1 /* Industrial I/O event handling 2 * 3 * Copyright (c) 2008 Jonathan Cameron 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 as published by 7 * the Free Software Foundation. 8 * 9 * Based on elements of hwmon and input subsystems. 10 */ 11 12 #include <linux/anon_inodes.h> 13 #include <linux/device.h> 14 #include <linux/fs.h> 15 #include <linux/kernel.h> 16 #include <linux/kfifo.h> 17 #include <linux/module.h> 18 #include <linux/poll.h> 19 #include <linux/sched.h> 20 #include <linux/slab.h> 21 #include <linux/uaccess.h> 22 #include <linux/wait.h> 23 #include <linux/iio/iio.h> 24 #include "iio_core.h" 25 #include <linux/iio/sysfs.h> 26 #include <linux/iio/events.h> 27 28 /** 29 * struct iio_event_interface - chrdev interface for an event line 30 * @wait: wait queue to allow blocking reads of events 31 * @det_events: list of detected events 32 * @dev_attr_list: list of event interface sysfs attribute 33 * @flags: file operations related flags including busy flag. 34 * @group: event interface sysfs attribute group 35 * @read_lock: lock to protect kfifo read operations 36 */ 37 struct iio_event_interface { 38 wait_queue_head_t wait; 39 DECLARE_KFIFO(det_events, struct iio_event_data, 16); 40 41 struct list_head dev_attr_list; 42 unsigned long flags; 43 struct attribute_group group; 44 struct mutex read_lock; 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_event_interface *ev_int = indio_dev->event_interface; 69 struct iio_event_data ev; 70 int copied; 71 72 if (!ev_int) 73 return 0; 74 75 /* Does anyone care? */ 76 if (iio_event_enabled(ev_int)) { 77 78 ev.id = ev_code; 79 ev.timestamp = timestamp; 80 81 copied = kfifo_put(&ev_int->det_events, ev); 82 if (copied != 0) 83 wake_up_poll(&ev_int->wait, POLLIN); 84 } 85 86 return 0; 87 } 88 EXPORT_SYMBOL(iio_push_event); 89 90 /** 91 * iio_event_poll() - poll the event queue to find out if it has data 92 * @filep: File structure pointer to identify the device 93 * @wait: Poll table pointer to add the wait queue on 94 * 95 * Return: (POLLIN | POLLRDNORM) if data is available for reading 96 * or a negative error code on failure 97 */ 98 static __poll_t iio_event_poll(struct file *filep, 99 struct poll_table_struct *wait) 100 { 101 struct iio_dev *indio_dev = filep->private_data; 102 struct iio_event_interface *ev_int = indio_dev->event_interface; 103 __poll_t events = 0; 104 105 if (!indio_dev->info) 106 return events; 107 108 poll_wait(filep, &ev_int->wait, wait); 109 110 if (!kfifo_is_empty(&ev_int->det_events)) 111 events = POLLIN | POLLRDNORM; 112 113 return events; 114 } 115 116 static ssize_t iio_event_chrdev_read(struct file *filep, 117 char __user *buf, 118 size_t count, 119 loff_t *f_ps) 120 { 121 struct iio_dev *indio_dev = filep->private_data; 122 struct iio_event_interface *ev_int = indio_dev->event_interface; 123 unsigned int copied; 124 int ret; 125 126 if (!indio_dev->info) 127 return -ENODEV; 128 129 if (count < sizeof(struct iio_event_data)) 130 return -EINVAL; 131 132 do { 133 if (kfifo_is_empty(&ev_int->det_events)) { 134 if (filep->f_flags & O_NONBLOCK) 135 return -EAGAIN; 136 137 ret = wait_event_interruptible(ev_int->wait, 138 !kfifo_is_empty(&ev_int->det_events) || 139 indio_dev->info == NULL); 140 if (ret) 141 return ret; 142 if (indio_dev->info == NULL) 143 return -ENODEV; 144 } 145 146 if (mutex_lock_interruptible(&ev_int->read_lock)) 147 return -ERESTARTSYS; 148 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied); 149 mutex_unlock(&ev_int->read_lock); 150 151 if (ret) 152 return ret; 153 154 /* 155 * If we couldn't read anything from the fifo (a different 156 * thread might have been faster) we either return -EAGAIN if 157 * the file descriptor is non-blocking, otherwise we go back to 158 * sleep and wait for more data to arrive. 159 */ 160 if (copied == 0 && (filep->f_flags & O_NONBLOCK)) 161 return -EAGAIN; 162 163 } while (copied == 0); 164 165 return copied; 166 } 167 168 static int iio_event_chrdev_release(struct inode *inode, struct file *filep) 169 { 170 struct iio_dev *indio_dev = filep->private_data; 171 struct iio_event_interface *ev_int = indio_dev->event_interface; 172 173 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 174 175 iio_device_put(indio_dev); 176 177 return 0; 178 } 179 180 static const struct file_operations iio_event_chrdev_fileops = { 181 .read = iio_event_chrdev_read, 182 .poll = iio_event_poll, 183 .release = iio_event_chrdev_release, 184 .owner = THIS_MODULE, 185 .llseek = noop_llseek, 186 }; 187 188 int iio_event_getfd(struct iio_dev *indio_dev) 189 { 190 struct iio_event_interface *ev_int = indio_dev->event_interface; 191 int fd; 192 193 if (ev_int == NULL) 194 return -ENODEV; 195 196 fd = mutex_lock_interruptible(&indio_dev->mlock); 197 if (fd) 198 return fd; 199 200 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { 201 fd = -EBUSY; 202 goto unlock; 203 } 204 205 iio_device_get(indio_dev); 206 207 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, 208 indio_dev, O_RDONLY | O_CLOEXEC); 209 if (fd < 0) { 210 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 211 iio_device_put(indio_dev); 212 } else { 213 kfifo_reset_out(&ev_int->det_events); 214 } 215 216 unlock: 217 mutex_unlock(&indio_dev->mlock); 218 return fd; 219 } 220 221 static const char * const iio_ev_type_text[] = { 222 [IIO_EV_TYPE_THRESH] = "thresh", 223 [IIO_EV_TYPE_MAG] = "mag", 224 [IIO_EV_TYPE_ROC] = "roc", 225 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive", 226 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive", 227 [IIO_EV_TYPE_CHANGE] = "change", 228 }; 229 230 static const char * const iio_ev_dir_text[] = { 231 [IIO_EV_DIR_EITHER] = "either", 232 [IIO_EV_DIR_RISING] = "rising", 233 [IIO_EV_DIR_FALLING] = "falling" 234 }; 235 236 static const char * const iio_ev_info_text[] = { 237 [IIO_EV_INFO_ENABLE] = "en", 238 [IIO_EV_INFO_VALUE] = "value", 239 [IIO_EV_INFO_HYSTERESIS] = "hysteresis", 240 [IIO_EV_INFO_PERIOD] = "period", 241 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db", 242 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db", 243 }; 244 245 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 246 { 247 return attr->c->event_spec[attr->address & 0xffff].dir; 248 } 249 250 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 251 { 252 return attr->c->event_spec[attr->address & 0xffff].type; 253 } 254 255 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 256 { 257 return (attr->address >> 16) & 0xffff; 258 } 259 260 static ssize_t iio_ev_state_store(struct device *dev, 261 struct device_attribute *attr, 262 const char *buf, 263 size_t len) 264 { 265 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 266 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 267 int ret; 268 bool val; 269 270 ret = strtobool(buf, &val); 271 if (ret < 0) 272 return ret; 273 274 ret = indio_dev->info->write_event_config(indio_dev, 275 this_attr->c, iio_ev_attr_type(this_attr), 276 iio_ev_attr_dir(this_attr), val); 277 278 return (ret < 0) ? ret : len; 279 } 280 281 static ssize_t iio_ev_state_show(struct device *dev, 282 struct device_attribute *attr, 283 char *buf) 284 { 285 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 286 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 287 int val; 288 289 val = indio_dev->info->read_event_config(indio_dev, 290 this_attr->c, iio_ev_attr_type(this_attr), 291 iio_ev_attr_dir(this_attr)); 292 if (val < 0) 293 return val; 294 else 295 return sprintf(buf, "%d\n", val); 296 } 297 298 static ssize_t iio_ev_value_show(struct device *dev, 299 struct device_attribute *attr, 300 char *buf) 301 { 302 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 303 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 304 int val, val2, val_arr[2]; 305 int ret; 306 307 ret = indio_dev->info->read_event_value(indio_dev, 308 this_attr->c, iio_ev_attr_type(this_attr), 309 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 310 &val, &val2); 311 if (ret < 0) 312 return ret; 313 val_arr[0] = val; 314 val_arr[1] = val2; 315 return iio_format_value(buf, ret, 2, val_arr); 316 } 317 318 static ssize_t iio_ev_value_store(struct device *dev, 319 struct device_attribute *attr, 320 const char *buf, 321 size_t len) 322 { 323 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 324 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 325 int val, val2; 326 int ret; 327 328 if (!indio_dev->info->write_event_value) 329 return -EINVAL; 330 331 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 332 if (ret) 333 return ret; 334 ret = indio_dev->info->write_event_value(indio_dev, 335 this_attr->c, iio_ev_attr_type(this_attr), 336 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 337 val, val2); 338 if (ret < 0) 339 return ret; 340 341 return len; 342 } 343 344 static int iio_device_add_event(struct iio_dev *indio_dev, 345 const struct iio_chan_spec *chan, unsigned int spec_index, 346 enum iio_event_type type, enum iio_event_direction dir, 347 enum iio_shared_by shared_by, const unsigned long *mask) 348 { 349 ssize_t (*show)(struct device *, struct device_attribute *, char *); 350 ssize_t (*store)(struct device *, struct device_attribute *, 351 const char *, size_t); 352 unsigned int attrcount = 0; 353 unsigned int i; 354 char *postfix; 355 int ret; 356 357 for_each_set_bit(i, mask, sizeof(*mask)*8) { 358 if (i >= ARRAY_SIZE(iio_ev_info_text)) 359 return -EINVAL; 360 if (dir != IIO_EV_DIR_NONE) 361 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 362 iio_ev_type_text[type], 363 iio_ev_dir_text[dir], 364 iio_ev_info_text[i]); 365 else 366 postfix = kasprintf(GFP_KERNEL, "%s_%s", 367 iio_ev_type_text[type], 368 iio_ev_info_text[i]); 369 if (postfix == NULL) 370 return -ENOMEM; 371 372 if (i == IIO_EV_INFO_ENABLE) { 373 show = iio_ev_state_show; 374 store = iio_ev_state_store; 375 } else { 376 show = iio_ev_value_show; 377 store = iio_ev_value_store; 378 } 379 380 ret = __iio_add_chan_devattr(postfix, chan, show, store, 381 (i << 16) | spec_index, shared_by, &indio_dev->dev, 382 &indio_dev->event_interface->dev_attr_list); 383 kfree(postfix); 384 385 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 386 continue; 387 388 if (ret) 389 return ret; 390 391 attrcount++; 392 } 393 394 return attrcount; 395 } 396 397 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 398 struct iio_chan_spec const *chan) 399 { 400 int ret = 0, i, attrcount = 0; 401 enum iio_event_direction dir; 402 enum iio_event_type type; 403 404 for (i = 0; i < chan->num_event_specs; i++) { 405 type = chan->event_spec[i].type; 406 dir = chan->event_spec[i].dir; 407 408 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 409 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 410 if (ret < 0) 411 return ret; 412 attrcount += ret; 413 414 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 415 IIO_SHARED_BY_TYPE, 416 &chan->event_spec[i].mask_shared_by_type); 417 if (ret < 0) 418 return ret; 419 attrcount += ret; 420 421 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 422 IIO_SHARED_BY_DIR, 423 &chan->event_spec[i].mask_shared_by_dir); 424 if (ret < 0) 425 return ret; 426 attrcount += ret; 427 428 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 429 IIO_SHARED_BY_ALL, 430 &chan->event_spec[i].mask_shared_by_all); 431 if (ret < 0) 432 return ret; 433 attrcount += ret; 434 } 435 ret = attrcount; 436 return ret; 437 } 438 439 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 440 { 441 int j, ret, attrcount = 0; 442 443 /* Dynamically created from the channels array */ 444 for (j = 0; j < indio_dev->num_channels; j++) { 445 ret = iio_device_add_event_sysfs(indio_dev, 446 &indio_dev->channels[j]); 447 if (ret < 0) 448 return ret; 449 attrcount += ret; 450 } 451 return attrcount; 452 } 453 454 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 455 { 456 int j; 457 458 for (j = 0; j < indio_dev->num_channels; j++) { 459 if (indio_dev->channels[j].num_event_specs != 0) 460 return true; 461 } 462 return false; 463 } 464 465 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 466 { 467 INIT_KFIFO(ev_int->det_events); 468 init_waitqueue_head(&ev_int->wait); 469 mutex_init(&ev_int->read_lock); 470 } 471 472 static const char *iio_event_group_name = "events"; 473 int iio_device_register_eventset(struct iio_dev *indio_dev) 474 { 475 struct iio_dev_attr *p; 476 int ret = 0, attrcount_orig = 0, attrcount, attrn; 477 struct attribute **attr; 478 479 if (!(indio_dev->info->event_attrs || 480 iio_check_for_dynamic_events(indio_dev))) 481 return 0; 482 483 indio_dev->event_interface = 484 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 485 if (indio_dev->event_interface == NULL) 486 return -ENOMEM; 487 488 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list); 489 490 iio_setup_ev_int(indio_dev->event_interface); 491 if (indio_dev->info->event_attrs != NULL) { 492 attr = indio_dev->info->event_attrs->attrs; 493 while (*attr++ != NULL) 494 attrcount_orig++; 495 } 496 attrcount = attrcount_orig; 497 if (indio_dev->channels) { 498 ret = __iio_add_event_config_attrs(indio_dev); 499 if (ret < 0) 500 goto error_free_setup_event_lines; 501 attrcount += ret; 502 } 503 504 indio_dev->event_interface->group.name = iio_event_group_name; 505 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1, 506 sizeof(indio_dev->event_interface->group.attrs[0]), 507 GFP_KERNEL); 508 if (indio_dev->event_interface->group.attrs == NULL) { 509 ret = -ENOMEM; 510 goto error_free_setup_event_lines; 511 } 512 if (indio_dev->info->event_attrs) 513 memcpy(indio_dev->event_interface->group.attrs, 514 indio_dev->info->event_attrs->attrs, 515 sizeof(indio_dev->event_interface->group.attrs[0]) 516 *attrcount_orig); 517 attrn = attrcount_orig; 518 /* Add all elements from the list. */ 519 list_for_each_entry(p, 520 &indio_dev->event_interface->dev_attr_list, 521 l) 522 indio_dev->event_interface->group.attrs[attrn++] = 523 &p->dev_attr.attr; 524 indio_dev->groups[indio_dev->groupcounter++] = 525 &indio_dev->event_interface->group; 526 527 return 0; 528 529 error_free_setup_event_lines: 530 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 531 kfree(indio_dev->event_interface); 532 indio_dev->event_interface = NULL; 533 return ret; 534 } 535 536 /** 537 * iio_device_wakeup_eventset - Wakes up the event waitqueue 538 * @indio_dev: The IIO device 539 * 540 * Wakes up the event waitqueue used for poll() and blocking read(). 541 * Should usually be called when the device is unregistered. 542 */ 543 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 544 { 545 if (indio_dev->event_interface == NULL) 546 return; 547 wake_up(&indio_dev->event_interface->wait); 548 } 549 550 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 551 { 552 if (indio_dev->event_interface == NULL) 553 return; 554 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 555 kfree(indio_dev->event_interface->group.attrs); 556 kfree(indio_dev->event_interface); 557 } 558