 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 = { 155 .rx_buf = spidev->rx_buffer, 156 .len = len, 157 .speed_hz = spidev->speed_hz, 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 /*-------------------------------------------------------------------------*/ 167 168 /* 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; 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; 180 181 mutex_lock(&spidev->buf_lock); 182 status = spidev_sync_read(spidev, count); 183 if (status > 0) { 184 unsigned long missing; 185 186 missing = copy_to_user(buf, spidev->rx_buffer, status); 187 if (missing == status) 188 status = -EFAULT; 189 else 190 status = status - missing; 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; 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; 211 212 mutex_lock(&spidev->buf_lock); 213 missing = copy_from_user(spidev->tx_buffer, buf, count); 214 if (missing == 0) 215 status = spidev_sync_write(spidev, count); 216 else 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; 230 unsigned n, total; 231 u8 *tx_buf, *rx_buf; 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 */ 243 tx_buf = spidev->tx_buffer; 244 rx_buf = spidev->rx_buffer; 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; 250 251 total += k_tmp->len; 252 if (total > bufsiz) { 253 status = -EMSGSIZE; 254 goto done; 255 } 256 257 if (u_tmp->rx_buf) { 258 k_tmp->rx_buf = rx_buf; 259 if (!access_ok(VERIFY_WRITE, (u8 __user *) 260 (uintptr_t) u_tmp->rx_buf, 261 u_tmp->len)) 262 goto done; 263 } 264 if (u_tmp->tx_buf) { 265 k_tmp->tx_buf = tx_buf; 266 if (copy_from_user(tx_buf, (const u8 __user *) 267 (uintptr_t) u_tmp->tx_buf, 268 u_tmp->len)) 269 goto done; 270 } 271 tx_buf += k_tmp->len; 272 rx_buf += k_tmp->len; 273 274 k_tmp->cs_change = !!u_tmp->cs_change; 275 k_tmp->tx_nbits = u_tmp->tx_nbits; 276 k_tmp->rx_nbits = u_tmp->rx_nbits; 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; 280 if (!k_tmp->speed_hz) 281 k_tmp->speed_hz = spidev->speed_hz; 282 #ifdef VERBOSE 283 dev_dbg(&spidev->spi->dev, 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 " : "", 289 u_tmp->bits_per_word ? : spidev->spi->bits_per_word, 290 u_tmp->delay_usecs, 291 u_tmp->speed_hz ? : spidev->spi->max_speed_hz); 292 #endif 293 spi_message_add_tail(k_tmp, &msg); 294 } 295 296 status = spidev_sync(spidev, &msg); 297 if (status < 0) 298 goto done; 299 300 /* copy any rx data out of bounce buffer */ 301 rx_buf = spidev->rx_buffer; 302 for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { 303 if (u_tmp->rx_buf) { 304 if (__copy_to_user((u8 __user *) 305 (uintptr_t) u_tmp->rx_buf, rx_buf, 306 u_tmp->len)) { 307 status = -EFAULT; 308 goto done; 309 } 310 } 311 rx_buf += u_tmp->len; 312 } 313 status = total; 314 315 done: 316 kfree(k_xfers); 317 return status; 318 } 319 320 static long 321 spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 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; 347 348 /* guard against device removal before, or while, 349 * we issue this ioctl. 350 */ 351 spidev = filp->private_data; 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; 358 359 /* 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); 366 367 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; 373 case SPI_IOC_RD_MODE32: 374 retval = __put_user(spi->mode & SPI_MODE_MASK, 375 (__u32 __user *)arg); 376 break; 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: 385 retval = __put_user(spidev->speed_hz, (__u32 __user *)arg); 386 break; 387 388 /* write requests */ 389 case SPI_IOC_WR_MODE: 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); 395 if (retval == 0) { 396 u32 save = spi->mode; 397 398 if (tmp & ~SPI_MODE_MASK) { 399 retval = -EINVAL; 400 break; 401 } 402 403 tmp |= spi->mode & ~SPI_MODE_MASK; 404 spi->mode = (u16)tmp; 405 retval = spi_setup(spi); 406 if (retval < 0) 407 spi->mode = save; 408 else 409 dev_dbg(&spi->dev, "spi mode %x\n", tmp); 410 } 411 break; 412 case SPI_IOC_WR_LSB_FIRST: 413 retval = __get_user(tmp, (__u8 __user *)arg); 414 if (retval == 0) { 415 u32 save = spi->mode; 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); 449 if (retval >= 0) 450 spidev->speed_hz = tmp; 451 else 452 dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); 453 spi->max_speed_hz = save; 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)) 460 || _IOC_DIR(cmd) != _IOC_WRITE) { 461 retval = -ENOTTY; 462 break; 463 } 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)) { 481 kfree(ioc); 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 } 491 492 mutex_unlock(&spidev->buf_lock); 493 spi_dev_put(spi); 494 return retval; 495 } 496 497 #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 */ 506 507 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) { 515 if (spidev->devt == inode->i_rdev) { 516 status = 0; 517 break; 518 } 519 } 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) { 529 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); 530 status = -ENOMEM; 531 goto err_find_dev; 532 } 533 } 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; 541 } 542 } 543 544 spidev->users++; 545 filp->private_data = spidev; 546 nonseekable_open(inode, filp); 547 548 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: 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; 567 568 /* last close? */ 569 spidev->users--; 570 if (!spidev->users) { 571 int dofree; 572 573 kfree(spidev->tx_buffer); 574 spidev->tx_buffer = NULL; 575 576 kfree(spidev->rx_buffer); 577 spidev->rx_buffer = NULL; 578 579 spidev->speed_hz = spidev->spi->max_speed_hz; 580 581 /* ... 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); 588 } 589 mutex_unlock(&device_list_lock); 590 591 return status; 592 } 593 594 static const struct file_operations spidev_fops = { 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, 602 .unlocked_ioctl = spidev_ioctl, 603 .compat_ioctl = spidev_compat_ioctl, 604 .open = spidev_open, 605 .release = spidev_release, 606 .llseek = no_llseek, 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 */ 615 616 static struct class *spidev_class; 617 618 /*-------------------------------------------------------------------------*/ 619 620 static int spidev_probe(struct spi_device *spi) 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; 633 spin_lock_init(&spidev->spi_lock); 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); 642 minor = find_first_zero_bit(minors, N_SPI_MINORS); 643 if (minor < N_SPI_MINORS) { 644 struct device *dev; 645 646 spidev->devt = MKDEV(SPIDEV_MAJOR, minor); 647 dev = device_create(spidev_class, &spi->dev, spidev->devt, 648 spidev, "spidev%d.%d", 649 spi->master->bus_num, spi->chip_select); 650 status = PTR_ERR_OR_ZERO(dev); 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); 657 list_add(&spidev->device_entry, &device_list); 658 } 659 mutex_unlock(&device_list_lock); 660 661 spidev->speed_hz = spi->max_speed_hz; 662 663 if (status == 0) 664 spi_set_drvdata(spi, spidev); 665 else 666 kfree(spidev); 667 668 return status; 669 } 670 671 static int spidev_remove(struct spi_device *spi) 672 { 673 struct spidev_data *spidev = spi_get_drvdata(spi); 674 675 /* 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); 679 680 /* prevent new opens */ 681 mutex_lock(&device_list_lock); 682 list_del(&spidev->device_entry); 683 device_destroy(spidev_class, spidev->devt); 684 clear_bit(MINOR(spidev->devt), minors); 685 if (spidev->users == 0) 686 kfree(spidev); 687 mutex_unlock(&device_list_lock); 688 689 return 0; 690 } 691 692 static const struct of_device_id spidev_dt_ids[] = { 693 { .compatible = "rohm,dh2228fv" }, 694 {}, 695 }; 696 697 MODULE_DEVICE_TABLE(of, spidev_dt_ids); 698 699 static struct spi_driver spidev_spi_driver = { 700 .driver = { 701 .name = "spidev", 702 .owner = THIS_MODULE, 703 .of_match_table = of_match_ptr(spidev_dt_ids), 704 }, 705 .probe = spidev_probe, 706 .remove = spidev_remove, 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; 729 730 spidev_class = class_create(THIS_MODULE, "spidev"); 731 if (IS_ERR(spidev_class)) { 732 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 733 return PTR_ERR(spidev_class); 734 } 735 736 status = spi_register_driver(&spidev_spi_driver); 737 if (status < 0) { 738 class_destroy(spidev_class); 739 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 740 } 741 return status; 742 } 743 module_init(spidev_init); 744 745 static void __exit spidev_exit(void) 746 { 747 spi_unregister_driver(&spidev_spi_driver); 748 class_destroy(spidev_class); 749 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 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"); 756 MODULE_ALIAS("spi:spidev"); 757