drivers/staging/iio/Documentation/iio_utils.h

   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
  10 /* Made up value to limit allocation sizes */
  11 #include <string.h>
  12 #include <stdlib.h>
  13 #include <ctype.h>
  14 #include <stdio.h>
  15 #include <stdint.h>
  16
  17 #define IIO_MAX_NAME_LENGTH 30
  18
  19 #define IIO_EV_CLASS_BUFFER             0
  20 #define IIO_BUFFER_EVENT_CODE(code)             \
  21         (IIO_EV_CLASS_BUFFER | (code << 8))
  22
  23 #define IIO_EVENT_CODE_RING_50_FULL     IIO_BUFFER_EVENT_CODE(0)
  24 #define IIO_EVENT_CODE_RING_75_FULL     IIO_BUFFER_EVENT_CODE(1)
  25 #define IIO_EVENT_CODE_RING_100_FULL    IIO_BUFFER_EVENT_CODE(2)
  26
  27
  28 #define FORMAT_SCAN_ELEMENTS_DIR "%s:buffer0/scan_elements"
  29 #define FORMAT_TYPE_FILE "%s_type"
  30
  31 const char *iio_dir = "/sys/bus/iio/devices/";
  32
  33 struct iio_event_data {
  34         int id;
  35         __s64 timestamp;
  36 };
  37
  38 /**
  39  * iioutils_break_up_name() - extract generic name from full channel name
  40  * @full_name: the full channel name
  41  * @generic_name: the output generic channel name
  42  **/
  43 static int iioutils_break_up_name(const char *full_name,
  44                                   char **generic_name)
  45 {
  46         char *current;
  47         char *w, *r;
  48         char *working;
  49         current = strdup(full_name);
  50         working = strtok(current, "_\0");
  51         w = working;
  52         r = working;
  53
  54         while(*r != '\0') {
  55                 if (!isdigit(*r)) {
  56                         *w = *r;
  57                         w++;
  58                 }
  59                 r++;
  60         }
  61         *w = '\0';
  62         *generic_name = strdup(working);
  63         free(current);
  64
  65         return 0;
  66 }
  67
  68 /**
  69  * struct iio_channel_info - information about a given channel
  70  * @name: channel name
  71  * @generic_name: general name for channel type
  72  * @scale: scale factor to be applied for conversion to si units
  73  * @offset: offset to be applied for conversion to si units
  74  * @index: the channel index in the buffer output
  75  * @bytes: number of bytes occupied in buffer output
  76  * @mask: a bit mask for the raw output
  77  * @is_signed: is the raw value stored signed
  78  * @enabled: is this channel enabled
  79  **/
  80 struct iio_channel_info {
  81         char *name;
  82         char *generic_name;
  83         float scale;
  84         float offset;
  85         unsigned index;
  86         unsigned bytes;
  87         unsigned bits_used;
  88         uint64_t mask;
  89         unsigned is_signed;
  90         unsigned enabled;
  91         unsigned location;
  92 };
  93
  94 /**
  95  * iioutils_get_type() - find and process _type attribute data
  96  * @is_signed: output whether channel is signed
  97  * @bytes: output how many bytes the channel storage occupies
  98  * @mask: output a bit mask for the raw data
  99  * @device_dir: the iio device directory
 100  * @name: the channel name
 101  * @generic_name: the channel type name
 102  **/
 103 inline int iioutils_get_type(unsigned *is_signed,
 104                              unsigned *bytes,
 105                              unsigned *bits_used,
 106                              uint64_t *mask,
 107                              const char *device_dir,
 108                              const char *name,
 109                              const char *generic_name)
 110 {
 111         FILE *sysfsfp;
 112         int ret;
 113         DIR *dp;
 114         char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
 115         char signchar;
 116         unsigned sizeint, padint;
 117         const struct dirent *ent;
 118
 119         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 120         if (ret < 0) {
 121                 ret = -ENOMEM;
 122                 goto error_ret;
 123         }
 124         ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
 125         if (ret < 0) {
 126                 ret = -ENOMEM;
 127                 goto error_free_scan_el_dir;
 128         }
 129         ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
 130         if (ret < 0) {
 131                 ret = -ENOMEM;
 132                 goto error_free_builtname;
 133         }
 134
 135         dp = opendir(scan_el_dir);
 136         if (dp == NULL) {
 137                 ret = -errno;
 138                 goto error_free_builtname_generic;
 139         }
 140         while (ent = readdir(dp), ent != NULL)
 141                 /*
 142                  * Do we allow devices to override a generic name with
 143                  * a specific one?
 144                  */
 145                 if ((strcmp(builtname, ent->d_name) == 0) ||
 146                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 147                         ret = asprintf(&filename,
 148                                        "%s/%s", scan_el_dir, ent->d_name);
 149                         if (ret < 0) {
 150                                 ret = -ENOMEM;
 151                                 goto error_closedir;
 152                         }
 153                         sysfsfp = fopen(filename, "r");
 154                         if (sysfsfp == NULL) {
 155                                 printf("failed to open %s\n", filename);
 156                                 ret = -errno;
 157                                 goto error_free_filename;
 158                         }
 159                         fscanf(sysfsfp,
 160                                "%c%u/%u", &signchar, bits_used, &padint);
 161                         *bytes = padint / 8;
 162                         if (sizeint == 64)
 163                                 *mask = ~0;
 164                         else
 165                                 *mask = (1 << *bits_used) - 1;
 166                         if (signchar == 's')
 167                                 *is_signed = 1;
 168                         else
 169                                 *is_signed = 0;
 170                 }
 171 error_free_filename:
 172         if (filename)
 173                 free(filename);
 174 error_closedir:
 175         closedir(dp);
 176 error_free_builtname_generic:
 177         free(builtname_generic);
 178 error_free_builtname:
 179         free(builtname);
 180 error_free_scan_el_dir:
 181         free(scan_el_dir);
 182 error_ret:
 183         return ret;
 184 }
 185
 186 inline int iioutils_get_param_float(float *output,
 187                                     const char *param_name,
 188                                     const char *device_dir,
 189                                     const char *name,
 190                                     const char *generic_name)
 191 {
 192         FILE *sysfsfp;
 193         int ret;
 194         DIR *dp;
 195         char *builtname, *builtname_generic;
 196         char *filename = NULL;
 197         const struct dirent *ent;
 198
 199         ret = asprintf(&builtname, "%s_%s", name, param_name);
 200         if (ret < 0) {
 201                 ret = -ENOMEM;
 202                 goto error_ret;
 203         }
 204         ret = asprintf(&builtname_generic,
 205                        "%s_%s", generic_name, param_name);
 206         if (ret < 0) {
 207                 ret = -ENOMEM;
 208                 goto error_free_builtname;
 209         }
 210         dp = opendir(device_dir);
 211         if (dp == NULL) {
 212                 ret = -errno;
 213                 goto error_free_builtname_generic;
 214         }
 215         while (ent = readdir(dp), ent != NULL)
 216                 if ((strcmp(builtname, ent->d_name) == 0) ||
 217                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 218                         ret = asprintf(&filename,
 219                                        "%s/%s", device_dir, ent->d_name);
 220                         if (ret < 0) {
 221                                 ret = -ENOMEM;
 222                                 goto error_closedir;
 223                         }
 224                         sysfsfp = fopen(filename, "r");
 225                         if (!sysfsfp) {
 226                                 ret = -errno;
 227                                 goto error_free_filename;
 228                         }
 229                         fscanf(sysfsfp, "%f", output);
 230                         break;
 231                 }
 232 error_free_filename:
 233         if (filename)
 234                 free(filename);
 235 error_closedir:
 236         closedir(dp);
 237 error_free_builtname_generic:
 238         free(builtname_generic);
 239 error_free_builtname:
 240         free(builtname);
 241 error_ret:
 242         return ret;
 243 }
 244
 245
 246 /**
 247  * build_channel_array() - function to figure out what channels are present
 248  * @device_dir: the IIO device directory in sysfs
 249  * @
 250  **/
 251 inline int build_channel_array(const char *device_dir,
 252                               struct iio_channel_info **ci_array,
 253                               int *counter)
 254 {
 255         DIR *dp;
 256         FILE *sysfsfp;
 257         int count = 0, temp, i;
 258         struct iio_channel_info *current;
 259         int ret;
 260         const struct dirent *ent;
 261         char *scan_el_dir;
 262         char *filename;
 263
 264         *counter = 0;
 265         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 266         if (ret < 0) {
 267                 ret = -ENOMEM;
 268                 goto error_ret;
 269         }
 270         dp = opendir(scan_el_dir);
 271         if (dp == NULL) {
 272                 ret = -errno;
 273                 goto error_free_name;
 274         }
 275         while (ent = readdir(dp), ent != NULL)
 276                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 277                            "_en") == 0) {
 278                         ret = asprintf(&filename,
 279                                        "%s/%s", scan_el_dir, ent->d_name);
 280                         if (ret < 0) {
 281                                 ret = -ENOMEM;
 282                                 goto error_close_dir;
 283                         }
 284                         sysfsfp = fopen(filename, "r");
 285                         if (sysfsfp == NULL) {
 286                                 ret = -errno;
 287                                 free(filename);
 288                                 goto error_close_dir;
 289                         }
 290                         fscanf(sysfsfp, "%u", &ret);
 291                         if (ret == 1)
 292                                 (*counter)++;
 293                         fclose(sysfsfp);
 294                         free(filename);
 295                 }
 296         *ci_array = malloc(sizeof(**ci_array)*(*counter));
 297         if (*ci_array == NULL) {
 298                 ret = -ENOMEM;
 299                 goto error_close_dir;
 300         }
 301         seekdir(dp, 0);
 302         while (ent = readdir(dp), ent != NULL) {
 303                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 304                            "_en") == 0) {
 305                         current = &(*ci_array)[count++];
 306                         ret = asprintf(&filename,
 307                                        "%s/%s", scan_el_dir, ent->d_name);
 308                         if (ret < 0) {
 309                                 ret = -ENOMEM;
 310                                 /* decrement count to avoid freeing name */
 311                                 count--;
 312                                 goto error_cleanup_array;
 313                         }
 314                         sysfsfp = fopen(filename, "r");
 315                         if (sysfsfp == NULL) {
 316                                 free(filename);
 317                                 ret = -errno;
 318                                 goto error_cleanup_array;
 319                         }
 320                         fscanf(sysfsfp, "%u", &current->enabled);
 321                         fclose(sysfsfp);
 322                         free(filename);
 323                         current->scale = 1.0;
 324                         current->offset = 0;
 325                         current->name = strndup(ent->d_name,
 326                                                 strlen(ent->d_name) -
 327                                                 strlen("_en"));
 328                         if (current->name == NULL) {
 329                                 free(filename);
 330                                 ret = -ENOMEM;
 331                                 goto error_cleanup_array;
 332                         }
 333                         /* Get the generic and specific name elements */
 334                         ret = iioutils_break_up_name(current->name,
 335                                                      &current->generic_name);
 336                         if (ret) {
 337                                 free(filename);
 338                                 goto error_cleanup_array;
 339                         }
 340                         ret = asprintf(&filename,
 341                                        "%s/%s_index",
 342                                        scan_el_dir,
 343                                        current->name);
 344                         if (ret < 0) {
 345                                 free(filename);
 346                                 ret = -ENOMEM;
 347                                 goto error_cleanup_array;
 348                         }
 349                         sysfsfp = fopen(filename, "r");
 350                         fscanf(sysfsfp, "%u", &current->index);
 351                         fclose(sysfsfp);
 352                         free(filename);
 353                         /* Find the scale */
 354                         ret = iioutils_get_param_float(&current->scale,
 355                                                        "scale",
 356                                                        device_dir,
 357                                                        current->name,
 358                                                        current->generic_name);
 359                         if (ret < 0)
 360                                 goto error_cleanup_array;
 361                         ret = iioutils_get_param_float(&current->offset,
 362                                                        "offset",
 363                                                        device_dir,
 364                                                        current->name,
 365                                                        current->generic_name);
 366                         if (ret < 0)
 367                                 goto error_cleanup_array;
 368                         ret = iioutils_get_type(&current->is_signed,
 369                                                 &current->bytes,
 370                                                 &current->bits_used,
 371                                                 &current->mask,
 372                                                 device_dir,
 373                                                 current->name,
 374                                                 current->generic_name);
 375                 }
 376         }
 377         /* reorder so that the array is in index order*/
 378         current = malloc(sizeof(**ci_array)**counter);
 379         if (current == NULL) {
 380                 ret = -ENOMEM;
 381                 goto error_cleanup_array;
 382         }
 383         closedir(dp);
 384         count = 0;
 385         temp = 0;
 386         while (count < *counter)
 387                 for (i = 0; i < *counter; i++)
 388                         if ((*ci_array)[i].index == temp) {
 389                                 memcpy(&current[count++],
 390                                        &(*ci_array)[i],
 391                                        sizeof(*current));
 392                                 temp++;
 393                                 break;
 394                         }
 395         free(*ci_array);
 396         *ci_array = current;
 397
 398         return 0;
 399
 400 error_cleanup_array:
 401         for (i = count - 1;  i >= 0; i++)
 402                 free((*ci_array)[i].name);
 403         free(*ci_array);
 404 error_close_dir:
 405         closedir(dp);
 406 error_free_name:
 407         free(scan_el_dir);
 408 error_ret:
 409         return ret;
 410 }
 411
 412 /**
 413  * find_type_by_name() - function to match top level types by name
 414  * @name: top level type instance name
 415  * @type: the type of top level instance being sort
 416  *
 417  * Typical types this is used for are device and trigger.
 418  **/
 419 inline int find_type_by_name(const char *name, const char *type)
 420 {
 421         const struct dirent *ent;
 422         int number, numstrlen;
 423
 424         FILE *nameFile;
 425         DIR *dp;
 426         char thisname[IIO_MAX_NAME_LENGTH];
 427         char *filename;
 428
 429         dp = opendir(iio_dir);
 430         if (dp == NULL) {
 431                 printf("No industrialio devices available");
 432                 return -ENODEV;
 433         }
 434
 435         while (ent = readdir(dp), ent != NULL) {
 436                 if (strcmp(ent->d_name, ".") != 0 &&
 437                         strcmp(ent->d_name, "..") != 0 &&
 438                         strlen(ent->d_name) > strlen(type) &&
 439                         strncmp(ent->d_name, type, strlen(type)) == 0) {
 440                         numstrlen = sscanf(ent->d_name + strlen(type),
 441                                            "%d",
 442                                            &number);
 443                         /* verify the next character is not a colon */
 444                         if (strncmp(ent->d_name + strlen(type) + numstrlen,
 445                                         ":",
 446                                         1) != 0) {
 447                                 filename = malloc(strlen(iio_dir)
 448                                                 + strlen(type)
 449                                                 + numstrlen
 450                                                 + 6);
 451                                 if (filename == NULL)
 452                                         return -ENOMEM;
 453                                 sprintf(filename, "%s%s%d/name",
 454                                         iio_dir,
 455                                         type,
 456                                         number);
 457                                 nameFile = fopen(filename, "r");
 458                                 if (!nameFile)
 459                                         continue;
 460                                 free(filename);
 461                                 fscanf(nameFile, "%s", thisname);
 462                                 if (strcmp(name, thisname) == 0)
 463                                         return number;
 464                                 fclose(nameFile);
 465                         }
 466                 }
 467         }
 468         return -ENODEV;
 469 }
 470
 471 inline int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
 472 {
 473         int ret;
 474         FILE *sysfsfp;
 475         int test;
 476         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 477         if (temp == NULL)
 478                 return -ENOMEM;
 479         sprintf(temp, "%s/%s", basedir, filename);
 480         sysfsfp = fopen(temp, "w");
 481         if (sysfsfp == NULL) {
 482                 printf("failed to open %s\n", temp);
 483                 ret = -errno;
 484                 goto error_free;
 485         }
 486         fprintf(sysfsfp, "%d", val);
 487         fclose(sysfsfp);
 488         if (verify) {
 489                 sysfsfp = fopen(temp, "r");
 490                 if (sysfsfp == NULL) {
 491                         printf("failed to open %s\n", temp);
 492                         ret = -errno;
 493                         goto error_free;
 494                 }
 495                 fscanf(sysfsfp, "%d", &test);
 496                 if (test != val) {
 497                         printf("Possible failure in int write %d to %s%s\n",
 498                                 val,
 499                                 basedir,
 500                                 filename);
 501                         ret = -1;
 502                 }
 503         }
 504 error_free:
 505         free(temp);
 506         return ret;
 507 }
 508
 509 int write_sysfs_int(char *filename, char *basedir, int val)
 510 {
 511         return _write_sysfs_int(filename, basedir, val, 0);
 512 }
 513
 514 int write_sysfs_int_and_verify(char *filename, char *basedir, int val)
 515 {
 516         return _write_sysfs_int(filename, basedir, val, 1);
 517 }
 518
 519 int _write_sysfs_string(char *filename, char *basedir, char *val, int verify)
 520 {
 521         int ret = 0;
 522         FILE  *sysfsfp;
 523         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 524         if (temp == NULL) {
 525                 printf("Memory allocation failed\n");
 526                 return -ENOMEM;
 527         }
 528         sprintf(temp, "%s/%s", basedir, filename);
 529         sysfsfp = fopen(temp, "w");
 530         if (sysfsfp == NULL) {
 531                 printf("Could not open %s\n", temp);
 532                 ret = -errno;
 533                 goto error_free;
 534         }
 535         fprintf(sysfsfp, "%s", val);
 536         fclose(sysfsfp);
 537         if (verify) {
 538                 sysfsfp = fopen(temp, "r");
 539                 if (sysfsfp == NULL) {
 540                         printf("could not open file to verify\n");
 541                         ret = -errno;
 542                         goto error_free;
 543                 }
 544                 fscanf(sysfsfp, "%s", temp);
 545                 if (strcmp(temp, val) != 0) {
 546                         printf("Possible failure in string write of %s "
 547                                 "Should be %s "
 548                                 "writen to %s\%s\n",
 549                                 temp,
 550                                 val,
 551                                 basedir,
 552                                 filename);
 553                         ret = -1;
 554                 }
 555         }
 556 error_free:
 557         free(temp);
 558
 559         return ret;
 560 }
 561
 562 /**
 563  * write_sysfs_string_and_verify() - string write, readback and verify
 564  * @filename: name of file to write to
 565  * @basedir: the sysfs directory in which the file is to be found
 566  * @val: the string to write
 567  **/
 568 int write_sysfs_string_and_verify(char *filename, char *basedir, char *val)
 569 {
 570         return _write_sysfs_string(filename, basedir, val, 1);
 571 }
 572
 573 int write_sysfs_string(char *filename, char *basedir, char *val)
 574 {
 575         return _write_sysfs_string(filename, basedir, val, 0);
 576 }
 577
 578 int read_sysfs_posint(char *filename, char *basedir)
 579 {
 580         int ret;
 581         FILE  *sysfsfp;
 582         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 583         if (temp == NULL) {
 584                 printf("Memory allocation failed");
 585                 return -ENOMEM;
 586         }
 587         sprintf(temp, "%s/%s", basedir, filename);
 588         sysfsfp = fopen(temp, "r");
 589         if (sysfsfp == NULL) {
 590                 ret = -errno;
 591                 goto error_free;
 592         }
 593         fscanf(sysfsfp, "%d\n", &ret);
 594         fclose(sysfsfp);
 595 error_free:
 596         free(temp);
 597         return ret;
 598 }
 599
 600 int read_sysfs_float(char *filename, char *basedir, float *val)
 601 {
 602         float ret = 0;
 603         FILE  *sysfsfp;
 604         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 605         if (temp == NULL) {
 606                 printf("Memory allocation failed");
 607                 return -ENOMEM;
 608         }
 609         sprintf(temp, "%s/%s", basedir, filename);
 610         sysfsfp = fopen(temp, "r");
 611         if (sysfsfp == NULL) {
 612                 ret = -errno;
 613                 goto error_free;
 614         }
 615         fscanf(sysfsfp, "%f\n", val);
 616         fclose(sysfsfp);
 617 error_free:
 618         free(temp);
 619         return ret;
 620 }