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 47static 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_CPHA | SPI_CPOL | 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 68struct 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 82static LIST_HEAD(device_list); 83static DEFINE_MUTEX(device_list_lock); 84 85static unsigned bufsiz = 4096; 86module_param(bufsiz, uint, S_IRUGO); 87MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); 88 89/*-------------------------------------------------------------------------*/ 90 91static ssize_t 92spidev_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 112static inline ssize_t 113spidev_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 127static inline ssize_t 128spidev_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 */ 145static ssize_t 146spidev_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 */ 174static ssize_t 175spidev_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 199static 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 315done: 316 kfree(k_xfers); 317 return status; 318} 319 320static struct spi_ioc_transfer * 321spidev_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 343static long 344spidev_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 case SPI_IOC_RD_MODE32: 380 tmp = spi->mode; 381 382 { 383 struct spi_controller *ctlr = spi->controller; 384 385 if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods && 386 ctlr->cs_gpiods[spi->chip_select]) 387 tmp &= ~SPI_CS_HIGH; 388 } 389 390 if (cmd == SPI_IOC_RD_MODE) 391 retval = put_user(tmp & SPI_MODE_MASK, 392 (__u8 __user *)arg); 393 else 394 retval = put_user(tmp & SPI_MODE_MASK, 395 (__u32 __user *)arg); 396 break; 397 case SPI_IOC_RD_LSB_FIRST: 398 retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, 399 (__u8 __user *)arg); 400 break; 401 case SPI_IOC_RD_BITS_PER_WORD: 402 retval = put_user(spi->bits_per_word, (__u8 __user *)arg); 403 break; 404 case SPI_IOC_RD_MAX_SPEED_HZ: 405 retval = put_user(spidev->speed_hz, (__u32 __user *)arg); 406 break; 407 408 /* write requests */ 409 case SPI_IOC_WR_MODE: 410 case SPI_IOC_WR_MODE32: 411 if (cmd == SPI_IOC_WR_MODE) 412 retval = get_user(tmp, (u8 __user *)arg); 413 else 414 retval = get_user(tmp, (u32 __user *)arg); 415 if (retval == 0) { 416 struct spi_controller *ctlr = spi->controller; 417 u32 save = spi->mode; 418 419 if (tmp & ~SPI_MODE_MASK) { 420 retval = -EINVAL; 421 break; 422 } 423 424 if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods && 425 ctlr->cs_gpiods[spi->chip_select]) 426 tmp |= SPI_CS_HIGH; 427 428 tmp |= spi->mode & ~SPI_MODE_MASK; 429 spi->mode = (u16)tmp; 430 retval = spi_setup(spi); 431 if (retval < 0) 432 spi->mode = save; 433 else 434 dev_dbg(&spi->dev, "spi mode %x\n", tmp); 435 } 436 break; 437 case SPI_IOC_WR_LSB_FIRST: 438 retval = get_user(tmp, (__u8 __user *)arg); 439 if (retval == 0) { 440 u32 save = spi->mode; 441 442 if (tmp) 443 spi->mode |= SPI_LSB_FIRST; 444 else 445 spi->mode &= ~SPI_LSB_FIRST; 446 retval = spi_setup(spi); 447 if (retval < 0) 448 spi->mode = save; 449 else 450 dev_dbg(&spi->dev, "%csb first\n", 451 tmp ? 'l' : 'm'); 452 } 453 break; 454 case SPI_IOC_WR_BITS_PER_WORD: 455 retval = get_user(tmp, (__u8 __user *)arg); 456 if (retval == 0) { 457 u8 save = spi->bits_per_word; 458 459 spi->bits_per_word = tmp; 460 retval = spi_setup(spi); 461 if (retval < 0) 462 spi->bits_per_word = save; 463 else 464 dev_dbg(&spi->dev, "%d bits per word\n", tmp); 465 } 466 break; 467 case SPI_IOC_WR_MAX_SPEED_HZ: 468 retval = get_user(tmp, (__u32 __user *)arg); 469 if (retval == 0) { 470 u32 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", 477 spidev->speed_hz); 478 } 479 spi->max_speed_hz = save; 480 } 481 break; 482 483 default: 484 /* segmented and/or full-duplex I/O request */ 485 /* Check message and copy into scratch area */ 486 ioc = spidev_get_ioc_message(cmd, 487 (struct spi_ioc_transfer __user *)arg, &n_ioc); 488 if (IS_ERR(ioc)) { 489 retval = PTR_ERR(ioc); 490 break; 491 } 492 if (!ioc) 493 break; /* n_ioc is also 0 */ 494 495 /* translate to spi_message, execute */ 496 retval = spidev_message(spidev, ioc, n_ioc); 497 kfree(ioc); 498 break; 499 } 500 501 mutex_unlock(&spidev->buf_lock); 502 spi_dev_put(spi); 503 return retval; 504} 505 506#ifdef CONFIG_COMPAT 507static long 508spidev_compat_ioc_message(struct file *filp, unsigned int cmd, 509 unsigned long arg) 510{ 511 struct spi_ioc_transfer __user *u_ioc; 512 int retval = 0; 513 struct spidev_data *spidev; 514 struct spi_device *spi; 515 unsigned n_ioc, n; 516 struct spi_ioc_transfer *ioc; 517 518 u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg); 519 520 /* guard against device removal before, or while, 521 * we issue this ioctl. 522 */ 523 spidev = filp->private_data; 524 spin_lock_irq(&spidev->spi_lock); 525 spi = spi_dev_get(spidev->spi); 526 spin_unlock_irq(&spidev->spi_lock); 527 528 if (spi == NULL) 529 return -ESHUTDOWN; 530 531 /* SPI_IOC_MESSAGE needs the buffer locked "normally" */ 532 mutex_lock(&spidev->buf_lock); 533 534 /* Check message and copy into scratch area */ 535 ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc); 536 if (IS_ERR(ioc)) { 537 retval = PTR_ERR(ioc); 538 goto done; 539 } 540 if (!ioc) 541 goto done; /* n_ioc is also 0 */ 542 543 /* Convert buffer pointers */ 544 for (n = 0; n < n_ioc; n++) { 545 ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf); 546 ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf); 547 } 548 549 /* translate to spi_message, execute */ 550 retval = spidev_message(spidev, ioc, n_ioc); 551 kfree(ioc); 552 553done: 554 mutex_unlock(&spidev->buf_lock); 555 spi_dev_put(spi); 556 return retval; 557} 558 559static long 560spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 561{ 562 if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC 563 && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) 564 && _IOC_DIR(cmd) == _IOC_WRITE) 565 return spidev_compat_ioc_message(filp, cmd, arg); 566 567 return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 568} 569#else 570#define spidev_compat_ioctl NULL 571#endif /* CONFIG_COMPAT */ 572 573static int spidev_open(struct inode *inode, struct file *filp) 574{ 575 struct spidev_data *spidev; 576 int status = -ENXIO; 577 578 mutex_lock(&device_list_lock); 579 580 list_for_each_entry(spidev, &device_list, device_entry) { 581 if (spidev->devt == inode->i_rdev) { 582 status = 0; 583 break; 584 } 585 } 586 587 if (status) { 588 pr_debug("spidev: nothing for minor %d\n", iminor(inode)); 589 goto err_find_dev; 590 } 591 592 if (!spidev->tx_buffer) { 593 spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); 594 if (!spidev->tx_buffer) { 595 status = -ENOMEM; 596 goto err_find_dev; 597 } 598 } 599 600 if (!spidev->rx_buffer) { 601 spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); 602 if (!spidev->rx_buffer) { 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 615err_alloc_rx_buf: 616 kfree(spidev->tx_buffer); 617 spidev->tx_buffer = NULL; 618err_find_dev: 619 mutex_unlock(&device_list_lock); 620 return status; 621} 622 623static 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 661static 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 683static struct class *spidev_class; 684 685#ifdef CONFIG_OF 686static const struct of_device_id spidev_dt_ids[] = { 687 { .compatible = "rohm,dh2228fv" }, 688 { .compatible = "lineartechnology,ltc2488" }, 689 { .compatible = "ge,achc" }, 690 { .compatible = "semtech,sx1301" }, 691 { .compatible = "lwn,bk4" }, 692 { .compatible = "dh,dhcom-board" }, 693 { .compatible = "menlo,m53cpld" }, 694 {}, 695}; 696MODULE_DEVICE_TABLE(of, spidev_dt_ids); 697#endif 698 699#ifdef CONFIG_ACPI 700 701/* Dummy SPI devices not to be used in production systems */ 702#define SPIDEV_ACPI_DUMMY 1 703 704static const struct acpi_device_id spidev_acpi_ids[] = { 705 /* 706 * The ACPI SPT000* devices are only meant for development and 707 * testing. Systems used in production should have a proper ACPI 708 * description of the connected peripheral and they should also use 709 * a proper driver instead of poking directly to the SPI bus. 710 */ 711 { "SPT0001", SPIDEV_ACPI_DUMMY }, 712 { "SPT0002", SPIDEV_ACPI_DUMMY }, 713 { "SPT0003", SPIDEV_ACPI_DUMMY }, 714 {}, 715}; 716MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids); 717 718static void spidev_probe_acpi(struct spi_device *spi) 719{ 720 const struct acpi_device_id *id; 721 722 if (!has_acpi_companion(&spi->dev)) 723 return; 724 725 id = acpi_match_device(spidev_acpi_ids, &spi->dev); 726 if (WARN_ON(!id)) 727 return; 728 729 if (id->driver_data == SPIDEV_ACPI_DUMMY) 730 dev_warn(&spi->dev, "do not use this driver in production systems!\n"); 731} 732#else 733static inline void spidev_probe_acpi(struct spi_device *spi) {} 734#endif 735 736/*-------------------------------------------------------------------------*/ 737 738static int spidev_probe(struct spi_device *spi) 739{ 740 struct spidev_data *spidev; 741 int status; 742 unsigned long minor; 743 744 /* 745 * spidev should never be referenced in DT without a specific 746 * compatible string, it is a Linux implementation thing 747 * rather than a description of the hardware. 748 */ 749 WARN(spi->dev.of_node && 750 of_device_is_compatible(spi->dev.of_node, "spidev"), 751 "%pOF: buggy DT: spidev listed directly in DT\n", spi->dev.of_node); 752 753 spidev_probe_acpi(spi); 754 755 /* Allocate driver data */ 756 spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); 757 if (!spidev) 758 return -ENOMEM; 759 760 /* Initialize the driver data */ 761 spidev->spi = spi; 762 spin_lock_init(&spidev->spi_lock); 763 mutex_init(&spidev->buf_lock); 764 765 INIT_LIST_HEAD(&spidev->device_entry); 766 767 /* If we can allocate a minor number, hook up this device. 768 * Reusing minors is fine so long as udev or mdev is working. 769 */ 770 mutex_lock(&device_list_lock); 771 minor = find_first_zero_bit(minors, N_SPI_MINORS); 772 if (minor < N_SPI_MINORS) { 773 struct device *dev; 774 775 spidev->devt = MKDEV(SPIDEV_MAJOR, minor); 776 dev = device_create(spidev_class, &spi->dev, spidev->devt, 777 spidev, "spidev%d.%d", 778 spi->master->bus_num, spi->chip_select); 779 status = PTR_ERR_OR_ZERO(dev); 780 } else { 781 dev_dbg(&spi->dev, "no minor number available!\n"); 782 status = -ENODEV; 783 } 784 if (status == 0) { 785 set_bit(minor, minors); 786 list_add(&spidev->device_entry, &device_list); 787 } 788 mutex_unlock(&device_list_lock); 789 790 spidev->speed_hz = spi->max_speed_hz; 791 792 if (status == 0) 793 spi_set_drvdata(spi, spidev); 794 else 795 kfree(spidev); 796 797 return status; 798} 799 800static int spidev_remove(struct spi_device *spi) 801{ 802 struct spidev_data *spidev = spi_get_drvdata(spi); 803 804 /* prevent new opens */ 805 mutex_lock(&device_list_lock); 806 /* make sure ops on existing fds can abort cleanly */ 807 spin_lock_irq(&spidev->spi_lock); 808 spidev->spi = NULL; 809 spin_unlock_irq(&spidev->spi_lock); 810 811 list_del(&spidev->device_entry); 812 device_destroy(spidev_class, spidev->devt); 813 clear_bit(MINOR(spidev->devt), minors); 814 if (spidev->users == 0) 815 kfree(spidev); 816 mutex_unlock(&device_list_lock); 817 818 return 0; 819} 820 821static struct spi_driver spidev_spi_driver = { 822 .driver = { 823 .name = "spidev", 824 .of_match_table = of_match_ptr(spidev_dt_ids), 825 .acpi_match_table = ACPI_PTR(spidev_acpi_ids), 826 }, 827 .probe = spidev_probe, 828 .remove = spidev_remove, 829 830 /* NOTE: suspend/resume methods are not necessary here. 831 * We don't do anything except pass the requests to/from 832 * the underlying controller. The refrigerator handles 833 * most issues; the controller driver handles the rest. 834 */ 835}; 836 837/*-------------------------------------------------------------------------*/ 838 839static int __init spidev_init(void) 840{ 841 int status; 842 843 /* Claim our 256 reserved device numbers. Then register a class 844 * that will key udev/mdev to add/remove /dev nodes. Last, register 845 * the driver which manages those device numbers. 846 */ 847 BUILD_BUG_ON(N_SPI_MINORS > 256); 848 status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); 849 if (status < 0) 850 return status; 851 852 spidev_class = class_create(THIS_MODULE, "spidev"); 853 if (IS_ERR(spidev_class)) { 854 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 855 return PTR_ERR(spidev_class); 856 } 857 858 status = spi_register_driver(&spidev_spi_driver); 859 if (status < 0) { 860 class_destroy(spidev_class); 861 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 862 } 863 return status; 864} 865module_init(spidev_init); 866 867static void __exit spidev_exit(void) 868{ 869 spi_unregister_driver(&spidev_spi_driver); 870 class_destroy(spidev_class); 871 unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); 872} 873module_exit(spidev_exit); 874 875MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); 876MODULE_DESCRIPTION("User mode SPI device interface"); 877MODULE_LICENSE("GPL"); 878MODULE_ALIAS("spi:spidev"); 879