drivers/iio/inkern.c

   1 /* The industrial I/O core in kernel channel mapping
   2  *
   3  * Copyright (c) 2011 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 #include <linux/err.h>
  10 #include <linux/export.h>
  11 #include <linux/slab.h>
  12 #include <linux/mutex.h>
  13 #include <linux/of.h>
  14
  15 #include <linux/iio/iio.h>
  16 #include "iio_core.h"
  17 #include <linux/iio/machine.h>
  18 #include <linux/iio/driver.h>
  19 #include <linux/iio/consumer.h>
  20
  21 struct iio_map_internal {
  22         struct iio_dev *indio_dev;
  23         struct iio_map *map;
  24         struct list_head l;
  25 };
  26
  27 static LIST_HEAD(iio_map_list);
  28 static DEFINE_MUTEX(iio_map_list_lock);
  29
  30 int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
  31 {
  32         int i = 0, ret = 0;
  33         struct iio_map_internal *mapi;
  34
  35         if (maps == NULL)
  36                 return 0;
  37
  38         mutex_lock(&iio_map_list_lock);
  39         while (maps[i].consumer_dev_name != NULL) {
  40                 mapi = kzalloc(sizeof(*mapi), GFP_KERNEL);
  41                 if (mapi == NULL) {
  42                         ret = -ENOMEM;
  43                         goto error_ret;
  44                 }
  45                 mapi->map = &maps[i];
  46                 mapi->indio_dev = indio_dev;
  47                 list_add(&mapi->l, &iio_map_list);
  48                 i++;
  49         }
  50 error_ret:
  51         mutex_unlock(&iio_map_list_lock);
  52
  53         return ret;
  54 }
  55 EXPORT_SYMBOL_GPL(iio_map_array_register);
  56
  57
  58 /*
  59  * Remove all map entries associated with the given iio device
  60  */
  61 int iio_map_array_unregister(struct iio_dev *indio_dev)
  62 {
  63         int ret = -ENODEV;
  64         struct iio_map_internal *mapi;
  65         struct list_head *pos, *tmp;
  66
  67         mutex_lock(&iio_map_list_lock);
  68         list_for_each_safe(pos, tmp, &iio_map_list) {
  69                 mapi = list_entry(pos, struct iio_map_internal, l);
  70                 if (indio_dev == mapi->indio_dev) {
  71                         list_del(&mapi->l);
  72                         kfree(mapi);
  73                         ret = 0;
  74                 }
  75         }
  76         mutex_unlock(&iio_map_list_lock);
  77         return ret;
  78 }
  79 EXPORT_SYMBOL_GPL(iio_map_array_unregister);
  80
  81 static const struct iio_chan_spec
  82 *iio_chan_spec_from_name(const struct iio_dev *indio_dev, const char *name)
  83 {
  84         int i;
  85         const struct iio_chan_spec *chan = NULL;
  86
  87         for (i = 0; i < indio_dev->num_channels; i++)
  88                 if (indio_dev->channels[i].datasheet_name &&
  89                     strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
  90                         chan = &indio_dev->channels[i];
  91                         break;
  92                 }
  93         return chan;
  94 }
  95
  96 #ifdef CONFIG_OF
  97
  98 static int iio_dev_node_match(struct device *dev, void *data)
  99 {
 100         return dev->of_node == data && dev->type == &iio_device_type;
 101 }
 102
 103 static int __of_iio_channel_get(struct iio_channel *channel,
 104                                 struct device_node *np, int index)
 105 {
 106         struct device *idev;
 107         struct iio_dev *indio_dev;
 108         int err;
 109         struct of_phandle_args iiospec;
 110
 111         err = of_parse_phandle_with_args(np, "io-channels",
 112                                          "#io-channel-cells",
 113                                          index, &iiospec);
 114         if (err)
 115                 return err;
 116
 117         idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
 118                                iio_dev_node_match);
 119         of_node_put(iiospec.np);
 120         if (idev == NULL)
 121                 return -EPROBE_DEFER;
 122
 123         indio_dev = dev_to_iio_dev(idev);
 124         channel->indio_dev = indio_dev;
 125         index = iiospec.args_count ? iiospec.args[0] : 0;
 126         if (index >= indio_dev->num_channels) {
 127                 err = -EINVAL;
 128                 goto err_put;
 129         }
 130         channel->channel = &indio_dev->channels[index];
 131
 132         return 0;
 133
 134 err_put:
 135         iio_device_put(indio_dev);
 136         return err;
 137 }
 138
 139 static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
 140 {
 141         struct iio_channel *channel;
 142         int err;
 143
 144         if (index < 0)
 145                 return ERR_PTR(-EINVAL);
 146
 147         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 148         if (channel == NULL)
 149                 return ERR_PTR(-ENOMEM);
 150
 151         err = __of_iio_channel_get(channel, np, index);
 152         if (err)
 153                 goto err_free_channel;
 154
 155         return channel;
 156
 157 err_free_channel:
 158         kfree(channel);
 159         return ERR_PTR(err);
 160 }
 161
 162 static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
 163                                                       const char *name)
 164 {
 165         struct iio_channel *chan = NULL;
 166
 167         /* Walk up the tree of devices looking for a matching iio channel */
 168         while (np) {
 169                 int index = 0;
 170
 171                 /*
 172                  * For named iio channels, first look up the name in the
 173                  * "io-channel-names" property.  If it cannot be found, the
 174                  * index will be an error code, and of_iio_channel_get()
 175                  * will fail.
 176                  */
 177                 if (name)
 178                         index = of_property_match_string(np, "io-channel-names",
 179                                                          name);
 180                 chan = of_iio_channel_get(np, index);
 181                 if (!IS_ERR(chan))
 182                         break;
 183                 else if (name && index >= 0) {
 184                         pr_err("ERROR: could not get IIO channel %s:%s(%i)\n",
 185                                 np->full_name, name ? name : "", index);
 186                         return NULL;
 187                 }
 188
 189                 /*
 190                  * No matching IIO channel found on this node.
 191                  * If the parent node has a "io-channel-ranges" property,
 192                  * then we can try one of its channels.
 193                  */
 194                 np = np->parent;
 195                 if (np && !of_get_property(np, "io-channel-ranges", NULL))
 196                         return NULL;
 197         }
 198
 199         return chan;
 200 }
 201
 202 static struct iio_channel *of_iio_channel_get_all(struct device *dev)
 203 {
 204         struct iio_channel *chans;
 205         int i, mapind, nummaps = 0;
 206         int ret;
 207
 208         do {
 209                 ret = of_parse_phandle_with_args(dev->of_node,
 210                                                  "io-channels",
 211                                                  "#io-channel-cells",
 212                                                  nummaps, NULL);
 213                 if (ret < 0)
 214                         break;
 215         } while (++nummaps);
 216
 217         if (nummaps == 0)       /* no error, return NULL to search map table */
 218                 return NULL;
 219
 220         /* NULL terminated array to save passing size */
 221         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 222         if (chans == NULL)
 223                 return ERR_PTR(-ENOMEM);
 224
 225         /* Search for OF matches */
 226         for (mapind = 0; mapind < nummaps; mapind++) {
 227                 ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
 228                                            mapind);
 229                 if (ret)
 230                         goto error_free_chans;
 231         }
 232         return chans;
 233
 234 error_free_chans:
 235         for (i = 0; i < mapind; i++)
 236                 iio_device_put(chans[i].indio_dev);
 237         kfree(chans);
 238         return ERR_PTR(ret);
 239 }
 240
 241 #else /* CONFIG_OF */
 242
 243 static inline struct iio_channel *
 244 of_iio_channel_get_by_name(struct device_node *np, const char *name)
 245 {
 246         return NULL;
 247 }
 248
 249 static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
 250 {
 251         return NULL;
 252 }
 253
 254 #endif /* CONFIG_OF */
 255
 256 static struct iio_channel *iio_channel_get_sys(const char *name,
 257                                                const char *channel_name)
 258 {
 259         struct iio_map_internal *c_i = NULL, *c = NULL;
 260         struct iio_channel *channel;
 261         int err;
 262
 263         if (name == NULL && channel_name == NULL)
 264                 return ERR_PTR(-ENODEV);
 265
 266         /* first find matching entry the channel map */
 267         mutex_lock(&iio_map_list_lock);
 268         list_for_each_entry(c_i, &iio_map_list, l) {
 269                 if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
 270                     (channel_name &&
 271                      strcmp(channel_name, c_i->map->consumer_channel) != 0))
 272                         continue;
 273                 c = c_i;
 274                 iio_device_get(c->indio_dev);
 275                 break;
 276         }
 277         mutex_unlock(&iio_map_list_lock);
 278         if (c == NULL)
 279                 return ERR_PTR(-ENODEV);
 280
 281         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 282         if (channel == NULL) {
 283                 err = -ENOMEM;
 284                 goto error_no_mem;
 285         }
 286
 287         channel->indio_dev = c->indio_dev;
 288
 289         if (c->map->adc_channel_label) {
 290                 channel->channel =
 291                         iio_chan_spec_from_name(channel->indio_dev,
 292                                                 c->map->adc_channel_label);
 293
 294                 if (channel->channel == NULL) {
 295                         err = -EINVAL;
 296                         goto error_no_chan;
 297                 }
 298         }
 299
 300         return channel;
 301
 302 error_no_chan:
 303         kfree(channel);
 304 error_no_mem:
 305         iio_device_put(c->indio_dev);
 306         return ERR_PTR(err);
 307 }
 308
 309 struct iio_channel *iio_channel_get(struct device *dev,
 310                                     const char *channel_name)
 311 {
 312         const char *name = dev ? dev_name(dev) : NULL;
 313         struct iio_channel *channel;
 314
 315         if (dev) {
 316                 channel = of_iio_channel_get_by_name(dev->of_node,
 317                                                      channel_name);
 318                 if (channel != NULL)
 319                         return channel;
 320         }
 321
 322         return iio_channel_get_sys(name, channel_name);
 323 }
 324 EXPORT_SYMBOL_GPL(iio_channel_get);
 325
 326 void iio_channel_release(struct iio_channel *channel)
 327 {
 328         iio_device_put(channel->indio_dev);
 329         kfree(channel);
 330 }
 331 EXPORT_SYMBOL_GPL(iio_channel_release);
 332
 333 struct iio_channel *iio_channel_get_all(struct device *dev)
 334 {
 335         const char *name;
 336         struct iio_channel *chans;
 337         struct iio_map_internal *c = NULL;
 338         int nummaps = 0;
 339         int mapind = 0;
 340         int i, ret;
 341
 342         if (dev == NULL)
 343                 return ERR_PTR(-EINVAL);
 344
 345         chans = of_iio_channel_get_all(dev);
 346         if (chans)
 347                 return chans;
 348
 349         name = dev_name(dev);
 350
 351         mutex_lock(&iio_map_list_lock);
 352         /* first count the matching maps */
 353         list_for_each_entry(c, &iio_map_list, l)
 354                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 355                         continue;
 356                 else
 357                         nummaps++;
 358
 359         if (nummaps == 0) {
 360                 ret = -ENODEV;
 361                 goto error_ret;
 362         }
 363
 364         /* NULL terminated array to save passing size */
 365         chans = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL);
 366         if (chans == NULL) {
 367                 ret = -ENOMEM;
 368                 goto error_ret;
 369         }
 370
 371         /* for each map fill in the chans element */
 372         list_for_each_entry(c, &iio_map_list, l) {
 373                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 374                         continue;
 375                 chans[mapind].indio_dev = c->indio_dev;
 376                 chans[mapind].data = c->map->consumer_data;
 377                 chans[mapind].channel =
 378                         iio_chan_spec_from_name(chans[mapind].indio_dev,
 379                                                 c->map->adc_channel_label);
 380                 if (chans[mapind].channel == NULL) {
 381                         ret = -EINVAL;
 382                         goto error_free_chans;
 383                 }
 384                 iio_device_get(chans[mapind].indio_dev);
 385                 mapind++;
 386         }
 387         if (mapind == 0) {
 388                 ret = -ENODEV;
 389                 goto error_free_chans;
 390         }
 391         mutex_unlock(&iio_map_list_lock);
 392
 393         return chans;
 394
 395 error_free_chans:
 396         for (i = 0; i < nummaps; i++)
 397                 iio_device_put(chans[i].indio_dev);
 398         kfree(chans);
 399 error_ret:
 400         mutex_unlock(&iio_map_list_lock);
 401
 402         return ERR_PTR(ret);
 403 }
 404 EXPORT_SYMBOL_GPL(iio_channel_get_all);
 405
 406 void iio_channel_release_all(struct iio_channel *channels)
 407 {
 408         struct iio_channel *chan = &channels[0];
 409
 410         while (chan->indio_dev) {
 411                 iio_device_put(chan->indio_dev);
 412                 chan++;
 413         }
 414         kfree(channels);
 415 }
 416 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 417
 418 static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
 419         enum iio_chan_info_enum info)
 420 {
 421         int unused;
 422
 423         if (val2 == NULL)
 424                 val2 = &unused;
 425
 426         return chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
 427                                                 val, val2, info);
 428 }
 429
 430 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 431 {
 432         int ret;
 433
 434         mutex_lock(&chan->indio_dev->info_exist_lock);
 435         if (chan->indio_dev->info == NULL) {
 436                 ret = -ENODEV;
 437                 goto err_unlock;
 438         }
 439
 440         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 441 err_unlock:
 442         mutex_unlock(&chan->indio_dev->info_exist_lock);
 443
 444         return ret;
 445 }
 446 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 447
 448 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 449         int raw, int *processed, unsigned int scale)
 450 {
 451         int scale_type, scale_val, scale_val2, offset;
 452         s64 raw64 = raw;
 453         int ret;
 454
 455         ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
 456         if (ret >= 0)
 457                 raw64 += offset;
 458
 459         scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
 460                                         IIO_CHAN_INFO_SCALE);
 461         if (scale_type < 0)
 462                 return scale_type;
 463
 464         switch (scale_type) {
 465         case IIO_VAL_INT:
 466                 *processed = raw64 * scale_val;
 467                 break;
 468         case IIO_VAL_INT_PLUS_MICRO:
 469                 if (scale_val2 < 0)
 470                         *processed = -raw64 * scale_val;
 471                 else
 472                         *processed = raw64 * scale_val;
 473                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 474                                       1000000LL);
 475                 break;
 476         case IIO_VAL_INT_PLUS_NANO:
 477                 if (scale_val2 < 0)
 478                         *processed = -raw64 * scale_val;
 479                 else
 480                         *processed = raw64 * scale_val;
 481                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 482                                       1000000000LL);
 483                 break;
 484         case IIO_VAL_FRACTIONAL:
 485                 *processed = div_s64(raw64 * (s64)scale_val * scale,
 486                                      scale_val2);
 487                 break;
 488         case IIO_VAL_FRACTIONAL_LOG2:
 489                 *processed = (raw64 * (s64)scale_val * scale) >> scale_val2;
 490                 break;
 491         default:
 492                 return -EINVAL;
 493         }
 494
 495         return 0;
 496 }
 497
 498 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 499         int *processed, unsigned int scale)
 500 {
 501         int ret;
 502
 503         mutex_lock(&chan->indio_dev->info_exist_lock);
 504         if (chan->indio_dev->info == NULL) {
 505                 ret = -ENODEV;
 506                 goto err_unlock;
 507         }
 508
 509         ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
 510                                                         scale);
 511 err_unlock:
 512         mutex_unlock(&chan->indio_dev->info_exist_lock);
 513
 514         return ret;
 515 }
 516 EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
 517
 518 int iio_read_channel_processed(struct iio_channel *chan, int *val)
 519 {
 520         int ret;
 521
 522         mutex_lock(&chan->indio_dev->info_exist_lock);
 523         if (chan->indio_dev->info == NULL) {
 524                 ret = -ENODEV;
 525                 goto err_unlock;
 526         }
 527
 528         if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
 529                 ret = iio_channel_read(chan, val, NULL,
 530                                        IIO_CHAN_INFO_PROCESSED);
 531         } else {
 532                 ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 533                 if (ret < 0)
 534                         goto err_unlock;
 535                 ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
 536         }
 537
 538 err_unlock:
 539         mutex_unlock(&chan->indio_dev->info_exist_lock);
 540
 541         return ret;
 542 }
 543 EXPORT_SYMBOL_GPL(iio_read_channel_processed);
 544
 545 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 546 {
 547         int ret;
 548
 549         mutex_lock(&chan->indio_dev->info_exist_lock);
 550         if (chan->indio_dev->info == NULL) {
 551                 ret = -ENODEV;
 552                 goto err_unlock;
 553         }
 554
 555         ret = iio_channel_read(chan, val, val2, IIO_CHAN_INFO_SCALE);
 556 err_unlock:
 557         mutex_unlock(&chan->indio_dev->info_exist_lock);
 558
 559         return ret;
 560 }
 561 EXPORT_SYMBOL_GPL(iio_read_channel_scale);
 562
 563 int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
 564 {
 565         int ret = 0;
 566         /* Need to verify underlying driver has not gone away */
 567
 568         mutex_lock(&chan->indio_dev->info_exist_lock);
 569         if (chan->indio_dev->info == NULL) {
 570                 ret = -ENODEV;
 571                 goto err_unlock;
 572         }
 573
 574         *type = chan->channel->type;
 575 err_unlock:
 576         mutex_unlock(&chan->indio_dev->info_exist_lock);
 577
 578         return ret;
 579 }
 580 EXPORT_SYMBOL_GPL(iio_get_channel_type);