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(&indio_dev->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(&indio_dev->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 }; 234 235 static const char * const iio_ev_dir_text[] = { 236 [IIO_EV_DIR_EITHER] = "either", 237 [IIO_EV_DIR_RISING] = "rising", 238 [IIO_EV_DIR_FALLING] = "falling" 239 }; 240 241 static const char * const iio_ev_info_text[] = { 242 [IIO_EV_INFO_ENABLE] = "en", 243 [IIO_EV_INFO_VALUE] = "value", 244 [IIO_EV_INFO_HYSTERESIS] = "hysteresis", 245 [IIO_EV_INFO_PERIOD] = "period", 246 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db", 247 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db", 248 [IIO_EV_INFO_TIMEOUT] = "timeout", 249 }; 250 251 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 252 { 253 return attr->c->event_spec[attr->address & 0xffff].dir; 254 } 255 256 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 257 { 258 return attr->c->event_spec[attr->address & 0xffff].type; 259 } 260 261 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 262 { 263 return (attr->address >> 16) & 0xffff; 264 } 265 266 static ssize_t iio_ev_state_store(struct device *dev, 267 struct device_attribute *attr, 268 const char *buf, 269 size_t len) 270 { 271 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 272 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 273 int ret; 274 bool val; 275 276 ret = strtobool(buf, &val); 277 if (ret < 0) 278 return ret; 279 280 ret = indio_dev->info->write_event_config(indio_dev, 281 this_attr->c, iio_ev_attr_type(this_attr), 282 iio_ev_attr_dir(this_attr), val); 283 284 return (ret < 0) ? ret : len; 285 } 286 287 static ssize_t iio_ev_state_show(struct device *dev, 288 struct device_attribute *attr, 289 char *buf) 290 { 291 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 292 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 293 int val; 294 295 val = indio_dev->info->read_event_config(indio_dev, 296 this_attr->c, iio_ev_attr_type(this_attr), 297 iio_ev_attr_dir(this_attr)); 298 if (val < 0) 299 return val; 300 else 301 return sysfs_emit(buf, "%d\n", val); 302 } 303 304 static ssize_t iio_ev_value_show(struct device *dev, 305 struct device_attribute *attr, 306 char *buf) 307 { 308 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 309 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 310 int val, val2, val_arr[2]; 311 int ret; 312 313 ret = indio_dev->info->read_event_value(indio_dev, 314 this_attr->c, iio_ev_attr_type(this_attr), 315 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 316 &val, &val2); 317 if (ret < 0) 318 return ret; 319 val_arr[0] = val; 320 val_arr[1] = val2; 321 return iio_format_value(buf, ret, 2, val_arr); 322 } 323 324 static ssize_t iio_ev_value_store(struct device *dev, 325 struct device_attribute *attr, 326 const char *buf, 327 size_t len) 328 { 329 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 330 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 331 int val, val2; 332 int ret; 333 334 if (!indio_dev->info->write_event_value) 335 return -EINVAL; 336 337 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 338 if (ret) 339 return ret; 340 ret = indio_dev->info->write_event_value(indio_dev, 341 this_attr->c, iio_ev_attr_type(this_attr), 342 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 343 val, val2); 344 if (ret < 0) 345 return ret; 346 347 return len; 348 } 349 350 static int iio_device_add_event(struct iio_dev *indio_dev, 351 const struct iio_chan_spec *chan, unsigned int spec_index, 352 enum iio_event_type type, enum iio_event_direction dir, 353 enum iio_shared_by shared_by, const unsigned long *mask) 354 { 355 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 356 ssize_t (*show)(struct device *, struct device_attribute *, char *); 357 ssize_t (*store)(struct device *, struct device_attribute *, 358 const char *, size_t); 359 unsigned int attrcount = 0; 360 unsigned int i; 361 char *postfix; 362 int ret; 363 364 for_each_set_bit(i, mask, sizeof(*mask)*8) { 365 if (i >= ARRAY_SIZE(iio_ev_info_text)) 366 return -EINVAL; 367 if (dir != IIO_EV_DIR_NONE) 368 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 369 iio_ev_type_text[type], 370 iio_ev_dir_text[dir], 371 iio_ev_info_text[i]); 372 else 373 postfix = kasprintf(GFP_KERNEL, "%s_%s", 374 iio_ev_type_text[type], 375 iio_ev_info_text[i]); 376 if (postfix == NULL) 377 return -ENOMEM; 378 379 if (i == IIO_EV_INFO_ENABLE) { 380 show = iio_ev_state_show; 381 store = iio_ev_state_store; 382 } else { 383 show = iio_ev_value_show; 384 store = iio_ev_value_store; 385 } 386 387 ret = __iio_add_chan_devattr(postfix, chan, show, store, 388 (i << 16) | spec_index, shared_by, &indio_dev->dev, 389 NULL, 390 &iio_dev_opaque->event_interface->dev_attr_list); 391 kfree(postfix); 392 393 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 394 continue; 395 396 if (ret) 397 return ret; 398 399 attrcount++; 400 } 401 402 return attrcount; 403 } 404 405 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 406 struct iio_chan_spec const *chan) 407 { 408 int ret = 0, i, attrcount = 0; 409 enum iio_event_direction dir; 410 enum iio_event_type type; 411 412 for (i = 0; i < chan->num_event_specs; i++) { 413 type = chan->event_spec[i].type; 414 dir = chan->event_spec[i].dir; 415 416 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 417 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 418 if (ret < 0) 419 return ret; 420 attrcount += ret; 421 422 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 423 IIO_SHARED_BY_TYPE, 424 &chan->event_spec[i].mask_shared_by_type); 425 if (ret < 0) 426 return ret; 427 attrcount += ret; 428 429 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 430 IIO_SHARED_BY_DIR, 431 &chan->event_spec[i].mask_shared_by_dir); 432 if (ret < 0) 433 return ret; 434 attrcount += ret; 435 436 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 437 IIO_SHARED_BY_ALL, 438 &chan->event_spec[i].mask_shared_by_all); 439 if (ret < 0) 440 return ret; 441 attrcount += ret; 442 } 443 ret = attrcount; 444 return ret; 445 } 446 447 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 448 { 449 int j, ret, attrcount = 0; 450 451 /* Dynamically created from the channels array */ 452 for (j = 0; j < indio_dev->num_channels; j++) { 453 ret = iio_device_add_event_sysfs(indio_dev, 454 &indio_dev->channels[j]); 455 if (ret < 0) 456 return ret; 457 attrcount += ret; 458 } 459 return attrcount; 460 } 461 462 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 463 { 464 int j; 465 466 for (j = 0; j < indio_dev->num_channels; j++) { 467 if (indio_dev->channels[j].num_event_specs != 0) 468 return true; 469 } 470 return false; 471 } 472 473 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 474 { 475 INIT_KFIFO(ev_int->det_events); 476 init_waitqueue_head(&ev_int->wait); 477 mutex_init(&ev_int->read_lock); 478 } 479 480 static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp, 481 unsigned int cmd, unsigned long arg) 482 { 483 int __user *ip = (int __user *)arg; 484 int fd; 485 486 if (cmd == IIO_GET_EVENT_FD_IOCTL) { 487 fd = iio_event_getfd(indio_dev); 488 if (fd < 0) 489 return fd; 490 if (copy_to_user(ip, &fd, sizeof(fd))) 491 return -EFAULT; 492 return 0; 493 } 494 495 return IIO_IOCTL_UNHANDLED; 496 } 497 498 static const char *iio_event_group_name = "events"; 499 int iio_device_register_eventset(struct iio_dev *indio_dev) 500 { 501 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 502 struct iio_event_interface *ev_int; 503 struct iio_dev_attr *p; 504 int ret = 0, attrcount_orig = 0, attrcount, attrn; 505 struct attribute **attr; 506 507 if (!(indio_dev->info->event_attrs || 508 iio_check_for_dynamic_events(indio_dev))) 509 return 0; 510 511 ev_int = kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 512 if (ev_int == NULL) 513 return -ENOMEM; 514 515 iio_dev_opaque->event_interface = ev_int; 516 517 INIT_LIST_HEAD(&ev_int->dev_attr_list); 518 519 iio_setup_ev_int(ev_int); 520 if (indio_dev->info->event_attrs != NULL) { 521 attr = indio_dev->info->event_attrs->attrs; 522 while (*attr++ != NULL) 523 attrcount_orig++; 524 } 525 attrcount = attrcount_orig; 526 if (indio_dev->channels) { 527 ret = __iio_add_event_config_attrs(indio_dev); 528 if (ret < 0) 529 goto error_free_setup_event_lines; 530 attrcount += ret; 531 } 532 533 ev_int->group.name = iio_event_group_name; 534 ev_int->group.attrs = kcalloc(attrcount + 1, 535 sizeof(ev_int->group.attrs[0]), 536 GFP_KERNEL); 537 if (ev_int->group.attrs == NULL) { 538 ret = -ENOMEM; 539 goto error_free_setup_event_lines; 540 } 541 if (indio_dev->info->event_attrs) 542 memcpy(ev_int->group.attrs, 543 indio_dev->info->event_attrs->attrs, 544 sizeof(ev_int->group.attrs[0]) * attrcount_orig); 545 attrn = attrcount_orig; 546 /* Add all elements from the list. */ 547 list_for_each_entry(p, &ev_int->dev_attr_list, l) 548 ev_int->group.attrs[attrn++] = &p->dev_attr.attr; 549 550 ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group); 551 if (ret) 552 goto error_free_setup_event_lines; 553 554 ev_int->ioctl_handler.ioctl = iio_event_ioctl; 555 iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev, 556 &ev_int->ioctl_handler); 557 558 return 0; 559 560 error_free_setup_event_lines: 561 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 562 kfree(ev_int); 563 iio_dev_opaque->event_interface = NULL; 564 return ret; 565 } 566 567 /** 568 * iio_device_wakeup_eventset - Wakes up the event waitqueue 569 * @indio_dev: The IIO device 570 * 571 * Wakes up the event waitqueue used for poll() and blocking read(). 572 * Should usually be called when the device is unregistered. 573 */ 574 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 575 { 576 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 577 578 if (iio_dev_opaque->event_interface == NULL) 579 return; 580 wake_up(&iio_dev_opaque->event_interface->wait); 581 } 582 583 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 584 { 585 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 586 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 587 588 if (ev_int == NULL) 589 return; 590 591 iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler); 592 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 593 kfree(ev_int->group.attrs); 594 kfree(ev_int); 595 iio_dev_opaque->event_interface = NULL; 596 } 597