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 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 (*bits_used == 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  * bsort_channel_array_by_index() - reorder so that the array is in index order
 247  *
 248  **/
 249
 250 inline void bsort_channel_array_by_index(struct iio_channel_info **ci_array,
 251                                          int cnt)
 252 {
 253
 254         struct iio_channel_info temp;
 255         int x, y;
 256
 257         for (x = 0; x < cnt; x++)
 258                 for (y = 0; y < (cnt - 1); y++)
 259                         if ((*ci_array)[y].index > (*ci_array)[y+1].index) {
 260                                 temp = (*ci_array)[y + 1];
 261                                 (*ci_array)[y + 1] = (*ci_array)[y];
 262                                 (*ci_array)[y] = temp;
 263                         }
 264 }
 265
 266 /**
 267  * build_channel_array() - function to figure out what channels are present
 268  * @device_dir: the IIO device directory in sysfs
 269  * @
 270  **/
 271 inline int build_channel_array(const char *device_dir,
 272                               struct iio_channel_info **ci_array,
 273                               int *counter)
 274 {
 275         DIR *dp;
 276         FILE *sysfsfp;
 277         int count, temp, i;
 278         struct iio_channel_info *current;
 279         int ret;
 280         const struct dirent *ent;
 281         char *scan_el_dir;
 282         char *filename;
 283
 284         *counter = 0;
 285         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 286         if (ret < 0) {
 287                 ret = -ENOMEM;
 288                 goto error_ret;
 289         }
 290         dp = opendir(scan_el_dir);
 291         if (dp == NULL) {
 292                 ret = -errno;
 293                 goto error_free_name;
 294         }
 295         while (ent = readdir(dp), ent != NULL)
 296                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 297                            "_en") == 0) {
 298                         ret = asprintf(&filename,
 299                                        "%s/%s", scan_el_dir, ent->d_name);
 300                         if (ret < 0) {
 301                                 ret = -ENOMEM;
 302                                 goto error_close_dir;
 303                         }
 304                         sysfsfp = fopen(filename, "r");
 305                         if (sysfsfp == NULL) {
 306                                 ret = -errno;
 307                                 free(filename);
 308                                 goto error_close_dir;
 309                         }
 310                         fscanf(sysfsfp, "%u", &ret);
 311                         if (ret == 1)
 312                                 (*counter)++;
 313                         fclose(sysfsfp);
 314                         free(filename);
 315                 }
 316         *ci_array = malloc(sizeof(**ci_array) * (*counter));
 317         if (*ci_array == NULL) {
 318                 ret = -ENOMEM;
 319                 goto error_close_dir;
 320         }
 321         seekdir(dp, 0);
 322         count = 0;
 323         while (ent = readdir(dp), ent != NULL) {
 324                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 325                            "_en") == 0) {
 326                         current = &(*ci_array)[count++];
 327                         ret = asprintf(&filename,
 328                                        "%s/%s", scan_el_dir, ent->d_name);
 329                         if (ret < 0) {
 330                                 ret = -ENOMEM;
 331                                 /* decrement count to avoid freeing name */
 332                                 count--;
 333                                 goto error_cleanup_array;
 334                         }
 335                         sysfsfp = fopen(filename, "r");
 336                         if (sysfsfp == NULL) {
 337                                 free(filename);
 338                                 ret = -errno;
 339                                 goto error_cleanup_array;
 340                         }
 341                         fscanf(sysfsfp, "%u", &current->enabled);
 342                         fclose(sysfsfp);
 343
 344                         if (!current->enabled) {
 345                                 free(filename);
 346                                 count--;
 347                                 continue;
 348                         }
 349
 350                         current->scale = 1.0;
 351                         current->offset = 0;
 352                         current->name = strndup(ent->d_name,
 353                                                 strlen(ent->d_name) -
 354                                                 strlen("_en"));
 355                         if (current->name == NULL) {
 356                                 free(filename);
 357                                 ret = -ENOMEM;
 358                                 goto error_cleanup_array;
 359                         }
 360                         /* Get the generic and specific name elements */
 361                         ret = iioutils_break_up_name(current->name,
 362                                                      &current->generic_name);
 363                         if (ret) {
 364                                 free(filename);
 365                                 goto error_cleanup_array;
 366                         }
 367                         ret = asprintf(&filename,
 368                                        "%s/%s_index",
 369                                        scan_el_dir,
 370                                        current->name);
 371                         if (ret < 0) {
 372                                 free(filename);
 373                                 ret = -ENOMEM;
 374                                 goto error_cleanup_array;
 375                         }
 376                         sysfsfp = fopen(filename, "r");
 377                         fscanf(sysfsfp, "%u", &current->index);
 378                         fclose(sysfsfp);
 379                         free(filename);
 380                         /* Find the scale */
 381                         ret = iioutils_get_param_float(&current->scale,
 382                                                        "scale",
 383                                                        device_dir,
 384                                                        current->name,
 385                                                        current->generic_name);
 386                         if (ret < 0)
 387                                 goto error_cleanup_array;
 388                         ret = iioutils_get_param_float(&current->offset,
 389                                                        "offset",
 390                                                        device_dir,
 391                                                        current->name,
 392                                                        current->generic_name);
 393                         if (ret < 0)
 394                                 goto error_cleanup_array;
 395                         ret = iioutils_get_type(&current->is_signed,
 396                                                 &current->bytes,
 397                                                 &current->bits_used,
 398                                                 &current->mask,
 399                                                 device_dir,
 400                                                 current->name,
 401                                                 current->generic_name);
 402                 }
 403         }
 404
 405         closedir(dp);
 406         /* reorder so that the array is in index order */
 407         bsort_channel_array_by_index(ci_array, *counter);
 408
 409         return 0;
 410
 411 error_cleanup_array:
 412         for (i = count - 1;  i >= 0; i--)
 413                 free((*ci_array)[i].name);
 414         free(*ci_array);
 415 error_close_dir:
 416         closedir(dp);
 417 error_free_name:
 418         free(scan_el_dir);
 419 error_ret:
 420         return ret;
 421 }
 422
 423 /**
 424  * find_type_by_name() - function to match top level types by name
 425  * @name: top level type instance name
 426  * @type: the type of top level instance being sort
 427  *
 428  * Typical types this is used for are device and trigger.
 429  **/
 430 inline int find_type_by_name(const char *name, const char *type)
 431 {
 432         const struct dirent *ent;
 433         int number, numstrlen;
 434
 435         FILE *nameFile;
 436         DIR *dp;
 437         char thisname[IIO_MAX_NAME_LENGTH];
 438         char *filename;
 439
 440         dp = opendir(iio_dir);
 441         if (dp == NULL) {
 442                 printf("No industrialio devices available");
 443                 return -ENODEV;
 444         }
 445
 446         while (ent = readdir(dp), ent != NULL) {
 447                 if (strcmp(ent->d_name, ".") != 0 &&
 448                         strcmp(ent->d_name, "..") != 0 &&
 449                         strlen(ent->d_name) > strlen(type) &&
 450                         strncmp(ent->d_name, type, strlen(type)) == 0) {
 451                         numstrlen = sscanf(ent->d_name + strlen(type),
 452                                            "%d",
 453                                            &number);
 454                         /* verify the next character is not a colon */
 455                         if (strncmp(ent->d_name + strlen(type) + numstrlen,
 456                                         ":",
 457                                         1) != 0) {
 458                                 filename = malloc(strlen(iio_dir)
 459                                                 + strlen(type)
 460                                                 + numstrlen
 461                                                 + 6);
 462                                 if (filename == NULL)
 463                                         return -ENOMEM;
 464                                 sprintf(filename, "%s%s%d/name",
 465                                         iio_dir,
 466                                         type,
 467                                         number);
 468                                 nameFile = fopen(filename, "r");
 469                                 if (!nameFile)
 470                                         continue;
 471                                 free(filename);
 472                                 fscanf(nameFile, "%s", thisname);
 473                                 if (strcmp(name, thisname) == 0)
 474                                         return number;
 475                                 fclose(nameFile);
 476                         }
 477                 }
 478         }
 479         return -ENODEV;
 480 }
 481
 482 inline int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
 483 {
 484         int ret;
 485         FILE *sysfsfp;
 486         int test;
 487         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 488         if (temp == NULL)
 489                 return -ENOMEM;
 490         sprintf(temp, "%s/%s", basedir, filename);
 491         sysfsfp = fopen(temp, "w");
 492         if (sysfsfp == NULL) {
 493                 printf("failed to open %s\n", temp);
 494                 ret = -errno;
 495                 goto error_free;
 496         }
 497         fprintf(sysfsfp, "%d", val);
 498         fclose(sysfsfp);
 499         if (verify) {
 500                 sysfsfp = fopen(temp, "r");
 501                 if (sysfsfp == NULL) {
 502                         printf("failed to open %s\n", temp);
 503                         ret = -errno;
 504                         goto error_free;
 505                 }
 506                 fscanf(sysfsfp, "%d", &test);
 507                 if (test != val) {
 508                         printf("Possible failure in int write %d to %s%s\n",
 509                                 val,
 510                                 basedir,
 511                                 filename);
 512                         ret = -1;
 513                 }
 514         }
 515 error_free:
 516         free(temp);
 517         return ret;
 518 }
 519
 520 int write_sysfs_int(char *filename, char *basedir, int val)
 521 {
 522         return _write_sysfs_int(filename, basedir, val, 0);
 523 }
 524
 525 int write_sysfs_int_and_verify(char *filename, char *basedir, int val)
 526 {
 527         return _write_sysfs_int(filename, basedir, val, 1);
 528 }
 529
 530 int _write_sysfs_string(char *filename, char *basedir, char *val, int verify)
 531 {
 532         int ret = 0;
 533         FILE  *sysfsfp;
 534         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 535         if (temp == NULL) {
 536                 printf("Memory allocation failed\n");
 537                 return -ENOMEM;
 538         }
 539         sprintf(temp, "%s/%s", basedir, filename);
 540         sysfsfp = fopen(temp, "w");
 541         if (sysfsfp == NULL) {
 542                 printf("Could not open %s\n", temp);
 543                 ret = -errno;
 544                 goto error_free;
 545         }
 546         fprintf(sysfsfp, "%s", val);
 547         fclose(sysfsfp);
 548         if (verify) {
 549                 sysfsfp = fopen(temp, "r");
 550                 if (sysfsfp == NULL) {
 551                         printf("could not open file to verify\n");
 552                         ret = -errno;
 553                         goto error_free;
 554                 }
 555                 fscanf(sysfsfp, "%s", temp);
 556                 if (strcmp(temp, val) != 0) {
 557                         printf("Possible failure in string write of %s "
 558                                 "Should be %s "
 559                                 "written to %s\%s\n",
 560                                 temp,
 561                                 val,
 562                                 basedir,
 563                                 filename);
 564                         ret = -1;
 565                 }
 566         }
 567 error_free:
 568         free(temp);
 569
 570         return ret;
 571 }
 572
 573 /**
 574  * write_sysfs_string_and_verify() - string write, readback and verify
 575  * @filename: name of file to write to
 576  * @basedir: the sysfs directory in which the file is to be found
 577  * @val: the string to write
 578  **/
 579 int write_sysfs_string_and_verify(char *filename, char *basedir, char *val)
 580 {
 581         return _write_sysfs_string(filename, basedir, val, 1);
 582 }
 583
 584 int write_sysfs_string(char *filename, char *basedir, char *val)
 585 {
 586         return _write_sysfs_string(filename, basedir, val, 0);
 587 }
 588
 589 int read_sysfs_posint(char *filename, char *basedir)
 590 {
 591         int ret;
 592         FILE  *sysfsfp;
 593         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 594         if (temp == NULL) {
 595                 printf("Memory allocation failed");
 596                 return -ENOMEM;
 597         }
 598         sprintf(temp, "%s/%s", basedir, filename);
 599         sysfsfp = fopen(temp, "r");
 600         if (sysfsfp == NULL) {
 601                 ret = -errno;
 602                 goto error_free;
 603         }
 604         fscanf(sysfsfp, "%d\n", &ret);
 605         fclose(sysfsfp);
 606 error_free:
 607         free(temp);
 608         return ret;
 609 }
 610
 611 int read_sysfs_float(char *filename, char *basedir, float *val)
 612 {
 613         float ret = 0;
 614         FILE  *sysfsfp;
 615         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 616         if (temp == NULL) {
 617                 printf("Memory allocation failed");
 618                 return -ENOMEM;
 619         }
 620         sprintf(temp, "%s/%s", basedir, filename);
 621         sysfsfp = fopen(temp, "r");
 622         if (sysfsfp == NULL) {
 623                 ret = -errno;
 624                 goto error_free;
 625         }
 626         fscanf(sysfsfp, "%f\n", val);
 627         fclose(sysfsfp);
 628 error_free:
 629         free(temp);
 630         return ret;
 631 }