1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Simple synchronous userspace interface to SPI devices 4 * 5 * Copyright (C) 2006 SWAPP 6 * Andrea Paterniani <a.paterniani@swapp-eng.it> 7 * Copyright (C) 2007 David Brownell (simplification, cleanup) 8 */ 9 10 #include <linux/init.h> 11 #include <linux/ioctl.h> 12 #include <linux/fs.h> 13 #include <linux/device.h> 14 #include <linux/err.h> 15 #include <linux/list.h> 16 #include <linux/errno.h> 17 #include <linux/mod_devicetable.h> 18 #include <linux/module.h> 19 #include <linux/mutex.h> 20 #include <linux/property.h> 21 #include <linux/slab.h> 22 #include <linux/compat.h> 23 24 #include <linux/spi/spi.h> 25 #include <linux/spi/spidev.h> 26 27 #include <linux/uaccess.h> 28 29 30 /* 31 * This supports access to SPI devices using normal userspace I/O calls. 32 * Note that while traditional UNIX/POSIX I/O semantics are half duplex, 33 * and often mask message boundaries, full SPI support requires full duplex 34 * transfers. There are several kinds of internal message boundaries to 35 * handle chipselect management and other protocol options. 36 * 37 * SPI has a character major number assigned. We allocate minor numbers 38 * dynamically using a bitmask. You must use hotplug tools, such as udev 39 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device 40 * nodes, since there is no fixed association of minor numbers with any 41 * particular SPI bus or device. 42 */ 43 #define SPIDEV_MAJOR 153 /* assigned */ 44 #define N_SPI_MINORS 32 /* ... up to 256 */ 45 46 static DECLARE_BITMAP(minors, N_SPI_MINORS); 47 48 static_assert(N_SPI_MINORS > 0 && N_SPI_MINORS <= 256); 49 50 /* Bit masks for spi_device.mode management. Note that incorrect 51 * settings for some settings can cause *lots* of trouble for other 52 * devices on a shared bus: 53 * 54 * - CS_HIGH ... this device will be active when it shouldn't be 55 * - 3WIRE ... when active, it won't behave as it should 56 * - NO_CS ... there will be no explicit message boundaries; this 57 * is completely incompatible with the shared bus model 58 * - READY ... transfers may proceed when they shouldn't. 59 * 60 * REVISIT should changing those flags be privileged? 61 */ 62 #define SPI_MODE_MASK (SPI_MODE_X_MASK | SPI_CS_HIGH \ 63 | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ 64 | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \ 65 | SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL \ 66 | SPI_RX_QUAD | SPI_RX_OCTAL \ 67 | SPI_RX_CPHA_FLIP | SPI_3WIRE_HIZ \ 68 | SPI_MOSI_IDLE_LOW) 69 70 struct spidev_data { 71 dev_t devt; 72 struct mutex spi_lock; 73 struct spi_device *spi; 74 struct list_head device_entry; 75 76 /* TX/RX buffers are NULL unless this device is open (users > 0) */ 77 struct mutex buf_lock; 78 unsigned users; 79 u8 *tx_buffer; 80 u8 *rx_buffer; 81 u32 speed_hz; 82 }; 83 84 static LIST_HEAD(device_list); 85 static DEFINE_MUTEX(device_list_lock); 86 87 static unsigned bufsiz = 4096; 88 module_param(bufsiz, uint, S_IRUGO); 89 MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); 90 91 /*-------------------------------------------------------------------------*/ 92 93 static ssize_t 94 spidev_sync_unlocked(struct spi_device *spi, struct spi_message *message) 95 { 96 ssize_t status; 97 98 status = spi_sync(spi, message); 99 if (status == 0) 100 status = message->actual_length; 101 102 return status; 103 } 104 105 static ssize_t 106 spidev_sync(struct spidev_data *spidev, struct spi_message *message) 107 { 108 ssize_t status; 109 struct spi_device *spi; 110 111 mutex_lock(&spidev->spi_lock); 112 spi = spidev->spi; 113 114 if (spi == NULL) 115 status = -ESHUTDOWN; 116 else 117 status = spidev_sync_unlocked(spi, message); 118 119 mutex_unlock(&spidev->spi_lock); 120 return status; 121 } 122 123 static inline ssize_t 124 spidev_sync_write(struct spidev_data *spidev, size_t len) 125 { 126 struct spi_transfer t = { 127 .tx_buf = spidev->tx_buffer, 128 .len = len, 129 .speed_hz = spidev->speed_hz, 130 }; 131 struct spi_message m; 132 133 spi_message_init(&m); 134 spi_message_add_tail(&t, &m); 135 return spidev_sync(spidev, &m); 136 } 137 138 static inline ssize_t 139 spidev_sync_read(struct spidev_data *spidev, size_t len) 140 { 141 struct spi_transfer t = { 142 .rx_buf = spidev->rx_buffer, 143 .len = len, 144 .speed_hz = spidev->speed_hz, 145 }; 146 struct spi_message m; 147 148 spi_message_init(&m); 149 spi_message_add_tail(&t, &m); 150 return spidev_sync(spidev, &m); 151 } 152 153 /*-------------------------------------------------------------------------*/ 154 155 /* Read-only message with current device setup */ 156 static ssize_t 157 spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) 158 { 159 struct spidev_data *spidev; 160 ssize_t status; 161 162 /* chipselect only toggles at start or end of operation */ 163 if (count > bufsiz) 164 return -EMSGSIZE; 165 166 spidev = filp->private_data; 167 168 mutex_lock(&spidev->buf_lock); 169 status = spidev_sync_read(spidev, count); 170 if (status > 0) { 171 unsigned long missing; 172 173 missing = copy_to_user(buf, spidev->rx_buffer, status); 174 if (missing == status) 175 status = -EFAULT; 176 else 177 status = status - missing; 178 } 179 mutex_unlock(&spidev->buf_lock); 180 181 return status; 182 } 183 184 /* Write-only message with current device setup */ 185 static ssize_t 186 spidev_write(struct file *filp, const char __user *buf, 187 size_t count, loff_t *f_pos) 188 { 189 struct spidev_data *spidev; 190 ssize_t status; 191 unsigned long missing; 192 193 /* chipselect only toggles at start or end of operation */ 194 if (count > bufsiz) 195 return -EMSGSIZE; 196 197 spidev = filp->private_data; 198 199 mutex_lock(&spidev->buf_lock); 200 missing = copy_from_user(spidev->tx_buffer, buf, count); 201 if (missing == 0) 202 status = spidev_sync_write(spidev, count); 203 else 204 status = -EFAULT; 205 mutex_unlock(&spidev->buf_lock); 206 207 return status; 208 } 209 210 static int spidev_message(struct spidev_data *spidev, 211 struct spi_ioc_transfer *u_xfers, unsigned n_xfers) 212 { 213 struct spi_message msg; 214 struct spi_transfer *k_xfers; 215 struct spi_transfer *k_tmp; 216 struct spi_ioc_transfer *u_tmp; 217 unsigned n, total, tx_total, rx_total; 218 u8 *tx_buf, *rx_buf; 219 int status = -EFAULT; 220 221 spi_message_init(&msg); 222 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); 223 if (k_xfers == NULL) 224 return -ENOMEM; 225 226 /* Construct spi_message, copying any tx data to bounce buffer. 227 * We walk the array of user-provided transfers, using each one 228 * to initialize a kernel version of the same transfer. 229 */ 230 tx_buf = spidev->tx_buffer; 231 rx_buf = spidev->rx_buffer; 232 total = 0; 233 tx_total = 0; 234 rx_total = 0; 235 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; 236 n; 237 n--, k_tmp++, u_tmp++) { 238 /* Ensure that also following allocations from rx_buf/tx_buf will meet 239 * DMA alignment requirements. 240 */ 241 unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_DMA_MINALIGN); 242 243 k_tmp->len = u_tmp->len; 244 245 total += k_tmp->len; 246 /* Since the function returns the total length of transfers 247 * on success, restrict the total to positive int values to 248 * avoid the return value looking like an error. Also check 249 * each transfer length to avoid arithmetic overflow. 250 */ 251 if (total > INT_MAX || k_tmp->len > INT_MAX) { 252 status = -EMSGSIZE; 253 goto done; 254 } 255 256 if (u_tmp->rx_buf) { 257 /* this transfer needs space in RX bounce buffer */ 258 rx_total += len_aligned; 259 if (rx_total > bufsiz) { 260 status = -EMSGSIZE; 261 goto done; 262 } 263 k_tmp->rx_buf = rx_buf; 264 rx_buf += len_aligned; 265 } 266 if (u_tmp->tx_buf) { 267 /* this transfer needs space in TX bounce buffer */ 268 tx_total += len_aligned; 269 if (tx_total > bufsiz) { 270 status = -EMSGSIZE; 271 goto done; 272 } 273 k_tmp->tx_buf = tx_buf; 274 if (copy_from_user(tx_buf, (const u8 __user *) 275 (uintptr_t) u_tmp->tx_buf, 276 u_tmp->len)) 277 goto done; 278 tx_buf += len_aligned; 279 } 280 281 k_tmp->cs_change = !!u_tmp->cs_change; 282 k_tmp->tx_nbits = u_tmp->tx_nbits; 283 k_tmp->rx_nbits = u_tmp->rx_nbits; 284 k_tmp->bits_per_word = u_tmp->bits_per_word; 285 k_tmp->delay.value = u_tmp->delay_usecs; 286 k_tmp->delay.unit = SPI_DELAY_UNIT_USECS; 287 k_tmp->speed_hz = u_tmp->speed_hz; 288 k_tmp->word_delay.value = u_tmp->word_delay_usecs; 289 k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS; 290 if (!k_tmp->speed_hz) 291 k_tmp->speed_hz = spidev->speed_hz; 292 #ifdef VERBOSE 293 dev_dbg(&spidev->spi->dev, 294 " xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n", 295 k_tmp->len, 296 k_tmp->rx_buf ? "rx " : "", 297 k_tmp->tx_buf ? "tx " : "", 298 k_tmp->cs_change ? "cs " : "", 299 k_tmp->bits_per_word ? : spidev->spi->bits_per_word, 300 k_tmp->delay.value, 301 k_tmp->word_delay.value, 302 k_tmp->speed_hz ? : spidev->spi->max_speed_hz); 303 #endif 304 spi_message_add_tail(k_tmp, &msg); 305 } 306 307 status = spidev_sync_unlocked(spidev->spi, &msg); 308 if (status < 0) 309 goto done; 310 311 /* copy any rx data out of bounce buffer */ 312 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; 313 n; 314 n--, k_tmp++, u_tmp++) { 315 if (u_tmp->rx_buf) { 316 if (copy_to_user((u8 __user *) 317 (uintptr_t) u_tmp->rx_buf, k_tmp->rx_buf, 318 u_tmp->len)) { 319 status = -EFAULT; 320 goto done; 321 } 322 } 323 } 324 status = total; 325 326 done: 327 kfree(k_xfers); 328 return status; 329 } 330 331 static struct spi_ioc_transfer * 332 spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc, 333 unsigned *n_ioc) 334 { 335 u32 tmp; 336 337 /* Check type, command number and direction */ 338 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC 339 || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) 340 || _IOC_DIR(cmd) != _IOC_WRITE) 341 return ERR_PTR(-ENOTTY); 342 343 tmp = _IOC_SIZE(cmd); 344 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) 345 return ERR_PTR(-EINVAL); 346 *n_ioc = tmp / sizeof(struct spi_ioc_transfer); 347 if (*n_ioc == 0) 348 return NULL; 349 350 /* copy into scratch area */ 351 return memdup_user(u_ioc, tmp); 352 } 353 354 static long 355 spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 356 { 357 int retval = 0; 358 struct spidev_data *spidev; 359 struct spi_device *spi; 360 struct spi_controller *ctlr; 361 u32 tmp; 362 unsigned n_ioc; 363 struct spi_ioc_transfer *ioc; 364 365 /* Check type and command number */ 366 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) 367 return -ENOTTY; 368 369 /* guard against device removal before, or while, 370 * we issue this ioctl. 371 */ 372 spidev = filp->private_data; 373 mutex_lock(&spidev->spi_lock); 374 spi = spi_dev_get(spidev->spi); 375 if (spi == NULL) { 376 mutex_unlock(&spidev->spi_lock); 377 return -ESHUTDOWN; 378 } 379 380 ctlr = spi->controller; 381 382 /* use the buffer lock here for triple duty: 383 * - prevent I/O (from us) so calling spi_setup() is safe; 384 * - prevent concurrent SPI_IOC_WR_* from morphing 385 * data fields while SPI_IOC_RD_* reads them; 386 * - SPI_IOC_MESSAGE needs the buffer locked "normally". 387 */ 388 mutex_lock(&spidev->buf_lock); 389 390 switch (cmd) { 391 /* read requests */ 392 case SPI_IOC_RD_MODE: 393 case SPI_IOC_RD_MODE32: 394 tmp = spi->mode & SPI_MODE_MASK; 395 396 if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0)) 397 tmp &= ~SPI_CS_HIGH; 398 399 if (cmd == SPI_IOC_RD_MODE) 400 retval = put_user(tmp, (__u8 __user *)arg); 401 else 402 retval = put_user(tmp, (__u32 __user *)arg); 403 break; 404 case SPI_IOC_RD_LSB_FIRST: 405 retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, 406 (__u8 __user *)arg); 407 break; 408 case SPI_IOC_RD_BITS_PER_WORD: 409 retval = put_user(spi->bits_per_word, (__u8 __user *)arg); 410 break; 411 case SPI_IOC_RD_MAX_SPEED_HZ: 412 retval = put_user(spidev->speed_hz, (__u32 __user *)arg); 413 break; 414 415 /* write requests */ 416 case SPI_IOC_WR_MODE: 417 case SPI_IOC_WR_MODE32: 418 if (cmd == SPI_IOC_WR_MODE) 419 retval = get_user(tmp, (u8 __user *)arg); 420 else 421 retval = get_user(tmp, (u32 __user *)arg); 422 if (retval == 0) { 423 u32 save = spi->mode; 424 425 if (tmp & ~SPI_MODE_MASK) { 426 retval = -EINVAL; 427 break; 428 } 429 430 if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0)) 431 tmp |= SPI_CS_HIGH; 432 433 tmp |= spi->mode & ~SPI_MODE_MASK; 434 spi->mode = tmp & SPI_MODE_USER_MASK; 435 retval = spi_setup(spi); 436 if (retval < 0) 437 spi->mode = save; 438 else 439 dev_dbg(&spi->dev, "spi mode %x\n", tmp); 440 } 441 break; 442 case SPI_IOC_WR_LSB_FIRST: 443 retval = get_user(tmp, (__u8 __user *)arg); 444 if (retval == 0) { 445 u32 save = spi->mode; 446 447 if (tmp) 448 spi->mode |= SPI_LSB_FIRST; 449 else 450 spi->mode &= ~SPI_LSB_FIRST; 451 retval = spi_setup(spi); 452 if (retval < 0) 453 spi->mode = save; 454 else 455 dev_dbg(&spi->dev, "%csb first\n", 456 tmp ? 'l' : 'm'); 457 } 458 break; 459 case SPI_IOC_WR_BITS_PER_WORD: 460 retval = get_user(tmp, (__u8 __user *)arg); 461 if (retval == 0) { 462 u8 save = spi->bits_per_word; 463 464 spi->bits_per_word = tmp; 465 retval = spi_setup(spi); 466 if (retval < 0) 467 spi->bits_per_word = save; 468 else 469 dev_dbg(&spi->dev, "%d bits per word\n", tmp); 470 } 471 break; 472 case SPI_IOC_WR_MAX_SPEED_HZ: { 473 u32 save; 474 475 retval = get_user(tmp, (__u32 __user *)arg); 476 if (retval) 477 break; 478 if (tmp == 0) { 479 retval = -EINVAL; 480 break; 481 } 482 483 save = spi->max_speed_hz; 484 485 spi->max_speed_hz = tmp; 486 retval = spi_setup(spi); 487 if (retval == 0) { 488 spidev->speed_hz = tmp; 489 dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz); 490 } 491 492 spi->max_speed_hz = save; 493 break; 494 } 495 default: 496 /* segmented and/or full-duplex I/O request */ 497 /* Check message and copy into scratch area */ 498 ioc = spidev_get_ioc_message(cmd, 499 (struct spi_ioc_transfer __user *)arg, &n_ioc); 500 if (IS_ERR(ioc)) { 501 retval = PTR_ERR(ioc); 502 break; 503 } 504 if (!ioc) 505 break; /* n_ioc is also 0 */ 506 507 /* translate to spi_message, execute */ 508 retval = spidev_message(spidev, ioc, n_ioc); 509 kfree(ioc); 510 break; 511 } 512 513 mutex_unlock(&spidev->buf_lock); 514 spi_dev_put(spi); 515 mutex_unlock(&spidev->spi_lock); 516 return retval; 517 } 518 519 #ifdef CONFIG_COMPAT 520 static long 521 spidev_compat_ioc_message(struct file *filp, unsigned int cmd, 522 unsigned long arg) 523 { 524 struct spi_ioc_transfer __user *u_ioc; 525 int retval = 0; 526 struct spidev_data *spidev; 527 struct spi_device *spi; 528 unsigned n_ioc, n; 529 struct spi_ioc_transfer *ioc; 530 531 u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg); 532 533 /* guard against device removal before, or while, 534 * we issue this ioctl. 535 */ 536 spidev = filp->private_data; 537 mutex_lock(&spidev->spi_lock); 538 spi = spi_dev_get(spidev->spi); 539 if (spi == NULL) { 540 mutex_unlock(&spidev->spi_lock); 541 return -ESHUTDOWN; 542 } 543 544 /* SPI_IOC_MESSAGE needs the buffer locked "normally" */ 545 mutex_lock(&spidev->buf_lock); 546 547 /* Check message and copy into scratch area */ 548 ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc); 549 if (IS_ERR(ioc)) { 550 retval = PTR_ERR(ioc); 551 goto done; 552 } 553 if (!ioc) 554 goto done; /* n_ioc is also 0 */ 555 556 /* Convert buffer pointers */ 557 for (n = 0; n < n_ioc; n++) { 558 ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf); 559 ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf); 560 } 561 562 /* translate to spi_message, execute */ 563 retval = spidev_message(spidev, ioc, n_ioc); 564 kfree(ioc); 565 566 done: 567 mutex_unlock(&spidev->buf_lock); 568 spi_dev_put(spi); 569 mutex_unlock(&spidev->spi_lock); 570 return retval; 571 } 572 573 static long 574 spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 575 { 576 if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC 577 && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) 578 && _IOC_DIR(cmd) == _IOC_WRITE) 579 return spidev_compat_ioc_message(filp, cmd, arg); 580 581 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 582 } 583 #else 584 #define spidev_compat_ioctl NULL 585 #endif /* CONFIG_COMPAT */ 586 587 static int spidev_open(struct inode *inode, struct file *filp) 588 { 589 struct spidev_data *spidev = NULL, *iter; 590 int status = -ENXIO; 591 592 mutex_lock(&device_list_lock); 593 594 list_for_each_entry(iter, &device_list, device_entry) { 595 if (iter->devt == inode->i_rdev) { 596 status = 0; 597 spidev = iter; 598 break; 599 } 600 } 601 602 if (!spidev) { 603 pr_debug("spidev: nothing for minor %d\n", iminor(inode)); 604 goto err_find_dev; 605 } 606 607 if (!spidev->tx_buffer) { 608 spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); 609 if (!spidev->tx_buffer) { 610 status = -ENOMEM; 611 goto err_find_dev; 612 } 613 } 614 615 if (!spidev->rx_buffer) { 616 spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); 617 if (!spidev->rx_buffer) { 618 status = -ENOMEM; 619 goto err_alloc_rx_buf; 620 } 621 } 622 623 spidev->users++; 624 filp->private_data = spidev; 625 stream_open(inode, filp); 626 627 mutex_unlock(&device_list_lock); 628 return 0; 629 630 err_alloc_rx_buf: 631 kfree(spidev->tx_buffer); 632 spidev->tx_buffer = NULL; 633 err_find_dev: 634 mutex_unlock(&device_list_lock); 635 return status; 636 } 637 638 static int spidev_release(struct inode *inode, struct file *filp) 639 { 640 struct spidev_data *spidev; 641 int dofree; 642 643 mutex_lock(&device_list_lock); 644 spidev = filp->private_data; 645 filp->private_data = NULL; 646 647 mutex_lock(&spidev->spi_lock); 648 /* ... after we unbound from the underlying device? */ 649 dofree = (spidev->spi == NULL); 650 mutex_unlock(&spidev->spi_lock); 651 652 /* last close? */ 653 spidev->users--; 654 if (!spidev->users) { 655 656 kfree(spidev->tx_buffer); 657 spidev->tx_buffer = NULL; 658 659 kfree(spidev->rx_buffer); 660 spidev->rx_buffer = NULL; 661 662 if (dofree) 663 kfree(spidev); 664 else 665 spidev->speed_hz = spidev->spi->max_speed_hz; 666 } 667 #ifdef CONFIG_SPI_SLAVE 668 if (!dofree) 669 spi_slave_abort(spidev->spi); 670 #endif 671 mutex_unlock(&device_list_lock); 672 673 return 0; 674 } 675 676 static const struct file_operations spidev_fops = { 677 .owner = THIS_MODULE, 678 /* REVISIT switch to aio primitives, so that userspace 679 * gets more complete API coverage. It'll simplify things 680 * too, except for the locking. 681 */ 682 .write = spidev_write, 683 .read = spidev_read, 684 .unlocked_ioctl = spidev_ioctl, 685 .compat_ioctl = spidev_compat_ioctl, 686 .open = spidev_open, 687 .release = spidev_release, 688 .llseek = no_llseek, 689 }; 690 691 /*-------------------------------------------------------------------------*/ 692 693 /* The main reason to have this class is to make mdev/udev create the 694 * /dev/spidevB.C character device nodes exposing our userspace API. 695 * It also simplifies memory management. 696 */ 697 698 static const struct class spidev_class = { 699 .name = "spidev", 700 }; 701 702 static const struct spi_device_id spidev_spi_ids[] = { 703 { .name = "dh2228fv" }, 704 { .name = "ltc2488" }, 705 { .name = "sx1301" }, 706 { .name = "bk4" }, 707 { .name = "dhcom-board" }, 708 { .name = "m53cpld" }, 709 { .name = "spi-petra" }, 710 { .name = "spi-authenta" }, 711 { .name = "em3581" }, 712 { .name = "si3210" }, 713 {}, 714 }; 715 MODULE_DEVICE_TABLE(spi, spidev_spi_ids); 716 717 /* 718 * spidev should never be referenced in DT without a specific compatible string, 719 * it is a Linux implementation thing rather than a description of the hardware. 720 */ 721 static int spidev_of_check(struct device *dev) 722 { 723 if (device_property_match_string(dev, "compatible", "spidev") < 0) 724 return 0; 725 726 dev_err(dev, "spidev listed directly in DT is not supported\n"); 727 return -EINVAL; 728 } 729 730 static const struct of_device_id spidev_dt_ids[] = { 731 { .compatible = "cisco,spi-petra", .data = &spidev_of_check }, 732 { .compatible = "dh,dhcom-board", .data = &spidev_of_check }, 733 { .compatible = "lineartechnology,ltc2488", .data = &spidev_of_check }, 734 { .compatible = "lwn,bk4", .data = &spidev_of_check }, 735 { .compatible = "menlo,m53cpld", .data = &spidev_of_check }, 736 { .compatible = "micron,spi-authenta", .data = &spidev_of_check }, 737 { .compatible = "rohm,dh2228fv", .data = &spidev_of_check }, 738 { .compatible = "semtech,sx1301", .data = &spidev_of_check }, 739 { .compatible = "silabs,em3581", .data = &spidev_of_check }, 740 { .compatible = "silabs,si3210", .data = &spidev_of_check }, 741 {}, 742 }; 743 MODULE_DEVICE_TABLE(of, spidev_dt_ids); 744 745 /* Dummy SPI devices not to be used in production systems */ 746 static int spidev_acpi_check(struct device *dev) 747 { 748 dev_warn(dev, "do not use this driver in production systems!\n"); 749 return 0; 750 } 751 752 static const struct acpi_device_id spidev_acpi_ids[] = { 753 /* 754 * The ACPI SPT000* devices are only meant for development and 755 * testing. Systems used in production should have a proper ACPI 756 * description of the connected peripheral and they should also use 757 * a proper driver instead of poking directly to the SPI bus. 758 */ 759 { "SPT0001", (kernel_ulong_t)&spidev_acpi_check }, 760 { "SPT0002", (kernel_ulong_t)&spidev_acpi_check }, 761 { "SPT0003", (kernel_ulong_t)&spidev_acpi_check }, 762 {}, 763 }; 764 MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids); 765 766 /*-------------------------------------------------------------------------*/ 767 768 static int spidev_probe(struct spi_device *spi) 769 { 770 int (*match)(struct device *dev); 771 struct spidev_data *spidev; 772 int status; 773 unsigned long minor; 774 775 match = device_get_match_data(&spi->dev); 776 if (match) { 777 status = match(&spi->dev); 778 if (status) 779 return status; 780 } 781 782 /* Allocate driver data */ 783 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); 784 if (!spidev) 785 return -ENOMEM; 786 787 /* Initialize the driver data */ 788 spidev->spi = spi; 789 mutex_init(&spidev->spi_lock); 790 mutex_init(&spidev->buf_lock); 791 792 INIT_LIST_HEAD(&spidev->device_entry); 793 794 /* If we can allocate a minor number, hook up this device. 795 * Reusing minors is fine so long as udev or mdev is working. 796 */ 797 mutex_lock(&device_list_lock); 798 minor = find_first_zero_bit(minors, N_SPI_MINORS); 799 if (minor < N_SPI_MINORS) { 800 struct device *dev; 801 802 spidev->devt = MKDEV(SPIDEV_MAJOR, minor); 803 dev = device_create(&spidev_class, &spi->dev, spidev->devt, 804 spidev, "spidev%d.%d", 805 spi->controller->bus_num, spi_get_chipselect(spi, 0)); 806 status = PTR_ERR_OR_ZERO(dev); 807 } else { 808 dev_dbg(&spi->dev, "no minor number available!\n"); 809 status = -ENODEV; 810 } 811 if (status == 0) { 812 set_bit(minor, minors); 813 list_add(&spidev->device_entry, &device_list); 814 } 815 mutex_unlock(&device_list_lock); 816 817 spidev->speed_hz = spi->max_speed_hz; 818 819 if (status == 0) 820 spi_set_drvdata(spi, spidev); 821 else 822 kfree(spidev); 823 824 return status; 825 } 826 827 static void spidev_remove(struct spi_device *spi) 828 { 829 struct spidev_data *spidev = spi_get_drvdata(spi); 830 831 /* prevent new opens */ 832 mutex_lock(&device_list_lock); 833 /* make sure ops on existing fds can abort cleanly */ 834 mutex_lock(&spidev->spi_lock); 835 spidev->spi = NULL; 836 mutex_unlock(&spidev->spi_lock); 837 838 list_del(&spidev->device_entry); 839 device_destroy(&spidev_class, spidev->devt); 840 clear_bit(MINOR(spidev->devt), minors); 841 if (spidev->users == 0) 842 kfree(spidev); 843 mutex_unlock(&device_list_lock); 844 } 845 846 static struct spi_driver spidev_spi_driver = { 847 .driver = { 848 .name = "spidev", 849 .of_match_table = spidev_dt_ids, 850 .acpi_match_table = spidev_acpi_ids, 851 }, 852 .probe = spidev_probe, 853 .remove = spidev_remove, 854 .id_table = spidev_spi_ids, 855 856 /* NOTE: suspend/resume methods are not necessary here. 857 * We don't do anything except pass the requests to/from 858 * the underlying controller. The refrigerator handles 859 * most issues; the controller driver handles the rest. 860 */ 861 }; 862 863 /*-------------------------------------------------------------------------*/ 864 865 static int __init spidev_init(void) 866 { 867 int status; 868 869 /* Claim our 256 reserved device numbers. Then register a class 870 * that will key udev/mdev to add/remove /dev nodes. Last, register 871 * the driver which manages those device numbers. 872 */ 873 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); 874 if (status < 0) 875 return status; 876 877 status = class_register(&spidev_class); 878 if (status) { 879 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 880 return status; 881 } 882 883 status = spi_register_driver(&spidev_spi_driver); 884 if (status < 0) { 885 class_unregister(&spidev_class); 886 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 887 } 888 return status; 889 } 890 module_init(spidev_init); 891 892 static void __exit spidev_exit(void) 893 { 894 spi_unregister_driver(&spidev_spi_driver); 895 class_unregister(&spidev_class); 896 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 897 } 898 module_exit(spidev_exit); 899 900 MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); 901 MODULE_DESCRIPTION("User mode SPI device interface"); 902 MODULE_LICENSE("GPL"); 903 MODULE_ALIAS("spi:spidev"); 904