drivers/staging/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 "iio.h"
  19 #include "trigger.h"
  20 #include "iio_core.h"
  21 #include "iio_core_trigger.h"
  22 #include "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 }
 170 EXPORT_SYMBOL(iio_trigger_poll_chained);
 171
 172 void iio_trigger_notify_done(struct iio_trigger *trig)
 173 {
 174         trig->use_count--;
 175         if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
 176                 if (trig->ops->try_reenable(trig)) {
 177                         /* Missed and interrupt so launch new poll now */
 178                         iio_trigger_poll(trig, 0);
 179                 }
 180 }
 181 EXPORT_SYMBOL(iio_trigger_notify_done);
 182
 183 /* Trigger Consumer related functions */
 184 static int iio_trigger_get_irq(struct iio_trigger *trig)
 185 {
 186         int ret;
 187         mutex_lock(&trig->pool_lock);
 188         ret = bitmap_find_free_region(trig->pool,
 189                                       CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 190                                       ilog2(1));
 191         mutex_unlock(&trig->pool_lock);
 192         if (ret >= 0)
 193                 ret += trig->subirq_base;
 194
 195         return ret;
 196 }
 197
 198 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
 199 {
 200         mutex_lock(&trig->pool_lock);
 201         clear_bit(irq - trig->subirq_base, trig->pool);
 202         mutex_unlock(&trig->pool_lock);
 203 }
 204
 205 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
 206  * may be needed if the pollfuncs do not include the data read for the
 207  * triggering device.
 208  * This is not currently handled.  Alternative of not enabling trigger unless
 209  * the relevant function is in there may be the best option.
 210  */
 211 /* Worth protecting against double additions?*/
 212 static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 213                                         struct iio_poll_func *pf)
 214 {
 215         int ret = 0;
 216         bool notinuse
 217                 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 218
 219         /* Prevent the module being removed whilst attached to a trigger */
 220         __module_get(pf->indio_dev->info->driver_module);
 221         pf->irq = iio_trigger_get_irq(trig);
 222         ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 223                                    pf->type, pf->name,
 224                                    pf);
 225         if (ret < 0) {
 226                 module_put(pf->indio_dev->info->driver_module);
 227                 return ret;
 228         }
 229
 230         if (trig->ops && trig->ops->set_trigger_state && notinuse) {
 231                 ret = trig->ops->set_trigger_state(trig, true);
 232                 if (ret < 0)
 233                         module_put(pf->indio_dev->info->driver_module);
 234         }
 235
 236         return ret;
 237 }
 238
 239 static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 240                                          struct iio_poll_func *pf)
 241 {
 242         int ret = 0;
 243         bool no_other_users
 244                 = (bitmap_weight(trig->pool,
 245                                  CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 246                    == 1);
 247         if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 248                 ret = trig->ops->set_trigger_state(trig, false);
 249                 if (ret)
 250                         goto error_ret;
 251         }
 252         iio_trigger_put_irq(trig, pf->irq);
 253         free_irq(pf->irq, pf);
 254         module_put(pf->indio_dev->info->driver_module);
 255
 256 error_ret:
 257         return ret;
 258 }
 259
 260 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 261 {
 262         struct iio_poll_func *pf = p;
 263         pf->timestamp = iio_get_time_ns();
 264         return IRQ_WAKE_THREAD;
 265 }
 266 EXPORT_SYMBOL(iio_pollfunc_store_time);
 267
 268 struct iio_poll_func
 269 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 270                     irqreturn_t (*thread)(int irq, void *p),
 271                     int type,
 272                     struct iio_dev *indio_dev,
 273                     const char *fmt,
 274                     ...)
 275 {
 276         va_list vargs;
 277         struct iio_poll_func *pf;
 278
 279         pf = kmalloc(sizeof *pf, GFP_KERNEL);
 280         if (pf == NULL)
 281                 return NULL;
 282         va_start(vargs, fmt);
 283         pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 284         va_end(vargs);
 285         if (pf->name == NULL) {
 286                 kfree(pf);
 287                 return NULL;
 288         }
 289         pf->h = h;
 290         pf->thread = thread;
 291         pf->type = type;
 292         pf->indio_dev = indio_dev;
 293
 294         return pf;
 295 }
 296 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
 297
 298 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 299 {
 300         kfree(pf->name);
 301         kfree(pf);
 302 }
 303 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
 304
 305 /**
 306  * iio_trigger_read_currrent() - trigger consumer sysfs query which trigger
 307  *
 308  * For trigger consumers the current_trigger interface allows the trigger
 309  * used by the device to be queried.
 310  **/
 311 static ssize_t iio_trigger_read_current(struct device *dev,
 312                                         struct device_attribute *attr,
 313                                         char *buf)
 314 {
 315         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 316
 317         if (indio_dev->trig)
 318                 return sprintf(buf, "%s\n", indio_dev->trig->name);
 319         return 0;
 320 }
 321
 322 /**
 323  * iio_trigger_write_current() trigger consumer sysfs set current trigger
 324  *
 325  * For trigger consumers the current_trigger interface allows the trigger
 326  * used for this device to be specified at run time based on the triggers
 327  * name.
 328  **/
 329 static ssize_t iio_trigger_write_current(struct device *dev,
 330                                          struct device_attribute *attr,
 331                                          const char *buf,
 332                                          size_t len)
 333 {
 334         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 335         struct iio_trigger *oldtrig = indio_dev->trig;
 336         struct iio_trigger *trig;
 337         int ret;
 338
 339         mutex_lock(&indio_dev->mlock);
 340         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 341                 mutex_unlock(&indio_dev->mlock);
 342                 return -EBUSY;
 343         }
 344         mutex_unlock(&indio_dev->mlock);
 345
 346         trig = iio_trigger_find_by_name(buf, len);
 347         if (oldtrig == trig)
 348                 return len;
 349
 350         if (trig && indio_dev->info->validate_trigger) {
 351                 ret = indio_dev->info->validate_trigger(indio_dev, trig);
 352                 if (ret)
 353                         return ret;
 354         }
 355
 356         if (trig && trig->ops && trig->ops->validate_device) {
 357                 ret = trig->ops->validate_device(trig, indio_dev);
 358                 if (ret)
 359                         return ret;
 360         }
 361
 362         indio_dev->trig = trig;
 363
 364         if (oldtrig && indio_dev->trig != oldtrig)
 365                 iio_put_trigger(oldtrig);
 366         if (indio_dev->trig)
 367                 iio_get_trigger(indio_dev->trig);
 368
 369         return len;
 370 }
 371
 372 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 373                    iio_trigger_read_current,
 374                    iio_trigger_write_current);
 375
 376 static struct attribute *iio_trigger_consumer_attrs[] = {
 377         &dev_attr_current_trigger.attr,
 378         NULL,
 379 };
 380
 381 static const struct attribute_group iio_trigger_consumer_attr_group = {
 382         .name = "trigger",
 383         .attrs = iio_trigger_consumer_attrs,
 384 };
 385
 386 static void iio_trig_release(struct device *device)
 387 {
 388         struct iio_trigger *trig = to_iio_trigger(device);
 389         int i;
 390
 391         if (trig->subirq_base) {
 392                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 393                         irq_modify_status(trig->subirq_base + i,
 394                                           IRQ_NOAUTOEN,
 395                                           IRQ_NOREQUEST | IRQ_NOPROBE);
 396                         irq_set_chip(trig->subirq_base + i,
 397                                      NULL);
 398                         irq_set_handler(trig->subirq_base + i,
 399                                         NULL);
 400                 }
 401
 402                 irq_free_descs(trig->subirq_base,
 403                                CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 404         }
 405         kfree(trig->name);
 406         kfree(trig);
 407 }
 408
 409 static struct device_type iio_trig_type = {
 410         .release = iio_trig_release,
 411 };
 412
 413 static void iio_trig_subirqmask(struct irq_data *d)
 414 {
 415         struct irq_chip *chip = irq_data_get_irq_chip(d);
 416         struct iio_trigger *trig
 417                 = container_of(chip,
 418                                struct iio_trigger, subirq_chip);
 419         trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 420 }
 421
 422 static void iio_trig_subirqunmask(struct irq_data *d)
 423 {
 424         struct irq_chip *chip = irq_data_get_irq_chip(d);
 425         struct iio_trigger *trig
 426                 = container_of(chip,
 427                                struct iio_trigger, subirq_chip);
 428         trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 429 }
 430
 431 struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
 432 {
 433         va_list vargs;
 434         struct iio_trigger *trig;
 435         trig = kzalloc(sizeof *trig, GFP_KERNEL);
 436         if (trig) {
 437                 int i;
 438                 trig->dev.type = &iio_trig_type;
 439                 trig->dev.bus = &iio_bus_type;
 440                 device_initialize(&trig->dev);
 441                 dev_set_drvdata(&trig->dev, (void *)trig);
 442
 443                 mutex_init(&trig->pool_lock);
 444                 trig->subirq_base
 445                         = irq_alloc_descs(-1, 0,
 446                                           CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 447                                           0);
 448                 if (trig->subirq_base < 0) {
 449                         kfree(trig);
 450                         return NULL;
 451                 }
 452                 va_start(vargs, fmt);
 453                 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 454                 va_end(vargs);
 455                 if (trig->name == NULL) {
 456                         irq_free_descs(trig->subirq_base,
 457                                        CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 458                         kfree(trig);
 459                         return NULL;
 460                 }
 461                 trig->subirq_chip.name = trig->name;
 462                 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 463                 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 464                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 465                         irq_set_chip(trig->subirq_base + i,
 466                                      &trig->subirq_chip);
 467                         irq_set_handler(trig->subirq_base + i,
 468                                         &handle_simple_irq);
 469                         irq_modify_status(trig->subirq_base + i,
 470                                           IRQ_NOREQUEST | IRQ_NOAUTOEN,
 471                                           IRQ_NOPROBE);
 472                 }
 473                 get_device(&trig->dev);
 474         }
 475         return trig;
 476 }
 477 EXPORT_SYMBOL(iio_allocate_trigger);
 478
 479 void iio_free_trigger(struct iio_trigger *trig)
 480 {
 481         if (trig)
 482                 put_device(&trig->dev);
 483 }
 484 EXPORT_SYMBOL(iio_free_trigger);
 485
 486 int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
 487 {
 488         indio_dev->groups[indio_dev->groupcounter++] =
 489                 &iio_trigger_consumer_attr_group;
 490
 491         return 0;
 492 }
 493
 494 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
 495 {
 496         /* Clean up and associated but not attached triggers references */
 497         if (indio_dev->trig)
 498                 iio_put_trigger(indio_dev->trig);
 499 }
 500
 501 int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
 502 {
 503         return indio_dev->trig
 504                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 505                                                indio_dev->pollfunc)
 506                 : 0;
 507 }
 508 EXPORT_SYMBOL(iio_triggered_buffer_postenable);
 509
 510 int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
 511 {
 512         return indio_dev->trig
 513                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 514                                                 indio_dev->pollfunc)
 515                 : 0;
 516 }
 517 EXPORT_SYMBOL(iio_triggered_buffer_predisable);