1 /* IIO - useful set of util functionality
3 * Copyright (c) 2008 Jonathan Cameron
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.
19 #include "iio_utils.h"
21 const char *iio_dir = "/sys/bus/iio/devices/";
23 static char * const iio_direction[] = {
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
33 * Returns 0 on success, or a negative error code if string extraction failed.
35 int iioutils_break_up_name(const char *full_name,
40 char *working, *prefix = "";
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];
50 current = strdup(full_name + strlen(prefix) + 1);
54 working = strtok(current, "_\0");
71 ret = asprintf(generic_name, "%s_%s", prefix, working);
74 return (ret == -1) ? -ENOMEM : 0;
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
89 * Returns a value >= 0 on success, otherwise a negative error code.
91 int iioutils_get_type(unsigned *is_signed,
97 const char *device_dir,
99 const char *generic_name)
104 char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
105 char signchar, endianchar;
107 const struct dirent *ent;
109 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
113 ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
116 goto error_free_scan_el_dir;
118 ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
121 goto error_free_builtname;
124 dp = opendir(scan_el_dir);
127 goto error_free_builtname_generic;
130 while (ent = readdir(dp), ent != NULL)
132 * Do we allow devices to override a generic name with
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);
143 sysfsfp = fopen(filename, "r");
144 if (sysfsfp == NULL) {
146 printf("failed to open %s\n", filename);
147 goto error_free_filename;
150 ret = fscanf(sysfsfp,
158 printf("failed to pass scan type description\n");
159 goto error_close_sysfsfp;
160 } else if (ret != 5) {
162 printf("scan type description didn't match\n");
163 goto error_close_sysfsfp;
165 *be = (endianchar == 'b');
167 if (*bits_used == 64)
170 *mask = (1 << *bits_used) - 1;
171 *is_signed = (signchar == 's');
172 if (fclose(sysfsfp)) {
174 printf("Failed to close %s\n", filename);
175 goto error_free_filename;
186 perror("iioutils_get_type(): Failed to close file");
192 if (closedir(dp) == -1)
193 perror("iioutils_get_type(): Failed to close directory");
195 error_free_builtname_generic:
196 free(builtname_generic);
197 error_free_builtname:
199 error_free_scan_el_dir:
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
213 * Returns a value >= 0 on success, otherwise a negative error code.
215 int iioutils_get_param_float(float *output,
216 const char *param_name,
217 const char *device_dir,
219 const char *generic_name)
224 char *builtname, *builtname_generic;
225 char *filename = NULL;
226 const struct dirent *ent;
228 ret = asprintf(&builtname, "%s_%s", name, param_name);
232 ret = asprintf(&builtname_generic,
233 "%s_%s", generic_name, param_name);
236 goto error_free_builtname;
238 dp = opendir(device_dir);
241 goto error_free_builtname_generic;
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);
253 sysfsfp = fopen(filename, "r");
256 goto error_free_filename;
259 if (fscanf(sysfsfp, "%f", output) != 1)
260 ret = errno ? -errno : -ENODATA;
268 if (closedir(dp) == -1)
269 perror("iioutils_get_param_float(): Failed to close directory");
271 error_free_builtname_generic:
272 free(builtname_generic);
273 error_free_builtname:
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
285 void bsort_channel_array_by_index(struct iio_channel_info **ci_array,
289 struct iio_channel_info temp;
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;
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
307 * Returns 0 on success, otherwise a negative error code.
309 int build_channel_array(const char *device_dir,
310 struct iio_channel_info **ci_array,
316 struct iio_channel_info *current;
318 const struct dirent *ent;
323 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
327 dp = opendir(scan_el_dir);
330 goto error_free_name;
332 while (ent = readdir(dp), ent != NULL)
333 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
335 ret = asprintf(&filename,
336 "%s/%s", scan_el_dir, ent->d_name);
339 goto error_close_dir;
341 sysfsfp = fopen(filename, "r");
342 if (sysfsfp == NULL) {
345 goto error_close_dir;
348 if (fscanf(sysfsfp, "%i", &ret) != 1) {
349 ret = errno ? -errno : -ENODATA;
351 perror("build_channel_array(): Failed to close file");
354 goto error_close_dir;
359 if (fclose(sysfsfp)) {
362 goto error_close_dir;
367 *ci_array = malloc(sizeof(**ci_array) * (*counter));
368 if (*ci_array == NULL) {
370 goto error_close_dir;
373 while (ent = readdir(dp), ent != NULL) {
374 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
376 int current_enabled = 0;
378 current = &(*ci_array)[count++];
379 ret = asprintf(&filename,
380 "%s/%s", scan_el_dir, ent->d_name);
383 /* decrement count to avoid freeing name */
385 goto error_cleanup_array;
387 sysfsfp = fopen(filename, "r");
388 if (sysfsfp == NULL) {
392 goto error_cleanup_array;
395 if (fscanf(sysfsfp, "%i", ¤t_enabled) != 1) {
396 ret = errno ? -errno : -ENODATA;
399 goto error_cleanup_array;
402 if (fclose(sysfsfp)) {
406 goto error_cleanup_array;
409 if (!current_enabled) {
415 current->scale = 1.0;
417 current->name = strndup(ent->d_name,
418 strlen(ent->d_name) -
420 if (current->name == NULL) {
424 goto error_cleanup_array;
426 /* Get the generic and specific name elements */
427 ret = iioutils_break_up_name(current->name,
428 ¤t->generic_name);
433 goto error_cleanup_array;
435 ret = asprintf(&filename,
442 goto error_cleanup_array;
444 sysfsfp = fopen(filename, "r");
445 if (sysfsfp == NULL) {
447 printf("failed to open %s\n", filename);
449 goto error_cleanup_array;
453 if (fscanf(sysfsfp, "%u", ¤t->index) != 1) {
454 ret = errno ? -errno : -ENODATA;
456 perror("build_channel_array(): Failed to close file");
459 goto error_cleanup_array;
462 if (fclose(sysfsfp)) {
465 goto error_cleanup_array;
470 ret = iioutils_get_param_float(¤t->scale,
474 current->generic_name);
476 goto error_cleanup_array;
477 ret = iioutils_get_param_float(¤t->offset,
481 current->generic_name);
483 goto error_cleanup_array;
484 ret = iioutils_get_type(¤t->is_signed,
492 current->generic_name);
494 goto error_cleanup_array;
498 if (closedir(dp) == -1) {
500 goto error_cleanup_array;
504 /* reorder so that the array is in index order */
505 bsort_channel_array_by_index(ci_array, *counter);
510 for (i = count - 1; i >= 0; i--) {
511 free((*ci_array)[i].name);
512 free((*ci_array)[i].generic_name);
517 if (closedir(dp) == -1)
518 perror("build_channel_array(): Failed to close dir");
526 int calc_digits(int num)
539 * find_type_by_name() - function to match top level types by name
540 * @name: top level type instance name
541 * @type: the type of top level instance being searched
543 * Returns the device number of a matched IIO device on success, otherwise a
544 * negative error code.
545 * Typical types this is used for are device and trigger.
547 int find_type_by_name(const char *name, const char *type)
549 const struct dirent *ent;
550 int number, numstrlen, ret;
554 char thisname[IIO_MAX_NAME_LENGTH];
557 dp = opendir(iio_dir);
559 printf("No industrialio devices available\n");
563 while (ent = readdir(dp), ent != NULL) {
564 if (strcmp(ent->d_name, ".") != 0 &&
565 strcmp(ent->d_name, "..") != 0 &&
566 strlen(ent->d_name) > strlen(type) &&
567 strncmp(ent->d_name, type, strlen(type)) == 0) {
569 ret = sscanf(ent->d_name + strlen(type), "%d", &number);
572 printf("failed to read element number\n");
573 goto error_close_dir;
574 } else if (ret != 1) {
576 printf("failed to match element number\n");
577 goto error_close_dir;
580 numstrlen = calc_digits(number);
581 /* verify the next character is not a colon */
582 if (strncmp(ent->d_name + strlen(type) + numstrlen,
585 filename = malloc(strlen(iio_dir)
589 if (filename == NULL) {
591 goto error_close_dir;
594 ret = sprintf(filename, "%s%s%d/name", iio_dir,
598 goto error_close_dir;
601 nameFile = fopen(filename, "r");
608 if (fscanf(nameFile, "%s", thisname) != 1) {
609 ret = errno ? -errno : -ENODATA;
610 goto error_close_dir;
613 if (fclose(nameFile)) {
615 goto error_close_dir;
618 if (strcmp(name, thisname) == 0) {
619 if (closedir(dp) == -1)
626 if (closedir(dp) == -1)
632 if (closedir(dp) == -1)
633 perror("find_type_by_name(): Failed to close directory");
637 static int _write_sysfs_int(const char *filename, const char *basedir, int val,
643 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
647 ret = sprintf(temp, "%s/%s", basedir, filename);
651 sysfsfp = fopen(temp, "w");
652 if (sysfsfp == NULL) {
654 printf("failed to open %s\n", temp);
657 ret = fprintf(sysfsfp, "%d", val);
660 perror("_write_sysfs_int(): Failed to close dir");
665 if (fclose(sysfsfp)) {
671 sysfsfp = fopen(temp, "r");
672 if (sysfsfp == NULL) {
674 printf("failed to open %s\n", temp);
677 if (fscanf(sysfsfp, "%d", &test) != 1) {
678 ret = errno ? -errno : -ENODATA;
680 perror("_write_sysfs_int(): Failed to close dir");
685 if (fclose(sysfsfp)) {
691 printf("Possible failure in int write %d to %s%s\n",
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
709 * Returns a value >= 0 on success, otherwise a negative error code.
711 int write_sysfs_int(const char *filename, const char *basedir, int val)
713 return _write_sysfs_int(filename, basedir, val, 0);
717 * write_sysfs_int_and_verify() - write an integer value to a sysfs file
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
723 * Returns a value >= 0 on success, otherwise a negative error code.
725 int write_sysfs_int_and_verify(const char *filename, const char *basedir,
728 return _write_sysfs_int(filename, basedir, val, 1);
731 static int _write_sysfs_string(const char *filename, const char *basedir,
732 const char *val, int verify)
736 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
739 printf("Memory allocation failed\n");
742 ret = sprintf(temp, "%s/%s", basedir, filename);
746 sysfsfp = fopen(temp, "w");
747 if (sysfsfp == NULL) {
749 printf("Could not open %s\n", temp);
752 ret = fprintf(sysfsfp, "%s", val);
755 perror("_write_sysfs_string(): Failed to close dir");
760 if (fclose(sysfsfp)) {
766 sysfsfp = fopen(temp, "r");
767 if (sysfsfp == NULL) {
769 printf("could not open file to verify\n");
772 if (fscanf(sysfsfp, "%s", temp) != 1) {
773 ret = errno ? -errno : -ENODATA;
775 perror("_write_sysfs_string(): Failed to close dir");
780 if (fclose(sysfsfp)) {
785 if (strcmp(temp, val) != 0) {
786 printf("Possible failure in string write of %s "
788 "written to %s\%s\n",
803 * write_sysfs_string_and_verify() - string write, readback and verify
804 * @filename: name of file to write to
805 * @basedir: the sysfs directory in which the file is to be found
806 * @val: the string to write
808 * Returns a value >= 0 on success, otherwise a negative error code.
810 int write_sysfs_string_and_verify(const char *filename, const char *basedir,
813 return _write_sysfs_string(filename, basedir, val, 1);
817 * write_sysfs_string() - write string to a sysfs file
818 * @filename: name of file to write to
819 * @basedir: the sysfs directory in which the file is to be found
820 * @val: the string to write
822 * Returns a value >= 0 on success, otherwise a negative error code.
824 int write_sysfs_string(const char *filename, const char *basedir,
827 return _write_sysfs_string(filename, basedir, val, 0);
831 * read_sysfs_posint() - read an integer value from file
832 * @filename: name of file to read from
833 * @basedir: the sysfs directory in which the file is to be found
835 * Returns the read integer value >= 0 on success, otherwise a negative error
838 int read_sysfs_posint(const char *filename, const char *basedir)
842 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
845 printf("Memory allocation failed");
848 ret = sprintf(temp, "%s/%s", basedir, filename);
852 sysfsfp = fopen(temp, "r");
853 if (sysfsfp == NULL) {
858 if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
859 ret = errno ? -errno : -ENODATA;
861 perror("read_sysfs_posint(): Failed to close dir");
875 * read_sysfs_float() - read a float value from file
876 * @filename: name of file to read from
877 * @basedir: the sysfs directory in which the file is to be found
878 * @val: output the read float value
880 * Returns a value >= 0 on success, otherwise a negative error code.
882 int read_sysfs_float(const char *filename, const char *basedir, float *val)
886 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
889 printf("Memory allocation failed");
892 ret = sprintf(temp, "%s/%s", basedir, filename);
896 sysfsfp = fopen(temp, "r");
897 if (sysfsfp == NULL) {
902 if (fscanf(sysfsfp, "%f\n", val) != 1) {
903 ret = errno ? -errno : -ENODATA;
905 perror("read_sysfs_float(): Failed to close dir");
919 * read_sysfs_string() - read a string from file
920 * @filename: name of file to read from
921 * @basedir: the sysfs directory in which the file is to be found
922 * @str: output the read string
924 * Returns a value >= 0 on success, otherwise a negative error code.
926 int read_sysfs_string(const char *filename, const char *basedir, char *str)
930 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
933 printf("Memory allocation failed");
936 ret = sprintf(temp, "%s/%s", basedir, filename);
940 sysfsfp = fopen(temp, "r");
941 if (sysfsfp == NULL) {
946 if (fscanf(sysfsfp, "%s\n", str) != 1) {
947 ret = errno ? -errno : -ENODATA;
949 perror("read_sysfs_string(): Failed to close dir");
962 #endif /* _IIO_UTILS_H */