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