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 * 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 46static DECLARE_BITMAP(minors, N_SPI_MINORS); 47 48/* Bit masks for spi_device.mode management. Note that incorrect 49 * settings for some settings can cause *lots* of trouble for other 50 * devices on a shared bus: 51 * 52 * - CS_HIGH ... this device will be active when it shouldn't be 53 * - 3WIRE ... when active, it won't behave as it should 54 * - NO_CS ... there will be no explicit message boundaries; this 55 * is completely incompatible with the shared bus model 56 * - READY ... transfers may proceed when they shouldn't. 57 * 58 * REVISIT should changing those flags be privileged? 59 */ 60#define SPI_MODE_MASK \ 61 (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP | SPI_NO_CS | SPI_READY | SPI_TX_DUAL | \ 62 SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL) 63 64struct spidev_data { 65 dev_t devt; 66 spinlock_t spi_lock; 67 struct spi_device *spi; 68 struct list_head device_entry; 69 70 /* TX/RX buffers are NULL unless this device is open (users > 0) */ 71 struct mutex buf_lock; 72 unsigned users; 73 u8 *tx_buffer; 74 u8 *rx_buffer; 75 u32 speed_hz; 76}; 77 78static LIST_HEAD(device_list); 79static DEFINE_MUTEX(device_list_lock); 80 81static unsigned bufsiz = 4096; 82module_param(bufsiz, uint, S_IRUGO); 83MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); 84 85/*-------------------------------------------------------------------------*/ 86 87static ssize_t spidev_sync(struct spidev_data *spidev, struct spi_message *message) 88{ 89 int status; 90 struct spi_device *spi; 91 92 spin_lock_irq(&spidev->spi_lock); 93 spi = spidev->spi; 94 spin_unlock_irq(&spidev->spi_lock); 95 96 if (spi == NULL) { 97 status = -ESHUTDOWN; 98 } else { 99 status = spi_sync(spi, message); 100 } 101 102 if (status == 0) { 103 status = message->actual_length; 104 } 105 106 return status; 107} 108 109static inline ssize_t spidev_sync_write(struct spidev_data *spidev, size_t len) 110{ 111 struct spi_transfer t = { 112 .tx_buf = spidev->tx_buffer, 113 .len = len, 114 .speed_hz = spidev->speed_hz, 115 }; 116 struct spi_message m; 117 118 spi_message_init(&m); 119 spi_message_add_tail(&t, &m); 120 return spidev_sync(spidev, &m); 121} 122 123static inline ssize_t spidev_sync_read(struct spidev_data *spidev, size_t len) 124{ 125 struct spi_transfer t = { 126 .rx_buf = spidev->rx_buffer, 127 .len = len, 128 .speed_hz = spidev->speed_hz, 129 }; 130 struct spi_message m; 131 132 spi_message_init(&m); 133 spi_message_add_tail(&t, &m); 134 return spidev_sync(spidev, &m); 135} 136 137/*-------------------------------------------------------------------------*/ 138 139/* Read-only message with current device setup */ 140static ssize_t 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; 144 145 /* chipselect only toggles at start or end of operation */ 146 if (count > bufsiz) { 147 return -EMSGSIZE; 148 } 149 150 spidev = filp->private_data; 151 152 mutex_lock(&spidev->buf_lock); 153 status = spidev_sync_read(spidev, count); 154 if (status > 0) { 155 unsigned long missing; 156 157 missing = copy_to_user(buf, spidev->rx_buffer, status); 158 if (missing == status) { 159 status = -EFAULT; 160 } else { 161 status = status - missing; 162 } 163 } 164 mutex_unlock(&spidev->buf_lock); 165 166 return status; 167} 168 169/* Write-only message with current device setup */ 170static ssize_t spidev_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) 171{ 172 struct spidev_data *spidev; 173 ssize_t status; 174 unsigned long missing; 175 176 /* chipselect only toggles at start or end of operation */ 177 if (count > bufsiz) { 178 return -EMSGSIZE; 179 } 180 181 spidev = filp->private_data; 182 183 mutex_lock(&spidev->buf_lock); 184 missing = copy_from_user(spidev->tx_buffer, buf, count); 185 if (missing == 0) { 186 status = spidev_sync_write(spidev, count); 187 } else { 188 status = -EFAULT; 189 } 190 mutex_unlock(&spidev->buf_lock); 191 192 return status; 193} 194 195static int spidev_message(struct spidev_data *spidev, struct spi_ioc_transfer *u_xfers, unsigned n_xfers) 196{ 197 struct spi_message msg; 198 struct spi_transfer *k_xfers; 199 struct spi_transfer *k_tmp; 200 struct spi_ioc_transfer *u_tmp; 201 unsigned n, total, tx_total, rx_total; 202 u8 *tx_buf, *rx_buf; 203 int status = -EFAULT; 204 205 spi_message_init(&msg); 206 k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); 207 if (k_xfers == NULL) { 208 return -ENOMEM; 209 } 210 211 /* Construct spi_message, copying any tx data to bounce buffer. 212 * We walk the array of user-provided transfers, using each one 213 * to initialize a kernel version of the same transfer. 214 */ 215 tx_buf = spidev->tx_buffer; 216 rx_buf = spidev->rx_buffer; 217 total = 0; 218 tx_total = 0; 219 rx_total = 0; 220 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; n; n--, k_tmp++, u_tmp++) { 221 /* Ensure that also following allocations from rx_buf/tx_buf will meet 222 * DMA alignment requirements. 223 */ 224 unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_KMALLOC_MINALIGN); 225 226 k_tmp->len = u_tmp->len; 227 228 total += k_tmp->len; 229 /* Since the function returns the total length of transfers 230 * on success, restrict the total to positive int values to 231 * avoid the return value looking like an error. Also check 232 * each transfer length to avoid arithmetic overflow. 233 */ 234 if (total > INT_MAX || k_tmp->len > INT_MAX) { 235 status = -EMSGSIZE; 236 goto done; 237 } 238 239 if (u_tmp->rx_buf) { 240 /* this transfer needs space in RX bounce buffer */ 241 rx_total += len_aligned; 242 if (rx_total > bufsiz) { 243 status = -EMSGSIZE; 244 goto done; 245 } 246 k_tmp->rx_buf = rx_buf; 247 rx_buf += len_aligned; 248 } 249 if (u_tmp->tx_buf) { 250 /* this transfer needs space in TX bounce buffer */ 251 tx_total += len_aligned; 252 if (tx_total > bufsiz) { 253 status = -EMSGSIZE; 254 goto done; 255 } 256 k_tmp->tx_buf = tx_buf; 257 if (copy_from_user(tx_buf, (const u8 __user *)(uintptr_t)u_tmp->tx_buf, u_tmp->len)) { 258 goto done; 259 } 260 tx_buf += len_aligned; 261 } 262 263 k_tmp->cs_change = !!u_tmp->cs_change; 264 k_tmp->tx_nbits = u_tmp->tx_nbits; 265 k_tmp->rx_nbits = u_tmp->rx_nbits; 266 k_tmp->bits_per_word = u_tmp->bits_per_word; 267 k_tmp->delay.value = u_tmp->delay_usecs; 268 k_tmp->delay.unit = SPI_DELAY_UNIT_USECS; 269 k_tmp->speed_hz = u_tmp->speed_hz; 270 k_tmp->word_delay.value = u_tmp->word_delay_usecs; 271 k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS; 272 if (!k_tmp->speed_hz) { 273 k_tmp->speed_hz = spidev->speed_hz; 274 } 275#ifdef VERBOSE 276 dev_dbg(&spidev->spi->dev, " xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n", k_tmp->len, 277 k_tmp->rx_buf ? "rx " : "", k_tmp->tx_buf ? "tx " : "", k_tmp->cs_change ? "cs " : "", 278 k_tmp->bits_per_word ?: spidev->spi->bits_per_word, k_tmp->delay.value, k_tmp->word_delay.value, 279 k_tmp->speed_hz ?: spidev->spi->max_speed_hz); 280#endif 281 spi_message_add_tail(k_tmp, &msg); 282 } 283 284 status = spidev_sync(spidev, &msg); 285 if (status < 0) { 286 goto done; 287 } 288 289 /* copy any rx data out of bounce buffer */ 290 for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; n; n--, k_tmp++, u_tmp++) { 291 if (u_tmp->rx_buf) { 292 if (copy_to_user((u8 __user *)(uintptr_t)u_tmp->rx_buf, k_tmp->rx_buf, u_tmp->len)) { 293 status = -EFAULT; 294 goto done; 295 } 296 } 297 } 298 status = total; 299 300done: 301 kfree(k_xfers); 302 return status; 303} 304 305static struct spi_ioc_transfer *spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc, 306 unsigned *n_ioc) 307{ 308 u32 tmp; 309 310 /* Check type, command number and direction */ 311 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) || _IOC_DIR(cmd) != _IOC_WRITE) { 312 return ERR_PTR(-ENOTTY); 313 } 314 315 tmp = _IOC_SIZE(cmd); 316 if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) { 317 return ERR_PTR(-EINVAL); 318 } 319 *n_ioc = tmp / sizeof(struct spi_ioc_transfer); 320 if (*n_ioc == 0) { 321 return NULL; 322 } 323 324 /* copy into scratch area */ 325 return memdup_user(u_ioc, tmp); 326} 327 328static long spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 329{ 330 int retval = 0; 331 struct spidev_data *spidev; 332 struct spi_device *spi; 333 u32 tmp; 334 unsigned n_ioc; 335 struct spi_ioc_transfer *ioc; 336 337 /* Check type and command number */ 338 if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) { 339 return -ENOTTY; 340 } 341 342 /* guard against device removal before, or while, 343 * we issue this ioctl. 344 */ 345 spidev = filp->private_data; 346 spin_lock_irq(&spidev->spi_lock); 347 spi = spi_dev_get(spidev->spi); 348 spin_unlock_irq(&spidev->spi_lock); 349 350 if (spi == NULL) { 351 return -ESHUTDOWN; 352 } 353 354 /* use the buffer lock here for triple duty: 355 * - prevent I/O (from us) so calling spi_setup() is safe; 356 * - prevent concurrent SPI_IOC_WR_* from morphing 357 * data fields while SPI_IOC_RD_* reads them; 358 * - SPI_IOC_MESSAGE needs the buffer locked "normally". 359 */ 360 mutex_lock(&spidev->buf_lock); 361 362 switch (cmd) { 363 /* read requests */ 364 case SPI_IOC_RD_MODE: 365 retval = put_user(spi->mode & SPI_MODE_MASK, (__u8 __user *)arg); 366 break; 367 case SPI_IOC_RD_MODE32: 368 retval = put_user(spi->mode & SPI_MODE_MASK, (__u32 __user *)arg); 369 break; 370 case SPI_IOC_RD_LSB_FIRST: 371 retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, (__u8 __user *)arg); 372 break; 373 case SPI_IOC_RD_BITS_PER_WORD: 374 retval = put_user(spi->bits_per_word, (__u8 __user *)arg); 375 break; 376 case SPI_IOC_RD_MAX_SPEED_HZ: 377 retval = put_user(spidev->speed_hz, (__u32 __user *)arg); 378 break; 379 380 /* write requests */ 381 case SPI_IOC_WR_MODE: 382 case SPI_IOC_WR_MODE32: 383 if (cmd == SPI_IOC_WR_MODE) { 384 retval = get_user(tmp, (u8 __user *)arg); 385 } else { 386 retval = get_user(tmp, (u32 __user *)arg); 387 } 388 if (retval == 0) { 389 struct spi_controller *ctlr = spi->controller; 390 u32 save = spi->mode; 391 392 if (tmp & ~SPI_MODE_MASK) { 393 retval = -EINVAL; 394 break; 395 } 396 397 if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods && ctlr->cs_gpiods[spi->chip_select]) { 398 tmp |= SPI_CS_HIGH; 399 } 400 401 tmp |= spi->mode & ~SPI_MODE_MASK; 402 spi->mode = (u16)tmp; 403 retval = spi_setup(spi); 404 if (retval < 0) { 405 spi->mode = save; 406 } else { 407 dev_dbg(&spi->dev, "spi mode %x\n", tmp); 408 } 409 } 410 break; 411 case SPI_IOC_WR_LSB_FIRST: 412 retval = get_user(tmp, (__u8 __user *)arg); 413 if (retval == 0) { 414 u32 save = spi->mode; 415 416 if (tmp) { 417 spi->mode |= SPI_LSB_FIRST; 418 } else { 419 spi->mode &= ~SPI_LSB_FIRST; 420 } 421 retval = spi_setup(spi); 422 if (retval < 0) { 423 spi->mode = save; 424 } else { 425 dev_dbg(&spi->dev, "%csb first\n", tmp ? 'l' : 'm'); 426 } 427 } 428 break; 429 case SPI_IOC_WR_BITS_PER_WORD: 430 retval = get_user(tmp, (__u8 __user *)arg); 431 if (retval == 0) { 432 u8 save = spi->bits_per_word; 433 434 spi->bits_per_word = tmp; 435 retval = spi_setup(spi); 436 if (retval < 0) { 437 spi->bits_per_word = save; 438 } else { 439 dev_dbg(&spi->dev, "%d bits per word\n", tmp); 440 } 441 } 442 break; 443 case SPI_IOC_WR_MAX_SPEED_HZ: 444 retval = get_user(tmp, (__u32 __user *)arg); 445 if (retval == 0) { 446 u32 save = spi->max_speed_hz; 447 448 spi->max_speed_hz = tmp; 449 retval = spi_setup(spi); 450 if (retval == 0) { 451 spidev->speed_hz = tmp; 452 dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz); 453 } 454 spi->max_speed_hz = save; 455 } 456 break; 457 458 default: 459 /* segmented and/or full-duplex I/O request */ 460 /* Check message and copy into scratch area */ 461 ioc = spidev_get_ioc_message(cmd, (struct spi_ioc_transfer __user *)arg, &n_ioc); 462 if (IS_ERR(ioc)) { 463 retval = PTR_ERR(ioc); 464 break; 465 } 466 if (!ioc) { 467 break; /* n_ioc is also 0 */ 468 } 469 470 /* translate to spi_message, execute */ 471 retval = spidev_message(spidev, ioc, n_ioc); 472 kfree(ioc); 473 break; 474 } 475 476 mutex_unlock(&spidev->buf_lock); 477 spi_dev_put(spi); 478 return retval; 479} 480 481#ifdef CONFIG_COMPAT 482static long spidev_compat_ioc_message(struct file *filp, unsigned int cmd, unsigned long arg) 483{ 484 struct spi_ioc_transfer __user *u_ioc; 485 int retval = 0; 486 struct spidev_data *spidev; 487 struct spi_device *spi; 488 unsigned n_ioc, n; 489 struct spi_ioc_transfer *ioc; 490 491 u_ioc = (struct spi_ioc_transfer __user *)compat_ptr(arg); 492 493 /* guard against device removal before, or while, 494 * we issue this ioctl. 495 */ 496 spidev = filp->private_data; 497 spin_lock_irq(&spidev->spi_lock); 498 spi = spi_dev_get(spidev->spi); 499 spin_unlock_irq(&spidev->spi_lock); 500 501 if (spi == NULL) { 502 return -ESHUTDOWN; 503 } 504 505 /* SPI_IOC_MESSAGE needs the buffer locked "normally" */ 506 mutex_lock(&spidev->buf_lock); 507 508 /* Check message and copy into scratch area */ 509 ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc); 510 if (IS_ERR(ioc)) { 511 retval = PTR_ERR(ioc); 512 goto done; 513 } 514 if (!ioc) { 515 goto done; /* n_ioc is also 0 */ 516 } 517 518 /* Convert buffer pointers */ 519 for (n = 0; n < n_ioc; n++) { 520 ioc[n].rx_buf = (uintptr_t)compat_ptr(ioc[n].rx_buf); 521 ioc[n].tx_buf = (uintptr_t)compat_ptr(ioc[n].tx_buf); 522 } 523 524 /* translate to spi_message, execute */ 525 retval = spidev_message(spidev, ioc, n_ioc); 526 kfree(ioc); 527 528done: 529 mutex_unlock(&spidev->buf_lock); 530 spi_dev_put(spi); 531 return retval; 532} 533 534static long spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 535{ 536 if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) && _IOC_DIR(cmd) == _IOC_WRITE) { 537 return spidev_compat_ioc_message(filp, cmd, arg); 538 } 539 540 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 541} 542#else 543#define spidev_compat_ioctl NULL 544#endif /* CONFIG_COMPAT */ 545 546static int spidev_open(struct inode *inode, struct file *filp) 547{ 548 struct spidev_data *spidev; 549 int status = -ENXIO; 550 551 mutex_lock(&device_list_lock); 552 553 list_for_each_entry(spidev, &device_list, device_entry) 554 { 555 if (spidev->devt == inode->i_rdev) { 556 status = 0; 557 break; 558 } 559 } 560 561 if (status) { 562 pr_debug("spidev: nothing for minor %d\n", iminor(inode)); 563 goto err_find_dev; 564 } 565 566 if (!spidev->tx_buffer) { 567 spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); 568 if (!spidev->tx_buffer) { 569 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); 570 status = -ENOMEM; 571 goto err_find_dev; 572 } 573 } 574 575 if (!spidev->rx_buffer) { 576 spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); 577 if (!spidev->rx_buffer) { 578 dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); 579 status = -ENOMEM; 580 goto err_alloc_rx_buf; 581 } 582 } 583 584 spidev->users++; 585 filp->private_data = spidev; 586 stream_open(inode, filp); 587 588 mutex_unlock(&device_list_lock); 589 return 0; 590 591err_alloc_rx_buf: 592 kfree(spidev->tx_buffer); 593 spidev->tx_buffer = NULL; 594err_find_dev: 595 mutex_unlock(&device_list_lock); 596 return status; 597} 598 599static int spidev_release(struct inode *inode, struct file *filp) 600{ 601 struct spidev_data *spidev; 602 int dofree; 603 604 mutex_lock(&device_list_lock); 605 spidev = filp->private_data; 606 filp->private_data = NULL; 607 608 spin_lock_irq(&spidev->spi_lock); 609 /* ... after we unbound from the underlying device? */ 610 dofree = (spidev->spi == NULL); 611 spin_unlock_irq(&spidev->spi_lock); 612 613 /* last close? */ 614 spidev->users--; 615 if (!spidev->users) { 616 kfree(spidev->tx_buffer); 617 spidev->tx_buffer = NULL; 618 619 kfree(spidev->rx_buffer); 620 spidev->rx_buffer = NULL; 621 622 if (dofree) { 623 kfree(spidev); 624 } else { 625 spidev->speed_hz = spidev->spi->max_speed_hz; 626 } 627 } 628#ifdef CONFIG_SPI_SLAVE 629 if (!dofree) { 630 spi_slave_abort(spidev->spi); 631 } 632#endif 633 mutex_unlock(&device_list_lock); 634 635 return 0; 636} 637 638static const struct file_operations spidev_fops = { 639 .owner = THIS_MODULE, 640 /* REVISIT switch to aio primitives, so that userspace 641 * gets more complete API coverage. It'll simplify things 642 * too, except for the locking. 643 */ 644 .write = spidev_write, 645 .read = spidev_read, 646 .unlocked_ioctl = spidev_ioctl, 647 .compat_ioctl = spidev_compat_ioctl, 648 .open = spidev_open, 649 .release = spidev_release, 650 .llseek = no_llseek, 651}; 652 653/*-------------------------------------------------------------------------*/ 654 655/* The main reason to have this class is to make mdev/udev create the 656 * /dev/spidevB.C character device nodes exposing our userspace API. 657 * It also simplifies memory management. 658 */ 659 660static struct class *spidev_class; 661 662#ifdef CONFIG_OF 663static const struct of_device_id spidev_dt_ids[] = { 664 {.compatible = "rohm,dh2228fv"}, 665 {.compatible = "lineartechnology,ltc2488"}, 666 {.compatible = "ge,achc"}, 667 {.compatible = "semtech,sx1301"}, 668 {.compatible = "lwn,bk4"}, 669 {.compatible = "dh,dhcom-board"}, 670 {.compatible = "menlo,m53cpld"}, 671 {.compatible = "rockchip,spidev"}, 672 {}, 673}; 674MODULE_DEVICE_TABLE(of, spidev_dt_ids); 675#endif 676 677#ifdef CONFIG_ACPI 678 679/* Dummy SPI devices not to be used in production systems */ 680#define SPIDEV_ACPI_DUMMY 1 681 682static const struct acpi_device_id spidev_acpi_ids[] = { 683 /* 684 * The ACPI SPT000* devices are only meant for development and 685 * testing. Systems used in production should have a proper ACPI 686 * description of the connected peripheral and they should also use 687 * a proper driver instead of poking directly to the SPI bus. 688 */ 689 {"SPT0001", SPIDEV_ACPI_DUMMY}, 690 {"SPT0002", SPIDEV_ACPI_DUMMY}, 691 {"SPT0003", SPIDEV_ACPI_DUMMY}, 692 {}, 693}; 694MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids); 695 696static void spidev_probe_acpi(struct spi_device *spi) 697{ 698 const struct acpi_device_id *id; 699 700 if (!has_acpi_companion(&spi->dev)) { 701 return; 702 } 703 704 id = acpi_match_device(spidev_acpi_ids, &spi->dev); 705 if (WARN_ON(!id)) { 706 return; 707 } 708 709 if (id->driver_data == SPIDEV_ACPI_DUMMY) { 710 dev_warn(&spi->dev, "do not use this driver in production systems!\n"); 711 } 712} 713#else 714static inline void spidev_probe_acpi(struct spi_device *spi) 715{ 716} 717#endif 718 719/*-------------------------------------------------------------------------*/ 720 721static int spidev_probe(struct spi_device *spi) 722{ 723 struct spidev_data *spidev; 724 int status; 725 unsigned long minor; 726 727 /* 728 * spidev should never be referenced in DT without a specific 729 * compatible string, it is a Linux implementation thing 730 * rather than a description of the hardware. 731 */ 732 WARN(spi->dev.of_node && of_device_is_compatible(spi->dev.of_node, "spidev"), 733 "%pOF: buggy DT: spidev listed directly in DT\n", spi->dev.of_node); 734 735 spidev_probe_acpi(spi); 736 737 /* Allocate driver data */ 738 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); 739 if (!spidev) { 740 return -ENOMEM; 741 } 742 743 /* Initialize the driver data */ 744 spidev->spi = spi; 745 spin_lock_init(&spidev->spi_lock); 746 mutex_init(&spidev->buf_lock); 747 748 INIT_LIST_HEAD(&spidev->device_entry); 749 750 /* If we can allocate a minor number, hook up this device. 751 * Reusing minors is fine so long as udev or mdev is working. 752 */ 753 mutex_lock(&device_list_lock); 754 minor = find_first_zero_bit(minors, N_SPI_MINORS); 755 if (minor < N_SPI_MINORS) { 756 struct device *dev; 757 758 spidev->devt = MKDEV(SPIDEV_MAJOR, minor); 759 dev = device_create(spidev_class, &spi->dev, spidev->devt, spidev, "spidev%d.%d", spi->master->bus_num, 760 spi->chip_select); 761 status = PTR_ERR_OR_ZERO(dev); 762 } else { 763 dev_dbg(&spi->dev, "no minor number available!\n"); 764 status = -ENODEV; 765 } 766 if (status == 0) { 767 set_bit(minor, minors); 768 list_add(&spidev->device_entry, &device_list); 769 } 770 mutex_unlock(&device_list_lock); 771 772 spidev->speed_hz = spi->max_speed_hz; 773 774 if (status == 0) { 775 spi_set_drvdata(spi, spidev); 776 } else { 777 kfree(spidev); 778 } 779 780 return status; 781} 782 783static int spidev_remove(struct spi_device *spi) 784{ 785 struct spidev_data *spidev = spi_get_drvdata(spi); 786 787 /* prevent new opens */ 788 mutex_lock(&device_list_lock); 789 /* make sure ops on existing fds can abort cleanly */ 790 spin_lock_irq(&spidev->spi_lock); 791 spidev->spi = NULL; 792 spin_unlock_irq(&spidev->spi_lock); 793 794 list_del(&spidev->device_entry); 795 device_destroy(spidev_class, spidev->devt); 796 clear_bit(MINOR(spidev->devt), minors); 797 if (spidev->users == 0) { 798 kfree(spidev); 799 } 800 mutex_unlock(&device_list_lock); 801 802 return 0; 803} 804 805static struct spi_driver spidev_spi_driver = { 806 .driver = 807 { 808 .name = "spidev", 809 .of_match_table = of_match_ptr(spidev_dt_ids), 810 .acpi_match_table = ACPI_PTR(spidev_acpi_ids), 811 }, 812 .probe = spidev_probe, 813 .remove = spidev_remove, 814 815 /* NOTE: suspend/resume methods are not necessary here. 816 * We don't do anything except pass the requests to/from 817 * the underlying controller. The refrigerator handles 818 * most issues; the controller driver handles the rest. 819 */ 820}; 821 822/*-------------------------------------------------------------------------*/ 823 824static int __init spidev_init(void) 825{ 826 int status; 827 828 /* Claim our 256 reserved device numbers. Then register a class 829 * that will key udev/mdev to add/remove /dev nodes. Last, register 830 * the driver which manages those device numbers. 831 */ 832 BUILD_BUG_ON(N_SPI_MINORS > 256); 833 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); 834 if (status < 0) { 835 return status; 836 } 837 838 spidev_class = class_create(THIS_MODULE, "spidev"); 839 if (IS_ERR(spidev_class)) { 840 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 841 return PTR_ERR(spidev_class); 842 } 843 844 status = spi_register_driver(&spidev_spi_driver); 845 if (status < 0) { 846 class_destroy(spidev_class); 847 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 848 } 849 return status; 850} 851module_init(spidev_init); 852 853static void __exit spidev_exit(void) 854{ 855 spi_unregister_driver(&spidev_spi_driver); 856 class_destroy(spidev_class); 857 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 858} 859module_exit(spidev_exit); 860 861MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); 862MODULE_DESCRIPTION("User mode SPI device interface"); 863MODULE_LICENSE("GPL"); 864MODULE_ALIAS("spi:spidev"); 865