drivers/iio/inkern.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* The industrial I/O core in kernel channel mapping
   3  *
   4  * Copyright (c) 2011 Jonathan Cameron
   5  */
   6 #include <linux/err.h>
   7 #include <linux/export.h>
   8 #include <linux/slab.h>
   9 #include <linux/mutex.h>
  10 #include <linux/of.h>
  11
  12 #include <linux/iio/iio.h>
  13 #include "iio_core.h"
  14 #include <linux/iio/machine.h>
  15 #include <linux/iio/driver.h>
  16 #include <linux/iio/consumer.h>
  17
  18 struct iio_map_internal {
  19         struct iio_dev *indio_dev;
  20         struct iio_map *map;
  21         struct list_head l;
  22 };
  23
  24 static LIST_HEAD(iio_map_list);
  25 static DEFINE_MUTEX(iio_map_list_lock);
  26
  27 static int iio_map_array_unregister_locked(struct iio_dev *indio_dev)
  28 {
  29         int ret = -ENODEV;
  30         struct iio_map_internal *mapi, *next;
  31
  32         list_for_each_entry_safe(mapi, next, &iio_map_list, l) {
  33                 if (indio_dev == mapi->indio_dev) {
  34                         list_del(&mapi->l);
  35                         kfree(mapi);
  36                         ret = 0;
  37                 }
  38         }
  39         return ret;
  40 }
  41
  42 int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
  43 {
  44         int i = 0, ret = 0;
  45         struct iio_map_internal *mapi;
  46
  47         if (maps == NULL)
  48                 return 0;
  49
  50         mutex_lock(&iio_map_list_lock);
  51         while (maps[i].consumer_dev_name != NULL) {
  52                 mapi = kzalloc(sizeof(*mapi), GFP_KERNEL);
  53                 if (mapi == NULL) {
  54                         ret = -ENOMEM;
  55                         goto error_ret;
  56                 }
  57                 mapi->map = &maps[i];
  58                 mapi->indio_dev = indio_dev;
  59                 list_add_tail(&mapi->l, &iio_map_list);
  60                 i++;
  61         }
  62 error_ret:
  63         if (ret)
  64                 iio_map_array_unregister_locked(indio_dev);
  65         mutex_unlock(&iio_map_list_lock);
  66
  67         return ret;
  68 }
  69 EXPORT_SYMBOL_GPL(iio_map_array_register);
  70
  71
  72 /*
  73  * Remove all map entries associated with the given iio device
  74  */
  75 int iio_map_array_unregister(struct iio_dev *indio_dev)
  76 {
  77         int ret;
  78
  79         mutex_lock(&iio_map_list_lock);
  80         ret = iio_map_array_unregister_locked(indio_dev);
  81         mutex_unlock(&iio_map_list_lock);
  82
  83         return ret;
  84 }
  85 EXPORT_SYMBOL_GPL(iio_map_array_unregister);
  86
  87 static const struct iio_chan_spec
  88 *iio_chan_spec_from_name(const struct iio_dev *indio_dev, const char *name)
  89 {
  90         int i;
  91         const struct iio_chan_spec *chan = NULL;
  92
  93         for (i = 0; i < indio_dev->num_channels; i++)
  94                 if (indio_dev->channels[i].datasheet_name &&
  95                     strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
  96                         chan = &indio_dev->channels[i];
  97                         break;
  98                 }
  99         return chan;
 100 }
 101
 102 #ifdef CONFIG_OF
 103
 104 static int iio_dev_node_match(struct device *dev, const void *data)
 105 {
 106         return dev->of_node == data && dev->type == &iio_device_type;
 107 }
 108
 109 /**
 110  * __of_iio_simple_xlate - translate iiospec to the IIO channel index
 111  * @indio_dev:  pointer to the iio_dev structure
 112  * @iiospec:    IIO specifier as found in the device tree
 113  *
 114  * This is simple translation function, suitable for the most 1:1 mapped
 115  * channels in IIO chips. This function performs only one sanity check:
 116  * whether IIO index is less than num_channels (that is specified in the
 117  * iio_dev).
 118  */
 119 static int __of_iio_simple_xlate(struct iio_dev *indio_dev,
 120                                 const struct of_phandle_args *iiospec)
 121 {
 122         if (!iiospec->args_count)
 123                 return 0;
 124
 125         if (iiospec->args[0] >= indio_dev->num_channels) {
 126                 dev_err(&indio_dev->dev, "invalid channel index %u\n",
 127                         iiospec->args[0]);
 128                 return -EINVAL;
 129         }
 130
 131         return iiospec->args[0];
 132 }
 133
 134 static int __of_iio_channel_get(struct iio_channel *channel,
 135                                 struct device_node *np, int index)
 136 {
 137         struct device *idev;
 138         struct iio_dev *indio_dev;
 139         int err;
 140         struct of_phandle_args iiospec;
 141
 142         err = of_parse_phandle_with_args(np, "io-channels",
 143                                          "#io-channel-cells",
 144                                          index, &iiospec);
 145         if (err)
 146                 return err;
 147
 148         idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
 149                                iio_dev_node_match);
 150         of_node_put(iiospec.np);
 151         if (idev == NULL)
 152                 return -EPROBE_DEFER;
 153
 154         indio_dev = dev_to_iio_dev(idev);
 155         channel->indio_dev = indio_dev;
 156         if (indio_dev->info->of_xlate)
 157                 index = indio_dev->info->of_xlate(indio_dev, &iiospec);
 158         else
 159                 index = __of_iio_simple_xlate(indio_dev, &iiospec);
 160         if (index < 0)
 161                 goto err_put;
 162         channel->channel = &indio_dev->channels[index];
 163
 164         return 0;
 165
 166 err_put:
 167         iio_device_put(indio_dev);
 168         return index;
 169 }
 170
 171 static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
 172 {
 173         struct iio_channel *channel;
 174         int err;
 175
 176         if (index < 0)
 177                 return ERR_PTR(-EINVAL);
 178
 179         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 180         if (channel == NULL)
 181                 return ERR_PTR(-ENOMEM);
 182
 183         err = __of_iio_channel_get(channel, np, index);
 184         if (err)
 185                 goto err_free_channel;
 186
 187         return channel;
 188
 189 err_free_channel:
 190         kfree(channel);
 191         return ERR_PTR(err);
 192 }
 193
 194 static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
 195                                                       const char *name)
 196 {
 197         struct iio_channel *chan = NULL;
 198
 199         /* Walk up the tree of devices looking for a matching iio channel */
 200         while (np) {
 201                 int index = 0;
 202
 203                 /*
 204                  * For named iio channels, first look up the name in the
 205                  * "io-channel-names" property.  If it cannot be found, the
 206                  * index will be an error code, and of_iio_channel_get()
 207                  * will fail.
 208                  */
 209                 if (name)
 210                         index = of_property_match_string(np, "io-channel-names",
 211                                                          name);
 212                 chan = of_iio_channel_get(np, index);
 213                 if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
 214                         break;
 215                 else if (name && index >= 0) {
 216                         pr_err("ERROR: could not get IIO channel %pOF:%s(%i)\n",
 217                                 np, name ? name : "", index);
 218                         return NULL;
 219                 }
 220
 221                 /*
 222                  * No matching IIO channel found on this node.
 223                  * If the parent node has a "io-channel-ranges" property,
 224                  * then we can try one of its channels.
 225                  */
 226                 np = np->parent;
 227                 if (np && !of_get_property(np, "io-channel-ranges", NULL))
 228                         return NULL;
 229         }
 230
 231         return chan;
 232 }
 233
 234 static struct iio_channel *of_iio_channel_get_all(struct device *dev)
 235 {
 236         struct iio_channel *chans;
 237         int i, mapind, nummaps = 0;
 238         int ret;
 239
 240         do {
 241                 ret = of_parse_phandle_with_args(dev->of_node,
 242                                                  "io-channels",
 243                                                  "#io-channel-cells",
 244                                                  nummaps, NULL);
 245                 if (ret < 0)
 246                         break;
 247         } while (++nummaps);
 248
 249         if (nummaps == 0)       /* no error, return NULL to search map table */
 250                 return NULL;
 251
 252         /* NULL terminated array to save passing size */
 253         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 254         if (chans == NULL)
 255                 return ERR_PTR(-ENOMEM);
 256
 257         /* Search for OF matches */
 258         for (mapind = 0; mapind < nummaps; mapind++) {
 259                 ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
 260                                            mapind);
 261                 if (ret)
 262                         goto error_free_chans;
 263         }
 264         return chans;
 265
 266 error_free_chans:
 267         for (i = 0; i < mapind; i++)
 268                 iio_device_put(chans[i].indio_dev);
 269         kfree(chans);
 270         return ERR_PTR(ret);
 271 }
 272
 273 #else /* CONFIG_OF */
 274
 275 static inline struct iio_channel *
 276 of_iio_channel_get_by_name(struct device_node *np, const char *name)
 277 {
 278         return NULL;
 279 }
 280
 281 static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
 282 {
 283         return NULL;
 284 }
 285
 286 #endif /* CONFIG_OF */
 287
 288 static struct iio_channel *iio_channel_get_sys(const char *name,
 289                                                const char *channel_name)
 290 {
 291         struct iio_map_internal *c_i = NULL, *c = NULL;
 292         struct iio_channel *channel;
 293         int err;
 294
 295         if (name == NULL && channel_name == NULL)
 296                 return ERR_PTR(-ENODEV);
 297
 298         /* first find matching entry the channel map */
 299         mutex_lock(&iio_map_list_lock);
 300         list_for_each_entry(c_i, &iio_map_list, l) {
 301                 if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
 302                     (channel_name &&
 303                      strcmp(channel_name, c_i->map->consumer_channel) != 0))
 304                         continue;
 305                 c = c_i;
 306                 iio_device_get(c->indio_dev);
 307                 break;
 308         }
 309         mutex_unlock(&iio_map_list_lock);
 310         if (c == NULL)
 311                 return ERR_PTR(-ENODEV);
 312
 313         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 314         if (channel == NULL) {
 315                 err = -ENOMEM;
 316                 goto error_no_mem;
 317         }
 318
 319         channel->indio_dev = c->indio_dev;
 320
 321         if (c->map->adc_channel_label) {
 322                 channel->channel =
 323                         iio_chan_spec_from_name(channel->indio_dev,
 324                                                 c->map->adc_channel_label);
 325
 326                 if (channel->channel == NULL) {
 327                         err = -EINVAL;
 328                         goto error_no_chan;
 329                 }
 330         }
 331
 332         return channel;
 333
 334 error_no_chan:
 335         kfree(channel);
 336 error_no_mem:
 337         iio_device_put(c->indio_dev);
 338         return ERR_PTR(err);
 339 }
 340
 341 struct iio_channel *iio_channel_get(struct device *dev,
 342                                     const char *channel_name)
 343 {
 344         const char *name = dev ? dev_name(dev) : NULL;
 345         struct iio_channel *channel;
 346
 347         if (dev) {
 348                 channel = of_iio_channel_get_by_name(dev->of_node,
 349                                                      channel_name);
 350                 if (channel != NULL)
 351                         return channel;
 352         }
 353
 354         return iio_channel_get_sys(name, channel_name);
 355 }
 356 EXPORT_SYMBOL_GPL(iio_channel_get);
 357
 358 void iio_channel_release(struct iio_channel *channel)
 359 {
 360         if (!channel)
 361                 return;
 362         iio_device_put(channel->indio_dev);
 363         kfree(channel);
 364 }
 365 EXPORT_SYMBOL_GPL(iio_channel_release);
 366
 367 static void devm_iio_channel_free(struct device *dev, void *res)
 368 {
 369         struct iio_channel *channel = *(struct iio_channel **)res;
 370
 371         iio_channel_release(channel);
 372 }
 373
 374 struct iio_channel *devm_iio_channel_get(struct device *dev,
 375                                          const char *channel_name)
 376 {
 377         struct iio_channel **ptr, *channel;
 378
 379         ptr = devres_alloc(devm_iio_channel_free, sizeof(*ptr), GFP_KERNEL);
 380         if (!ptr)
 381                 return ERR_PTR(-ENOMEM);
 382
 383         channel = iio_channel_get(dev, channel_name);
 384         if (IS_ERR(channel)) {
 385                 devres_free(ptr);
 386                 return channel;
 387         }
 388
 389         *ptr = channel;
 390         devres_add(dev, ptr);
 391
 392         return channel;
 393 }
 394 EXPORT_SYMBOL_GPL(devm_iio_channel_get);
 395
 396 struct iio_channel *iio_channel_get_all(struct device *dev)
 397 {
 398         const char *name;
 399         struct iio_channel *chans;
 400         struct iio_map_internal *c = NULL;
 401         int nummaps = 0;
 402         int mapind = 0;
 403         int i, ret;
 404
 405         if (dev == NULL)
 406                 return ERR_PTR(-EINVAL);
 407
 408         chans = of_iio_channel_get_all(dev);
 409         if (chans)
 410                 return chans;
 411
 412         name = dev_name(dev);
 413
 414         mutex_lock(&iio_map_list_lock);
 415         /* first count the matching maps */
 416         list_for_each_entry(c, &iio_map_list, l)
 417                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 418                         continue;
 419                 else
 420                         nummaps++;
 421
 422         if (nummaps == 0) {
 423                 ret = -ENODEV;
 424                 goto error_ret;
 425         }
 426
 427         /* NULL terminated array to save passing size */
 428         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 429         if (chans == NULL) {
 430                 ret = -ENOMEM;
 431                 goto error_ret;
 432         }
 433
 434         /* for each map fill in the chans element */
 435         list_for_each_entry(c, &iio_map_list, l) {
 436                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 437                         continue;
 438                 chans[mapind].indio_dev = c->indio_dev;
 439                 chans[mapind].data = c->map->consumer_data;
 440                 chans[mapind].channel =
 441                         iio_chan_spec_from_name(chans[mapind].indio_dev,
 442                                                 c->map->adc_channel_label);
 443                 if (chans[mapind].channel == NULL) {
 444                         ret = -EINVAL;
 445                         goto error_free_chans;
 446                 }
 447                 iio_device_get(chans[mapind].indio_dev);
 448                 mapind++;
 449         }
 450         if (mapind == 0) {
 451                 ret = -ENODEV;
 452                 goto error_free_chans;
 453         }
 454         mutex_unlock(&iio_map_list_lock);
 455
 456         return chans;
 457
 458 error_free_chans:
 459         for (i = 0; i < nummaps; i++)
 460                 iio_device_put(chans[i].indio_dev);
 461         kfree(chans);
 462 error_ret:
 463         mutex_unlock(&iio_map_list_lock);
 464
 465         return ERR_PTR(ret);
 466 }
 467 EXPORT_SYMBOL_GPL(iio_channel_get_all);
 468
 469 void iio_channel_release_all(struct iio_channel *channels)
 470 {
 471         struct iio_channel *chan = &channels[0];
 472
 473         while (chan->indio_dev) {
 474                 iio_device_put(chan->indio_dev);
 475                 chan++;
 476         }
 477         kfree(channels);
 478 }
 479 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 480
 481 static void devm_iio_channel_free_all(struct device *dev, void *res)
 482 {
 483         struct iio_channel *channels = *(struct iio_channel **)res;
 484
 485         iio_channel_release_all(channels);
 486 }
 487
 488 struct iio_channel *devm_iio_channel_get_all(struct device *dev)
 489 {
 490         struct iio_channel **ptr, *channels;
 491
 492         ptr = devres_alloc(devm_iio_channel_free_all, sizeof(*ptr), GFP_KERNEL);
 493         if (!ptr)
 494                 return ERR_PTR(-ENOMEM);
 495
 496         channels = iio_channel_get_all(dev);
 497         if (IS_ERR(channels)) {
 498                 devres_free(ptr);
 499                 return channels;
 500         }
 501
 502         *ptr = channels;
 503         devres_add(dev, ptr);
 504
 505         return channels;
 506 }
 507 EXPORT_SYMBOL_GPL(devm_iio_channel_get_all);
 508
 509 static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
 510         enum iio_chan_info_enum info)
 511 {
 512         int unused;
 513         int vals[INDIO_MAX_RAW_ELEMENTS];
 514         int ret;
 515         int val_len = 2;
 516
 517         if (val2 == NULL)
 518                 val2 = &unused;
 519
 520         if (!iio_channel_has_info(chan->channel, info))
 521                 return -EINVAL;
 522
 523         if (chan->indio_dev->info->read_raw_multi) {
 524                 ret = chan->indio_dev->info->read_raw_multi(chan->indio_dev,
 525                                         chan->channel, INDIO_MAX_RAW_ELEMENTS,
 526                                         vals, &val_len, info);
 527                 *val = vals[0];
 528                 *val2 = vals[1];
 529         } else
 530                 ret = chan->indio_dev->info->read_raw(chan->indio_dev,
 531                                         chan->channel, val, val2, info);
 532
 533         return ret;
 534 }
 535
 536 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 537 {
 538         int ret;
 539
 540         mutex_lock(&chan->indio_dev->info_exist_lock);
 541         if (chan->indio_dev->info == NULL) {
 542                 ret = -ENODEV;
 543                 goto err_unlock;
 544         }
 545
 546         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 547 err_unlock:
 548         mutex_unlock(&chan->indio_dev->info_exist_lock);
 549
 550         return ret;
 551 }
 552 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 553
 554 int iio_read_channel_average_raw(struct iio_channel *chan, int *val)
 555 {
 556         int ret;
 557
 558         mutex_lock(&chan->indio_dev->info_exist_lock);
 559         if (chan->indio_dev->info == NULL) {
 560                 ret = -ENODEV;
 561                 goto err_unlock;
 562         }
 563
 564         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_AVERAGE_RAW);
 565 err_unlock:
 566         mutex_unlock(&chan->indio_dev->info_exist_lock);
 567
 568         return ret;
 569 }
 570 EXPORT_SYMBOL_GPL(iio_read_channel_average_raw);
 571
 572 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 573         int raw, int *processed, unsigned int scale)
 574 {
 575         int scale_type, scale_val, scale_val2, offset;
 576         s64 raw64 = raw;
 577         int ret;
 578
 579         ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
 580         if (ret >= 0)
 581                 raw64 += offset;
 582
 583         scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
 584                                         IIO_CHAN_INFO_SCALE);
 585         if (scale_type < 0) {
 586                 /*
 587                  * Just pass raw values as processed if no scaling is
 588                  * available.
 589                  */
 590                 *processed = raw;
 591                 return 0;
 592         }
 593
 594         switch (scale_type) {
 595         case IIO_VAL_INT:
 596                 *processed = raw64 * scale_val;
 597                 break;
 598         case IIO_VAL_INT_PLUS_MICRO:
 599                 if (scale_val2 < 0)
 600                         *processed = -raw64 * scale_val;
 601                 else
 602                         *processed = raw64 * scale_val;
 603                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 604                                       1000000LL);
 605                 break;
 606         case IIO_VAL_INT_PLUS_NANO:
 607                 if (scale_val2 < 0)
 608                         *processed = -raw64 * scale_val;
 609                 else
 610                         *processed = raw64 * scale_val;
 611                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 612                                       1000000000LL);
 613                 break;
 614         case IIO_VAL_FRACTIONAL:
 615                 *processed = div_s64(raw64 * (s64)scale_val * scale,
 616                                      scale_val2);
 617                 break;
 618         case IIO_VAL_FRACTIONAL_LOG2:
 619                 *processed = (raw64 * (s64)scale_val * scale) >> scale_val2;
 620                 break;
 621         default:
 622                 return -EINVAL;
 623         }
 624
 625         return 0;
 626 }
 627
 628 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 629         int *processed, unsigned int scale)
 630 {
 631         int ret;
 632
 633         mutex_lock(&chan->indio_dev->info_exist_lock);
 634         if (chan->indio_dev->info == NULL) {
 635                 ret = -ENODEV;
 636                 goto err_unlock;
 637         }
 638
 639         ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
 640                                                         scale);
 641 err_unlock:
 642         mutex_unlock(&chan->indio_dev->info_exist_lock);
 643
 644         return ret;
 645 }
 646 EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
 647
 648 int iio_read_channel_attribute(struct iio_channel *chan, int *val, int *val2,
 649                                enum iio_chan_info_enum attribute)
 650 {
 651         int ret;
 652
 653         mutex_lock(&chan->indio_dev->info_exist_lock);
 654         if (chan->indio_dev->info == NULL) {
 655                 ret = -ENODEV;
 656                 goto err_unlock;
 657         }
 658
 659         ret = iio_channel_read(chan, val, val2, attribute);
 660 err_unlock:
 661         mutex_unlock(&chan->indio_dev->info_exist_lock);
 662
 663         return ret;
 664 }
 665 EXPORT_SYMBOL_GPL(iio_read_channel_attribute);
 666
 667 int iio_read_channel_offset(struct iio_channel *chan, int *val, int *val2)
 668 {
 669         return iio_read_channel_attribute(chan, val, val2, IIO_CHAN_INFO_OFFSET);
 670 }
 671 EXPORT_SYMBOL_GPL(iio_read_channel_offset);
 672
 673 int iio_read_channel_processed(struct iio_channel *chan, int *val)
 674 {
 675         int ret;
 676
 677         mutex_lock(&chan->indio_dev->info_exist_lock);
 678         if (chan->indio_dev->info == NULL) {
 679                 ret = -ENODEV;
 680                 goto err_unlock;
 681         }
 682
 683         if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
 684                 ret = iio_channel_read(chan, val, NULL,
 685                                        IIO_CHAN_INFO_PROCESSED);
 686         } else {
 687                 ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 688                 if (ret < 0)
 689                         goto err_unlock;
 690                 ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
 691         }
 692
 693 err_unlock:
 694         mutex_unlock(&chan->indio_dev->info_exist_lock);
 695
 696         return ret;
 697 }
 698 EXPORT_SYMBOL_GPL(iio_read_channel_processed);
 699
 700 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 701 {
 702         return iio_read_channel_attribute(chan, val, val2, IIO_CHAN_INFO_SCALE);
 703 }
 704 EXPORT_SYMBOL_GPL(iio_read_channel_scale);
 705
 706 static int iio_channel_read_avail(struct iio_channel *chan,
 707                                   const int **vals, int *type, int *length,
 708                                   enum iio_chan_info_enum info)
 709 {
 710         if (!iio_channel_has_available(chan->channel, info))
 711                 return -EINVAL;
 712
 713         return chan->indio_dev->info->read_avail(chan->indio_dev, chan->channel,
 714                                                  vals, type, length, info);
 715 }
 716
 717 int iio_read_avail_channel_attribute(struct iio_channel *chan,
 718                                      const int **vals, int *type, int *length,
 719                                      enum iio_chan_info_enum attribute)
 720 {
 721         int ret;
 722
 723         mutex_lock(&chan->indio_dev->info_exist_lock);
 724         if (!chan->indio_dev->info) {
 725                 ret = -ENODEV;
 726                 goto err_unlock;
 727         }
 728
 729         ret = iio_channel_read_avail(chan, vals, type, length, attribute);
 730 err_unlock:
 731         mutex_unlock(&chan->indio_dev->info_exist_lock);
 732
 733         return ret;
 734 }
 735 EXPORT_SYMBOL_GPL(iio_read_avail_channel_attribute);
 736
 737 int iio_read_avail_channel_raw(struct iio_channel *chan,
 738                                const int **vals, int *length)
 739 {
 740         int ret;
 741         int type;
 742
 743         ret = iio_read_avail_channel_attribute(chan, vals, &type, length,
 744                                          IIO_CHAN_INFO_RAW);
 745
 746         if (ret >= 0 && type != IIO_VAL_INT)
 747                 /* raw values are assumed to be IIO_VAL_INT */
 748                 ret = -EINVAL;
 749
 750         return ret;
 751 }
 752 EXPORT_SYMBOL_GPL(iio_read_avail_channel_raw);
 753
 754 static int iio_channel_read_max(struct iio_channel *chan,
 755                                 int *val, int *val2, int *type,
 756                                 enum iio_chan_info_enum info)
 757 {
 758         int unused;
 759         const int *vals;
 760         int length;
 761         int ret;
 762
 763         if (!val2)
 764                 val2 = &unused;
 765
 766         ret = iio_channel_read_avail(chan, &vals, type, &length, info);
 767         switch (ret) {
 768         case IIO_AVAIL_RANGE:
 769                 switch (*type) {
 770                 case IIO_VAL_INT:
 771                         *val = vals[2];
 772                         break;
 773                 default:
 774                         *val = vals[4];
 775                         *val2 = vals[5];
 776                 }
 777                 return 0;
 778
 779         case IIO_AVAIL_LIST:
 780                 if (length <= 0)
 781                         return -EINVAL;
 782                 switch (*type) {
 783                 case IIO_VAL_INT:
 784                         *val = vals[--length];
 785                         while (length) {
 786                                 if (vals[--length] > *val)
 787                                         *val = vals[length];
 788                         }
 789                         break;
 790                 default:
 791                         /* FIXME: learn about max for other iio values */
 792                         return -EINVAL;
 793                 }
 794                 return 0;
 795
 796         default:
 797                 return ret;
 798         }
 799 }
 800
 801 int iio_read_max_channel_raw(struct iio_channel *chan, int *val)
 802 {
 803         int ret;
 804         int type;
 805
 806         mutex_lock(&chan->indio_dev->info_exist_lock);
 807         if (!chan->indio_dev->info) {
 808                 ret = -ENODEV;
 809                 goto err_unlock;
 810         }
 811
 812         ret = iio_channel_read_max(chan, val, NULL, &type, IIO_CHAN_INFO_RAW);
 813 err_unlock:
 814         mutex_unlock(&chan->indio_dev->info_exist_lock);
 815
 816         return ret;
 817 }
 818 EXPORT_SYMBOL_GPL(iio_read_max_channel_raw);
 819
 820 int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
 821 {
 822         int ret = 0;
 823         /* Need to verify underlying driver has not gone away */
 824
 825         mutex_lock(&chan->indio_dev->info_exist_lock);
 826         if (chan->indio_dev->info == NULL) {
 827                 ret = -ENODEV;
 828                 goto err_unlock;
 829         }
 830
 831         *type = chan->channel->type;
 832 err_unlock:
 833         mutex_unlock(&chan->indio_dev->info_exist_lock);
 834
 835         return ret;
 836 }
 837 EXPORT_SYMBOL_GPL(iio_get_channel_type);
 838
 839 static int iio_channel_write(struct iio_channel *chan, int val, int val2,
 840                              enum iio_chan_info_enum info)
 841 {
 842         return chan->indio_dev->info->write_raw(chan->indio_dev,
 843                                                 chan->channel, val, val2, info);
 844 }
 845
 846 int iio_write_channel_attribute(struct iio_channel *chan, int val, int val2,
 847                                 enum iio_chan_info_enum attribute)
 848 {
 849         int ret;
 850
 851         mutex_lock(&chan->indio_dev->info_exist_lock);
 852         if (chan->indio_dev->info == NULL) {
 853                 ret = -ENODEV;
 854                 goto err_unlock;
 855         }
 856
 857         ret = iio_channel_write(chan, val, val2, attribute);
 858 err_unlock:
 859         mutex_unlock(&chan->indio_dev->info_exist_lock);
 860
 861         return ret;
 862 }
 863 EXPORT_SYMBOL_GPL(iio_write_channel_attribute);
 864
 865 int iio_write_channel_raw(struct iio_channel *chan, int val)
 866 {
 867         return iio_write_channel_attribute(chan, val, 0, IIO_CHAN_INFO_RAW);
 868 }
 869 EXPORT_SYMBOL_GPL(iio_write_channel_raw);
 870
 871 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan)
 872 {
 873         const struct iio_chan_spec_ext_info *ext_info;
 874         unsigned int i = 0;
 875
 876         if (!chan->channel->ext_info)
 877                 return i;
 878
 879         for (ext_info = chan->channel->ext_info; ext_info->name; ext_info++)
 880                 ++i;
 881
 882         return i;
 883 }
 884 EXPORT_SYMBOL_GPL(iio_get_channel_ext_info_count);
 885
 886 static const struct iio_chan_spec_ext_info *iio_lookup_ext_info(
 887                                                 const struct iio_channel *chan,
 888                                                 const char *attr)
 889 {
 890         const struct iio_chan_spec_ext_info *ext_info;
 891
 892         if (!chan->channel->ext_info)
 893                 return NULL;
 894
 895         for (ext_info = chan->channel->ext_info; ext_info->name; ++ext_info) {
 896                 if (!strcmp(attr, ext_info->name))
 897                         return ext_info;
 898         }
 899
 900         return NULL;
 901 }
 902
 903 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
 904                                   const char *attr, char *buf)
 905 {
 906         const struct iio_chan_spec_ext_info *ext_info;
 907
 908         ext_info = iio_lookup_ext_info(chan, attr);
 909         if (!ext_info)
 910                 return -EINVAL;
 911
 912         return ext_info->read(chan->indio_dev, ext_info->private,
 913                               chan->channel, buf);
 914 }
 915 EXPORT_SYMBOL_GPL(iio_read_channel_ext_info);
 916
 917 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
 918                                    const char *buf, size_t len)
 919 {
 920         const struct iio_chan_spec_ext_info *ext_info;
 921
 922         ext_info = iio_lookup_ext_info(chan, attr);
 923         if (!ext_info)
 924                 return -EINVAL;
 925
 926         return ext_info->write(chan->indio_dev, ext_info->private,
 927                                chan->channel, buf, len);
 928 }
 929 EXPORT_SYMBOL_GPL(iio_write_channel_ext_info);