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 /** 48 * iio_push_event() - try to add event to the list for userspace reading 49 * @indio_dev: IIO device structure 50 * @ev_code: What event 51 * @timestamp: When the event occurred 52 * 53 * Note: The caller must make sure that this function is not running 54 * concurrently for the same indio_dev more than once. 55 **/ 56 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp) 57 { 58 struct iio_event_interface *ev_int = indio_dev->event_interface; 59 struct iio_event_data ev; 60 int copied; 61 62 /* Does anyone care? */ 63 if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { 64 65 ev.id = ev_code; 66 ev.timestamp = timestamp; 67 68 copied = kfifo_put(&ev_int->det_events, ev); 69 if (copied != 0) 70 wake_up_poll(&ev_int->wait, POLLIN); 71 } 72 73 return 0; 74 } 75 EXPORT_SYMBOL(iio_push_event); 76 77 /** 78 * iio_event_poll() - poll the event queue to find out if it has data 79 * @filep: File structure pointer to identify the device 80 * @wait: Poll table pointer to add the wait queue on 81 * 82 * Return: (POLLIN | POLLRDNORM) if data is available for reading 83 * or a negative error code on failure 84 */ 85 static unsigned int iio_event_poll(struct file *filep, 86 struct poll_table_struct *wait) 87 { 88 struct iio_dev *indio_dev = filep->private_data; 89 struct iio_event_interface *ev_int = indio_dev->event_interface; 90 unsigned int events = 0; 91 92 if (!indio_dev->info) 93 return events; 94 95 poll_wait(filep, &ev_int->wait, wait); 96 97 if (!kfifo_is_empty(&ev_int->det_events)) 98 events = POLLIN | POLLRDNORM; 99 100 return events; 101 } 102 103 static ssize_t iio_event_chrdev_read(struct file *filep, 104 char __user *buf, 105 size_t count, 106 loff_t *f_ps) 107 { 108 struct iio_dev *indio_dev = filep->private_data; 109 struct iio_event_interface *ev_int = indio_dev->event_interface; 110 unsigned int copied; 111 int ret; 112 113 if (!indio_dev->info) 114 return -ENODEV; 115 116 if (count < sizeof(struct iio_event_data)) 117 return -EINVAL; 118 119 do { 120 if (kfifo_is_empty(&ev_int->det_events)) { 121 if (filep->f_flags & O_NONBLOCK) 122 return -EAGAIN; 123 124 ret = wait_event_interruptible(ev_int->wait, 125 !kfifo_is_empty(&ev_int->det_events) || 126 indio_dev->info == NULL); 127 if (ret) 128 return ret; 129 if (indio_dev->info == NULL) 130 return -ENODEV; 131 } 132 133 if (mutex_lock_interruptible(&ev_int->read_lock)) 134 return -ERESTARTSYS; 135 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied); 136 mutex_unlock(&ev_int->read_lock); 137 138 if (ret) 139 return ret; 140 141 /* 142 * If we couldn't read anything from the fifo (a different 143 * thread might have been faster) we either return -EAGAIN if 144 * the file descriptor is non-blocking, otherwise we go back to 145 * sleep and wait for more data to arrive. 146 */ 147 if (copied == 0 && (filep->f_flags & O_NONBLOCK)) 148 return -EAGAIN; 149 150 } while (copied == 0); 151 152 return copied; 153 } 154 155 static int iio_event_chrdev_release(struct inode *inode, struct file *filep) 156 { 157 struct iio_dev *indio_dev = filep->private_data; 158 struct iio_event_interface *ev_int = indio_dev->event_interface; 159 160 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 161 162 iio_device_put(indio_dev); 163 164 return 0; 165 } 166 167 static const struct file_operations iio_event_chrdev_fileops = { 168 .read = iio_event_chrdev_read, 169 .poll = iio_event_poll, 170 .release = iio_event_chrdev_release, 171 .owner = THIS_MODULE, 172 .llseek = noop_llseek, 173 }; 174 175 int iio_event_getfd(struct iio_dev *indio_dev) 176 { 177 struct iio_event_interface *ev_int = indio_dev->event_interface; 178 int fd; 179 180 if (ev_int == NULL) 181 return -ENODEV; 182 183 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) 184 return -EBUSY; 185 186 iio_device_get(indio_dev); 187 188 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, 189 indio_dev, O_RDONLY | O_CLOEXEC); 190 if (fd < 0) { 191 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 192 iio_device_put(indio_dev); 193 } else { 194 kfifo_reset_out(&ev_int->det_events); 195 } 196 197 return fd; 198 } 199 200 static const char * const iio_ev_type_text[] = { 201 [IIO_EV_TYPE_THRESH] = "thresh", 202 [IIO_EV_TYPE_MAG] = "mag", 203 [IIO_EV_TYPE_ROC] = "roc", 204 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive", 205 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive", 206 [IIO_EV_TYPE_CHANGE] = "change", 207 }; 208 209 static const char * const iio_ev_dir_text[] = { 210 [IIO_EV_DIR_EITHER] = "either", 211 [IIO_EV_DIR_RISING] = "rising", 212 [IIO_EV_DIR_FALLING] = "falling" 213 }; 214 215 static const char * const iio_ev_info_text[] = { 216 [IIO_EV_INFO_ENABLE] = "en", 217 [IIO_EV_INFO_VALUE] = "value", 218 [IIO_EV_INFO_HYSTERESIS] = "hysteresis", 219 [IIO_EV_INFO_PERIOD] = "period", 220 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db", 221 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db", 222 }; 223 224 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 225 { 226 return attr->c->event_spec[attr->address & 0xffff].dir; 227 } 228 229 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 230 { 231 return attr->c->event_spec[attr->address & 0xffff].type; 232 } 233 234 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 235 { 236 return (attr->address >> 16) & 0xffff; 237 } 238 239 static ssize_t iio_ev_state_store(struct device *dev, 240 struct device_attribute *attr, 241 const char *buf, 242 size_t len) 243 { 244 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 245 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 246 int ret; 247 bool val; 248 249 ret = strtobool(buf, &val); 250 if (ret < 0) 251 return ret; 252 253 ret = indio_dev->info->write_event_config(indio_dev, 254 this_attr->c, iio_ev_attr_type(this_attr), 255 iio_ev_attr_dir(this_attr), val); 256 257 return (ret < 0) ? ret : len; 258 } 259 260 static ssize_t iio_ev_state_show(struct device *dev, 261 struct device_attribute *attr, 262 char *buf) 263 { 264 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 265 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 266 int val; 267 268 val = indio_dev->info->read_event_config(indio_dev, 269 this_attr->c, iio_ev_attr_type(this_attr), 270 iio_ev_attr_dir(this_attr)); 271 if (val < 0) 272 return val; 273 else 274 return sprintf(buf, "%d\n", val); 275 } 276 277 static ssize_t iio_ev_value_show(struct device *dev, 278 struct device_attribute *attr, 279 char *buf) 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 val, val2, val_arr[2]; 284 int ret; 285 286 ret = indio_dev->info->read_event_value(indio_dev, 287 this_attr->c, iio_ev_attr_type(this_attr), 288 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 289 &val, &val2); 290 if (ret < 0) 291 return ret; 292 val_arr[0] = val; 293 val_arr[1] = val2; 294 return iio_format_value(buf, ret, 2, val_arr); 295 } 296 297 static ssize_t iio_ev_value_store(struct device *dev, 298 struct device_attribute *attr, 299 const char *buf, 300 size_t len) 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; 305 int ret; 306 307 if (!indio_dev->info->write_event_value) 308 return -EINVAL; 309 310 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 311 if (ret) 312 return ret; 313 ret = indio_dev->info->write_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; 319 320 return len; 321 } 322 323 static int iio_device_add_event(struct iio_dev *indio_dev, 324 const struct iio_chan_spec *chan, unsigned int spec_index, 325 enum iio_event_type type, enum iio_event_direction dir, 326 enum iio_shared_by shared_by, const unsigned long *mask) 327 { 328 ssize_t (*show)(struct device *, struct device_attribute *, char *); 329 ssize_t (*store)(struct device *, struct device_attribute *, 330 const char *, size_t); 331 unsigned int attrcount = 0; 332 unsigned int i; 333 char *postfix; 334 int ret; 335 336 for_each_set_bit(i, mask, sizeof(*mask)*8) { 337 if (i >= ARRAY_SIZE(iio_ev_info_text)) 338 return -EINVAL; 339 if (dir != IIO_EV_DIR_NONE) 340 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 341 iio_ev_type_text[type], 342 iio_ev_dir_text[dir], 343 iio_ev_info_text[i]); 344 else 345 postfix = kasprintf(GFP_KERNEL, "%s_%s", 346 iio_ev_type_text[type], 347 iio_ev_info_text[i]); 348 if (postfix == NULL) 349 return -ENOMEM; 350 351 if (i == IIO_EV_INFO_ENABLE) { 352 show = iio_ev_state_show; 353 store = iio_ev_state_store; 354 } else { 355 show = iio_ev_value_show; 356 store = iio_ev_value_store; 357 } 358 359 ret = __iio_add_chan_devattr(postfix, chan, show, store, 360 (i << 16) | spec_index, shared_by, &indio_dev->dev, 361 &indio_dev->event_interface->dev_attr_list); 362 kfree(postfix); 363 364 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 365 continue; 366 367 if (ret) 368 return ret; 369 370 attrcount++; 371 } 372 373 return attrcount; 374 } 375 376 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 377 struct iio_chan_spec const *chan) 378 { 379 int ret = 0, i, attrcount = 0; 380 enum iio_event_direction dir; 381 enum iio_event_type type; 382 383 for (i = 0; i < chan->num_event_specs; i++) { 384 type = chan->event_spec[i].type; 385 dir = chan->event_spec[i].dir; 386 387 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 388 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 389 if (ret < 0) 390 return ret; 391 attrcount += ret; 392 393 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 394 IIO_SHARED_BY_TYPE, 395 &chan->event_spec[i].mask_shared_by_type); 396 if (ret < 0) 397 return ret; 398 attrcount += ret; 399 400 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 401 IIO_SHARED_BY_DIR, 402 &chan->event_spec[i].mask_shared_by_dir); 403 if (ret < 0) 404 return ret; 405 attrcount += ret; 406 407 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 408 IIO_SHARED_BY_ALL, 409 &chan->event_spec[i].mask_shared_by_all); 410 if (ret < 0) 411 return ret; 412 attrcount += ret; 413 } 414 ret = attrcount; 415 return ret; 416 } 417 418 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 419 { 420 int j, ret, attrcount = 0; 421 422 /* Dynamically created from the channels array */ 423 for (j = 0; j < indio_dev->num_channels; j++) { 424 ret = iio_device_add_event_sysfs(indio_dev, 425 &indio_dev->channels[j]); 426 if (ret < 0) 427 return ret; 428 attrcount += ret; 429 } 430 return attrcount; 431 } 432 433 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 434 { 435 int j; 436 437 for (j = 0; j < indio_dev->num_channels; j++) { 438 if (indio_dev->channels[j].num_event_specs != 0) 439 return true; 440 } 441 return false; 442 } 443 444 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 445 { 446 INIT_KFIFO(ev_int->det_events); 447 init_waitqueue_head(&ev_int->wait); 448 mutex_init(&ev_int->read_lock); 449 } 450 451 static const char *iio_event_group_name = "events"; 452 int iio_device_register_eventset(struct iio_dev *indio_dev) 453 { 454 struct iio_dev_attr *p; 455 int ret = 0, attrcount_orig = 0, attrcount, attrn; 456 struct attribute **attr; 457 458 if (!(indio_dev->info->event_attrs || 459 iio_check_for_dynamic_events(indio_dev))) 460 return 0; 461 462 indio_dev->event_interface = 463 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 464 if (indio_dev->event_interface == NULL) 465 return -ENOMEM; 466 467 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list); 468 469 iio_setup_ev_int(indio_dev->event_interface); 470 if (indio_dev->info->event_attrs != NULL) { 471 attr = indio_dev->info->event_attrs->attrs; 472 while (*attr++ != NULL) 473 attrcount_orig++; 474 } 475 attrcount = attrcount_orig; 476 if (indio_dev->channels) { 477 ret = __iio_add_event_config_attrs(indio_dev); 478 if (ret < 0) 479 goto error_free_setup_event_lines; 480 attrcount += ret; 481 } 482 483 indio_dev->event_interface->group.name = iio_event_group_name; 484 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1, 485 sizeof(indio_dev->event_interface->group.attrs[0]), 486 GFP_KERNEL); 487 if (indio_dev->event_interface->group.attrs == NULL) { 488 ret = -ENOMEM; 489 goto error_free_setup_event_lines; 490 } 491 if (indio_dev->info->event_attrs) 492 memcpy(indio_dev->event_interface->group.attrs, 493 indio_dev->info->event_attrs->attrs, 494 sizeof(indio_dev->event_interface->group.attrs[0]) 495 *attrcount_orig); 496 attrn = attrcount_orig; 497 /* Add all elements from the list. */ 498 list_for_each_entry(p, 499 &indio_dev->event_interface->dev_attr_list, 500 l) 501 indio_dev->event_interface->group.attrs[attrn++] = 502 &p->dev_attr.attr; 503 indio_dev->groups[indio_dev->groupcounter++] = 504 &indio_dev->event_interface->group; 505 506 return 0; 507 508 error_free_setup_event_lines: 509 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 510 kfree(indio_dev->event_interface); 511 indio_dev->event_interface = NULL; 512 return ret; 513 } 514 515 /** 516 * iio_device_wakeup_eventset - Wakes up the event waitqueue 517 * @indio_dev: The IIO device 518 * 519 * Wakes up the event waitqueue used for poll() and blocking read(). 520 * Should usually be called when the device is unregistered. 521 */ 522 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 523 { 524 if (indio_dev->event_interface == NULL) 525 return; 526 wake_up(&indio_dev->event_interface->wait); 527 } 528 529 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 530 { 531 if (indio_dev->event_interface == NULL) 532 return; 533 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 534 kfree(indio_dev->event_interface->group.attrs); 535 kfree(indio_dev->event_interface); 536 } 537