Andrea Paterniani | 814a8d5 | 2007-05-08 00:32:15 -0700 | [diff] [blame] | 1 | /* |
| 2 | * spidev.c -- 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/list.h> |
| 29 | #include <linux/errno.h> |
| 30 | #include <linux/mutex.h> |
| 31 | #include <linux/slab.h> |
| 32 | |
| 33 | #include <linux/spi/spi.h> |
| 34 | #include <linux/spi/spidev.h> |
| 35 | |
| 36 | #include <asm/uaccess.h> |
| 37 | |
| 38 | |
| 39 | /* |
| 40 | * This supports acccess to SPI devices using normal userspace I/O calls. |
| 41 | * Note that while traditional UNIX/POSIX I/O semantics are half duplex, |
| 42 | * and often mask message boundaries, full SPI support requires full duplex |
| 43 | * transfers. There are several kinds of of internal message boundaries to |
| 44 | * handle chipselect management and other protocol options. |
| 45 | * |
| 46 | * SPI has a character major number assigned. We allocate minor numbers |
| 47 | * dynamically using a bitmask. You must use hotplug tools, such as udev |
| 48 | * (or mdev with busybox) to create and destroy the /dev/spidevB.C device |
| 49 | * nodes, since there is no fixed association of minor numbers with any |
| 50 | * particular SPI bus or device. |
| 51 | */ |
| 52 | #define SPIDEV_MAJOR 153 /* assigned */ |
| 53 | #define N_SPI_MINORS 32 /* ... up to 256 */ |
| 54 | |
| 55 | static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG]; |
| 56 | |
| 57 | |
| 58 | /* Bit masks for spi_device.mode management */ |
| 59 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL) |
| 60 | |
| 61 | |
| 62 | struct spidev_data { |
| 63 | struct device dev; |
| 64 | struct spi_device *spi; |
| 65 | struct list_head device_entry; |
| 66 | |
| 67 | struct mutex buf_lock; |
| 68 | unsigned users; |
| 69 | u8 *buffer; |
| 70 | }; |
| 71 | |
| 72 | static LIST_HEAD(device_list); |
| 73 | static DEFINE_MUTEX(device_list_lock); |
| 74 | |
| 75 | static unsigned bufsiz = 4096; |
| 76 | module_param(bufsiz, uint, S_IRUGO); |
| 77 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); |
| 78 | |
| 79 | /*-------------------------------------------------------------------------*/ |
| 80 | |
| 81 | /* Read-only message with current device setup */ |
| 82 | static ssize_t |
| 83 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) |
| 84 | { |
| 85 | struct spidev_data *spidev; |
| 86 | struct spi_device *spi; |
| 87 | ssize_t status = 0; |
| 88 | |
| 89 | /* chipselect only toggles at start or end of operation */ |
| 90 | if (count > bufsiz) |
| 91 | return -EMSGSIZE; |
| 92 | |
| 93 | spidev = filp->private_data; |
| 94 | spi = spidev->spi; |
| 95 | |
| 96 | mutex_lock(&spidev->buf_lock); |
| 97 | status = spi_read(spi, spidev->buffer, count); |
| 98 | if (status == 0) { |
| 99 | unsigned long missing; |
| 100 | |
| 101 | missing = copy_to_user(buf, spidev->buffer, count); |
| 102 | if (count && missing == count) |
| 103 | status = -EFAULT; |
| 104 | else |
| 105 | status = count - missing; |
| 106 | } |
| 107 | mutex_unlock(&spidev->buf_lock); |
| 108 | |
| 109 | return status; |
| 110 | } |
| 111 | |
| 112 | /* Write-only message with current device setup */ |
| 113 | static ssize_t |
| 114 | spidev_write(struct file *filp, const char __user *buf, |
| 115 | size_t count, loff_t *f_pos) |
| 116 | { |
| 117 | struct spidev_data *spidev; |
| 118 | struct spi_device *spi; |
| 119 | ssize_t status = 0; |
| 120 | unsigned long missing; |
| 121 | |
| 122 | /* chipselect only toggles at start or end of operation */ |
| 123 | if (count > bufsiz) |
| 124 | return -EMSGSIZE; |
| 125 | |
| 126 | spidev = filp->private_data; |
| 127 | spi = spidev->spi; |
| 128 | |
| 129 | mutex_lock(&spidev->buf_lock); |
| 130 | missing = copy_from_user(spidev->buffer, buf, count); |
| 131 | if (missing == 0) { |
| 132 | status = spi_write(spi, spidev->buffer, count); |
| 133 | if (status == 0) |
| 134 | status = count; |
| 135 | } else |
| 136 | status = -EFAULT; |
| 137 | mutex_unlock(&spidev->buf_lock); |
| 138 | |
| 139 | return status; |
| 140 | } |
| 141 | |
| 142 | static int spidev_message(struct spidev_data *spidev, |
| 143 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) |
| 144 | { |
| 145 | struct spi_message msg; |
| 146 | struct spi_transfer *k_xfers; |
| 147 | struct spi_transfer *k_tmp; |
| 148 | struct spi_ioc_transfer *u_tmp; |
| 149 | struct spi_device *spi = spidev->spi; |
| 150 | unsigned n, total; |
| 151 | u8 *buf; |
| 152 | int status = -EFAULT; |
| 153 | |
| 154 | spi_message_init(&msg); |
| 155 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); |
| 156 | if (k_xfers == NULL) |
| 157 | return -ENOMEM; |
| 158 | |
| 159 | /* Construct spi_message, copying any tx data to bounce buffer. |
| 160 | * We walk the array of user-provided transfers, using each one |
| 161 | * to initialize a kernel version of the same transfer. |
| 162 | */ |
| 163 | mutex_lock(&spidev->buf_lock); |
| 164 | buf = spidev->buffer; |
| 165 | total = 0; |
| 166 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; |
| 167 | n; |
| 168 | n--, k_tmp++, u_tmp++) { |
| 169 | k_tmp->len = u_tmp->len; |
| 170 | |
| 171 | if (u_tmp->rx_buf) { |
| 172 | k_tmp->rx_buf = buf; |
| 173 | if (!access_ok(VERIFY_WRITE, u_tmp->rx_buf, u_tmp->len)) |
| 174 | goto done; |
| 175 | } |
| 176 | if (u_tmp->tx_buf) { |
| 177 | k_tmp->tx_buf = buf; |
| 178 | if (copy_from_user(buf, (const u8 __user *)u_tmp->tx_buf, |
| 179 | u_tmp->len)) |
| 180 | goto done; |
| 181 | } |
| 182 | |
| 183 | total += k_tmp->len; |
| 184 | if (total > bufsiz) { |
| 185 | status = -EMSGSIZE; |
| 186 | goto done; |
| 187 | } |
| 188 | buf += k_tmp->len; |
| 189 | |
| 190 | k_tmp->cs_change = !!u_tmp->cs_change; |
| 191 | k_tmp->bits_per_word = u_tmp->bits_per_word; |
| 192 | k_tmp->delay_usecs = u_tmp->delay_usecs; |
| 193 | k_tmp->speed_hz = u_tmp->speed_hz; |
| 194 | #ifdef VERBOSE |
| 195 | dev_dbg(&spi->dev, |
| 196 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", |
| 197 | u_tmp->len, |
| 198 | u_tmp->rx_buf ? "rx " : "", |
| 199 | u_tmp->tx_buf ? "tx " : "", |
| 200 | u_tmp->cs_change ? "cs " : "", |
| 201 | u_tmp->bits_per_word ? : spi->bits_per_word, |
| 202 | u_tmp->delay_usecs, |
| 203 | u_tmp->speed_hz ? : spi->max_speed_hz); |
| 204 | #endif |
| 205 | spi_message_add_tail(k_tmp, &msg); |
| 206 | } |
| 207 | |
| 208 | status = spi_sync(spi, &msg); |
| 209 | if (status < 0) |
| 210 | goto done; |
| 211 | |
| 212 | /* copy any rx data out of bounce buffer */ |
| 213 | buf = spidev->buffer; |
| 214 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { |
| 215 | if (u_tmp->rx_buf) { |
| 216 | if (__copy_to_user((u8 __user *)u_tmp->rx_buf, buf, |
| 217 | u_tmp->len)) { |
| 218 | status = -EFAULT; |
| 219 | goto done; |
| 220 | } |
| 221 | } |
| 222 | buf += u_tmp->len; |
| 223 | } |
| 224 | status = total; |
| 225 | |
| 226 | done: |
| 227 | mutex_unlock(&spidev->buf_lock); |
| 228 | kfree(k_xfers); |
| 229 | return status; |
| 230 | } |
| 231 | |
| 232 | static int |
| 233 | spidev_ioctl(struct inode *inode, struct file *filp, |
| 234 | unsigned int cmd, unsigned long arg) |
| 235 | { |
| 236 | int err = 0; |
| 237 | int retval = 0; |
| 238 | struct spidev_data *spidev; |
| 239 | struct spi_device *spi; |
| 240 | u32 tmp; |
| 241 | unsigned n_ioc; |
| 242 | struct spi_ioc_transfer *ioc; |
| 243 | |
| 244 | /* Check type and command number */ |
| 245 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) |
| 246 | return -ENOTTY; |
| 247 | |
| 248 | /* Check access direction once here; don't repeat below. |
| 249 | * IOC_DIR is from the user perspective, while access_ok is |
| 250 | * from the kernel perspective; so they look reversed. |
| 251 | */ |
| 252 | if (_IOC_DIR(cmd) & _IOC_READ) |
| 253 | err = !access_ok(VERIFY_WRITE, |
| 254 | (void __user *)arg, _IOC_SIZE(cmd)); |
| 255 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) |
| 256 | err = !access_ok(VERIFY_READ, |
| 257 | (void __user *)arg, _IOC_SIZE(cmd)); |
| 258 | if (err) |
| 259 | return -EFAULT; |
| 260 | |
| 261 | spidev = filp->private_data; |
| 262 | spi = spidev->spi; |
| 263 | |
| 264 | switch (cmd) { |
| 265 | /* read requests */ |
| 266 | case SPI_IOC_RD_MODE: |
| 267 | retval = __put_user(spi->mode & SPI_MODE_MASK, |
| 268 | (__u8 __user *)arg); |
| 269 | break; |
| 270 | case SPI_IOC_RD_LSB_FIRST: |
| 271 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, |
| 272 | (__u8 __user *)arg); |
| 273 | break; |
| 274 | case SPI_IOC_RD_BITS_PER_WORD: |
| 275 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); |
| 276 | break; |
| 277 | case SPI_IOC_RD_MAX_SPEED_HZ: |
| 278 | retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg); |
| 279 | break; |
| 280 | |
| 281 | /* write requests */ |
| 282 | case SPI_IOC_WR_MODE: |
| 283 | retval = __get_user(tmp, (u8 __user *)arg); |
| 284 | if (retval == 0) { |
| 285 | u8 save = spi->mode; |
| 286 | |
| 287 | if (tmp & ~SPI_MODE_MASK) { |
| 288 | retval = -EINVAL; |
| 289 | break; |
| 290 | } |
| 291 | |
| 292 | tmp |= spi->mode & ~SPI_MODE_MASK; |
| 293 | spi->mode = (u8)tmp; |
| 294 | retval = spi_setup(spi); |
| 295 | if (retval < 0) |
| 296 | spi->mode = save; |
| 297 | else |
| 298 | dev_dbg(&spi->dev, "spi mode %02x\n", tmp); |
| 299 | } |
| 300 | break; |
| 301 | case SPI_IOC_WR_LSB_FIRST: |
| 302 | retval = __get_user(tmp, (__u8 __user *)arg); |
| 303 | if (retval == 0) { |
| 304 | u8 save = spi->mode; |
| 305 | |
| 306 | if (tmp) |
| 307 | spi->mode |= SPI_LSB_FIRST; |
| 308 | else |
| 309 | spi->mode &= ~SPI_LSB_FIRST; |
| 310 | retval = spi_setup(spi); |
| 311 | if (retval < 0) |
| 312 | spi->mode = save; |
| 313 | else |
| 314 | dev_dbg(&spi->dev, "%csb first\n", |
| 315 | tmp ? 'l' : 'm'); |
| 316 | } |
| 317 | break; |
| 318 | case SPI_IOC_WR_BITS_PER_WORD: |
| 319 | retval = __get_user(tmp, (__u8 __user *)arg); |
| 320 | if (retval == 0) { |
| 321 | u8 save = spi->bits_per_word; |
| 322 | |
| 323 | spi->bits_per_word = tmp; |
| 324 | retval = spi_setup(spi); |
| 325 | if (retval < 0) |
| 326 | spi->bits_per_word = save; |
| 327 | else |
| 328 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); |
| 329 | } |
| 330 | break; |
| 331 | case SPI_IOC_WR_MAX_SPEED_HZ: |
| 332 | retval = __get_user(tmp, (__u32 __user *)arg); |
| 333 | if (retval == 0) { |
| 334 | u32 save = spi->max_speed_hz; |
| 335 | |
| 336 | spi->max_speed_hz = tmp; |
| 337 | retval = spi_setup(spi); |
| 338 | if (retval < 0) |
| 339 | spi->max_speed_hz = save; |
| 340 | else |
| 341 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); |
| 342 | } |
| 343 | break; |
| 344 | |
| 345 | default: |
| 346 | /* segmented and/or full-duplex I/O request */ |
| 347 | if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) |
| 348 | || _IOC_DIR(cmd) != _IOC_WRITE) |
| 349 | return -ENOTTY; |
| 350 | |
| 351 | tmp = _IOC_SIZE(cmd); |
| 352 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { |
| 353 | retval = -EINVAL; |
| 354 | break; |
| 355 | } |
| 356 | n_ioc = tmp / sizeof(struct spi_ioc_transfer); |
| 357 | if (n_ioc == 0) |
| 358 | break; |
| 359 | |
| 360 | /* copy into scratch area */ |
| 361 | ioc = kmalloc(tmp, GFP_KERNEL); |
| 362 | if (!ioc) { |
| 363 | retval = -ENOMEM; |
| 364 | break; |
| 365 | } |
| 366 | if (__copy_from_user(ioc, (void __user *)arg, tmp)) { |
| 367 | retval = -EFAULT; |
| 368 | break; |
| 369 | } |
| 370 | |
| 371 | /* translate to spi_message, execute */ |
| 372 | retval = spidev_message(spidev, ioc, n_ioc); |
| 373 | kfree(ioc); |
| 374 | break; |
| 375 | } |
| 376 | return retval; |
| 377 | } |
| 378 | |
| 379 | static int spidev_open(struct inode *inode, struct file *filp) |
| 380 | { |
| 381 | struct spidev_data *spidev; |
| 382 | int status = -ENXIO; |
| 383 | |
| 384 | mutex_lock(&device_list_lock); |
| 385 | |
| 386 | list_for_each_entry(spidev, &device_list, device_entry) { |
| 387 | if (spidev->dev.devt == inode->i_rdev) { |
| 388 | status = 0; |
| 389 | break; |
| 390 | } |
| 391 | } |
| 392 | if (status == 0) { |
| 393 | if (!spidev->buffer) { |
| 394 | spidev->buffer = kmalloc(bufsiz, GFP_KERNEL); |
| 395 | if (!spidev->buffer) { |
| 396 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); |
| 397 | status = -ENOMEM; |
| 398 | } |
| 399 | } |
| 400 | if (status == 0) { |
| 401 | spidev->users++; |
| 402 | filp->private_data = spidev; |
| 403 | nonseekable_open(inode, filp); |
| 404 | } |
| 405 | } else |
| 406 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); |
| 407 | |
| 408 | mutex_unlock(&device_list_lock); |
| 409 | return status; |
| 410 | } |
| 411 | |
| 412 | static int spidev_release(struct inode *inode, struct file *filp) |
| 413 | { |
| 414 | struct spidev_data *spidev; |
| 415 | int status = 0; |
| 416 | |
| 417 | mutex_lock(&device_list_lock); |
| 418 | spidev = filp->private_data; |
| 419 | filp->private_data = NULL; |
| 420 | spidev->users--; |
| 421 | if (!spidev->users) { |
| 422 | kfree(spidev->buffer); |
| 423 | spidev->buffer = NULL; |
| 424 | } |
| 425 | mutex_unlock(&device_list_lock); |
| 426 | |
| 427 | return status; |
| 428 | } |
| 429 | |
| 430 | static struct file_operations spidev_fops = { |
| 431 | .owner = THIS_MODULE, |
| 432 | /* REVISIT switch to aio primitives, so that userspace |
| 433 | * gets more complete API coverage. It'll simplify things |
| 434 | * too, except for the locking. |
| 435 | */ |
| 436 | .write = spidev_write, |
| 437 | .read = spidev_read, |
| 438 | .ioctl = spidev_ioctl, |
| 439 | .open = spidev_open, |
| 440 | .release = spidev_release, |
| 441 | }; |
| 442 | |
| 443 | /*-------------------------------------------------------------------------*/ |
| 444 | |
| 445 | /* The main reason to have this class is to make mdev/udev create the |
| 446 | * /dev/spidevB.C character device nodes exposing our userspace API. |
| 447 | * It also simplifies memory management. |
| 448 | */ |
| 449 | |
| 450 | static void spidev_classdev_release(struct device *dev) |
| 451 | { |
| 452 | struct spidev_data *spidev; |
| 453 | |
| 454 | spidev = container_of(dev, struct spidev_data, dev); |
| 455 | kfree(spidev); |
| 456 | } |
| 457 | |
| 458 | static struct class spidev_class = { |
| 459 | .name = "spidev", |
| 460 | .owner = THIS_MODULE, |
| 461 | .dev_release = spidev_classdev_release, |
| 462 | }; |
| 463 | |
| 464 | /*-------------------------------------------------------------------------*/ |
| 465 | |
| 466 | static int spidev_probe(struct spi_device *spi) |
| 467 | { |
| 468 | struct spidev_data *spidev; |
| 469 | int status; |
| 470 | unsigned long minor; |
| 471 | |
| 472 | /* Allocate driver data */ |
| 473 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); |
| 474 | if (!spidev) |
| 475 | return -ENOMEM; |
| 476 | |
| 477 | /* Initialize the driver data */ |
| 478 | spidev->spi = spi; |
| 479 | mutex_init(&spidev->buf_lock); |
| 480 | |
| 481 | INIT_LIST_HEAD(&spidev->device_entry); |
| 482 | |
| 483 | /* If we can allocate a minor number, hook up this device. |
| 484 | * Reusing minors is fine so long as udev or mdev is working. |
| 485 | */ |
| 486 | mutex_lock(&device_list_lock); |
Domen Puncer | 0a4dd77 | 2007-05-15 23:57:05 -0700 | [diff] [blame] | 487 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
Andrea Paterniani | 814a8d5 | 2007-05-08 00:32:15 -0700 | [diff] [blame] | 488 | if (minor < N_SPI_MINORS) { |
| 489 | spidev->dev.parent = &spi->dev; |
| 490 | spidev->dev.class = &spidev_class; |
| 491 | spidev->dev.devt = MKDEV(SPIDEV_MAJOR, minor); |
| 492 | snprintf(spidev->dev.bus_id, sizeof spidev->dev.bus_id, |
| 493 | "spidev%d.%d", |
| 494 | spi->master->bus_num, spi->chip_select); |
| 495 | status = device_register(&spidev->dev); |
| 496 | } else { |
| 497 | dev_dbg(&spi->dev, "no minor number available!\n"); |
| 498 | status = -ENODEV; |
| 499 | } |
| 500 | if (status == 0) { |
| 501 | set_bit(minor, minors); |
| 502 | dev_set_drvdata(&spi->dev, spidev); |
| 503 | list_add(&spidev->device_entry, &device_list); |
| 504 | } |
| 505 | mutex_unlock(&device_list_lock); |
| 506 | |
| 507 | if (status != 0) |
| 508 | kfree(spidev); |
| 509 | |
| 510 | return status; |
| 511 | } |
| 512 | |
| 513 | static int spidev_remove(struct spi_device *spi) |
| 514 | { |
| 515 | struct spidev_data *spidev = dev_get_drvdata(&spi->dev); |
| 516 | |
| 517 | mutex_lock(&device_list_lock); |
| 518 | |
| 519 | list_del(&spidev->device_entry); |
| 520 | dev_set_drvdata(&spi->dev, NULL); |
| 521 | clear_bit(MINOR(spidev->dev.devt), minors); |
| 522 | device_unregister(&spidev->dev); |
| 523 | |
| 524 | mutex_unlock(&device_list_lock); |
| 525 | |
| 526 | return 0; |
| 527 | } |
| 528 | |
| 529 | static struct spi_driver spidev_spi = { |
| 530 | .driver = { |
| 531 | .name = "spidev", |
| 532 | .owner = THIS_MODULE, |
| 533 | }, |
| 534 | .probe = spidev_probe, |
| 535 | .remove = __devexit_p(spidev_remove), |
| 536 | |
| 537 | /* NOTE: suspend/resume methods are not necessary here. |
| 538 | * We don't do anything except pass the requests to/from |
| 539 | * the underlying controller. The refrigerator handles |
| 540 | * most issues; the controller driver handles the rest. |
| 541 | */ |
| 542 | }; |
| 543 | |
| 544 | /*-------------------------------------------------------------------------*/ |
| 545 | |
| 546 | static int __init spidev_init(void) |
| 547 | { |
| 548 | int status; |
| 549 | |
| 550 | /* Claim our 256 reserved device numbers. Then register a class |
| 551 | * that will key udev/mdev to add/remove /dev nodes. Last, register |
| 552 | * the driver which manages those device numbers. |
| 553 | */ |
| 554 | BUILD_BUG_ON(N_SPI_MINORS > 256); |
| 555 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); |
| 556 | if (status < 0) |
| 557 | return status; |
| 558 | |
| 559 | status = class_register(&spidev_class); |
| 560 | if (status < 0) { |
| 561 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
| 562 | return status; |
| 563 | } |
| 564 | |
| 565 | status = spi_register_driver(&spidev_spi); |
| 566 | if (status < 0) { |
| 567 | class_unregister(&spidev_class); |
| 568 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
| 569 | } |
| 570 | return status; |
| 571 | } |
| 572 | module_init(spidev_init); |
| 573 | |
| 574 | static void __exit spidev_exit(void) |
| 575 | { |
| 576 | spi_unregister_driver(&spidev_spi); |
| 577 | class_unregister(&spidev_class); |
| 578 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi.driver.name); |
| 579 | } |
| 580 | module_exit(spidev_exit); |
| 581 | |
| 582 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); |
| 583 | MODULE_DESCRIPTION("User mode SPI device interface"); |
| 584 | MODULE_LICENSE("GPL"); |