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