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 */ 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 }; 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 **/ 55 int 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 } 74 EXPORT_SYMBOL(iio_push_event); 75 76 /** 77 * iio_event_poll() - poll the event queue to find out if it has data 78 */ 79 static 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 97 static 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 } 148 149 static 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 } 160 161 static 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 }; 168 169 int 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 } 193 194 static 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 }; 201 202 static 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 }; 207 208 static 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 }; 213 214 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 215 { 216 return attr->c->event_spec[attr->address & 0xffff].dir; 217 } 218 219 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 220 { 221 return attr->c->event_spec[attr->address & 0xffff].type; 222 } 223 224 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 225 { 226 return (attr->address >> 16) & 0xffff; 227 } 228 229 static ssize_t iio_ev_state_store(struct device *dev, 230 struct device_attribute *attr, 231 const char *buf, 232 size_t len) 233 { 234 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 235 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 236 int ret; 237 bool val; 238 239 ret = strtobool(buf, &val); 240 if (ret < 0) 241 return ret; 242 243 ret = indio_dev->info->write_event_config(indio_dev, 244 this_attr->c, iio_ev_attr_type(this_attr), 245 iio_ev_attr_dir(this_attr), val); 246 247 return (ret < 0) ? ret : len; 248 } 249 250 static ssize_t iio_ev_state_show(struct device *dev, 251 struct device_attribute *attr, 252 char *buf) 253 { 254 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 255 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 256 int val; 257 258 val = indio_dev->info->read_event_config(indio_dev, 259 this_attr->c, iio_ev_attr_type(this_attr), 260 iio_ev_attr_dir(this_attr)); 261 if (val < 0) 262 return val; 263 else 264 return sprintf(buf, "%d\n", val); 265 } 266 267 static ssize_t iio_ev_value_show(struct device *dev, 268 struct device_attribute *attr, 269 char *buf) 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 val, val2; 274 int ret; 275 276 ret = indio_dev->info->read_event_value(indio_dev, 277 this_attr->c, iio_ev_attr_type(this_attr), 278 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 279 &val, &val2); 280 if (ret < 0) 281 return ret; 282 return iio_format_value(buf, ret, val, val2); 283 } 284 285 static ssize_t iio_ev_value_store(struct device *dev, 286 struct device_attribute *attr, 287 const char *buf, 288 size_t len) 289 { 290 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 291 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 292 int val, val2; 293 int ret; 294 295 if (!indio_dev->info->write_event_value) 296 return -EINVAL; 297 298 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 299 if (ret) 300 return ret; 301 ret = indio_dev->info->write_event_value(indio_dev, 302 this_attr->c, iio_ev_attr_type(this_attr), 303 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 304 val, val2); 305 if (ret < 0) 306 return ret; 307 308 return len; 309 } 310 311 static int iio_device_add_event(struct iio_dev *indio_dev, 312 const struct iio_chan_spec *chan, unsigned int spec_index, 313 enum iio_event_type type, enum iio_event_direction dir, 314 enum iio_shared_by shared_by, const unsigned long *mask) 315 { 316 ssize_t (*show)(struct device *, struct device_attribute *, char *); 317 ssize_t (*store)(struct device *, struct device_attribute *, 318 const char *, size_t); 319 unsigned int attrcount = 0; 320 unsigned int i; 321 char *postfix; 322 int ret; 323 324 for_each_set_bit(i, mask, sizeof(*mask)) { 325 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 326 iio_ev_type_text[type], iio_ev_dir_text[dir], 327 iio_ev_info_text[i]); 328 if (postfix == NULL) 329 return -ENOMEM; 330 331 if (i == IIO_EV_INFO_ENABLE) { 332 show = iio_ev_state_show; 333 store = iio_ev_state_store; 334 } else { 335 show = iio_ev_value_show; 336 store = iio_ev_value_store; 337 } 338 339 ret = __iio_add_chan_devattr(postfix, chan, show, store, 340 (i << 16) | spec_index, shared_by, &indio_dev->dev, 341 &indio_dev->event_interface->dev_attr_list); 342 kfree(postfix); 343 344 if (ret) 345 return ret; 346 347 attrcount++; 348 } 349 350 return attrcount; 351 } 352 353 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 354 struct iio_chan_spec const *chan) 355 { 356 int ret = 0, i, attrcount = 0; 357 enum iio_event_direction dir; 358 enum iio_event_type type; 359 360 for (i = 0; i < chan->num_event_specs; i++) { 361 type = chan->event_spec[i].type; 362 dir = chan->event_spec[i].dir; 363 364 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 365 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 366 if (ret < 0) 367 return ret; 368 attrcount += ret; 369 370 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 371 IIO_SHARED_BY_TYPE, 372 &chan->event_spec[i].mask_shared_by_type); 373 if (ret < 0) 374 return ret; 375 attrcount += ret; 376 377 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 378 IIO_SHARED_BY_DIR, 379 &chan->event_spec[i].mask_shared_by_dir); 380 if (ret < 0) 381 return ret; 382 attrcount += ret; 383 384 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 385 IIO_SHARED_BY_ALL, 386 &chan->event_spec[i].mask_shared_by_all); 387 if (ret < 0) 388 return ret; 389 attrcount += ret; 390 } 391 ret = attrcount; 392 return ret; 393 } 394 395 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 396 { 397 int j, ret, attrcount = 0; 398 399 /* Dynically created from the channels array */ 400 for (j = 0; j < indio_dev->num_channels; j++) { 401 ret = iio_device_add_event_sysfs(indio_dev, 402 &indio_dev->channels[j]); 403 if (ret < 0) 404 return ret; 405 attrcount += ret; 406 } 407 return attrcount; 408 } 409 410 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 411 { 412 int j; 413 414 for (j = 0; j < indio_dev->num_channels; j++) { 415 if (indio_dev->channels[j].num_event_specs != 0) 416 return true; 417 } 418 return false; 419 } 420 421 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 422 { 423 INIT_KFIFO(ev_int->det_events); 424 init_waitqueue_head(&ev_int->wait); 425 mutex_init(&ev_int->read_lock); 426 } 427 428 static const char *iio_event_group_name = "events"; 429 int iio_device_register_eventset(struct iio_dev *indio_dev) 430 { 431 struct iio_dev_attr *p; 432 int ret = 0, attrcount_orig = 0, attrcount, attrn; 433 struct attribute **attr; 434 435 if (!(indio_dev->info->event_attrs || 436 iio_check_for_dynamic_events(indio_dev))) 437 return 0; 438 439 indio_dev->event_interface = 440 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 441 if (indio_dev->event_interface == NULL) 442 return -ENOMEM; 443 444 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list); 445 446 iio_setup_ev_int(indio_dev->event_interface); 447 if (indio_dev->info->event_attrs != NULL) { 448 attr = indio_dev->info->event_attrs->attrs; 449 while (*attr++ != NULL) 450 attrcount_orig++; 451 } 452 attrcount = attrcount_orig; 453 if (indio_dev->channels) { 454 ret = __iio_add_event_config_attrs(indio_dev); 455 if (ret < 0) 456 goto error_free_setup_event_lines; 457 attrcount += ret; 458 } 459 460 indio_dev->event_interface->group.name = iio_event_group_name; 461 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1, 462 sizeof(indio_dev->event_interface->group.attrs[0]), 463 GFP_KERNEL); 464 if (indio_dev->event_interface->group.attrs == NULL) { 465 ret = -ENOMEM; 466 goto error_free_setup_event_lines; 467 } 468 if (indio_dev->info->event_attrs) 469 memcpy(indio_dev->event_interface->group.attrs, 470 indio_dev->info->event_attrs->attrs, 471 sizeof(indio_dev->event_interface->group.attrs[0]) 472 *attrcount_orig); 473 attrn = attrcount_orig; 474 /* Add all elements from the list. */ 475 list_for_each_entry(p, 476 &indio_dev->event_interface->dev_attr_list, 477 l) 478 indio_dev->event_interface->group.attrs[attrn++] = 479 &p->dev_attr.attr; 480 indio_dev->groups[indio_dev->groupcounter++] = 481 &indio_dev->event_interface->group; 482 483 return 0; 484 485 error_free_setup_event_lines: 486 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 487 kfree(indio_dev->event_interface); 488 return ret; 489 } 490 491 /** 492 * iio_device_wakeup_eventset - Wakes up the event waitqueue 493 * @indio_dev: The IIO device 494 * 495 * Wakes up the event waitqueue used for poll() and blocking read(). 496 * Should usually be called when the device is unregistered. 497 */ 498 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 499 { 500 if (indio_dev->event_interface == NULL) 501 return; 502 wake_up(&indio_dev->event_interface->wait); 503 } 504 505 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 506 { 507 if (indio_dev->event_interface == NULL) 508 return; 509 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 510 kfree(indio_dev->event_interface->group.attrs); 511 kfree(indio_dev->event_interface); 512 } 513