drivers/iio/industrialio-trigger.c

   1 /* The industrial I/O core, trigger handling functions
   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
  10 #include <linux/kernel.h>
  11 #include <linux/idr.h>
  12 #include <linux/err.h>
  13 #include <linux/device.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/list.h>
  16 #include <linux/slab.h>
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/trigger.h>
  20 #include "iio_core.h"
  21 #include "iio_core_trigger.h"
  22 #include <linux/iio/trigger_consumer.h>
  23
  24 /* RFC - Question of approach
  25  * Make the common case (single sensor single trigger)
  26  * simple by starting trigger capture from when first sensors
  27  * is added.
  28  *
  29  * Complex simultaneous start requires use of 'hold' functionality
  30  * of the trigger. (not implemented)
  31  *
  32  * Any other suggestions?
  33  */
  34
  35 static DEFINE_IDA(iio_trigger_ida);
  36
  37 /* Single list of all available triggers */
  38 static LIST_HEAD(iio_trigger_list);
  39 static DEFINE_MUTEX(iio_trigger_list_lock);
  40
  41 /**
  42  * iio_trigger_read_name() - retrieve useful identifying name
  43  **/
  44 static ssize_t iio_trigger_read_name(struct device *dev,
  45                                      struct device_attribute *attr,
  46                                      char *buf)
  47 {
  48         struct iio_trigger *trig = to_iio_trigger(dev);
  49         return sprintf(buf, "%s\n", trig->name);
  50 }
  51
  52 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
  53
  54 static struct attribute *iio_trig_dev_attrs[] = {
  55         &dev_attr_name.attr,
  56         NULL,
  57 };
  58
  59 static struct attribute_group iio_trig_attr_group = {
  60         .attrs  = iio_trig_dev_attrs,
  61 };
  62
  63 static const struct attribute_group *iio_trig_attr_groups[] = {
  64         &iio_trig_attr_group,
  65         NULL
  66 };
  67
  68 int iio_trigger_register(struct iio_trigger *trig_info)
  69 {
  70         int ret;
  71
  72         trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
  73         if (trig_info->id < 0) {
  74                 ret = trig_info->id;
  75                 goto error_ret;
  76         }
  77         /* Set the name used for the sysfs directory etc */
  78         dev_set_name(&trig_info->dev, "trigger%ld",
  79                      (unsigned long) trig_info->id);
  80
  81         ret = device_add(&trig_info->dev);
  82         if (ret)
  83                 goto error_unregister_id;
  84
  85         /* Add to list of available triggers held by the IIO core */
  86         mutex_lock(&iio_trigger_list_lock);
  87         list_add_tail(&trig_info->list, &iio_trigger_list);
  88         mutex_unlock(&iio_trigger_list_lock);
  89
  90         return 0;
  91
  92 error_unregister_id:
  93         ida_simple_remove(&iio_trigger_ida, trig_info->id);
  94 error_ret:
  95         return ret;
  96 }
  97 EXPORT_SYMBOL(iio_trigger_register);
  98
  99 void iio_trigger_unregister(struct iio_trigger *trig_info)
 100 {
 101         mutex_lock(&iio_trigger_list_lock);
 102         list_del(&trig_info->list);
 103         mutex_unlock(&iio_trigger_list_lock);
 104
 105         ida_simple_remove(&iio_trigger_ida, trig_info->id);
 106         /* Possible issue in here */
 107         device_unregister(&trig_info->dev);
 108 }
 109 EXPORT_SYMBOL(iio_trigger_unregister);
 110
 111 static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 112                                                     size_t len)
 113 {
 114         struct iio_trigger *trig = NULL, *iter;
 115
 116         mutex_lock(&iio_trigger_list_lock);
 117         list_for_each_entry(iter, &iio_trigger_list, list)
 118                 if (sysfs_streq(iter->name, name)) {
 119                         trig = iter;
 120                         break;
 121                 }
 122         mutex_unlock(&iio_trigger_list_lock);
 123
 124         return trig;
 125 }
 126
 127 void iio_trigger_poll(struct iio_trigger *trig, s64 time)
 128 {
 129         int i;
 130         if (!trig->use_count)
 131                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 132                         if (trig->subirqs[i].enabled) {
 133                                 trig->use_count++;
 134                                 generic_handle_irq(trig->subirq_base + i);
 135                         }
 136 }
 137 EXPORT_SYMBOL(iio_trigger_poll);
 138
 139 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
 140 {
 141         iio_trigger_poll(private, iio_get_time_ns());
 142         return IRQ_HANDLED;
 143 }
 144 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
 145
 146 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
 147 {
 148         int i;
 149         if (!trig->use_count)
 150                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 151                         if (trig->subirqs[i].enabled) {
 152                                 trig->use_count++;
 153                                 handle_nested_irq(trig->subirq_base + i);
 154                         }
 155 }
 156 EXPORT_SYMBOL(iio_trigger_poll_chained);
 157
 158 void iio_trigger_notify_done(struct iio_trigger *trig)
 159 {
 160         trig->use_count--;
 161         if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
 162                 if (trig->ops->try_reenable(trig))
 163                         /* Missed an interrupt so launch new poll now */
 164                         iio_trigger_poll(trig, 0);
 165 }
 166 EXPORT_SYMBOL(iio_trigger_notify_done);
 167
 168 /* Trigger Consumer related functions */
 169 static int iio_trigger_get_irq(struct iio_trigger *trig)
 170 {
 171         int ret;
 172         mutex_lock(&trig->pool_lock);
 173         ret = bitmap_find_free_region(trig->pool,
 174                                       CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 175                                       ilog2(1));
 176         mutex_unlock(&trig->pool_lock);
 177         if (ret >= 0)
 178                 ret += trig->subirq_base;
 179
 180         return ret;
 181 }
 182
 183 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
 184 {
 185         mutex_lock(&trig->pool_lock);
 186         clear_bit(irq - trig->subirq_base, trig->pool);
 187         mutex_unlock(&trig->pool_lock);
 188 }
 189
 190 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
 191  * may be needed if the pollfuncs do not include the data read for the
 192  * triggering device.
 193  * This is not currently handled.  Alternative of not enabling trigger unless
 194  * the relevant function is in there may be the best option.
 195  */
 196 /* Worth protecting against double additions? */
 197 static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 198                                         struct iio_poll_func *pf)
 199 {
 200         int ret = 0;
 201         bool notinuse
 202                 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 203
 204         /* Prevent the module from being removed whilst attached to a trigger */
 205         __module_get(pf->indio_dev->info->driver_module);
 206         pf->irq = iio_trigger_get_irq(trig);
 207         ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 208                                    pf->type, pf->name,
 209                                    pf);
 210         if (ret < 0) {
 211                 module_put(pf->indio_dev->info->driver_module);
 212                 return ret;
 213         }
 214
 215         if (trig->ops && trig->ops->set_trigger_state && notinuse) {
 216                 ret = trig->ops->set_trigger_state(trig, true);
 217                 if (ret < 0)
 218                         module_put(pf->indio_dev->info->driver_module);
 219         }
 220
 221         return ret;
 222 }
 223
 224 static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
 225                                          struct iio_poll_func *pf)
 226 {
 227         int ret = 0;
 228         bool no_other_users
 229                 = (bitmap_weight(trig->pool,
 230                                  CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 231                    == 1);
 232         if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 233                 ret = trig->ops->set_trigger_state(trig, false);
 234                 if (ret)
 235                         goto error_ret;
 236         }
 237         iio_trigger_put_irq(trig, pf->irq);
 238         free_irq(pf->irq, pf);
 239         module_put(pf->indio_dev->info->driver_module);
 240
 241 error_ret:
 242         return ret;
 243 }
 244
 245 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 246 {
 247         struct iio_poll_func *pf = p;
 248         pf->timestamp = iio_get_time_ns();
 249         return IRQ_WAKE_THREAD;
 250 }
 251 EXPORT_SYMBOL(iio_pollfunc_store_time);
 252
 253 struct iio_poll_func
 254 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 255                     irqreturn_t (*thread)(int irq, void *p),
 256                     int type,
 257                     struct iio_dev *indio_dev,
 258                     const char *fmt,
 259                     ...)
 260 {
 261         va_list vargs;
 262         struct iio_poll_func *pf;
 263
 264         pf = kmalloc(sizeof *pf, GFP_KERNEL);
 265         if (pf == NULL)
 266                 return NULL;
 267         va_start(vargs, fmt);
 268         pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 269         va_end(vargs);
 270         if (pf->name == NULL) {
 271                 kfree(pf);
 272                 return NULL;
 273         }
 274         pf->h = h;
 275         pf->thread = thread;
 276         pf->type = type;
 277         pf->indio_dev = indio_dev;
 278
 279         return pf;
 280 }
 281 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
 282
 283 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 284 {
 285         kfree(pf->name);
 286         kfree(pf);
 287 }
 288 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
 289
 290 /**
 291  * iio_trigger_read_current() - trigger consumer sysfs query current trigger
 292  *
 293  * For trigger consumers the current_trigger interface allows the trigger
 294  * used by the device to be queried.
 295  **/
 296 static ssize_t iio_trigger_read_current(struct device *dev,
 297                                         struct device_attribute *attr,
 298                                         char *buf)
 299 {
 300         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 301
 302         if (indio_dev->trig)
 303                 return sprintf(buf, "%s\n", indio_dev->trig->name);
 304         return 0;
 305 }
 306
 307 /**
 308  * iio_trigger_write_current() - trigger consumer sysfs set current trigger
 309  *
 310  * For trigger consumers the current_trigger interface allows the trigger
 311  * used for this device to be specified at run time based on the triggers
 312  * name.
 313  **/
 314 static ssize_t iio_trigger_write_current(struct device *dev,
 315                                          struct device_attribute *attr,
 316                                          const char *buf,
 317                                          size_t len)
 318 {
 319         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 320         struct iio_trigger *oldtrig = indio_dev->trig;
 321         struct iio_trigger *trig;
 322         int ret;
 323
 324         mutex_lock(&indio_dev->mlock);
 325         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 326                 mutex_unlock(&indio_dev->mlock);
 327                 return -EBUSY;
 328         }
 329         mutex_unlock(&indio_dev->mlock);
 330
 331         trig = iio_trigger_find_by_name(buf, len);
 332         if (oldtrig == trig)
 333                 return len;
 334
 335         if (trig && indio_dev->info->validate_trigger) {
 336                 ret = indio_dev->info->validate_trigger(indio_dev, trig);
 337                 if (ret)
 338                         return ret;
 339         }
 340
 341         if (trig && trig->ops && trig->ops->validate_device) {
 342                 ret = trig->ops->validate_device(trig, indio_dev);
 343                 if (ret)
 344                         return ret;
 345         }
 346
 347         indio_dev->trig = trig;
 348
 349         if (oldtrig && indio_dev->trig != oldtrig)
 350                 iio_trigger_put(oldtrig);
 351         if (indio_dev->trig)
 352                 iio_trigger_get(indio_dev->trig);
 353
 354         return len;
 355 }
 356
 357 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 358                    iio_trigger_read_current,
 359                    iio_trigger_write_current);
 360
 361 static struct attribute *iio_trigger_consumer_attrs[] = {
 362         &dev_attr_current_trigger.attr,
 363         NULL,
 364 };
 365
 366 static const struct attribute_group iio_trigger_consumer_attr_group = {
 367         .name = "trigger",
 368         .attrs = iio_trigger_consumer_attrs,
 369 };
 370
 371 static void iio_trig_release(struct device *device)
 372 {
 373         struct iio_trigger *trig = to_iio_trigger(device);
 374         int i;
 375
 376         if (trig->subirq_base) {
 377                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 378                         irq_modify_status(trig->subirq_base + i,
 379                                           IRQ_NOAUTOEN,
 380                                           IRQ_NOREQUEST | IRQ_NOPROBE);
 381                         irq_set_chip(trig->subirq_base + i,
 382                                      NULL);
 383                         irq_set_handler(trig->subirq_base + i,
 384                                         NULL);
 385                 }
 386
 387                 irq_free_descs(trig->subirq_base,
 388                                CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 389         }
 390         kfree(trig->name);
 391         kfree(trig);
 392 }
 393
 394 static struct device_type iio_trig_type = {
 395         .release = iio_trig_release,
 396         .groups = iio_trig_attr_groups,
 397 };
 398
 399 static void iio_trig_subirqmask(struct irq_data *d)
 400 {
 401         struct irq_chip *chip = irq_data_get_irq_chip(d);
 402         struct iio_trigger *trig
 403                 = container_of(chip,
 404                                struct iio_trigger, subirq_chip);
 405         trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 406 }
 407
 408 static void iio_trig_subirqunmask(struct irq_data *d)
 409 {
 410         struct irq_chip *chip = irq_data_get_irq_chip(d);
 411         struct iio_trigger *trig
 412                 = container_of(chip,
 413                                struct iio_trigger, subirq_chip);
 414         trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 415 }
 416
 417 struct iio_trigger *iio_trigger_alloc(const char *fmt, ...)
 418 {
 419         va_list vargs;
 420         struct iio_trigger *trig;
 421         trig = kzalloc(sizeof *trig, GFP_KERNEL);
 422         if (trig) {
 423                 int i;
 424                 trig->dev.type = &iio_trig_type;
 425                 trig->dev.bus = &iio_bus_type;
 426                 device_initialize(&trig->dev);
 427
 428                 mutex_init(&trig->pool_lock);
 429                 trig->subirq_base
 430                         = irq_alloc_descs(-1, 0,
 431                                           CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 432                                           0);
 433                 if (trig->subirq_base < 0) {
 434                         kfree(trig);
 435                         return NULL;
 436                 }
 437                 va_start(vargs, fmt);
 438                 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 439                 va_end(vargs);
 440                 if (trig->name == NULL) {
 441                         irq_free_descs(trig->subirq_base,
 442                                        CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 443                         kfree(trig);
 444                         return NULL;
 445                 }
 446                 trig->subirq_chip.name = trig->name;
 447                 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 448                 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 449                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 450                         irq_set_chip(trig->subirq_base + i,
 451                                      &trig->subirq_chip);
 452                         irq_set_handler(trig->subirq_base + i,
 453                                         &handle_simple_irq);
 454                         irq_modify_status(trig->subirq_base + i,
 455                                           IRQ_NOREQUEST | IRQ_NOAUTOEN,
 456                                           IRQ_NOPROBE);
 457                 }
 458                 get_device(&trig->dev);
 459         }
 460         return trig;
 461 }
 462 EXPORT_SYMBOL(iio_trigger_alloc);
 463
 464 void iio_trigger_free(struct iio_trigger *trig)
 465 {
 466         if (trig)
 467                 put_device(&trig->dev);
 468 }
 469 EXPORT_SYMBOL(iio_trigger_free);
 470
 471 void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
 472 {
 473         indio_dev->groups[indio_dev->groupcounter++] =
 474                 &iio_trigger_consumer_attr_group;
 475 }
 476
 477 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
 478 {
 479         /* Clean up an associated but not attached trigger reference */
 480         if (indio_dev->trig)
 481                 iio_trigger_put(indio_dev->trig);
 482 }
 483
 484 int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
 485 {
 486         return iio_trigger_attach_poll_func(indio_dev->trig,
 487                                             indio_dev->pollfunc);
 488 }
 489 EXPORT_SYMBOL(iio_triggered_buffer_postenable);
 490
 491 int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
 492 {
 493         return iio_trigger_detach_poll_func(indio_dev->trig,
 494                                              indio_dev->pollfunc);
 495 }
 496 EXPORT_SYMBOL(iio_triggered_buffer_predisable);