tools/iio/iio_utils.c

   1 /* IIO - useful set of util functionality
   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 #ifndef _IIO_UTILS_H
  10 #define _IIO_UTILS_H
  11
  12 #include <string.h>
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <stdint.h>
  16 #include <dirent.h>
  17 #include <errno.h>
  18 #include <ctype.h>
  19 #include "iio_utils.h"
  20
  21 const char *iio_dir = "/sys/bus/iio/devices/";
  22
  23 static char * const iio_direction[] = {
  24         "in",
  25         "out",
  26 };
  27
  28 /**
  29  * iioutils_break_up_name() - extract generic name from full channel name
  30  * @full_name: the full channel name
  31  * @generic_name: the output generic channel name
  32  *
  33  * Returns 0 on success, or a negative error code if string extraction failed.
  34  **/
  35 int iioutils_break_up_name(const char *full_name, char **generic_name)
  36 {
  37         char *current;
  38         char *w, *r;
  39         char *working, *prefix = "";
  40         int i, ret;
  41
  42         for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
  43                 if (!strncmp(full_name, iio_direction[i],
  44                              strlen(iio_direction[i]))) {
  45                         prefix = iio_direction[i];
  46                         break;
  47                 }
  48
  49         current = strdup(full_name + strlen(prefix) + 1);
  50         if (!current)
  51                 return -ENOMEM;
  52
  53         working = strtok(current, "_\0");
  54         if (!working) {
  55                 free(current);
  56                 return -EINVAL;
  57         }
  58
  59         w = working;
  60         r = working;
  61
  62         while (*r != '\0') {
  63                 if (!isdigit(*r)) {
  64                         *w = *r;
  65                         w++;
  66                 }
  67
  68                 r++;
  69         }
  70         *w = '\0';
  71         ret = asprintf(generic_name, "%s_%s", prefix, working);
  72         free(current);
  73
  74         return (ret == -1) ? -ENOMEM : 0;
  75 }
  76
  77 /**
  78  * iioutils_get_type() - find and process _type attribute data
  79  * @is_signed: output whether channel is signed
  80  * @bytes: output how many bytes the channel storage occupies
  81  * @bits_used: output number of valid bits of data
  82  * @shift: output amount of bits to shift right data before applying bit mask
  83  * @mask: output a bit mask for the raw data
  84  * @be: output if data in big endian
  85  * @device_dir: the IIO device directory
  86  * @name: the channel name
  87  * @generic_name: the channel type name
  88  *
  89  * Returns a value >= 0 on success, otherwise a negative error code.
  90  **/
  91 int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
  92                       unsigned *shift, uint64_t *mask, unsigned *be,
  93                       const char *device_dir, const char *name,
  94                       const char *generic_name)
  95 {
  96         FILE *sysfsfp;
  97         int ret;
  98         DIR *dp;
  99         char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
 100         char signchar, endianchar;
 101         unsigned padint;
 102         const struct dirent *ent;
 103
 104         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 105         if (ret < 0)
 106                 return -ENOMEM;
 107
 108         ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
 109         if (ret < 0) {
 110                 ret = -ENOMEM;
 111                 goto error_free_scan_el_dir;
 112         }
 113         ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
 114         if (ret < 0) {
 115                 ret = -ENOMEM;
 116                 goto error_free_builtname;
 117         }
 118
 119         dp = opendir(scan_el_dir);
 120         if (!dp) {
 121                 ret = -errno;
 122                 goto error_free_builtname_generic;
 123         }
 124
 125         ret = -ENOENT;
 126         while (ent = readdir(dp), ent)
 127                 /*
 128                  * Do we allow devices to override a generic name with
 129                  * a specific one?
 130                  */
 131                 if ((strcmp(builtname, ent->d_name) == 0) ||
 132                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 133                         ret = asprintf(&filename,
 134                                        "%s/%s", scan_el_dir, ent->d_name);
 135                         if (ret < 0) {
 136                                 ret = -ENOMEM;
 137                                 goto error_closedir;
 138                         }
 139
 140                         sysfsfp = fopen(filename, "r");
 141                         if (!sysfsfp) {
 142                                 ret = -errno;
 143                                 fprintf(stderr, "failed to open %s\n",
 144                                         filename);
 145                                 goto error_free_filename;
 146                         }
 147
 148                         ret = fscanf(sysfsfp,
 149                                      "%ce:%c%u/%u>>%u",
 150                                      &endianchar,
 151                                      &signchar,
 152                                      bits_used,
 153                                      &padint, shift);
 154                         if (ret < 0) {
 155                                 ret = -errno;
 156                                 fprintf(stderr,
 157                                         "failed to pass scan type description\n");
 158                                 goto error_close_sysfsfp;
 159                         } else if (ret != 5) {
 160                                 ret = -EIO;
 161                                 fprintf(stderr,
 162                                         "scan type description didn't match\n");
 163                                 goto error_close_sysfsfp;
 164                         }
 165
 166                         *be = (endianchar == 'b');
 167                         *bytes = padint / 8;
 168                         if (*bits_used == 64)
 169                                 *mask = ~0;
 170                         else
 171                                 *mask = (1 << *bits_used) - 1;
 172
 173                         *is_signed = (signchar == 's');
 174                         if (fclose(sysfsfp)) {
 175                                 ret = -errno;
 176                                 fprintf(stderr, "Failed to close %s\n",
 177                                         filename);
 178                                 goto error_free_filename;
 179                         }
 180
 181                         sysfsfp = 0;
 182                         free(filename);
 183                         filename = 0;
 184                 }
 185
 186 error_close_sysfsfp:
 187         if (sysfsfp)
 188                 if (fclose(sysfsfp))
 189                         perror("iioutils_get_type(): Failed to close file");
 190
 191 error_free_filename:
 192         if (filename)
 193                 free(filename);
 194
 195 error_closedir:
 196         if (closedir(dp) == -1)
 197                 perror("iioutils_get_type(): Failed to close directory");
 198
 199 error_free_builtname_generic:
 200         free(builtname_generic);
 201 error_free_builtname:
 202         free(builtname);
 203 error_free_scan_el_dir:
 204         free(scan_el_dir);
 205
 206         return ret;
 207 }
 208
 209 /**
 210  * iioutils_get_param_float() - read a float value from a channel parameter
 211  * @output: output the float value
 212  * @param_name: the parameter name to read
 213  * @device_dir: the IIO device directory in sysfs
 214  * @name: the channel name
 215  * @generic_name: the channel type name
 216  *
 217  * Returns a value >= 0 on success, otherwise a negative error code.
 218  **/
 219 int iioutils_get_param_float(float *output, const char *param_name,
 220                              const char *device_dir, const char *name,
 221                              const char *generic_name)
 222 {
 223         FILE *sysfsfp;
 224         int ret;
 225         DIR *dp;
 226         char *builtname, *builtname_generic;
 227         char *filename = NULL;
 228         const struct dirent *ent;
 229
 230         ret = asprintf(&builtname, "%s_%s", name, param_name);
 231         if (ret < 0)
 232                 return -ENOMEM;
 233
 234         ret = asprintf(&builtname_generic,
 235                        "%s_%s", generic_name, param_name);
 236         if (ret < 0) {
 237                 ret = -ENOMEM;
 238                 goto error_free_builtname;
 239         }
 240
 241         dp = opendir(device_dir);
 242         if (!dp) {
 243                 ret = -errno;
 244                 goto error_free_builtname_generic;
 245         }
 246
 247         ret = -ENOENT;
 248         while (ent = readdir(dp), ent)
 249                 if ((strcmp(builtname, ent->d_name) == 0) ||
 250                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 251                         ret = asprintf(&filename,
 252                                        "%s/%s", device_dir, ent->d_name);
 253                         if (ret < 0) {
 254                                 ret = -ENOMEM;
 255                                 goto error_closedir;
 256                         }
 257
 258                         sysfsfp = fopen(filename, "r");
 259                         if (!sysfsfp) {
 260                                 ret = -errno;
 261                                 goto error_free_filename;
 262                         }
 263
 264                         errno = 0;
 265                         if (fscanf(sysfsfp, "%f", output) != 1)
 266                                 ret = errno ? -errno : -ENODATA;
 267
 268                         break;
 269                 }
 270 error_free_filename:
 271         if (filename)
 272                 free(filename);
 273
 274 error_closedir:
 275         if (closedir(dp) == -1)
 276                 perror("iioutils_get_param_float(): Failed to close directory");
 277
 278 error_free_builtname_generic:
 279         free(builtname_generic);
 280 error_free_builtname:
 281         free(builtname);
 282
 283         return ret;
 284 }
 285
 286 /**
 287  * bsort_channel_array_by_index() - sort the array in index order
 288  * @ci_array: the iio_channel_info array to be sorted
 289  * @cnt: the amount of array elements
 290  **/
 291
 292 void bsort_channel_array_by_index(struct iio_channel_info **ci_array, int cnt)
 293 {
 294         struct iio_channel_info temp;
 295         int x, y;
 296
 297         for (x = 0; x < cnt; x++)
 298                 for (y = 0; y < (cnt - 1); y++)
 299                         if ((*ci_array)[y].index > (*ci_array)[y + 1].index) {
 300                                 temp = (*ci_array)[y + 1];
 301                                 (*ci_array)[y + 1] = (*ci_array)[y];
 302                                 (*ci_array)[y] = temp;
 303                         }
 304 }
 305
 306 /**
 307  * build_channel_array() - function to figure out what channels are present
 308  * @device_dir: the IIO device directory in sysfs
 309  * @ci_array: output the resulting array of iio_channel_info
 310  * @counter: output the amount of array elements
 311  *
 312  * Returns 0 on success, otherwise a negative error code.
 313  **/
 314 int build_channel_array(const char *device_dir,
 315                         struct iio_channel_info **ci_array, int *counter)
 316 {
 317         DIR *dp;
 318         FILE *sysfsfp;
 319         int count = 0, i;
 320         struct iio_channel_info *current;
 321         int ret;
 322         const struct dirent *ent;
 323         char *scan_el_dir;
 324         char *filename;
 325
 326         *counter = 0;
 327         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 328         if (ret < 0)
 329                 return -ENOMEM;
 330
 331         dp = opendir(scan_el_dir);
 332         if (!dp) {
 333                 ret = -errno;
 334                 goto error_free_name;
 335         }
 336
 337         while (ent = readdir(dp), ent)
 338                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 339                            "_en") == 0) {
 340                         ret = asprintf(&filename,
 341                                        "%s/%s", scan_el_dir, ent->d_name);
 342                         if (ret < 0) {
 343                                 ret = -ENOMEM;
 344                                 goto error_close_dir;
 345                         }
 346
 347                         sysfsfp = fopen(filename, "r");
 348                         if (!sysfsfp) {
 349                                 ret = -errno;
 350                                 free(filename);
 351                                 goto error_close_dir;
 352                         }
 353
 354                         errno = 0;
 355                         if (fscanf(sysfsfp, "%i", &ret) != 1) {
 356                                 ret = errno ? -errno : -ENODATA;
 357                                 if (fclose(sysfsfp))
 358                                         perror("build_channel_array(): Failed to close file");
 359
 360                                 free(filename);
 361                                 goto error_close_dir;
 362                         }
 363                         if (ret == 1)
 364                                 (*counter)++;
 365
 366                         if (fclose(sysfsfp)) {
 367                                 ret = -errno;
 368                                 free(filename);
 369                                 goto error_close_dir;
 370                         }
 371
 372                         free(filename);
 373                 }
 374
 375         *ci_array = malloc(sizeof(**ci_array) * (*counter));
 376         if (!*ci_array) {
 377                 ret = -ENOMEM;
 378                 goto error_close_dir;
 379         }
 380
 381         seekdir(dp, 0);
 382         while (ent = readdir(dp), ent) {
 383                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 384                            "_en") == 0) {
 385                         int current_enabled = 0;
 386
 387                         current = &(*ci_array)[count++];
 388                         ret = asprintf(&filename,
 389                                        "%s/%s", scan_el_dir, ent->d_name);
 390                         if (ret < 0) {
 391                                 ret = -ENOMEM;
 392                                 /* decrement count to avoid freeing name */
 393                                 count--;
 394                                 goto error_cleanup_array;
 395                         }
 396
 397                         sysfsfp = fopen(filename, "r");
 398                         if (!sysfsfp) {
 399                                 ret = -errno;
 400                                 free(filename);
 401                                 count--;
 402                                 goto error_cleanup_array;
 403                         }
 404
 405                         errno = 0;
 406                         if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
 407                                 ret = errno ? -errno : -ENODATA;
 408                                 free(filename);
 409                                 count--;
 410                                 goto error_cleanup_array;
 411                         }
 412
 413                         if (fclose(sysfsfp)) {
 414                                 ret = -errno;
 415                                 free(filename);
 416                                 count--;
 417                                 goto error_cleanup_array;
 418                         }
 419
 420                         if (!current_enabled) {
 421                                 free(filename);
 422                                 count--;
 423                                 continue;
 424                         }
 425
 426                         current->scale = 1.0;
 427                         current->offset = 0;
 428                         current->name = strndup(ent->d_name,
 429                                                 strlen(ent->d_name) -
 430                                                 strlen("_en"));
 431                         if (!current->name) {
 432                                 free(filename);
 433                                 ret = -ENOMEM;
 434                                 count--;
 435                                 goto error_cleanup_array;
 436                         }
 437
 438                         /* Get the generic and specific name elements */
 439                         ret = iioutils_break_up_name(current->name,
 440                                                      &current->generic_name);
 441                         if (ret) {
 442                                 free(filename);
 443                                 free(current->name);
 444                                 count--;
 445                                 goto error_cleanup_array;
 446                         }
 447
 448                         ret = asprintf(&filename,
 449                                        "%s/%s_index",
 450                                        scan_el_dir,
 451                                        current->name);
 452                         if (ret < 0) {
 453                                 free(filename);
 454                                 ret = -ENOMEM;
 455                                 goto error_cleanup_array;
 456                         }
 457
 458                         sysfsfp = fopen(filename, "r");
 459                         if (!sysfsfp) {
 460                                 ret = -errno;
 461                                 fprintf(stderr, "failed to open %s\n",
 462                                         filename);
 463                                 free(filename);
 464                                 goto error_cleanup_array;
 465                         }
 466
 467                         errno = 0;
 468                         if (fscanf(sysfsfp, "%u", &current->index) != 1) {
 469                                 ret = errno ? -errno : -ENODATA;
 470                                 if (fclose(sysfsfp))
 471                                         perror("build_channel_array(): Failed to close file");
 472
 473                                 free(filename);
 474                                 goto error_cleanup_array;
 475                         }
 476
 477                         if (fclose(sysfsfp)) {
 478                                 ret = -errno;
 479                                 free(filename);
 480                                 goto error_cleanup_array;
 481                         }
 482
 483                         free(filename);
 484                         /* Find the scale */
 485                         ret = iioutils_get_param_float(&current->scale,
 486                                                        "scale",
 487                                                        device_dir,
 488                                                        current->name,
 489                                                        current->generic_name);
 490                         if ((ret < 0) && (ret != -ENOENT))
 491                                 goto error_cleanup_array;
 492
 493                         ret = iioutils_get_param_float(&current->offset,
 494                                                        "offset",
 495                                                        device_dir,
 496                                                        current->name,
 497                                                        current->generic_name);
 498                         if ((ret < 0) && (ret != -ENOENT))
 499                                 goto error_cleanup_array;
 500
 501                         ret = iioutils_get_type(&current->is_signed,
 502                                                 &current->bytes,
 503                                                 &current->bits_used,
 504                                                 &current->shift,
 505                                                 &current->mask,
 506                                                 &current->be,
 507                                                 device_dir,
 508                                                 current->name,
 509                                                 current->generic_name);
 510                         if (ret < 0)
 511                                 goto error_cleanup_array;
 512                 }
 513         }
 514
 515         if (closedir(dp) == -1) {
 516                 ret = -errno;
 517                 goto error_cleanup_array;
 518         }
 519
 520         free(scan_el_dir);
 521         /* reorder so that the array is in index order */
 522         bsort_channel_array_by_index(ci_array, *counter);
 523
 524         return 0;
 525
 526 error_cleanup_array:
 527         for (i = count - 1;  i >= 0; i--) {
 528                 free((*ci_array)[i].name);
 529                 free((*ci_array)[i].generic_name);
 530         }
 531         free(*ci_array);
 532 error_close_dir:
 533         if (dp)
 534                 if (closedir(dp) == -1)
 535                         perror("build_channel_array(): Failed to close dir");
 536
 537 error_free_name:
 538         free(scan_el_dir);
 539
 540         return ret;
 541 }
 542
 543 int calc_digits(int num)
 544 {
 545         int count = 0;
 546
 547         while (num != 0) {
 548                 num /= 10;
 549                 count++;
 550         }
 551
 552         return count;
 553 }
 554
 555 /**
 556  * find_type_by_name() - function to match top level types by name
 557  * @name: top level type instance name
 558  * @type: the type of top level instance being searched
 559  *
 560  * Returns the device number of a matched IIO device on success, otherwise a
 561  * negative error code.
 562  * Typical types this is used for are device and trigger.
 563  **/
 564 int find_type_by_name(const char *name, const char *type)
 565 {
 566         const struct dirent *ent;
 567         int number, numstrlen, ret;
 568
 569         FILE *namefp;
 570         DIR *dp;
 571         char thisname[IIO_MAX_NAME_LENGTH];
 572         char *filename;
 573
 574         dp = opendir(iio_dir);
 575         if (!dp) {
 576                 fprintf(stderr, "No industrialio devices available\n");
 577                 return -ENODEV;
 578         }
 579
 580         while (ent = readdir(dp), ent) {
 581                 if (strcmp(ent->d_name, ".") != 0 &&
 582                     strcmp(ent->d_name, "..") != 0 &&
 583                     strlen(ent->d_name) > strlen(type) &&
 584                     strncmp(ent->d_name, type, strlen(type)) == 0) {
 585                         errno = 0;
 586                         ret = sscanf(ent->d_name + strlen(type), "%d", &number);
 587                         if (ret < 0) {
 588                                 ret = -errno;
 589                                 fprintf(stderr,
 590                                         "failed to read element number\n");
 591                                 goto error_close_dir;
 592                         } else if (ret != 1) {
 593                                 ret = -EIO;
 594                                 fprintf(stderr,
 595                                         "failed to match element number\n");
 596                                 goto error_close_dir;
 597                         }
 598
 599                         numstrlen = calc_digits(number);
 600                         /* verify the next character is not a colon */
 601                         if (strncmp(ent->d_name + strlen(type) + numstrlen,
 602                             ":", 1) != 0) {
 603                                 filename = malloc(strlen(iio_dir) + strlen(type)
 604                                                   + numstrlen + 6);
 605                                 if (!filename) {
 606                                         ret = -ENOMEM;
 607                                         goto error_close_dir;
 608                                 }
 609
 610                                 ret = sprintf(filename, "%s%s%d/name", iio_dir,
 611                                               type, number);
 612                                 if (ret < 0) {
 613                                         free(filename);
 614                                         goto error_close_dir;
 615                                 }
 616
 617                                 namefp = fopen(filename, "r");
 618                                 if (!namefp) {
 619                                         free(filename);
 620                                         continue;
 621                                 }
 622
 623                                 free(filename);
 624                                 errno = 0;
 625                                 if (fscanf(namefp, "%s", thisname) != 1) {
 626                                         ret = errno ? -errno : -ENODATA;
 627                                         goto error_close_dir;
 628                                 }
 629
 630                                 if (fclose(namefp)) {
 631                                         ret = -errno;
 632                                         goto error_close_dir;
 633                                 }
 634
 635                                 if (strcmp(name, thisname) == 0) {
 636                                         if (closedir(dp) == -1)
 637                                                 return -errno;
 638
 639                                         return number;
 640                                 }
 641                         }
 642                 }
 643         }
 644         if (closedir(dp) == -1)
 645                 return -errno;
 646
 647         return -ENODEV;
 648
 649 error_close_dir:
 650         if (closedir(dp) == -1)
 651                 perror("find_type_by_name(): Failed to close directory");
 652
 653         return ret;
 654 }
 655
 656 static int _write_sysfs_int(const char *filename, const char *basedir, int val,
 657                             int verify)
 658 {
 659         int ret = 0;
 660         FILE *sysfsfp;
 661         int test;
 662         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 663
 664         if (!temp)
 665                 return -ENOMEM;
 666
 667         ret = sprintf(temp, "%s/%s", basedir, filename);
 668         if (ret < 0)
 669                 goto error_free;
 670
 671         sysfsfp = fopen(temp, "w");
 672         if (!sysfsfp) {
 673                 ret = -errno;
 674                 fprintf(stderr, "failed to open %s\n", temp);
 675                 goto error_free;
 676         }
 677
 678         ret = fprintf(sysfsfp, "%d", val);
 679         if (ret < 0) {
 680                 if (fclose(sysfsfp))
 681                         perror("_write_sysfs_int(): Failed to close dir");
 682
 683                 goto error_free;
 684         }
 685
 686         if (fclose(sysfsfp)) {
 687                 ret = -errno;
 688                 goto error_free;
 689         }
 690
 691         if (verify) {
 692                 sysfsfp = fopen(temp, "r");
 693                 if (!sysfsfp) {
 694                         ret = -errno;
 695                         fprintf(stderr, "failed to open %s\n", temp);
 696                         goto error_free;
 697                 }
 698
 699                 if (fscanf(sysfsfp, "%d", &test) != 1) {
 700                         ret = errno ? -errno : -ENODATA;
 701                         if (fclose(sysfsfp))
 702                                 perror("_write_sysfs_int(): Failed to close dir");
 703
 704                         goto error_free;
 705                 }
 706
 707                 if (fclose(sysfsfp)) {
 708                         ret = -errno;
 709                         goto error_free;
 710                 }
 711
 712                 if (test != val) {
 713                         fprintf(stderr,
 714                                 "Possible failure in int write %d to %s/%s\n",
 715                                 val, basedir, filename);
 716                         ret = -1;
 717                 }
 718         }
 719
 720 error_free:
 721         free(temp);
 722         return ret;
 723 }
 724
 725 /**
 726  * write_sysfs_int() - write an integer value to a sysfs file
 727  * @filename: name of the file to write to
 728  * @basedir: the sysfs directory in which the file is to be found
 729  * @val: integer value to write to file
 730  *
 731  * Returns a value >= 0 on success, otherwise a negative error code.
 732  **/
 733 int write_sysfs_int(const char *filename, const char *basedir, int val)
 734 {
 735         return _write_sysfs_int(filename, basedir, val, 0);
 736 }
 737
 738 /**
 739  * write_sysfs_int_and_verify() - write an integer value to a sysfs file
 740  *                                and verify
 741  * @filename: name of the file to write to
 742  * @basedir: the sysfs directory in which the file is to be found
 743  * @val: integer value to write to file
 744  *
 745  * Returns a value >= 0 on success, otherwise a negative error code.
 746  **/
 747 int write_sysfs_int_and_verify(const char *filename, const char *basedir,
 748                                int val)
 749 {
 750         return _write_sysfs_int(filename, basedir, val, 1);
 751 }
 752
 753 static int _write_sysfs_string(const char *filename, const char *basedir,
 754                                const char *val, int verify)
 755 {
 756         int ret = 0;
 757         FILE  *sysfsfp;
 758         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 759
 760         if (!temp) {
 761                 fprintf(stderr, "Memory allocation failed\n");
 762                 return -ENOMEM;
 763         }
 764
 765         ret = sprintf(temp, "%s/%s", basedir, filename);
 766         if (ret < 0)
 767                 goto error_free;
 768
 769         sysfsfp = fopen(temp, "w");
 770         if (!sysfsfp) {
 771                 ret = -errno;
 772                 fprintf(stderr, "Could not open %s\n", temp);
 773                 goto error_free;
 774         }
 775
 776         ret = fprintf(sysfsfp, "%s", val);
 777         if (ret < 0) {
 778                 if (fclose(sysfsfp))
 779                         perror("_write_sysfs_string(): Failed to close dir");
 780
 781                 goto error_free;
 782         }
 783
 784         if (fclose(sysfsfp)) {
 785                 ret = -errno;
 786                 goto error_free;
 787         }
 788
 789         if (verify) {
 790                 sysfsfp = fopen(temp, "r");
 791                 if (!sysfsfp) {
 792                         ret = -errno;
 793                         fprintf(stderr, "Could not open file to verify\n");
 794                         goto error_free;
 795                 }
 796
 797                 if (fscanf(sysfsfp, "%s", temp) != 1) {
 798                         ret = errno ? -errno : -ENODATA;
 799                         if (fclose(sysfsfp))
 800                                 perror("_write_sysfs_string(): Failed to close dir");
 801
 802                         goto error_free;
 803                 }
 804
 805                 if (fclose(sysfsfp)) {
 806                         ret = -errno;
 807                         goto error_free;
 808                 }
 809
 810                 if (strcmp(temp, val) != 0) {
 811                         fprintf(stderr,
 812                                 "Possible failure in string write of %s "
 813                                 "Should be %s written to %s/%s\n", temp, val,
 814                                 basedir, filename);
 815                         ret = -1;
 816                 }
 817         }
 818
 819 error_free:
 820         free(temp);
 821
 822         return ret;
 823 }
 824
 825 /**
 826  * write_sysfs_string_and_verify() - string write, readback and verify
 827  * @filename: name of file to write to
 828  * @basedir: the sysfs directory in which the file is to be found
 829  * @val: the string to write
 830  *
 831  * Returns a value >= 0 on success, otherwise a negative error code.
 832  **/
 833 int write_sysfs_string_and_verify(const char *filename, const char *basedir,
 834                                   const char *val)
 835 {
 836         return _write_sysfs_string(filename, basedir, val, 1);
 837 }
 838
 839 /**
 840  * write_sysfs_string() - write string to a sysfs file
 841  * @filename: name of file to write to
 842  * @basedir: the sysfs directory in which the file is to be found
 843  * @val: the string to write
 844  *
 845  * Returns a value >= 0 on success, otherwise a negative error code.
 846  **/
 847 int write_sysfs_string(const char *filename, const char *basedir,
 848                        const char *val)
 849 {
 850         return _write_sysfs_string(filename, basedir, val, 0);
 851 }
 852
 853 /**
 854  * read_sysfs_posint() - read an integer value from file
 855  * @filename: name of file to read from
 856  * @basedir: the sysfs directory in which the file is to be found
 857  *
 858  * Returns the read integer value >= 0 on success, otherwise a negative error
 859  * code.
 860  **/
 861 int read_sysfs_posint(const char *filename, const char *basedir)
 862 {
 863         int ret;
 864         FILE  *sysfsfp;
 865         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 866
 867         if (!temp) {
 868                 fprintf(stderr, "Memory allocation failed");
 869                 return -ENOMEM;
 870         }
 871
 872         ret = sprintf(temp, "%s/%s", basedir, filename);
 873         if (ret < 0)
 874                 goto error_free;
 875
 876         sysfsfp = fopen(temp, "r");
 877         if (!sysfsfp) {
 878                 ret = -errno;
 879                 goto error_free;
 880         }
 881
 882         errno = 0;
 883         if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
 884                 ret = errno ? -errno : -ENODATA;
 885                 if (fclose(sysfsfp))
 886                         perror("read_sysfs_posint(): Failed to close dir");
 887
 888                 goto error_free;
 889         }
 890
 891         if (fclose(sysfsfp))
 892                 ret = -errno;
 893
 894 error_free:
 895         free(temp);
 896
 897         return ret;
 898 }
 899
 900 /**
 901  * read_sysfs_float() - read a float value from file
 902  * @filename: name of file to read from
 903  * @basedir: the sysfs directory in which the file is to be found
 904  * @val: output the read float value
 905  *
 906  * Returns a value >= 0 on success, otherwise a negative error code.
 907  **/
 908 int read_sysfs_float(const char *filename, const char *basedir, float *val)
 909 {
 910         int ret = 0;
 911         FILE  *sysfsfp;
 912         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 913
 914         if (!temp) {
 915                 fprintf(stderr, "Memory allocation failed");
 916                 return -ENOMEM;
 917         }
 918
 919         ret = sprintf(temp, "%s/%s", basedir, filename);
 920         if (ret < 0)
 921                 goto error_free;
 922
 923         sysfsfp = fopen(temp, "r");
 924         if (!sysfsfp) {
 925                 ret = -errno;
 926                 goto error_free;
 927         }
 928
 929         errno = 0;
 930         if (fscanf(sysfsfp, "%f\n", val) != 1) {
 931                 ret = errno ? -errno : -ENODATA;
 932                 if (fclose(sysfsfp))
 933                         perror("read_sysfs_float(): Failed to close dir");
 934
 935                 goto error_free;
 936         }
 937
 938         if (fclose(sysfsfp))
 939                 ret = -errno;
 940
 941 error_free:
 942         free(temp);
 943
 944         return ret;
 945 }
 946
 947 /**
 948  * read_sysfs_string() - read a string from file
 949  * @filename: name of file to read from
 950  * @basedir: the sysfs directory in which the file is to be found
 951  * @str: output the read string
 952  *
 953  * Returns a value >= 0 on success, otherwise a negative error code.
 954  **/
 955 int read_sysfs_string(const char *filename, const char *basedir, char *str)
 956 {
 957         int ret = 0;
 958         FILE  *sysfsfp;
 959         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 960
 961         if (!temp) {
 962                 fprintf(stderr, "Memory allocation failed");
 963                 return -ENOMEM;
 964         }
 965
 966         ret = sprintf(temp, "%s/%s", basedir, filename);
 967         if (ret < 0)
 968                 goto error_free;
 969
 970         sysfsfp = fopen(temp, "r");
 971         if (!sysfsfp) {
 972                 ret = -errno;
 973                 goto error_free;
 974         }
 975
 976         errno = 0;
 977         if (fscanf(sysfsfp, "%s\n", str) != 1) {
 978                 ret = errno ? -errno : -ENODATA;
 979                 if (fclose(sysfsfp))
 980                         perror("read_sysfs_string(): Failed to close dir");
 981
 982                 goto error_free;
 983         }
 984
 985         if (fclose(sysfsfp))
 986                 ret = -errno;
 987
 988 error_free:
 989         free(temp);
 990
 991         return ret;
 992 }
 993
 994 #endif /* _IIO_UTILS_H */