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.
16 #include "iio_utils.h"
18 const char *iio_dir = "/sys/bus/iio/devices/";
20 static char * const iio_direction[] = {
26 * iioutils_break_up_name() - extract generic name from full channel name
27 * @full_name: the full channel name
28 * @generic_name: the output generic channel name
30 * Returns 0 on success, or a negative error code if string extraction failed.
32 int iioutils_break_up_name(const char *full_name, char **generic_name)
36 char *working, *prefix = "";
39 for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
40 if (!strncmp(full_name, iio_direction[i],
41 strlen(iio_direction[i]))) {
42 prefix = iio_direction[i];
46 current = strdup(full_name + strlen(prefix) + 1);
50 working = strtok(current, "_\0");
68 ret = asprintf(generic_name, "%s_%s", prefix, working);
71 return (ret == -1) ? -ENOMEM : 0;
75 * iioutils_get_type() - find and process _type attribute data
76 * @is_signed: output whether channel is signed
77 * @bytes: output how many bytes the channel storage occupies
78 * @bits_used: output number of valid bits of data
79 * @shift: output amount of bits to shift right data before applying bit mask
80 * @mask: output a bit mask for the raw data
81 * @be: output if data in big endian
82 * @device_dir: the IIO device directory
83 * @name: the channel name
84 * @generic_name: the channel type name
86 * Returns a value >= 0 on success, otherwise a negative error code.
88 int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
89 unsigned *shift, uint64_t *mask, unsigned *be,
90 const char *device_dir, const char *name,
91 const char *generic_name)
96 char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
97 char signchar, endianchar;
99 const struct dirent *ent;
101 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
105 ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
108 goto error_free_scan_el_dir;
110 ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
113 goto error_free_builtname;
116 dp = opendir(scan_el_dir);
119 goto error_free_builtname_generic;
123 while (ent = readdir(dp), ent)
124 if ((strcmp(builtname, ent->d_name) == 0) ||
125 (strcmp(builtname_generic, ent->d_name) == 0)) {
126 ret = asprintf(&filename,
127 "%s/%s", scan_el_dir, ent->d_name);
133 sysfsfp = fopen(filename, "r");
136 fprintf(stderr, "failed to open %s\n",
138 goto error_free_filename;
141 ret = fscanf(sysfsfp,
150 "failed to pass scan type description\n");
151 goto error_close_sysfsfp;
152 } else if (ret != 5) {
155 "scan type description didn't match\n");
156 goto error_close_sysfsfp;
159 *be = (endianchar == 'b');
161 if (*bits_used == 64)
164 *mask = (1ULL << *bits_used) - 1ULL;
166 *is_signed = (signchar == 's');
167 if (fclose(sysfsfp)) {
169 fprintf(stderr, "Failed to close %s\n",
171 goto error_free_filename;
179 * Avoid having a more generic entry overwriting
182 if (strcmp(builtname, ent->d_name) == 0)
189 perror("iioutils_get_type(): Failed to close file");
196 if (closedir(dp) == -1)
197 perror("iioutils_get_type(): Failed to close directory");
199 error_free_builtname_generic:
200 free(builtname_generic);
201 error_free_builtname:
203 error_free_scan_el_dir:
210 * iioutils_get_param_float() - read a float value from a channel parameter
211 * @output: output the float value
212 * @param_name: the parameter name to read
213 * @device_dir: the IIO device directory in sysfs
214 * @name: the channel name
215 * @generic_name: the channel type name
217 * Returns a value >= 0 on success, otherwise a negative error code.
219 int iioutils_get_param_float(float *output, const char *param_name,
220 const char *device_dir, const char *name,
221 const char *generic_name)
226 char *builtname, *builtname_generic;
227 char *filename = NULL;
228 const struct dirent *ent;
230 ret = asprintf(&builtname, "%s_%s", name, param_name);
234 ret = asprintf(&builtname_generic,
235 "%s_%s", generic_name, param_name);
238 goto error_free_builtname;
241 dp = opendir(device_dir);
244 goto error_free_builtname_generic;
248 while (ent = readdir(dp), ent)
249 if ((strcmp(builtname, ent->d_name) == 0) ||
250 (strcmp(builtname_generic, ent->d_name) == 0)) {
251 ret = asprintf(&filename,
252 "%s/%s", device_dir, ent->d_name);
258 sysfsfp = fopen(filename, "r");
261 goto error_free_filename;
265 if (fscanf(sysfsfp, "%f", output) != 1)
266 ret = errno ? -errno : -ENODATA;
275 if (closedir(dp) == -1)
276 perror("iioutils_get_param_float(): Failed to close directory");
278 error_free_builtname_generic:
279 free(builtname_generic);
280 error_free_builtname:
287 * bsort_channel_array_by_index() - sort the array in index order
288 * @ci_array: the iio_channel_info array to be sorted
289 * @cnt: the amount of array elements
292 void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
294 struct iio_channel_info temp;
297 for (x = 0; x < cnt; x++)
298 for (y = 0; y < (cnt - 1); y++)
299 if (ci_array[y].index > ci_array[y + 1].index) {
300 temp = ci_array[y + 1];
301 ci_array[y + 1] = ci_array[y];
307 * build_channel_array() - function to figure out what channels are present
308 * @device_dir: the IIO device directory in sysfs
309 * @ci_array: output the resulting array of iio_channel_info
310 * @counter: output the amount of array elements
312 * Returns 0 on success, otherwise a negative error code.
314 int build_channel_array(const char *device_dir,
315 struct iio_channel_info **ci_array, int *counter)
320 struct iio_channel_info *current;
322 const struct dirent *ent;
327 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
331 dp = opendir(scan_el_dir);
334 goto error_free_name;
337 while (ent = readdir(dp), ent)
338 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
340 ret = asprintf(&filename,
341 "%s/%s", scan_el_dir, ent->d_name);
344 goto error_close_dir;
347 sysfsfp = fopen(filename, "r");
351 goto error_close_dir;
355 if (fscanf(sysfsfp, "%i", &ret) != 1) {
356 ret = errno ? -errno : -ENODATA;
358 perror("build_channel_array(): Failed to close file");
361 goto error_close_dir;
366 if (fclose(sysfsfp)) {
369 goto error_close_dir;
375 *ci_array = malloc(sizeof(**ci_array) * (*counter));
378 goto error_close_dir;
382 while (ent = readdir(dp), ent) {
383 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
385 int current_enabled = 0;
387 current = &(*ci_array)[count++];
388 ret = asprintf(&filename,
389 "%s/%s", scan_el_dir, ent->d_name);
392 /* decrement count to avoid freeing name */
394 goto error_cleanup_array;
397 sysfsfp = fopen(filename, "r");
402 goto error_cleanup_array;
406 if (fscanf(sysfsfp, "%i", ¤t_enabled) != 1) {
407 ret = errno ? -errno : -ENODATA;
410 goto error_cleanup_array;
413 if (fclose(sysfsfp)) {
417 goto error_cleanup_array;
420 if (!current_enabled) {
426 current->scale = 1.0;
428 current->name = strndup(ent->d_name,
429 strlen(ent->d_name) -
431 if (!current->name) {
435 goto error_cleanup_array;
438 /* Get the generic and specific name elements */
439 ret = iioutils_break_up_name(current->name,
440 ¤t->generic_name);
445 goto error_cleanup_array;
448 ret = asprintf(&filename,
455 goto error_cleanup_array;
458 sysfsfp = fopen(filename, "r");
461 fprintf(stderr, "failed to open %s\n",
464 goto error_cleanup_array;
468 if (fscanf(sysfsfp, "%u", ¤t->index) != 1) {
469 ret = errno ? -errno : -ENODATA;
471 perror("build_channel_array(): Failed to close file");
474 goto error_cleanup_array;
477 if (fclose(sysfsfp)) {
480 goto error_cleanup_array;
485 ret = iioutils_get_param_float(¤t->scale,
489 current->generic_name);
490 if ((ret < 0) && (ret != -ENOENT))
491 goto error_cleanup_array;
493 ret = iioutils_get_param_float(¤t->offset,
497 current->generic_name);
498 if ((ret < 0) && (ret != -ENOENT))
499 goto error_cleanup_array;
501 ret = iioutils_get_type(¤t->is_signed,
509 current->generic_name);
511 goto error_cleanup_array;
515 if (closedir(dp) == -1) {
517 goto error_cleanup_array;
521 /* reorder so that the array is in index order */
522 bsort_channel_array_by_index(*ci_array, *counter);
527 for (i = count - 1; i >= 0; i--) {
528 free((*ci_array)[i].name);
529 free((*ci_array)[i].generic_name);
536 if (closedir(dp) == -1)
537 perror("build_channel_array(): Failed to close dir");
545 static int calc_digits(int num)
558 * find_type_by_name() - function to match top level types by name
559 * @name: top level type instance name
560 * @type: the type of top level instance being searched
562 * Returns the device number of a matched IIO device on success, otherwise a
563 * negative error code.
564 * Typical types this is used for are device and trigger.
566 int find_type_by_name(const char *name, const char *type)
568 const struct dirent *ent;
569 int number, numstrlen, ret;
573 char thisname[IIO_MAX_NAME_LENGTH];
576 dp = opendir(iio_dir);
578 fprintf(stderr, "No industrialio devices available\n");
582 while (ent = readdir(dp), ent) {
583 if (strcmp(ent->d_name, ".") != 0 &&
584 strcmp(ent->d_name, "..") != 0 &&
585 strlen(ent->d_name) > strlen(type) &&
586 strncmp(ent->d_name, type, strlen(type)) == 0) {
588 ret = sscanf(ent->d_name + strlen(type), "%d", &number);
592 "failed to read element number\n");
593 goto error_close_dir;
594 } else if (ret != 1) {
597 "failed to match element number\n");
598 goto error_close_dir;
601 numstrlen = calc_digits(number);
602 /* verify the next character is not a colon */
603 if (strncmp(ent->d_name + strlen(type) + numstrlen,
605 filename = malloc(strlen(iio_dir) + strlen(type)
609 goto error_close_dir;
612 ret = sprintf(filename, "%s%s%d/name", iio_dir,
616 goto error_close_dir;
619 namefp = fopen(filename, "r");
627 if (fscanf(namefp, "%s", thisname) != 1) {
628 ret = errno ? -errno : -ENODATA;
629 goto error_close_dir;
632 if (fclose(namefp)) {
634 goto error_close_dir;
637 if (strcmp(name, thisname) == 0) {
638 if (closedir(dp) == -1)
646 if (closedir(dp) == -1)
652 if (closedir(dp) == -1)
653 perror("find_type_by_name(): Failed to close directory");
658 static int _write_sysfs_int(const char *filename, const char *basedir, int val,
664 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
669 ret = sprintf(temp, "%s/%s", basedir, filename);
673 sysfsfp = fopen(temp, "w");
676 fprintf(stderr, "failed to open %s\n", temp);
680 ret = fprintf(sysfsfp, "%d", val);
683 perror("_write_sysfs_int(): Failed to close dir");
688 if (fclose(sysfsfp)) {
694 sysfsfp = fopen(temp, "r");
697 fprintf(stderr, "failed to open %s\n", temp);
701 if (fscanf(sysfsfp, "%d", &test) != 1) {
702 ret = errno ? -errno : -ENODATA;
704 perror("_write_sysfs_int(): Failed to close dir");
709 if (fclose(sysfsfp)) {
716 "Possible failure in int write %d to %s/%s\n",
717 val, basedir, filename);
728 * write_sysfs_int() - write an integer value to a sysfs file
729 * @filename: name of the file to write to
730 * @basedir: the sysfs directory in which the file is to be found
731 * @val: integer value to write to file
733 * Returns a value >= 0 on success, otherwise a negative error code.
735 int write_sysfs_int(const char *filename, const char *basedir, int val)
737 return _write_sysfs_int(filename, basedir, val, 0);
741 * write_sysfs_int_and_verify() - write an integer value to a sysfs file
743 * @filename: name of the file to write to
744 * @basedir: the sysfs directory in which the file is to be found
745 * @val: integer value to write to file
747 * Returns a value >= 0 on success, otherwise a negative error code.
749 int write_sysfs_int_and_verify(const char *filename, const char *basedir,
752 return _write_sysfs_int(filename, basedir, val, 1);
755 static int _write_sysfs_string(const char *filename, const char *basedir,
756 const char *val, int verify)
760 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
763 fprintf(stderr, "Memory allocation failed\n");
767 ret = sprintf(temp, "%s/%s", basedir, filename);
771 sysfsfp = fopen(temp, "w");
774 fprintf(stderr, "Could not open %s\n", temp);
778 ret = fprintf(sysfsfp, "%s", val);
781 perror("_write_sysfs_string(): Failed to close dir");
786 if (fclose(sysfsfp)) {
792 sysfsfp = fopen(temp, "r");
795 fprintf(stderr, "Could not open file to verify\n");
799 if (fscanf(sysfsfp, "%s", temp) != 1) {
800 ret = errno ? -errno : -ENODATA;
802 perror("_write_sysfs_string(): Failed to close dir");
807 if (fclose(sysfsfp)) {
812 if (strcmp(temp, val) != 0) {
814 "Possible failure in string write of %s "
815 "Should be %s written to %s/%s\n", temp, val,
828 * write_sysfs_string_and_verify() - string write, readback and verify
829 * @filename: name of file to write to
830 * @basedir: the sysfs directory in which the file is to be found
831 * @val: the string to write
833 * Returns a value >= 0 on success, otherwise a negative error code.
835 int write_sysfs_string_and_verify(const char *filename, const char *basedir,
838 return _write_sysfs_string(filename, basedir, val, 1);
842 * write_sysfs_string() - write string to a sysfs file
843 * @filename: name of file to write to
844 * @basedir: the sysfs directory in which the file is to be found
845 * @val: the string to write
847 * Returns a value >= 0 on success, otherwise a negative error code.
849 int write_sysfs_string(const char *filename, const char *basedir,
852 return _write_sysfs_string(filename, basedir, val, 0);
856 * read_sysfs_posint() - read an integer value from file
857 * @filename: name of file to read from
858 * @basedir: the sysfs directory in which the file is to be found
860 * Returns the read integer value >= 0 on success, otherwise a negative error
863 int read_sysfs_posint(const char *filename, const char *basedir)
867 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
870 fprintf(stderr, "Memory allocation failed");
874 ret = sprintf(temp, "%s/%s", basedir, filename);
878 sysfsfp = fopen(temp, "r");
885 if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
886 ret = errno ? -errno : -ENODATA;
888 perror("read_sysfs_posint(): Failed to close dir");
903 * read_sysfs_float() - read a float value from file
904 * @filename: name of file to read from
905 * @basedir: the sysfs directory in which the file is to be found
906 * @val: output the read float value
908 * Returns a value >= 0 on success, otherwise a negative error code.
910 int read_sysfs_float(const char *filename, const char *basedir, float *val)
914 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
917 fprintf(stderr, "Memory allocation failed");
921 ret = sprintf(temp, "%s/%s", basedir, filename);
925 sysfsfp = fopen(temp, "r");
932 if (fscanf(sysfsfp, "%f\n", val) != 1) {
933 ret = errno ? -errno : -ENODATA;
935 perror("read_sysfs_float(): Failed to close dir");
950 * read_sysfs_string() - read a string from file
951 * @filename: name of file to read from
952 * @basedir: the sysfs directory in which the file is to be found
953 * @str: output the read string
955 * Returns a value >= 0 on success, otherwise a negative error code.
957 int read_sysfs_string(const char *filename, const char *basedir, char *str)
961 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
964 fprintf(stderr, "Memory allocation failed");
968 ret = sprintf(temp, "%s/%s", basedir, filename);
972 sysfsfp = fopen(temp, "r");
979 if (fscanf(sysfsfp, "%s\n", str) != 1) {
980 ret = errno ? -errno : -ENODATA;
982 perror("read_sysfs_string(): Failed to close dir");