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 = dev_get_drvdata(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 /**
  55  * iio_trigger_register_sysfs() - create a device for this trigger
  56  * @trig_info:  the trigger
  57  *
  58  * Also adds any control attribute registered by the trigger driver
  59  **/
  60 static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
  61 {
  62         return sysfs_add_file_to_group(&trig_info->dev.kobj,
  63                                        &dev_attr_name.attr,
  64                                        NULL);
  65 }
  66
  67 static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
  68 {
  69         sysfs_remove_file_from_group(&trig_info->dev.kobj,
  70                                            &dev_attr_name.attr,
  71                                            NULL);
  72 }
  73
  74 int iio_trigger_register(struct iio_trigger *trig_info)
  75 {
  76         int ret;
  77
  78         trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
  79         if (trig_info->id < 0) {
  80                 ret = trig_info->id;
  81                 goto error_ret;
  82         }
  83         /* Set the name used for the sysfs directory etc */
  84         dev_set_name(&trig_info->dev, "trigger%ld",
  85                      (unsigned long) trig_info->id);
  86
  87         ret = device_add(&trig_info->dev);
  88         if (ret)
  89                 goto error_unregister_id;
  90
  91         ret = iio_trigger_register_sysfs(trig_info);
  92         if (ret)
  93                 goto error_device_del;
  94
  95         /* Add to list of available triggers held by the IIO core */
  96         mutex_lock(&iio_trigger_list_lock);
  97         list_add_tail(&trig_info->list, &iio_trigger_list);
  98         mutex_unlock(&iio_trigger_list_lock);
  99
 100         return 0;
 101
 102 error_device_del:
 103         device_del(&trig_info->dev);
 104 error_unregister_id:
 105         ida_simple_remove(&iio_trigger_ida, trig_info->id);
 106 error_ret:
 107         return ret;
 108 }
 109 EXPORT_SYMBOL(iio_trigger_register);
 110
 111 void iio_trigger_unregister(struct iio_trigger *trig_info)
 112 {
 113         mutex_lock(&iio_trigger_list_lock);
 114         list_del(&trig_info->list);
 115         mutex_unlock(&iio_trigger_list_lock);
 116
 117         iio_trigger_unregister_sysfs(trig_info);
 118         ida_simple_remove(&iio_trigger_ida, trig_info->id);
 119         /* Possible issue in here */
 120         device_unregister(&trig_info->dev);
 121 }
 122 EXPORT_SYMBOL(iio_trigger_unregister);
 123
 124 static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 125                                                     size_t len)
 126 {
 127         struct iio_trigger *trig = NULL, *iter;
 128
 129         mutex_lock(&iio_trigger_list_lock);
 130         list_for_each_entry(iter, &iio_trigger_list, list)
 131                 if (sysfs_streq(iter->name, name)) {
 132                         trig = iter;
 133                         break;
 134                 }
 135         mutex_unlock(&iio_trigger_list_lock);
 136
 137         return trig;
 138 }
 139
 140 void iio_trigger_poll(struct iio_trigger *trig, s64 time)
 141 {
 142         int i;
 143         if (!trig->use_count)
 144                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 145                         if (trig->subirqs[i].enabled) {
 146                                 trig->use_count++;
 147                                 generic_handle_irq(trig->subirq_base + i);
 148                         }
 149 }
 150 EXPORT_SYMBOL(iio_trigger_poll);
 151
 152 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
 153 {
 154         iio_trigger_poll(private, iio_get_time_ns());
 155         return IRQ_HANDLED;
 156 }
 157 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
 158
 159 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
 160 {
 161         int i;
 162         if (!trig->use_count)
 163                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 164                         if (trig->subirqs[i].enabled) {
 165                                 trig->use_count++;
 166                                 handle_nested_irq(trig->subirq_base + i);
 167                         }
 168 }
 169 EXPORT_SYMBOL(iio_trigger_poll_chained);
 170
 171 void iio_trigger_notify_done(struct iio_trigger *trig)
 172 {
 173         trig->use_count--;
 174         if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
 175                 if (trig->ops->try_reenable(trig))
 176                         /* Missed and interrupt so launch new poll now */
 177                         iio_trigger_poll(trig, 0);
 178 }
 179 EXPORT_SYMBOL(iio_trigger_notify_done);
 180
 181 /* Trigger Consumer related functions */
 182 static int iio_trigger_get_irq(struct iio_trigger *trig)
 183 {
 184         int ret;
 185         mutex_lock(&trig->pool_lock);
 186         ret = bitmap_find_free_region(trig->pool,
 187                                       CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 188                                       ilog2(1));
 189         mutex_unlock(&trig->pool_lock);
 190         if (ret >= 0)
 191                 ret += trig->subirq_base;
 192
 193         return ret;
 194 }
 195
 196 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
 197 {
 198         mutex_lock(&trig->pool_lock);
 199         clear_bit(irq - trig->subirq_base, trig->pool);
 200         mutex_unlock(&trig->pool_lock);
 201 }
 202
 203 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
 204  * may be needed if the pollfuncs do not include the data read for the
 205  * triggering device.
 206  * This is not currently handled.  Alternative of not enabling trigger unless
 207  * the relevant function is in there may be the best option.
 208  */
 209 /* Worth protecting against double additions?*/
 210 static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 211                                         struct iio_poll_func *pf)
 212 {
 213         int ret = 0;
 214         bool notinuse
 215                 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 216
 217         /* Prevent the module being removed whilst attached to a trigger */
 218         __module_get(pf->indio_dev->info->driver_module);
 219         pf->irq = iio_trigger_get_irq(trig);
 220         ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 221                                    pf->type, pf->name,
 222                                    pf);
 223         if (ret < 0) {
 224                 module_put(pf->indio_dev->info->driver_module);
 225                 return ret;
 226         }
 227
 228         if (trig->ops && trig->ops->set_trigger_state && notinuse) {
 229                 ret = trig->ops->set_trigger_state(trig, true);
 230                 if (ret < 0)
 231                         module_put(pf->indio_dev->info->driver_module);
 232         }
 233
 234         return ret;
 235 }
 236
 237 static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 238                                          struct iio_poll_func *pf)
 239 {
 240         int ret = 0;
 241         bool no_other_users
 242                 = (bitmap_weight(trig->pool,
 243                                  CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 244                    == 1);
 245         if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 246                 ret = trig->ops->set_trigger_state(trig, false);
 247                 if (ret)
 248                         goto error_ret;
 249         }
 250         iio_trigger_put_irq(trig, pf->irq);
 251         free_irq(pf->irq, pf);
 252         module_put(pf->indio_dev->info->driver_module);
 253
 254 error_ret:
 255         return ret;
 256 }
 257
 258 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 259 {
 260         struct iio_poll_func *pf = p;
 261         pf->timestamp = iio_get_time_ns();
 262         return IRQ_WAKE_THREAD;
 263 }
 264 EXPORT_SYMBOL(iio_pollfunc_store_time);
 265
 266 struct iio_poll_func
 267 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 268                     irqreturn_t (*thread)(int irq, void *p),
 269                     int type,
 270                     struct iio_dev *indio_dev,
 271                     const char *fmt,
 272                     ...)
 273 {
 274         va_list vargs;
 275         struct iio_poll_func *pf;
 276
 277         pf = kmalloc(sizeof *pf, GFP_KERNEL);
 278         if (pf == NULL)
 279                 return NULL;
 280         va_start(vargs, fmt);
 281         pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 282         va_end(vargs);
 283         if (pf->name == NULL) {
 284                 kfree(pf);
 285                 return NULL;
 286         }
 287         pf->h = h;
 288         pf->thread = thread;
 289         pf->type = type;
 290         pf->indio_dev = indio_dev;
 291
 292         return pf;
 293 }
 294 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
 295
 296 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 297 {
 298         kfree(pf->name);
 299         kfree(pf);
 300 }
 301 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
 302
 303 /**
 304  * iio_trigger_read_current() - trigger consumer sysfs query which trigger
 305  *
 306  * For trigger consumers the current_trigger interface allows the trigger
 307  * used by the device to be queried.
 308  **/
 309 static ssize_t iio_trigger_read_current(struct device *dev,
 310                                         struct device_attribute *attr,
 311                                         char *buf)
 312 {
 313         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 314
 315         if (indio_dev->trig)
 316                 return sprintf(buf, "%s\n", indio_dev->trig->name);
 317         return 0;
 318 }
 319
 320 /**
 321  * iio_trigger_write_current() trigger consumer sysfs set current trigger
 322  *
 323  * For trigger consumers the current_trigger interface allows the trigger
 324  * used for this device to be specified at run time based on the triggers
 325  * name.
 326  **/
 327 static ssize_t iio_trigger_write_current(struct device *dev,
 328                                          struct device_attribute *attr,
 329                                          const char *buf,
 330                                          size_t len)
 331 {
 332         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 333         struct iio_trigger *oldtrig = indio_dev->trig;
 334         struct iio_trigger *trig;
 335         int ret;
 336
 337         mutex_lock(&indio_dev->mlock);
 338         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 339                 mutex_unlock(&indio_dev->mlock);
 340                 return -EBUSY;
 341         }
 342         mutex_unlock(&indio_dev->mlock);
 343
 344         trig = iio_trigger_find_by_name(buf, len);
 345         if (oldtrig == trig)
 346                 return len;
 347
 348         if (trig && indio_dev->info->validate_trigger) {
 349                 ret = indio_dev->info->validate_trigger(indio_dev, trig);
 350                 if (ret)
 351                         return ret;
 352         }
 353
 354         if (trig && trig->ops && trig->ops->validate_device) {
 355                 ret = trig->ops->validate_device(trig, indio_dev);
 356                 if (ret)
 357                         return ret;
 358         }
 359
 360         indio_dev->trig = trig;
 361
 362         if (oldtrig && indio_dev->trig != oldtrig)
 363                 iio_trigger_put(oldtrig);
 364         if (indio_dev->trig)
 365                 iio_trigger_get(indio_dev->trig);
 366
 367         return len;
 368 }
 369
 370 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 371                    iio_trigger_read_current,
 372                    iio_trigger_write_current);
 373
 374 static struct attribute *iio_trigger_consumer_attrs[] = {
 375         &dev_attr_current_trigger.attr,
 376         NULL,
 377 };
 378
 379 static const struct attribute_group iio_trigger_consumer_attr_group = {
 380         .name = "trigger",
 381         .attrs = iio_trigger_consumer_attrs,
 382 };
 383
 384 static void iio_trig_release(struct device *device)
 385 {
 386         struct iio_trigger *trig = to_iio_trigger(device);
 387         int i;
 388
 389         if (trig->subirq_base) {
 390                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 391                         irq_modify_status(trig->subirq_base + i,
 392                                           IRQ_NOAUTOEN,
 393                                           IRQ_NOREQUEST | IRQ_NOPROBE);
 394                         irq_set_chip(trig->subirq_base + i,
 395                                      NULL);
 396                         irq_set_handler(trig->subirq_base + i,
 397                                         NULL);
 398                 }
 399
 400                 irq_free_descs(trig->subirq_base,
 401                                CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 402         }
 403         kfree(trig->name);
 404         kfree(trig);
 405 }
 406
 407 static struct device_type iio_trig_type = {
 408         .release = iio_trig_release,
 409 };
 410
 411 static void iio_trig_subirqmask(struct irq_data *d)
 412 {
 413         struct irq_chip *chip = irq_data_get_irq_chip(d);
 414         struct iio_trigger *trig
 415                 = container_of(chip,
 416                                struct iio_trigger, subirq_chip);
 417         trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 418 }
 419
 420 static void iio_trig_subirqunmask(struct irq_data *d)
 421 {
 422         struct irq_chip *chip = irq_data_get_irq_chip(d);
 423         struct iio_trigger *trig
 424                 = container_of(chip,
 425                                struct iio_trigger, subirq_chip);
 426         trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 427 }
 428
 429 struct iio_trigger *iio_trigger_alloc(const char *fmt, ...)
 430 {
 431         va_list vargs;
 432         struct iio_trigger *trig;
 433         trig = kzalloc(sizeof *trig, GFP_KERNEL);
 434         if (trig) {
 435                 int i;
 436                 trig->dev.type = &iio_trig_type;
 437                 trig->dev.bus = &iio_bus_type;
 438                 device_initialize(&trig->dev);
 439                 dev_set_drvdata(&trig->dev, (void *)trig);
 440
 441                 mutex_init(&trig->pool_lock);
 442                 trig->subirq_base
 443                         = irq_alloc_descs(-1, 0,
 444                                           CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 445                                           0);
 446                 if (trig->subirq_base < 0) {
 447                         kfree(trig);
 448                         return NULL;
 449                 }
 450                 va_start(vargs, fmt);
 451                 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 452                 va_end(vargs);
 453                 if (trig->name == NULL) {
 454                         irq_free_descs(trig->subirq_base,
 455                                        CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 456                         kfree(trig);
 457                         return NULL;
 458                 }
 459                 trig->subirq_chip.name = trig->name;
 460                 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 461                 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 462                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 463                         irq_set_chip(trig->subirq_base + i,
 464                                      &trig->subirq_chip);
 465                         irq_set_handler(trig->subirq_base + i,
 466                                         &handle_simple_irq);
 467                         irq_modify_status(trig->subirq_base + i,
 468                                           IRQ_NOREQUEST | IRQ_NOAUTOEN,
 469                                           IRQ_NOPROBE);
 470                 }
 471                 get_device(&trig->dev);
 472         }
 473         return trig;
 474 }
 475 EXPORT_SYMBOL(iio_trigger_alloc);
 476
 477 void iio_trigger_free(struct iio_trigger *trig)
 478 {
 479         if (trig)
 480                 put_device(&trig->dev);
 481 }
 482 EXPORT_SYMBOL(iio_trigger_free);
 483
 484 void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
 485 {
 486         indio_dev->groups[indio_dev->groupcounter++] =
 487                 &iio_trigger_consumer_attr_group;
 488 }
 489
 490 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
 491 {
 492         /* Clean up and associated but not attached triggers references */
 493         if (indio_dev->trig)
 494                 iio_trigger_put(indio_dev->trig);
 495 }
 496
 497 int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
 498 {
 499         return iio_trigger_attach_poll_func(indio_dev->trig,
 500                                             indio_dev->pollfunc);
 501 }
 502 EXPORT_SYMBOL(iio_triggered_buffer_postenable);
 503
 504 int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
 505 {
 506         return iio_trigger_dettach_poll_func(indio_dev->trig,
 507                                              indio_dev->pollfunc);
 508 }
 509 EXPORT_SYMBOL(iio_triggered_buffer_predisable);