1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Industrial I/O event handling 3 * 4 * Copyright (c) 2008 Jonathan Cameron 5 * 6 * Based on elements of hwmon and input subsystems. 7 */ 8 9 #include <linux/anon_inodes.h> 10 #include <linux/device.h> 11 #include <linux/fs.h> 12 #include <linux/kernel.h> 13 #include <linux/kfifo.h> 14 #include <linux/module.h> 15 #include <linux/poll.h> 16 #include <linux/sched.h> 17 #include <linux/slab.h> 18 #include <linux/uaccess.h> 19 #include <linux/wait.h> 20 #include <linux/iio/iio.h> 21 #include <linux/iio/iio-opaque.h> 22 #include "iio_core.h" 23 #include <linux/iio/sysfs.h> 24 #include <linux/iio/events.h> 25 26 /** 27 * struct iio_event_interface - chrdev interface for an event line 28 * @wait: wait queue to allow blocking reads of events 29 * @det_events: list of detected events 30 * @dev_attr_list: list of event interface sysfs attribute 31 * @flags: file operations related flags including busy flag. 32 * @group: event interface sysfs attribute group 33 * @read_lock: lock to protect kfifo read operations 34 * @ioctl_handler: handler for event ioctl() calls 35 */ 36 struct iio_event_interface { 37 wait_queue_head_t wait; 38 DECLARE_KFIFO(det_events, struct iio_event_data, 16); 39 40 struct list_head dev_attr_list; 41 unsigned long flags; 42 struct attribute_group group; 43 struct mutex read_lock; 44 struct iio_ioctl_handler ioctl_handler; 45 }; 46 47 bool iio_event_enabled(const struct iio_event_interface *ev_int) 48 { 49 return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 50 } 51 52 /** 53 * iio_push_event() - try to add event to the list for userspace reading 54 * @indio_dev: IIO device structure 55 * @ev_code: What event 56 * @timestamp: When the event occurred 57 * 58 * Note: The caller must make sure that this function is not running 59 * concurrently for the same indio_dev more than once. 60 * 61 * This function may be safely used as soon as a valid reference to iio_dev has 62 * been obtained via iio_device_alloc(), but any events that are submitted 63 * before iio_device_register() has successfully completed will be silently 64 * discarded. 65 **/ 66 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp) 67 { 68 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 69 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 70 struct iio_event_data ev; 71 int copied; 72 73 if (!ev_int) 74 return 0; 75 76 /* Does anyone care? */ 77 if (iio_event_enabled(ev_int)) { 78 79 ev.id = ev_code; 80 ev.timestamp = timestamp; 81 82 copied = kfifo_put(&ev_int->det_events, ev); 83 if (copied != 0) 84 wake_up_poll(&ev_int->wait, EPOLLIN); 85 } 86 87 return 0; 88 } 89 EXPORT_SYMBOL(iio_push_event); 90 91 /** 92 * iio_event_poll() - poll the event queue to find out if it has data 93 * @filep: File structure pointer to identify the device 94 * @wait: Poll table pointer to add the wait queue on 95 * 96 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading 97 * or a negative error code on failure 98 */ 99 static __poll_t iio_event_poll(struct file *filep, 100 struct poll_table_struct *wait) 101 { 102 struct iio_dev *indio_dev = filep->private_data; 103 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 104 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 105 __poll_t events = 0; 106 107 if (!indio_dev->info) 108 return events; 109 110 poll_wait(filep, &ev_int->wait, wait); 111 112 if (!kfifo_is_empty(&ev_int->det_events)) 113 events = EPOLLIN | EPOLLRDNORM; 114 115 return events; 116 } 117 118 static ssize_t iio_event_chrdev_read(struct file *filep, 119 char __user *buf, 120 size_t count, 121 loff_t *f_ps) 122 { 123 struct iio_dev *indio_dev = filep->private_data; 124 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 125 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 126 unsigned int copied; 127 int ret; 128 129 if (!indio_dev->info) 130 return -ENODEV; 131 132 if (count < sizeof(struct iio_event_data)) 133 return -EINVAL; 134 135 do { 136 if (kfifo_is_empty(&ev_int->det_events)) { 137 if (filep->f_flags & O_NONBLOCK) 138 return -EAGAIN; 139 140 ret = wait_event_interruptible(ev_int->wait, 141 !kfifo_is_empty(&ev_int->det_events) || 142 indio_dev->info == NULL); 143 if (ret) 144 return ret; 145 if (indio_dev->info == NULL) 146 return -ENODEV; 147 } 148 149 if (mutex_lock_interruptible(&ev_int->read_lock)) 150 return -ERESTARTSYS; 151 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied); 152 mutex_unlock(&ev_int->read_lock); 153 154 if (ret) 155 return ret; 156 157 /* 158 * If we couldn't read anything from the fifo (a different 159 * thread might have been faster) we either return -EAGAIN if 160 * the file descriptor is non-blocking, otherwise we go back to 161 * sleep and wait for more data to arrive. 162 */ 163 if (copied == 0 && (filep->f_flags & O_NONBLOCK)) 164 return -EAGAIN; 165 166 } while (copied == 0); 167 168 return copied; 169 } 170 171 static int iio_event_chrdev_release(struct inode *inode, struct file *filep) 172 { 173 struct iio_dev *indio_dev = filep->private_data; 174 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 175 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 176 177 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 178 179 iio_device_put(indio_dev); 180 181 return 0; 182 } 183 184 static const struct file_operations iio_event_chrdev_fileops = { 185 .read = iio_event_chrdev_read, 186 .poll = iio_event_poll, 187 .release = iio_event_chrdev_release, 188 .owner = THIS_MODULE, 189 .llseek = noop_llseek, 190 }; 191 192 static int iio_event_getfd(struct iio_dev *indio_dev) 193 { 194 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 195 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 196 int fd; 197 198 if (ev_int == NULL) 199 return -ENODEV; 200 201 fd = mutex_lock_interruptible(&iio_dev_opaque->mlock); 202 if (fd) 203 return fd; 204 205 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { 206 fd = -EBUSY; 207 goto unlock; 208 } 209 210 iio_device_get(indio_dev); 211 212 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, 213 indio_dev, O_RDONLY | O_CLOEXEC); 214 if (fd < 0) { 215 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 216 iio_device_put(indio_dev); 217 } else { 218 kfifo_reset_out(&ev_int->det_events); 219 } 220 221 unlock: 222 mutex_unlock(&iio_dev_opaque->mlock); 223 return fd; 224 } 225 226 static const char * const iio_ev_type_text[] = { 227 [IIO_EV_TYPE_THRESH] = "thresh", 228 [IIO_EV_TYPE_MAG] = "mag", 229 [IIO_EV_TYPE_ROC] = "roc", 230 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive", 231 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive", 232 [IIO_EV_TYPE_CHANGE] = "change", 233 [IIO_EV_TYPE_MAG_REFERENCED] = "mag_referenced", 234 [IIO_EV_TYPE_GESTURE] = "gesture", 235 [IIO_EV_TYPE_FAULT] = "fault", 236 }; 237 238 static const char * const iio_ev_dir_text[] = { 239 [IIO_EV_DIR_EITHER] = "either", 240 [IIO_EV_DIR_RISING] = "rising", 241 [IIO_EV_DIR_FALLING] = "falling", 242 [IIO_EV_DIR_SINGLETAP] = "singletap", 243 [IIO_EV_DIR_DOUBLETAP] = "doubletap", 244 [IIO_EV_DIR_FAULT_OPENWIRE] = "openwire", 245 }; 246 247 static const char * const iio_ev_info_text[] = { 248 [IIO_EV_INFO_ENABLE] = "en", 249 [IIO_EV_INFO_VALUE] = "value", 250 [IIO_EV_INFO_HYSTERESIS] = "hysteresis", 251 [IIO_EV_INFO_PERIOD] = "period", 252 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db", 253 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db", 254 [IIO_EV_INFO_TIMEOUT] = "timeout", 255 [IIO_EV_INFO_RESET_TIMEOUT] = "reset_timeout", 256 [IIO_EV_INFO_TAP2_MIN_DELAY] = "tap2_min_delay", 257 [IIO_EV_INFO_RUNNING_PERIOD] = "runningperiod", 258 [IIO_EV_INFO_RUNNING_COUNT] = "runningcount", 259 }; 260 261 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 262 { 263 return attr->c->event_spec[attr->address & 0xffff].dir; 264 } 265 266 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 267 { 268 return attr->c->event_spec[attr->address & 0xffff].type; 269 } 270 271 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 272 { 273 return (attr->address >> 16) & 0xffff; 274 } 275 276 static ssize_t iio_ev_state_store(struct device *dev, 277 struct device_attribute *attr, 278 const char *buf, 279 size_t len) 280 { 281 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 282 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 283 int ret; 284 bool val; 285 286 ret = kstrtobool(buf, &val); 287 if (ret < 0) 288 return ret; 289 290 if (!indio_dev->info->write_event_config) 291 return -EINVAL; 292 293 ret = indio_dev->info->write_event_config(indio_dev, 294 this_attr->c, iio_ev_attr_type(this_attr), 295 iio_ev_attr_dir(this_attr), val); 296 297 return (ret < 0) ? ret : len; 298 } 299 300 static ssize_t iio_ev_state_show(struct device *dev, 301 struct device_attribute *attr, 302 char *buf) 303 { 304 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 305 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 306 int val; 307 308 if (!indio_dev->info->read_event_config) 309 return -EINVAL; 310 311 val = indio_dev->info->read_event_config(indio_dev, 312 this_attr->c, iio_ev_attr_type(this_attr), 313 iio_ev_attr_dir(this_attr)); 314 if (val < 0) 315 return val; 316 else 317 return sysfs_emit(buf, "%d\n", val); 318 } 319 320 static ssize_t iio_ev_value_show(struct device *dev, 321 struct device_attribute *attr, 322 char *buf) 323 { 324 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 325 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 326 int val, val2, val_arr[2]; 327 int ret; 328 329 if (!indio_dev->info->read_event_value) 330 return -EINVAL; 331 332 ret = indio_dev->info->read_event_value(indio_dev, 333 this_attr->c, iio_ev_attr_type(this_attr), 334 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 335 &val, &val2); 336 if (ret < 0) 337 return ret; 338 val_arr[0] = val; 339 val_arr[1] = val2; 340 return iio_format_value(buf, ret, 2, val_arr); 341 } 342 343 static ssize_t iio_ev_value_store(struct device *dev, 344 struct device_attribute *attr, 345 const char *buf, 346 size_t len) 347 { 348 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 349 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 350 int val, val2; 351 int ret; 352 353 if (!indio_dev->info->write_event_value) 354 return -EINVAL; 355 356 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 357 if (ret) 358 return ret; 359 ret = indio_dev->info->write_event_value(indio_dev, 360 this_attr->c, iio_ev_attr_type(this_attr), 361 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 362 val, val2); 363 if (ret < 0) 364 return ret; 365 366 return len; 367 } 368 369 static ssize_t iio_ev_label_show(struct device *dev, 370 struct device_attribute *attr, 371 char *buf) 372 { 373 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 374 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 375 376 if (indio_dev->info->read_event_label) 377 return indio_dev->info->read_event_label(indio_dev, 378 this_attr->c, iio_ev_attr_type(this_attr), 379 iio_ev_attr_dir(this_attr), buf); 380 381 return -EINVAL; 382 } 383 384 static int iio_device_add_event(struct iio_dev *indio_dev, 385 const struct iio_chan_spec *chan, unsigned int spec_index, 386 enum iio_event_type type, enum iio_event_direction dir, 387 enum iio_shared_by shared_by, const unsigned long *mask) 388 { 389 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 390 ssize_t (*show)(struct device *dev, struct device_attribute *attr, 391 char *buf); 392 ssize_t (*store)(struct device *dev, struct device_attribute *attr, 393 const char *buf, size_t len); 394 unsigned int attrcount = 0; 395 unsigned int i; 396 char *postfix; 397 int ret; 398 399 for_each_set_bit(i, mask, sizeof(*mask)*8) { 400 if (i >= ARRAY_SIZE(iio_ev_info_text)) 401 return -EINVAL; 402 if (dir != IIO_EV_DIR_NONE) 403 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 404 iio_ev_type_text[type], 405 iio_ev_dir_text[dir], 406 iio_ev_info_text[i]); 407 else 408 postfix = kasprintf(GFP_KERNEL, "%s_%s", 409 iio_ev_type_text[type], 410 iio_ev_info_text[i]); 411 if (postfix == NULL) 412 return -ENOMEM; 413 414 if (i == IIO_EV_INFO_ENABLE) { 415 show = iio_ev_state_show; 416 store = iio_ev_state_store; 417 } else { 418 show = iio_ev_value_show; 419 store = iio_ev_value_store; 420 } 421 422 ret = __iio_add_chan_devattr(postfix, chan, show, store, 423 (i << 16) | spec_index, shared_by, &indio_dev->dev, 424 NULL, 425 &iio_dev_opaque->event_interface->dev_attr_list); 426 kfree(postfix); 427 428 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 429 continue; 430 431 if (ret) 432 return ret; 433 434 attrcount++; 435 } 436 437 return attrcount; 438 } 439 440 static int iio_device_add_event_label(struct iio_dev *indio_dev, 441 const struct iio_chan_spec *chan, 442 unsigned int spec_index, 443 enum iio_event_type type, 444 enum iio_event_direction dir) 445 { 446 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 447 char *postfix; 448 int ret; 449 450 if (!indio_dev->info->read_event_label) 451 return 0; 452 453 if (dir != IIO_EV_DIR_NONE) 454 postfix = kasprintf(GFP_KERNEL, "%s_%s_label", 455 iio_ev_type_text[type], 456 iio_ev_dir_text[dir]); 457 else 458 postfix = kasprintf(GFP_KERNEL, "%s_label", 459 iio_ev_type_text[type]); 460 if (postfix == NULL) 461 return -ENOMEM; 462 463 ret = __iio_add_chan_devattr(postfix, chan, &iio_ev_label_show, NULL, 464 spec_index, IIO_SEPARATE, &indio_dev->dev, NULL, 465 &iio_dev_opaque->event_interface->dev_attr_list); 466 467 kfree(postfix); 468 469 if (ret < 0) 470 return ret; 471 472 return 1; 473 } 474 475 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 476 struct iio_chan_spec const *chan) 477 { 478 int ret = 0, i, attrcount = 0; 479 enum iio_event_direction dir; 480 enum iio_event_type type; 481 482 for (i = 0; i < chan->num_event_specs; i++) { 483 type = chan->event_spec[i].type; 484 dir = chan->event_spec[i].dir; 485 486 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 487 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 488 if (ret < 0) 489 return ret; 490 attrcount += ret; 491 492 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 493 IIO_SHARED_BY_TYPE, 494 &chan->event_spec[i].mask_shared_by_type); 495 if (ret < 0) 496 return ret; 497 attrcount += ret; 498 499 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 500 IIO_SHARED_BY_DIR, 501 &chan->event_spec[i].mask_shared_by_dir); 502 if (ret < 0) 503 return ret; 504 attrcount += ret; 505 506 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 507 IIO_SHARED_BY_ALL, 508 &chan->event_spec[i].mask_shared_by_all); 509 if (ret < 0) 510 return ret; 511 attrcount += ret; 512 513 ret = iio_device_add_event_label(indio_dev, chan, i, type, dir); 514 if (ret < 0) 515 return ret; 516 attrcount += ret; 517 } 518 ret = attrcount; 519 return ret; 520 } 521 522 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 523 { 524 int j, ret, attrcount = 0; 525 526 /* Dynamically created from the channels array */ 527 for (j = 0; j < indio_dev->num_channels; j++) { 528 ret = iio_device_add_event_sysfs(indio_dev, 529 &indio_dev->channels[j]); 530 if (ret < 0) 531 return ret; 532 attrcount += ret; 533 } 534 return attrcount; 535 } 536 537 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 538 { 539 int j; 540 541 for (j = 0; j < indio_dev->num_channels; j++) { 542 if (indio_dev->channels[j].num_event_specs != 0) 543 return true; 544 } 545 return false; 546 } 547 548 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 549 { 550 INIT_KFIFO(ev_int->det_events); 551 init_waitqueue_head(&ev_int->wait); 552 mutex_init(&ev_int->read_lock); 553 } 554 555 static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp, 556 unsigned int cmd, unsigned long arg) 557 { 558 int __user *ip = (int __user *)arg; 559 int fd; 560 561 if (cmd == IIO_GET_EVENT_FD_IOCTL) { 562 fd = iio_event_getfd(indio_dev); 563 if (fd < 0) 564 return fd; 565 if (copy_to_user(ip, &fd, sizeof(fd))) 566 return -EFAULT; 567 return 0; 568 } 569 570 return IIO_IOCTL_UNHANDLED; 571 } 572 573 static const char *iio_event_group_name = "events"; 574 int iio_device_register_eventset(struct iio_dev *indio_dev) 575 { 576 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 577 struct iio_event_interface *ev_int; 578 struct iio_dev_attr *p; 579 int ret = 0, attrcount_orig = 0, attrcount, attrn; 580 struct attribute **attr; 581 582 if (!(indio_dev->info->event_attrs || 583 iio_check_for_dynamic_events(indio_dev))) 584 return 0; 585 586 ev_int = kzalloc(sizeof(*ev_int), GFP_KERNEL); 587 if (!ev_int) 588 return -ENOMEM; 589 590 iio_dev_opaque->event_interface = ev_int; 591 592 INIT_LIST_HEAD(&ev_int->dev_attr_list); 593 594 iio_setup_ev_int(ev_int); 595 if (indio_dev->info->event_attrs != NULL) { 596 attr = indio_dev->info->event_attrs->attrs; 597 while (*attr++ != NULL) 598 attrcount_orig++; 599 } 600 attrcount = attrcount_orig; 601 if (indio_dev->channels) { 602 ret = __iio_add_event_config_attrs(indio_dev); 603 if (ret < 0) 604 goto error_free_setup_event_lines; 605 attrcount += ret; 606 } 607 608 ev_int->group.name = iio_event_group_name; 609 ev_int->group.attrs = kcalloc(attrcount + 1, 610 sizeof(ev_int->group.attrs[0]), 611 GFP_KERNEL); 612 if (ev_int->group.attrs == NULL) { 613 ret = -ENOMEM; 614 goto error_free_setup_event_lines; 615 } 616 if (indio_dev->info->event_attrs) 617 memcpy(ev_int->group.attrs, 618 indio_dev->info->event_attrs->attrs, 619 sizeof(ev_int->group.attrs[0]) * attrcount_orig); 620 attrn = attrcount_orig; 621 /* Add all elements from the list. */ 622 list_for_each_entry(p, &ev_int->dev_attr_list, l) 623 ev_int->group.attrs[attrn++] = &p->dev_attr.attr; 624 625 ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group); 626 if (ret) 627 goto error_free_group_attrs; 628 629 ev_int->ioctl_handler.ioctl = iio_event_ioctl; 630 iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev, 631 &ev_int->ioctl_handler); 632 633 return 0; 634 635 error_free_group_attrs: 636 kfree(ev_int->group.attrs); 637 error_free_setup_event_lines: 638 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 639 kfree(ev_int); 640 iio_dev_opaque->event_interface = NULL; 641 return ret; 642 } 643 644 /** 645 * iio_device_wakeup_eventset - Wakes up the event waitqueue 646 * @indio_dev: The IIO device 647 * 648 * Wakes up the event waitqueue used for poll() and blocking read(). 649 * Should usually be called when the device is unregistered. 650 */ 651 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 652 { 653 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 654 655 if (iio_dev_opaque->event_interface == NULL) 656 return; 657 wake_up(&iio_dev_opaque->event_interface->wait); 658 } 659 660 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 661 { 662 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 663 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 664 665 if (ev_int == NULL) 666 return; 667 668 iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler); 669 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 670 kfree(ev_int->group.attrs); 671 kfree(ev_int); 672 iio_dev_opaque->event_interface = NULL; 673 } 674