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 */ 36struct 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}; 45 46/** 47 * iio_push_event() - try to add event to the list for userspace reading 48 * @indio_dev: IIO device structure 49 * @ev_code: What event 50 * @timestamp: When the event occurred 51 * 52 * Note: The caller must make sure that this function is not running 53 * concurrently for the same indio_dev more than once. 54 **/ 55int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp) 56{ 57 struct iio_event_interface *ev_int = indio_dev->event_interface; 58 struct iio_event_data ev; 59 int copied; 60 61 /* Does anyone care? */ 62 if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { 63 64 ev.id = ev_code; 65 ev.timestamp = timestamp; 66 67 copied = kfifo_put(&ev_int->det_events, ev); 68 if (copied != 0) 69 wake_up_poll(&ev_int->wait, POLLIN); 70 } 71 72 return 0; 73} 74EXPORT_SYMBOL(iio_push_event); 75 76/** 77 * iio_event_poll() - poll the event queue to find out if it has data 78 */ 79static unsigned int iio_event_poll(struct file *filep, 80 struct poll_table_struct *wait) 81{ 82 struct iio_dev *indio_dev = filep->private_data; 83 struct iio_event_interface *ev_int = indio_dev->event_interface; 84 unsigned int events = 0; 85 86 if (!indio_dev->info) 87 return -ENODEV; 88 89 poll_wait(filep, &ev_int->wait, wait); 90 91 if (!kfifo_is_empty(&ev_int->det_events)) 92 events = POLLIN | POLLRDNORM; 93 94 return events; 95} 96 97static ssize_t iio_event_chrdev_read(struct file *filep, 98 char __user *buf, 99 size_t count, 100 loff_t *f_ps) 101{ 102 struct iio_dev *indio_dev = filep->private_data; 103 struct iio_event_interface *ev_int = indio_dev->event_interface; 104 unsigned int copied; 105 int ret; 106 107 if (!indio_dev->info) 108 return -ENODEV; 109 110 if (count < sizeof(struct iio_event_data)) 111 return -EINVAL; 112 113 do { 114 if (kfifo_is_empty(&ev_int->det_events)) { 115 if (filep->f_flags & O_NONBLOCK) 116 return -EAGAIN; 117 118 ret = wait_event_interruptible(ev_int->wait, 119 !kfifo_is_empty(&ev_int->det_events) || 120 indio_dev->info == NULL); 121 if (ret) 122 return ret; 123 if (indio_dev->info == NULL) 124 return -ENODEV; 125 } 126 127 if (mutex_lock_interruptible(&ev_int->read_lock)) 128 return -ERESTARTSYS; 129 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied); 130 mutex_unlock(&ev_int->read_lock); 131 132 if (ret) 133 return ret; 134 135 /* 136 * If we couldn't read anything from the fifo (a different 137 * thread might have been faster) we either return -EAGAIN if 138 * the file descriptor is non-blocking, otherwise we go back to 139 * sleep and wait for more data to arrive. 140 */ 141 if (copied == 0 && (filep->f_flags & O_NONBLOCK)) 142 return -EAGAIN; 143 144 } while (copied == 0); 145 146 return copied; 147} 148 149static int iio_event_chrdev_release(struct inode *inode, struct file *filep) 150{ 151 struct iio_dev *indio_dev = filep->private_data; 152 struct iio_event_interface *ev_int = indio_dev->event_interface; 153 154 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 155 156 iio_device_put(indio_dev); 157 158 return 0; 159} 160 161static const struct file_operations iio_event_chrdev_fileops = { 162 .read = iio_event_chrdev_read, 163 .poll = iio_event_poll, 164 .release = iio_event_chrdev_release, 165 .owner = THIS_MODULE, 166 .llseek = noop_llseek, 167}; 168 169int iio_event_getfd(struct iio_dev *indio_dev) 170{ 171 struct iio_event_interface *ev_int = indio_dev->event_interface; 172 int fd; 173 174 if (ev_int == NULL) 175 return -ENODEV; 176 177 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) 178 return -EBUSY; 179 180 iio_device_get(indio_dev); 181 182 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, 183 indio_dev, O_RDONLY | O_CLOEXEC); 184 if (fd < 0) { 185 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 186 iio_device_put(indio_dev); 187 } else { 188 kfifo_reset_out(&ev_int->det_events); 189 } 190 191 return fd; 192} 193 194static const char * const iio_ev_type_text[] = { 195 [IIO_EV_TYPE_THRESH] = "thresh", 196 [IIO_EV_TYPE_MAG] = "mag", 197 [IIO_EV_TYPE_ROC] = "roc", 198 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive", 199 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive", 200}; 201 202static const char * const iio_ev_dir_text[] = { 203 [IIO_EV_DIR_EITHER] = "either", 204 [IIO_EV_DIR_RISING] = "rising", 205 [IIO_EV_DIR_FALLING] = "falling" 206}; 207 208static const char * const iio_ev_info_text[] = { 209 [IIO_EV_INFO_ENABLE] = "en", 210 [IIO_EV_INFO_VALUE] = "value", 211 [IIO_EV_INFO_HYSTERESIS] = "hysteresis", 212 [IIO_EV_INFO_PERIOD] = "period", 213}; 214 215static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 216{ 217 return attr->c->event_spec[attr->address & 0xffff].dir; 218} 219 220static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 221{ 222 return attr->c->event_spec[attr->address & 0xffff].type; 223} 224 225static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 226{ 227 return (attr->address >> 16) & 0xffff; 228} 229 230static ssize_t iio_ev_state_store(struct device *dev, 231 struct device_attribute *attr, 232 const char *buf, 233 size_t len) 234{ 235 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 236 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 237 int ret; 238 bool val; 239 240 ret = strtobool(buf, &val); 241 if (ret < 0) 242 return ret; 243 244 ret = indio_dev->info->write_event_config(indio_dev, 245 this_attr->c, iio_ev_attr_type(this_attr), 246 iio_ev_attr_dir(this_attr), val); 247 248 return (ret < 0) ? ret : len; 249} 250 251static ssize_t iio_ev_state_show(struct device *dev, 252 struct device_attribute *attr, 253 char *buf) 254{ 255 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 256 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 257 int val; 258 259 val = indio_dev->info->read_event_config(indio_dev, 260 this_attr->c, iio_ev_attr_type(this_attr), 261 iio_ev_attr_dir(this_attr)); 262 if (val < 0) 263 return val; 264 else 265 return sprintf(buf, "%d\n", val); 266} 267 268static ssize_t iio_ev_value_show(struct device *dev, 269 struct device_attribute *attr, 270 char *buf) 271{ 272 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 273 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 274 int val, val2, val_arr[2]; 275 int ret; 276 277 ret = indio_dev->info->read_event_value(indio_dev, 278 this_attr->c, iio_ev_attr_type(this_attr), 279 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 280 &val, &val2); 281 if (ret < 0) 282 return ret; 283 val_arr[0] = val; 284 val_arr[1] = val2; 285 return iio_format_value(buf, ret, 2, val_arr); 286} 287 288static ssize_t iio_ev_value_store(struct device *dev, 289 struct device_attribute *attr, 290 const char *buf, 291 size_t len) 292{ 293 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 294 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 295 int val, val2; 296 int ret; 297 298 if (!indio_dev->info->write_event_value) 299 return -EINVAL; 300 301 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 302 if (ret) 303 return ret; 304 ret = indio_dev->info->write_event_value(indio_dev, 305 this_attr->c, iio_ev_attr_type(this_attr), 306 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 307 val, val2); 308 if (ret < 0) 309 return ret; 310 311 return len; 312} 313 314static int iio_device_add_event(struct iio_dev *indio_dev, 315 const struct iio_chan_spec *chan, unsigned int spec_index, 316 enum iio_event_type type, enum iio_event_direction dir, 317 enum iio_shared_by shared_by, const unsigned long *mask) 318{ 319 ssize_t (*show)(struct device *, struct device_attribute *, char *); 320 ssize_t (*store)(struct device *, struct device_attribute *, 321 const char *, size_t); 322 unsigned int attrcount = 0; 323 unsigned int i; 324 char *postfix; 325 int ret; 326 327 for_each_set_bit(i, mask, sizeof(*mask)*8) { 328 if (i >= ARRAY_SIZE(iio_ev_info_text)) 329 return -EINVAL; 330 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 331 iio_ev_type_text[type], iio_ev_dir_text[dir], 332 iio_ev_info_text[i]); 333 if (postfix == NULL) 334 return -ENOMEM; 335 336 if (i == IIO_EV_INFO_ENABLE) { 337 show = iio_ev_state_show; 338 store = iio_ev_state_store; 339 } else { 340 show = iio_ev_value_show; 341 store = iio_ev_value_store; 342 } 343 344 ret = __iio_add_chan_devattr(postfix, chan, show, store, 345 (i << 16) | spec_index, shared_by, &indio_dev->dev, 346 &indio_dev->event_interface->dev_attr_list); 347 kfree(postfix); 348 349 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 350 continue; 351 352 if (ret) 353 return ret; 354 355 attrcount++; 356 } 357 358 return attrcount; 359} 360 361static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 362 struct iio_chan_spec const *chan) 363{ 364 int ret = 0, i, attrcount = 0; 365 enum iio_event_direction dir; 366 enum iio_event_type type; 367 368 for (i = 0; i < chan->num_event_specs; i++) { 369 type = chan->event_spec[i].type; 370 dir = chan->event_spec[i].dir; 371 372 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 373 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 374 if (ret < 0) 375 return ret; 376 attrcount += ret; 377 378 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 379 IIO_SHARED_BY_TYPE, 380 &chan->event_spec[i].mask_shared_by_type); 381 if (ret < 0) 382 return ret; 383 attrcount += ret; 384 385 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 386 IIO_SHARED_BY_DIR, 387 &chan->event_spec[i].mask_shared_by_dir); 388 if (ret < 0) 389 return ret; 390 attrcount += ret; 391 392 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 393 IIO_SHARED_BY_ALL, 394 &chan->event_spec[i].mask_shared_by_all); 395 if (ret < 0) 396 return ret; 397 attrcount += ret; 398 } 399 ret = attrcount; 400 return ret; 401} 402 403static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 404{ 405 int j, ret, attrcount = 0; 406 407 /* Dynically created from the channels array */ 408 for (j = 0; j < indio_dev->num_channels; j++) { 409 ret = iio_device_add_event_sysfs(indio_dev, 410 &indio_dev->channels[j]); 411 if (ret < 0) 412 return ret; 413 attrcount += ret; 414 } 415 return attrcount; 416} 417 418static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 419{ 420 int j; 421 422 for (j = 0; j < indio_dev->num_channels; j++) { 423 if (indio_dev->channels[j].num_event_specs != 0) 424 return true; 425 } 426 return false; 427} 428 429static void iio_setup_ev_int(struct iio_event_interface *ev_int) 430{ 431 INIT_KFIFO(ev_int->det_events); 432 init_waitqueue_head(&ev_int->wait); 433 mutex_init(&ev_int->read_lock); 434} 435 436static const char *iio_event_group_name = "events"; 437int iio_device_register_eventset(struct iio_dev *indio_dev) 438{ 439 struct iio_dev_attr *p; 440 int ret = 0, attrcount_orig = 0, attrcount, attrn; 441 struct attribute **attr; 442 443 if (!(indio_dev->info->event_attrs || 444 iio_check_for_dynamic_events(indio_dev))) 445 return 0; 446 447 indio_dev->event_interface = 448 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 449 if (indio_dev->event_interface == NULL) 450 return -ENOMEM; 451 452 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list); 453 454 iio_setup_ev_int(indio_dev->event_interface); 455 if (indio_dev->info->event_attrs != NULL) { 456 attr = indio_dev->info->event_attrs->attrs; 457 while (*attr++ != NULL) 458 attrcount_orig++; 459 } 460 attrcount = attrcount_orig; 461 if (indio_dev->channels) { 462 ret = __iio_add_event_config_attrs(indio_dev); 463 if (ret < 0) 464 goto error_free_setup_event_lines; 465 attrcount += ret; 466 } 467 468 indio_dev->event_interface->group.name = iio_event_group_name; 469 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1, 470 sizeof(indio_dev->event_interface->group.attrs[0]), 471 GFP_KERNEL); 472 if (indio_dev->event_interface->group.attrs == NULL) { 473 ret = -ENOMEM; 474 goto error_free_setup_event_lines; 475 } 476 if (indio_dev->info->event_attrs) 477 memcpy(indio_dev->event_interface->group.attrs, 478 indio_dev->info->event_attrs->attrs, 479 sizeof(indio_dev->event_interface->group.attrs[0]) 480 *attrcount_orig); 481 attrn = attrcount_orig; 482 /* Add all elements from the list. */ 483 list_for_each_entry(p, 484 &indio_dev->event_interface->dev_attr_list, 485 l) 486 indio_dev->event_interface->group.attrs[attrn++] = 487 &p->dev_attr.attr; 488 indio_dev->groups[indio_dev->groupcounter++] = 489 &indio_dev->event_interface->group; 490 491 return 0; 492 493error_free_setup_event_lines: 494 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 495 mutex_destroy(&indio_dev->event_interface->read_lock); 496 kfree(indio_dev->event_interface); 497 return ret; 498} 499 500/** 501 * iio_device_wakeup_eventset - Wakes up the event waitqueue 502 * @indio_dev: The IIO device 503 * 504 * Wakes up the event waitqueue used for poll() and blocking read(). 505 * Should usually be called when the device is unregistered. 506 */ 507void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 508{ 509 if (indio_dev->event_interface == NULL) 510 return; 511 wake_up(&indio_dev->event_interface->wait); 512} 513 514void iio_device_unregister_eventset(struct iio_dev *indio_dev) 515{ 516 if (indio_dev->event_interface == NULL) 517 return; 518 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 519 kfree(indio_dev->event_interface->group.attrs); 520 mutex_destroy(&indio_dev->event_interface->read_lock); 521 kfree(indio_dev->event_interface); 522} 523