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