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 unsigned users; 78 u8 *tx_buffer; 79 u8 *rx_buffer; 80 u32 speed_hz; 81 }; 82 83 static LIST_HEAD(device_list); 84 static DEFINE_MUTEX(device_list_lock); 85 86 static unsigned bufsiz = 4096; 87 module_param(bufsiz, uint, S_IRUGO); 88 MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); 89 90 /*-------------------------------------------------------------------------*/ 91 92 static ssize_t 93 spidev_sync_unlocked(struct spi_device *spi, struct spi_message *message) 94 { 95 ssize_t status; 96 97 status = spi_sync(spi, message); 98 if (status == 0) 99 status = message->actual_length; 100 101 return status; 102 } 103 104 static inline ssize_t 105 spidev_sync_write(struct spidev_data *spidev, size_t len) 106 { 107 struct spi_transfer t = { 108 .tx_buf = spidev->tx_buffer, 109 .len = len, 110 .speed_hz = spidev->speed_hz, 111 }; 112 struct spi_message m; 113 114 spi_message_init(&m); 115 spi_message_add_tail(&t, &m); 116 117 return spidev_sync_unlocked(spidev->spi, &m); 118 } 119 120 static inline ssize_t 121 spidev_sync_read(struct spidev_data *spidev, size_t len) 122 { 123 struct spi_transfer t = { 124 .rx_buf = spidev->rx_buffer, 125 .len = len, 126 .speed_hz = spidev->speed_hz, 127 }; 128 struct spi_message m; 129 130 spi_message_init(&m); 131 spi_message_add_tail(&t, &m); 132 133 return spidev_sync_unlocked(spidev->spi, &m); 134 } 135 136 /*-------------------------------------------------------------------------*/ 137 138 /* Read-only message with current device setup */ 139 static ssize_t 140 spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) 141 { 142 struct spidev_data *spidev; 143 ssize_t status = -ESHUTDOWN; 144 145 /* chipselect only toggles at start or end of operation */ 146 if (count > bufsiz) 147 return -EMSGSIZE; 148 149 spidev = filp->private_data; 150 151 mutex_lock(&spidev->spi_lock); 152 153 if (spidev->spi == NULL) 154 goto err_spi_removed; 155 156 status = spidev_sync_read(spidev, count); 157 if (status > 0) { 158 unsigned long missing; 159 160 missing = copy_to_user(buf, spidev->rx_buffer, status); 161 if (missing == status) 162 status = -EFAULT; 163 else 164 status = status - missing; 165 } 166 167 err_spi_removed: 168 mutex_unlock(&spidev->spi_lock); 169 170 return status; 171 } 172 173 /* Write-only message with current device setup */ 174 static ssize_t 175 spidev_write(struct file *filp, const char __user *buf, 176 size_t count, loff_t *f_pos) 177 { 178 struct spidev_data *spidev; 179 ssize_t status = -ESHUTDOWN; 180 unsigned long missing; 181 182 /* chipselect only toggles at start or end of operation */ 183 if (count > bufsiz) 184 return -EMSGSIZE; 185 186 spidev = filp->private_data; 187 188 mutex_lock(&spidev->spi_lock); 189 190 if (spidev->spi == NULL) 191 goto err_spi_removed; 192 193 missing = copy_from_user(spidev->tx_buffer, buf, count); 194 if (missing == 0) 195 status = spidev_sync_write(spidev, count); 196 else 197 status = -EFAULT; 198 199 err_spi_removed: 200 mutex_unlock(&spidev->spi_lock); 201 202 return status; 203 } 204 205 static int spidev_message(struct spidev_data *spidev, 206 struct spi_ioc_transfer *u_xfers, unsigned n_xfers) 207 { 208 struct spi_message msg; 209 struct spi_transfer *k_xfers; 210 struct spi_transfer *k_tmp; 211 struct spi_ioc_transfer *u_tmp; 212 unsigned n, total, tx_total, rx_total; 213 u8 *tx_buf, *rx_buf; 214 int status = -EFAULT; 215 216 spi_message_init(&msg); 217 k_xfers = kzalloc_objs(*k_tmp, n_xfers); 218 if (k_xfers == NULL) 219 return -ENOMEM; 220 221 /* Construct spi_message, copying any tx data to bounce buffer. 222 * We walk the array of user-provided transfers, using each one 223 * to initialize a kernel version of the same transfer. 224 */ 225 tx_buf = spidev->tx_buffer; 226 rx_buf = spidev->rx_buffer; 227 total = 0; 228 tx_total = 0; 229 rx_total = 0; 230 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; 231 n; 232 n--, k_tmp++, u_tmp++) { 233 /* Ensure that also following allocations from rx_buf/tx_buf will meet 234 * DMA alignment requirements. 235 */ 236 unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_DMA_MINALIGN); 237 238 k_tmp->len = u_tmp->len; 239 240 total += k_tmp->len; 241 /* Since the function returns the total length of transfers 242 * on success, restrict the total to positive int values to 243 * avoid the return value looking like an error. Also check 244 * each transfer length to avoid arithmetic overflow. 245 */ 246 if (total > INT_MAX || k_tmp->len > INT_MAX) { 247 status = -EMSGSIZE; 248 goto done; 249 } 250 251 if (u_tmp->rx_buf) { 252 /* this transfer needs space in RX bounce buffer */ 253 rx_total += len_aligned; 254 if (rx_total > bufsiz) { 255 status = -EMSGSIZE; 256 goto done; 257 } 258 k_tmp->rx_buf = rx_buf; 259 rx_buf += len_aligned; 260 } 261 if (u_tmp->tx_buf) { 262 /* this transfer needs space in TX bounce buffer */ 263 tx_total += len_aligned; 264 if (tx_total > bufsiz) { 265 status = -EMSGSIZE; 266 goto done; 267 } 268 k_tmp->tx_buf = tx_buf; 269 if (copy_from_user(tx_buf, (const u8 __user *) 270 (uintptr_t) u_tmp->tx_buf, 271 u_tmp->len)) 272 goto done; 273 tx_buf += len_aligned; 274 } 275 276 k_tmp->cs_change = !!u_tmp->cs_change; 277 k_tmp->tx_nbits = u_tmp->tx_nbits; 278 k_tmp->rx_nbits = u_tmp->rx_nbits; 279 k_tmp->bits_per_word = u_tmp->bits_per_word; 280 k_tmp->delay.value = u_tmp->delay_usecs; 281 k_tmp->delay.unit = SPI_DELAY_UNIT_USECS; 282 k_tmp->speed_hz = u_tmp->speed_hz; 283 k_tmp->word_delay.value = u_tmp->word_delay_usecs; 284 k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS; 285 if (!k_tmp->speed_hz) 286 k_tmp->speed_hz = spidev->speed_hz; 287 #ifdef VERBOSE 288 dev_dbg(&spidev->spi->dev, 289 " xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n", 290 k_tmp->len, 291 k_tmp->rx_buf ? "rx " : "", 292 k_tmp->tx_buf ? "tx " : "", 293 k_tmp->cs_change ? "cs " : "", 294 k_tmp->bits_per_word ? : spidev->spi->bits_per_word, 295 k_tmp->delay.value, 296 k_tmp->word_delay.value, 297 k_tmp->speed_hz ? : spidev->spi->max_speed_hz); 298 #endif 299 spi_message_add_tail(k_tmp, &msg); 300 } 301 302 status = spidev_sync_unlocked(spidev->spi, &msg); 303 if (status < 0) 304 goto done; 305 306 /* copy any rx data out of bounce buffer */ 307 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; 308 n; 309 n--, k_tmp++, u_tmp++) { 310 if (u_tmp->rx_buf) { 311 if (copy_to_user((u8 __user *) 312 (uintptr_t) u_tmp->rx_buf, k_tmp->rx_buf, 313 u_tmp->len)) { 314 status = -EFAULT; 315 goto done; 316 } 317 } 318 } 319 status = total; 320 321 done: 322 kfree(k_xfers); 323 return status; 324 } 325 326 static struct spi_ioc_transfer * 327 spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc, 328 unsigned *n_ioc) 329 { 330 u32 tmp; 331 332 /* Check type, command number and direction */ 333 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC 334 || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) 335 || _IOC_DIR(cmd) != _IOC_WRITE) 336 return ERR_PTR(-ENOTTY); 337 338 tmp = _IOC_SIZE(cmd); 339 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) 340 return ERR_PTR(-EINVAL); 341 *n_ioc = tmp / sizeof(struct spi_ioc_transfer); 342 if (*n_ioc == 0) 343 return NULL; 344 345 /* copy into scratch area */ 346 return memdup_user(u_ioc, tmp); 347 } 348 349 static long 350 spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 351 { 352 int retval = 0; 353 struct spidev_data *spidev; 354 struct spi_device *spi; 355 struct spi_controller *ctlr; 356 u32 tmp; 357 unsigned n_ioc; 358 struct spi_ioc_transfer *ioc; 359 360 /* Check type and command number */ 361 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) 362 return -ENOTTY; 363 364 /* guard against device removal before, or while, 365 * we issue this ioctl. 366 */ 367 spidev = filp->private_data; 368 mutex_lock(&spidev->spi_lock); 369 spi = spi_dev_get(spidev->spi); 370 if (spi == NULL) { 371 mutex_unlock(&spidev->spi_lock); 372 return -ESHUTDOWN; 373 } 374 375 ctlr = spi->controller; 376 377 switch (cmd) { 378 /* read requests */ 379 case SPI_IOC_RD_MODE: 380 case SPI_IOC_RD_MODE32: 381 tmp = spi->mode & SPI_MODE_MASK; 382 383 if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0)) 384 tmp &= ~SPI_CS_HIGH; 385 386 if (cmd == SPI_IOC_RD_MODE) 387 retval = put_user(tmp, (__u8 __user *)arg); 388 else 389 retval = put_user(tmp, (__u32 __user *)arg); 390 break; 391 case SPI_IOC_RD_LSB_FIRST: 392 retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, 393 (__u8 __user *)arg); 394 break; 395 case SPI_IOC_RD_BITS_PER_WORD: 396 retval = put_user(spi->bits_per_word, (__u8 __user *)arg); 397 break; 398 case SPI_IOC_RD_MAX_SPEED_HZ: 399 retval = put_user(spidev->speed_hz, (__u32 __user *)arg); 400 break; 401 402 /* write requests */ 403 case SPI_IOC_WR_MODE: 404 case SPI_IOC_WR_MODE32: 405 if (cmd == SPI_IOC_WR_MODE) 406 retval = get_user(tmp, (u8 __user *)arg); 407 else 408 retval = get_user(tmp, (u32 __user *)arg); 409 if (retval == 0) { 410 u32 save = spi->mode; 411 412 if (tmp & ~SPI_MODE_MASK) { 413 retval = -EINVAL; 414 break; 415 } 416 417 if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0)) 418 tmp |= SPI_CS_HIGH; 419 420 tmp |= spi->mode & ~SPI_MODE_MASK; 421 spi->mode = tmp & SPI_MODE_USER_MASK; 422 retval = spi_setup(spi); 423 if (retval < 0) 424 spi->mode = save; 425 else 426 dev_dbg(&spi->dev, "spi mode %x\n", tmp); 427 } 428 break; 429 case SPI_IOC_WR_LSB_FIRST: 430 retval = get_user(tmp, (__u8 __user *)arg); 431 if (retval == 0) { 432 u32 save = spi->mode; 433 434 if (tmp) 435 spi->mode |= SPI_LSB_FIRST; 436 else 437 spi->mode &= ~SPI_LSB_FIRST; 438 retval = spi_setup(spi); 439 if (retval < 0) 440 spi->mode = save; 441 else 442 dev_dbg(&spi->dev, "%csb first\n", 443 tmp ? 'l' : 'm'); 444 } 445 break; 446 case SPI_IOC_WR_BITS_PER_WORD: 447 retval = get_user(tmp, (__u8 __user *)arg); 448 if (retval == 0) { 449 u8 save = spi->bits_per_word; 450 451 spi->bits_per_word = tmp; 452 retval = spi_setup(spi); 453 if (retval < 0) 454 spi->bits_per_word = save; 455 else 456 dev_dbg(&spi->dev, "%d bits per word\n", tmp); 457 } 458 break; 459 case SPI_IOC_WR_MAX_SPEED_HZ: { 460 u32 save; 461 462 retval = get_user(tmp, (__u32 __user *)arg); 463 if (retval) 464 break; 465 if (tmp == 0) { 466 retval = -EINVAL; 467 break; 468 } 469 470 save = spi->max_speed_hz; 471 472 spi->max_speed_hz = tmp; 473 retval = spi_setup(spi); 474 if (retval == 0) { 475 spidev->speed_hz = tmp; 476 dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz); 477 } 478 479 spi->max_speed_hz = save; 480 break; 481 } 482 default: 483 /* segmented and/or full-duplex I/O request */ 484 /* Check message and copy into scratch area */ 485 ioc = spidev_get_ioc_message(cmd, 486 (struct spi_ioc_transfer __user *)arg, &n_ioc); 487 if (IS_ERR(ioc)) { 488 retval = PTR_ERR(ioc); 489 break; 490 } 491 if (!ioc) 492 break; /* n_ioc is also 0 */ 493 494 /* translate to spi_message, execute */ 495 retval = spidev_message(spidev, ioc, n_ioc); 496 kfree(ioc); 497 break; 498 } 499 500 spi_dev_put(spi); 501 mutex_unlock(&spidev->spi_lock); 502 return retval; 503 } 504 505 #ifdef CONFIG_COMPAT 506 static long 507 spidev_compat_ioc_message(struct file *filp, unsigned int cmd, 508 unsigned long arg) 509 { 510 struct spi_ioc_transfer __user *u_ioc; 511 int retval = 0; 512 struct spidev_data *spidev; 513 struct spi_device *spi; 514 unsigned n_ioc, n; 515 struct spi_ioc_transfer *ioc; 516 517 u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg); 518 519 /* guard against device removal before, or while, 520 * we issue this ioctl. 521 */ 522 spidev = filp->private_data; 523 mutex_lock(&spidev->spi_lock); 524 spi = spi_dev_get(spidev->spi); 525 if (spi == NULL) { 526 mutex_unlock(&spidev->spi_lock); 527 return -ESHUTDOWN; 528 } 529 530 /* Check message and copy into scratch area */ 531 ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc); 532 if (IS_ERR(ioc)) { 533 retval = PTR_ERR(ioc); 534 goto done; 535 } 536 if (!ioc) 537 goto done; /* n_ioc is also 0 */ 538 539 /* Convert buffer pointers */ 540 for (n = 0; n < n_ioc; n++) { 541 ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf); 542 ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf); 543 } 544 545 /* translate to spi_message, execute */ 546 retval = spidev_message(spidev, ioc, n_ioc); 547 kfree(ioc); 548 549 done: 550 spi_dev_put(spi); 551 mutex_unlock(&spidev->spi_lock); 552 return retval; 553 } 554 555 static long 556 spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 557 { 558 if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC 559 && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) 560 && _IOC_DIR(cmd) == _IOC_WRITE) 561 return spidev_compat_ioc_message(filp, cmd, arg); 562 563 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 564 } 565 #else 566 #define spidev_compat_ioctl NULL 567 #endif /* CONFIG_COMPAT */ 568 569 static int spidev_open(struct inode *inode, struct file *filp) 570 { 571 struct spidev_data *spidev = NULL, *iter; 572 int status = -ENXIO; 573 574 mutex_lock(&device_list_lock); 575 576 list_for_each_entry(iter, &device_list, device_entry) { 577 if (iter->devt == inode->i_rdev) { 578 status = 0; 579 spidev = iter; 580 break; 581 } 582 } 583 584 if (!spidev) { 585 pr_debug("spidev: nothing for minor %d\n", iminor(inode)); 586 goto err_find_dev; 587 } 588 589 if (!spidev->tx_buffer) { 590 spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); 591 if (!spidev->tx_buffer) { 592 status = -ENOMEM; 593 goto err_find_dev; 594 } 595 } 596 597 if (!spidev->rx_buffer) { 598 spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); 599 if (!spidev->rx_buffer) { 600 status = -ENOMEM; 601 goto err_alloc_rx_buf; 602 } 603 } 604 605 spidev->users++; 606 filp->private_data = spidev; 607 stream_open(inode, filp); 608 609 mutex_unlock(&device_list_lock); 610 return 0; 611 612 err_alloc_rx_buf: 613 kfree(spidev->tx_buffer); 614 spidev->tx_buffer = NULL; 615 err_find_dev: 616 mutex_unlock(&device_list_lock); 617 return status; 618 } 619 620 static int spidev_release(struct inode *inode, struct file *filp) 621 { 622 struct spidev_data *spidev; 623 int dofree; 624 625 mutex_lock(&device_list_lock); 626 spidev = filp->private_data; 627 filp->private_data = NULL; 628 629 mutex_lock(&spidev->spi_lock); 630 /* ... after we unbound from the underlying device? */ 631 dofree = (spidev->spi == NULL); 632 mutex_unlock(&spidev->spi_lock); 633 634 /* last close? */ 635 spidev->users--; 636 if (!spidev->users) { 637 638 kfree(spidev->tx_buffer); 639 spidev->tx_buffer = NULL; 640 641 kfree(spidev->rx_buffer); 642 spidev->rx_buffer = NULL; 643 644 if (dofree) 645 kfree(spidev); 646 else 647 spidev->speed_hz = spidev->spi->max_speed_hz; 648 } 649 #ifdef CONFIG_SPI_SLAVE 650 if (!dofree) 651 spi_target_abort(spidev->spi); 652 #endif 653 mutex_unlock(&device_list_lock); 654 655 return 0; 656 } 657 658 static const struct file_operations spidev_fops = { 659 .owner = THIS_MODULE, 660 /* REVISIT switch to aio primitives, so that userspace 661 * gets more complete API coverage. It'll simplify things 662 * too, except for the locking. 663 */ 664 .write = spidev_write, 665 .read = spidev_read, 666 .unlocked_ioctl = spidev_ioctl, 667 .compat_ioctl = spidev_compat_ioctl, 668 .open = spidev_open, 669 .release = spidev_release, 670 }; 671 672 /*-------------------------------------------------------------------------*/ 673 674 /* The main reason to have this class is to make mdev/udev create the 675 * /dev/spidevB.C character device nodes exposing our userspace API. 676 * It also simplifies memory management. 677 */ 678 679 static const struct class spidev_class = { 680 .name = "spidev", 681 }; 682 683 /* 684 * The spi device ids are expected to match the device names of the 685 * spidev_dt_ids array below. Both arrays are kept in the same ordering. 686 */ 687 static const struct spi_device_id spidev_spi_ids[] = { 688 { .name = /* abb */ "spi-sensor" }, 689 { .name = /* arduino */ "unoq-mcu" }, 690 { .name = /* cisco */ "spi-petra" }, 691 { .name = /* dh */ "dhcom-board" }, 692 { .name = /* elgin */ "jg10309-01" }, 693 { .name = /* gocontroll */ "moduline-module-slot"}, 694 { .name = /* lineartechnology */ "ltc2488" }, 695 { .name = /* lwn */ "bk4" }, 696 { .name = /* lwn */ "bk4-spi" }, 697 { .name = /* menlo */ "m53cpld" }, 698 { .name = /* micron */ "spi-authenta" }, 699 { .name = /* rohm */ "bh2228fv" }, 700 { .name = /* rohm */ "dh2228fv" }, 701 { .name = /* semtech */ "sx1301" }, 702 { .name = /* silabs */ "em3581" }, 703 { .name = /* silabs */ "si3210" }, 704 {}, 705 }; 706 MODULE_DEVICE_TABLE(spi, spidev_spi_ids); 707 708 /* 709 * spidev should never be referenced in DT without a specific compatible string, 710 * it is a Linux implementation thing rather than a description of the hardware. 711 */ 712 static int spidev_of_check(struct device *dev) 713 { 714 if (device_property_match_string(dev, "compatible", "spidev") < 0) 715 return 0; 716 717 dev_err(dev, "spidev listed directly in DT is not supported\n"); 718 return -EINVAL; 719 } 720 721 static const struct of_device_id spidev_dt_ids[] = { 722 { .compatible = "abb,spi-sensor", .data = &spidev_of_check }, 723 { .compatible = "arduino,unoq-mcu", .data = &spidev_of_check }, 724 { .compatible = "cisco,spi-petra", .data = &spidev_of_check }, 725 { .compatible = "dh,dhcom-board", .data = &spidev_of_check }, 726 { .compatible = "elgin,jg10309-01", .data = &spidev_of_check }, 727 { .compatible = "gocontroll,moduline-module-slot", .data = &spidev_of_check}, 728 { .compatible = "lineartechnology,ltc2488", .data = &spidev_of_check }, 729 { .compatible = "lwn,bk4", .data = &spidev_of_check }, 730 { .compatible = "lwn,bk4-spi", .data = &spidev_of_check }, 731 { .compatible = "menlo,m53cpld", .data = &spidev_of_check }, 732 { .compatible = "micron,spi-authenta", .data = &spidev_of_check }, 733 { .compatible = "rohm,bh2228fv", .data = &spidev_of_check }, 734 { .compatible = "rohm,dh2228fv", .data = &spidev_of_check }, 735 { .compatible = "semtech,sx1301", .data = &spidev_of_check }, 736 { .compatible = "silabs,em3581", .data = &spidev_of_check }, 737 { .compatible = "silabs,si3210", .data = &spidev_of_check }, 738 {}, 739 }; 740 MODULE_DEVICE_TABLE(of, spidev_dt_ids); 741 742 /* Dummy SPI devices not to be used in production systems */ 743 static int spidev_acpi_check(struct device *dev) 744 { 745 dev_warn(dev, "do not use this driver in production systems!\n"); 746 return 0; 747 } 748 749 static const struct acpi_device_id spidev_acpi_ids[] = { 750 /* 751 * The ACPI SPT000* devices are only meant for development and 752 * testing. Systems used in production should have a proper ACPI 753 * description of the connected peripheral and they should also use 754 * a proper driver instead of poking directly to the SPI bus. 755 */ 756 { "SPT0001", (kernel_ulong_t)&spidev_acpi_check }, 757 { "SPT0002", (kernel_ulong_t)&spidev_acpi_check }, 758 { "SPT0003", (kernel_ulong_t)&spidev_acpi_check }, 759 {}, 760 }; 761 MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids); 762 763 /*-------------------------------------------------------------------------*/ 764 765 static int spidev_probe(struct spi_device *spi) 766 { 767 int (*match)(struct device *dev); 768 struct spidev_data *spidev; 769 int status; 770 unsigned long minor; 771 772 match = device_get_match_data(&spi->dev); 773 if (match) { 774 status = match(&spi->dev); 775 if (status) 776 return status; 777 } 778 779 /* Allocate driver data */ 780 spidev = kzalloc_obj(*spidev); 781 if (!spidev) 782 return -ENOMEM; 783 784 /* Initialize the driver data */ 785 spidev->spi = spi; 786 mutex_init(&spidev->spi_lock); 787 788 INIT_LIST_HEAD(&spidev->device_entry); 789 790 /* If we can allocate a minor number, hook up this device. 791 * Reusing minors is fine so long as udev or mdev is working. 792 */ 793 mutex_lock(&device_list_lock); 794 minor = find_first_zero_bit(minors, N_SPI_MINORS); 795 if (minor < N_SPI_MINORS) { 796 struct device *dev; 797 798 spidev->devt = MKDEV(SPIDEV_MAJOR, minor); 799 dev = device_create(&spidev_class, &spi->dev, spidev->devt, 800 spidev, "spidev%d.%d", 801 spi->controller->bus_num, spi_get_chipselect(spi, 0)); 802 status = PTR_ERR_OR_ZERO(dev); 803 } else { 804 dev_dbg(&spi->dev, "no minor number available!\n"); 805 status = -ENODEV; 806 } 807 if (status == 0) { 808 set_bit(minor, minors); 809 list_add(&spidev->device_entry, &device_list); 810 } 811 mutex_unlock(&device_list_lock); 812 813 spidev->speed_hz = spi->max_speed_hz; 814 815 if (status == 0) 816 spi_set_drvdata(spi, spidev); 817 else 818 kfree(spidev); 819 820 return status; 821 } 822 823 static void spidev_remove(struct spi_device *spi) 824 { 825 struct spidev_data *spidev = spi_get_drvdata(spi); 826 827 /* prevent new opens */ 828 mutex_lock(&device_list_lock); 829 /* make sure ops on existing fds can abort cleanly */ 830 mutex_lock(&spidev->spi_lock); 831 spidev->spi = NULL; 832 mutex_unlock(&spidev->spi_lock); 833 834 list_del(&spidev->device_entry); 835 device_destroy(&spidev_class, spidev->devt); 836 clear_bit(MINOR(spidev->devt), minors); 837 if (spidev->users == 0) 838 kfree(spidev); 839 mutex_unlock(&device_list_lock); 840 } 841 842 static struct spi_driver spidev_spi_driver = { 843 .driver = { 844 .name = "spidev", 845 .of_match_table = spidev_dt_ids, 846 .acpi_match_table = spidev_acpi_ids, 847 }, 848 .probe = spidev_probe, 849 .remove = spidev_remove, 850 .id_table = spidev_spi_ids, 851 852 /* NOTE: suspend/resume methods are not necessary here. 853 * We don't do anything except pass the requests to/from 854 * the underlying controller. The refrigerator handles 855 * most issues; the controller driver handles the rest. 856 */ 857 }; 858 859 /*-------------------------------------------------------------------------*/ 860 861 static int __init spidev_init(void) 862 { 863 int status; 864 865 /* Claim our 256 reserved device numbers. Then register a class 866 * that will key udev/mdev to add/remove /dev nodes. Last, register 867 * the driver which manages those device numbers. 868 */ 869 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); 870 if (status < 0) 871 return status; 872 873 status = class_register(&spidev_class); 874 if (status) { 875 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 876 return status; 877 } 878 879 status = spi_register_driver(&spidev_spi_driver); 880 if (status < 0) { 881 class_unregister(&spidev_class); 882 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 883 } 884 return status; 885 } 886 module_init(spidev_init); 887 888 static void __exit spidev_exit(void) 889 { 890 spi_unregister_driver(&spidev_spi_driver); 891 class_unregister(&spidev_class); 892 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 893 } 894 module_exit(spidev_exit); 895 896 MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); 897 MODULE_DESCRIPTION("User mode SPI device interface"); 898 MODULE_LICENSE("GPL"); 899 MODULE_ALIAS("spi:spidev"); 900