1 // SPDX-License-Identifier: GPL-2.0-only
2 /* IIO - useful set of util functionality
4 * Copyright (c) 2008 Jonathan Cameron
13 #include "iio_utils.h"
15 const char *iio_dir = "/sys/bus/iio/devices/";
17 static char * const iio_direction[] = {
23 * iioutils_break_up_name() - extract generic name from full channel name
24 * @full_name: the full channel name
25 * @generic_name: the output generic channel name
27 * Returns 0 on success, or a negative error code if string extraction failed.
29 int iioutils_break_up_name(const char *full_name, char **generic_name)
33 char *working, *prefix = "";
36 for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
37 if (!strncmp(full_name, iio_direction[i],
38 strlen(iio_direction[i]))) {
39 prefix = iio_direction[i];
43 current = strdup(full_name + strlen(prefix) + 1);
47 working = strtok(current, "_\0");
65 ret = asprintf(generic_name, "%s_%s", prefix, working);
68 return (ret == -1) ? -ENOMEM : 0;
72 * iioutils_get_type() - find and process _type attribute data
73 * @is_signed: output whether channel is signed
74 * @bytes: output how many bytes the channel storage occupies
75 * @bits_used: output number of valid bits of data
76 * @shift: output amount of bits to shift right data before applying bit mask
77 * @mask: output a bit mask for the raw data
78 * @be: output if data in big endian
79 * @device_dir: the IIO device directory
80 * @name: the channel name
81 * @generic_name: the channel type name
83 * Returns a value >= 0 on success, otherwise a negative error code.
85 int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
86 unsigned *shift, uint64_t *mask, unsigned *be,
87 const char *device_dir, const char *name,
88 const char *generic_name)
93 char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
94 char signchar, endianchar;
96 const struct dirent *ent;
98 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
102 ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
105 goto error_free_scan_el_dir;
107 ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
110 goto error_free_builtname;
113 dp = opendir(scan_el_dir);
116 goto error_free_builtname_generic;
120 while (ent = readdir(dp), ent)
121 if ((strcmp(builtname, ent->d_name) == 0) ||
122 (strcmp(builtname_generic, ent->d_name) == 0)) {
123 ret = asprintf(&filename,
124 "%s/%s", scan_el_dir, ent->d_name);
130 sysfsfp = fopen(filename, "r");
133 fprintf(stderr, "failed to open %s\n",
135 goto error_free_filename;
138 ret = fscanf(sysfsfp,
147 "failed to pass scan type description\n");
148 goto error_close_sysfsfp;
149 } else if (ret != 5) {
152 "scan type description didn't match\n");
153 goto error_close_sysfsfp;
156 *be = (endianchar == 'b');
158 if (*bits_used == 64)
161 *mask = (1ULL << *bits_used) - 1ULL;
163 *is_signed = (signchar == 's');
164 if (fclose(sysfsfp)) {
166 fprintf(stderr, "Failed to close %s\n",
168 goto error_free_filename;
176 * Avoid having a more generic entry overwriting
179 if (strcmp(builtname, ent->d_name) == 0)
186 perror("iioutils_get_type(): Failed to close file");
193 if (closedir(dp) == -1)
194 perror("iioutils_get_type(): Failed to close directory");
196 error_free_builtname_generic:
197 free(builtname_generic);
198 error_free_builtname:
200 error_free_scan_el_dir:
207 * iioutils_get_param_float() - read a float value from a channel parameter
208 * @output: output the float value
209 * @param_name: the parameter name to read
210 * @device_dir: the IIO device directory in sysfs
211 * @name: the channel name
212 * @generic_name: the channel type name
214 * Returns a value >= 0 on success, otherwise a negative error code.
216 int iioutils_get_param_float(float *output, const char *param_name,
217 const char *device_dir, const char *name,
218 const char *generic_name)
223 char *builtname, *builtname_generic;
224 char *filename = NULL;
225 const struct dirent *ent;
227 ret = asprintf(&builtname, "%s_%s", name, param_name);
231 ret = asprintf(&builtname_generic,
232 "%s_%s", generic_name, param_name);
235 goto error_free_builtname;
238 dp = opendir(device_dir);
241 goto error_free_builtname_generic;
245 while (ent = readdir(dp), ent)
246 if ((strcmp(builtname, ent->d_name) == 0) ||
247 (strcmp(builtname_generic, ent->d_name) == 0)) {
248 ret = asprintf(&filename,
249 "%s/%s", device_dir, ent->d_name);
255 sysfsfp = fopen(filename, "r");
258 goto error_free_filename;
262 if (fscanf(sysfsfp, "%f", output) != 1)
263 ret = errno ? -errno : -ENODATA;
272 if (closedir(dp) == -1)
273 perror("iioutils_get_param_float(): Failed to close directory");
275 error_free_builtname_generic:
276 free(builtname_generic);
277 error_free_builtname:
284 * bsort_channel_array_by_index() - sort the array in index order
285 * @ci_array: the iio_channel_info array to be sorted
286 * @cnt: the amount of array elements
289 void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
291 struct iio_channel_info temp;
294 for (x = 0; x < cnt; x++)
295 for (y = 0; y < (cnt - 1); y++)
296 if (ci_array[y].index > ci_array[y + 1].index) {
297 temp = ci_array[y + 1];
298 ci_array[y + 1] = ci_array[y];
304 * build_channel_array() - function to figure out what channels are present
305 * @device_dir: the IIO device directory in sysfs
306 * @ci_array: output the resulting array of iio_channel_info
307 * @counter: output the amount of array elements
309 * Returns 0 on success, otherwise a negative error code.
311 int build_channel_array(const char *device_dir,
312 struct iio_channel_info **ci_array, int *counter)
317 struct iio_channel_info *current;
319 const struct dirent *ent;
324 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
328 dp = opendir(scan_el_dir);
331 goto error_free_name;
334 while (ent = readdir(dp), ent)
335 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
337 ret = asprintf(&filename,
338 "%s/%s", scan_el_dir, ent->d_name);
341 goto error_close_dir;
344 sysfsfp = fopen(filename, "r");
348 goto error_close_dir;
352 if (fscanf(sysfsfp, "%i", &ret) != 1) {
353 ret = errno ? -errno : -ENODATA;
355 perror("build_channel_array(): Failed to close file");
358 goto error_close_dir;
363 if (fclose(sysfsfp)) {
366 goto error_close_dir;
372 *ci_array = malloc(sizeof(**ci_array) * (*counter));
375 goto error_close_dir;
379 while (ent = readdir(dp), ent) {
380 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
382 int current_enabled = 0;
384 current = &(*ci_array)[count++];
385 ret = asprintf(&filename,
386 "%s/%s", scan_el_dir, ent->d_name);
389 /* decrement count to avoid freeing name */
391 goto error_cleanup_array;
394 sysfsfp = fopen(filename, "r");
399 goto error_cleanup_array;
403 if (fscanf(sysfsfp, "%i", ¤t_enabled) != 1) {
404 ret = errno ? -errno : -ENODATA;
407 goto error_cleanup_array;
410 if (fclose(sysfsfp)) {
414 goto error_cleanup_array;
417 if (!current_enabled) {
423 current->scale = 1.0;
425 current->name = strndup(ent->d_name,
426 strlen(ent->d_name) -
428 if (!current->name) {
432 goto error_cleanup_array;
435 /* Get the generic and specific name elements */
436 ret = iioutils_break_up_name(current->name,
437 ¤t->generic_name);
442 goto error_cleanup_array;
445 ret = asprintf(&filename,
452 goto error_cleanup_array;
455 sysfsfp = fopen(filename, "r");
458 fprintf(stderr, "failed to open %s\n",
461 goto error_cleanup_array;
465 if (fscanf(sysfsfp, "%u", ¤t->index) != 1) {
466 ret = errno ? -errno : -ENODATA;
468 perror("build_channel_array(): Failed to close file");
471 goto error_cleanup_array;
474 if (fclose(sysfsfp)) {
477 goto error_cleanup_array;
482 ret = iioutils_get_param_float(¤t->scale,
486 current->generic_name);
487 if ((ret < 0) && (ret != -ENOENT))
488 goto error_cleanup_array;
490 ret = iioutils_get_param_float(¤t->offset,
494 current->generic_name);
495 if ((ret < 0) && (ret != -ENOENT))
496 goto error_cleanup_array;
498 ret = iioutils_get_type(¤t->is_signed,
506 current->generic_name);
508 goto error_cleanup_array;
512 if (closedir(dp) == -1) {
514 goto error_cleanup_array;
518 /* reorder so that the array is in index order */
519 bsort_channel_array_by_index(*ci_array, *counter);
524 for (i = count - 1; i >= 0; i--) {
525 free((*ci_array)[i].name);
526 free((*ci_array)[i].generic_name);
533 if (closedir(dp) == -1)
534 perror("build_channel_array(): Failed to close dir");
542 static int calc_digits(int num)
555 * find_type_by_name() - function to match top level types by name
556 * @name: top level type instance name
557 * @type: the type of top level instance being searched
559 * Returns the device number of a matched IIO device on success, otherwise a
560 * negative error code.
561 * Typical types this is used for are device and trigger.
563 int find_type_by_name(const char *name, const char *type)
565 const struct dirent *ent;
566 int number, numstrlen, ret;
570 char thisname[IIO_MAX_NAME_LENGTH];
573 dp = opendir(iio_dir);
575 fprintf(stderr, "No industrialio devices available\n");
579 while (ent = readdir(dp), ent) {
580 if (strcmp(ent->d_name, ".") != 0 &&
581 strcmp(ent->d_name, "..") != 0 &&
582 strlen(ent->d_name) > strlen(type) &&
583 strncmp(ent->d_name, type, strlen(type)) == 0) {
585 ret = sscanf(ent->d_name + strlen(type), "%d", &number);
589 "failed to read element number\n");
590 goto error_close_dir;
591 } else if (ret != 1) {
594 "failed to match element number\n");
595 goto error_close_dir;
598 numstrlen = calc_digits(number);
599 /* verify the next character is not a colon */
600 if (strncmp(ent->d_name + strlen(type) + numstrlen,
602 filename = malloc(strlen(iio_dir) + strlen(type)
606 goto error_close_dir;
609 ret = sprintf(filename, "%s%s%d/name", iio_dir,
613 goto error_close_dir;
616 namefp = fopen(filename, "r");
624 if (fscanf(namefp, "%s", thisname) != 1) {
625 ret = errno ? -errno : -ENODATA;
626 goto error_close_dir;
629 if (fclose(namefp)) {
631 goto error_close_dir;
634 if (strcmp(name, thisname) == 0) {
635 if (closedir(dp) == -1)
643 if (closedir(dp) == -1)
649 if (closedir(dp) == -1)
650 perror("find_type_by_name(): Failed to close directory");
655 static int _write_sysfs_int(const char *filename, const char *basedir, int val,
661 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
666 ret = sprintf(temp, "%s/%s", basedir, filename);
670 sysfsfp = fopen(temp, "w");
673 fprintf(stderr, "failed to open %s\n", temp);
677 ret = fprintf(sysfsfp, "%d", val);
680 perror("_write_sysfs_int(): Failed to close dir");
685 if (fclose(sysfsfp)) {
691 sysfsfp = fopen(temp, "r");
694 fprintf(stderr, "failed to open %s\n", temp);
698 if (fscanf(sysfsfp, "%d", &test) != 1) {
699 ret = errno ? -errno : -ENODATA;
701 perror("_write_sysfs_int(): Failed to close dir");
706 if (fclose(sysfsfp)) {
713 "Possible failure in int write %d to %s/%s\n",
714 val, basedir, filename);
725 * write_sysfs_int() - write an integer value to a sysfs file
726 * @filename: name of the file to write to
727 * @basedir: the sysfs directory in which the file is to be found
728 * @val: integer value to write to file
730 * Returns a value >= 0 on success, otherwise a negative error code.
732 int write_sysfs_int(const char *filename, const char *basedir, int val)
734 return _write_sysfs_int(filename, basedir, val, 0);
738 * write_sysfs_int_and_verify() - write an integer value to a sysfs file
740 * @filename: name of the file to write to
741 * @basedir: the sysfs directory in which the file is to be found
742 * @val: integer value to write to file
744 * Returns a value >= 0 on success, otherwise a negative error code.
746 int write_sysfs_int_and_verify(const char *filename, const char *basedir,
749 return _write_sysfs_int(filename, basedir, val, 1);
752 static int _write_sysfs_string(const char *filename, const char *basedir,
753 const char *val, int verify)
757 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
760 fprintf(stderr, "Memory allocation failed\n");
764 ret = sprintf(temp, "%s/%s", basedir, filename);
768 sysfsfp = fopen(temp, "w");
771 fprintf(stderr, "Could not open %s\n", temp);
775 ret = fprintf(sysfsfp, "%s", val);
778 perror("_write_sysfs_string(): Failed to close dir");
783 if (fclose(sysfsfp)) {
789 sysfsfp = fopen(temp, "r");
792 fprintf(stderr, "Could not open file to verify\n");
796 if (fscanf(sysfsfp, "%s", temp) != 1) {
797 ret = errno ? -errno : -ENODATA;
799 perror("_write_sysfs_string(): Failed to close dir");
804 if (fclose(sysfsfp)) {
809 if (strcmp(temp, val) != 0) {
811 "Possible failure in string write of %s "
812 "Should be %s written to %s/%s\n", temp, val,
825 * write_sysfs_string_and_verify() - string write, readback and verify
826 * @filename: name of file to write to
827 * @basedir: the sysfs directory in which the file is to be found
828 * @val: the string to write
830 * Returns a value >= 0 on success, otherwise a negative error code.
832 int write_sysfs_string_and_verify(const char *filename, const char *basedir,
835 return _write_sysfs_string(filename, basedir, val, 1);
839 * write_sysfs_string() - write string to a sysfs file
840 * @filename: name of file to write to
841 * @basedir: the sysfs directory in which the file is to be found
842 * @val: the string to write
844 * Returns a value >= 0 on success, otherwise a negative error code.
846 int write_sysfs_string(const char *filename, const char *basedir,
849 return _write_sysfs_string(filename, basedir, val, 0);
853 * read_sysfs_posint() - read an integer value from file
854 * @filename: name of file to read from
855 * @basedir: the sysfs directory in which the file is to be found
857 * Returns the read integer value >= 0 on success, otherwise a negative error
860 int read_sysfs_posint(const char *filename, const char *basedir)
864 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
867 fprintf(stderr, "Memory allocation failed");
871 ret = sprintf(temp, "%s/%s", basedir, filename);
875 sysfsfp = fopen(temp, "r");
882 if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
883 ret = errno ? -errno : -ENODATA;
885 perror("read_sysfs_posint(): Failed to close dir");
900 * read_sysfs_float() - read a float value from file
901 * @filename: name of file to read from
902 * @basedir: the sysfs directory in which the file is to be found
903 * @val: output the read float value
905 * Returns a value >= 0 on success, otherwise a negative error code.
907 int read_sysfs_float(const char *filename, const char *basedir, float *val)
911 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
914 fprintf(stderr, "Memory allocation failed");
918 ret = sprintf(temp, "%s/%s", basedir, filename);
922 sysfsfp = fopen(temp, "r");
929 if (fscanf(sysfsfp, "%f\n", val) != 1) {
930 ret = errno ? -errno : -ENODATA;
932 perror("read_sysfs_float(): Failed to close dir");
947 * read_sysfs_string() - read a string from file
948 * @filename: name of file to read from
949 * @basedir: the sysfs directory in which the file is to be found
950 * @str: output the read string
952 * Returns a value >= 0 on success, otherwise a negative error code.
954 int read_sysfs_string(const char *filename, const char *basedir, char *str)
958 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
961 fprintf(stderr, "Memory allocation failed");
965 ret = sprintf(temp, "%s/%s", basedir, filename);
969 sysfsfp = fopen(temp, "r");
976 if (fscanf(sysfsfp, "%s\n", str) != 1) {
977 ret = errno ? -errno : -ENODATA;
979 perror("read_sysfs_string(): Failed to close dir");