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