Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 994 insertions, 0 deletions

diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
new file mode 100644
index 000000000..55272fef3
--- /dev/null
+++ b/tools/iio/iio_utils.c
@@ -0,0 +1,994 @@
+/* IIO - useful set of util functionality
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <dirent.h>
+#include <errno.h>
+#include <ctype.h>
+#include "iio_utils.h"
+
+const char *iio_dir = "/sys/bus/iio/devices/";
+
+static char * const iio_direction[] = {
+	"in",
+	"out",
+};
+
+/**
+ * iioutils_break_up_name() - extract generic name from full channel name
+ * @full_name: the full channel name
+ * @generic_name: the output generic channel name
+ *
+ * Returns 0 on success, or a negative error code if string extraction failed.
+ **/
+int iioutils_break_up_name(const char *full_name, char **generic_name)
+{
+	char *current;
+	char *w, *r;
+	char *working, *prefix = "";
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
+		if (!strncmp(full_name, iio_direction[i],
+			     strlen(iio_direction[i]))) {
+			prefix = iio_direction[i];
+			break;
+		}
+
+	current = strdup(full_name + strlen(prefix) + 1);
+	if (!current)
+		return -ENOMEM;
+
+	working = strtok(current, "_\0");
+	if (!working) {
+		free(current);
+		return -EINVAL;
+	}
+
+	w = working;
+	r = working;
+
+	while (*r != '\0') {
+		if (!isdigit(*r)) {
+			*w = *r;
+			w++;
+		}
+
+		r++;
+	}
+	*w = '\0';
+	ret = asprintf(generic_name, "%s_%s", prefix, working);
+	free(current);
+
+	return (ret == -1) ? -ENOMEM : 0;
+}
+
+/**
+ * iioutils_get_type() - find and process _type attribute data
+ * @is_signed: output whether channel is signed
+ * @bytes: output how many bytes the channel storage occupies
+ * @bits_used: output number of valid bits of data
+ * @shift: output amount of bits to shift right data before applying bit mask
+ * @mask: output a bit mask for the raw data
+ * @be: output if data in big endian
+ * @device_dir: the IIO device directory
+ * @name: the channel name
+ * @generic_name: the channel type name
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
+		      unsigned *shift, uint64_t *mask, unsigned *be,
+		      const char *device_dir, const char *name,
+		      const char *generic_name)
+{
+	FILE *sysfsfp;
+	int ret;
+	DIR *dp;
+	char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
+	char signchar, endianchar;
+	unsigned padint;
+	const struct dirent *ent;
+
+	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
+	if (ret < 0)
+		return -ENOMEM;
+
+	ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto error_free_scan_el_dir;
+	}
+	ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto error_free_builtname;
+	}
+
+	dp = opendir(scan_el_dir);
+	if (!dp) {
+		ret = -errno;
+		goto error_free_builtname_generic;
+	}
+
+	ret = -ENOENT;
+	while (ent = readdir(dp), ent)
+		if ((strcmp(builtname, ent->d_name) == 0) ||
+		    (strcmp(builtname_generic, ent->d_name) == 0)) {
+			ret = asprintf(&filename,
+				       "%s/%s", scan_el_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				goto error_closedir;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				fprintf(stderr, "failed to open %s\n",
+					filename);
+				goto error_free_filename;
+			}
+
+			ret = fscanf(sysfsfp,
+				     "%ce:%c%u/%u>>%u",
+				     &endianchar,
+				     &signchar,
+				     bits_used,
+				     &padint, shift);
+			if (ret < 0) {
+				ret = -errno;
+				fprintf(stderr,
+					"failed to pass scan type description\n");
+				goto error_close_sysfsfp;
+			} else if (ret != 5) {
+				ret = -EIO;
+				fprintf(stderr,
+					"scan type description didn't match\n");
+				goto error_close_sysfsfp;
+			}
+
+			*be = (endianchar == 'b');
+			*bytes = padint / 8;
+			if (*bits_used == 64)
+				*mask = ~(0ULL);
+			else
+				*mask = (1ULL << *bits_used) - 1ULL;
+
+			*is_signed = (signchar == 's');
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				fprintf(stderr, "Failed to close %s\n",
+					filename);
+				goto error_free_filename;
+			}
+
+			sysfsfp = 0;
+			free(filename);
+			filename = 0;
+
+			/*
+			 * Avoid having a more generic entry overwriting
+			 * the settings.
+			 */
+			if (strcmp(builtname, ent->d_name) == 0)
+				break;
+		}
+
+error_close_sysfsfp:
+	if (sysfsfp)
+		if (fclose(sysfsfp))
+			perror("iioutils_get_type(): Failed to close file");
+
+error_free_filename:
+	if (filename)
+		free(filename);
+
+error_closedir:
+	if (closedir(dp) == -1)
+		perror("iioutils_get_type(): Failed to close directory");
+
+error_free_builtname_generic:
+	free(builtname_generic);
+error_free_builtname:
+	free(builtname);
+error_free_scan_el_dir:
+	free(scan_el_dir);
+
+	return ret;
+}
+
+/**
+ * iioutils_get_param_float() - read a float value from a channel parameter
+ * @output: output the float value
+ * @param_name: the parameter name to read
+ * @device_dir: the IIO device directory in sysfs
+ * @name: the channel name
+ * @generic_name: the channel type name
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int iioutils_get_param_float(float *output, const char *param_name,
+			     const char *device_dir, const char *name,
+			     const char *generic_name)
+{
+	FILE *sysfsfp;
+	int ret;
+	DIR *dp;
+	char *builtname, *builtname_generic;
+	char *filename = NULL;
+	const struct dirent *ent;
+
+	ret = asprintf(&builtname, "%s_%s", name, param_name);
+	if (ret < 0)
+		return -ENOMEM;
+
+	ret = asprintf(&builtname_generic,
+		       "%s_%s", generic_name, param_name);
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto error_free_builtname;
+	}
+
+	dp = opendir(device_dir);
+	if (!dp) {
+		ret = -errno;
+		goto error_free_builtname_generic;
+	}
+
+	ret = -ENOENT;
+	while (ent = readdir(dp), ent)
+		if ((strcmp(builtname, ent->d_name) == 0) ||
+		    (strcmp(builtname_generic, ent->d_name) == 0)) {
+			ret = asprintf(&filename,
+				       "%s/%s", device_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				goto error_closedir;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				goto error_free_filename;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%f", output) != 1)
+				ret = errno ? -errno : -ENODATA;
+
+			break;
+		}
+error_free_filename:
+	if (filename)
+		free(filename);
+
+error_closedir:
+	if (closedir(dp) == -1)
+		perror("iioutils_get_param_float(): Failed to close directory");
+
+error_free_builtname_generic:
+	free(builtname_generic);
+error_free_builtname:
+	free(builtname);
+
+	return ret;
+}
+
+/**
+ * bsort_channel_array_by_index() - sort the array in index order
+ * @ci_array: the iio_channel_info array to be sorted
+ * @cnt: the amount of array elements
+ **/
+
+void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
+{
+	struct iio_channel_info temp;
+	int x, y;
+
+	for (x = 0; x < cnt; x++)
+		for (y = 0; y < (cnt - 1); y++)
+			if (ci_array[y].index > ci_array[y + 1].index) {
+				temp = ci_array[y + 1];
+				ci_array[y + 1] = ci_array[y];
+				ci_array[y] = temp;
+			}
+}
+
+/**
+ * build_channel_array() - function to figure out what channels are present
+ * @device_dir: the IIO device directory in sysfs
+ * @ci_array: output the resulting array of iio_channel_info
+ * @counter: output the amount of array elements
+ *
+ * Returns 0 on success, otherwise a negative error code.
+ **/
+int build_channel_array(const char *device_dir,
+			struct iio_channel_info **ci_array, int *counter)
+{
+	DIR *dp;
+	FILE *sysfsfp;
+	int count = 0, i;
+	struct iio_channel_info *current;
+	int ret;
+	const struct dirent *ent;
+	char *scan_el_dir;
+	char *filename;
+
+	*counter = 0;
+	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
+	if (ret < 0)
+		return -ENOMEM;
+
+	dp = opendir(scan_el_dir);
+	if (!dp) {
+		ret = -errno;
+		goto error_free_name;
+	}
+
+	while (ent = readdir(dp), ent)
+		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
+			   "_en") == 0) {
+			ret = asprintf(&filename,
+				       "%s/%s", scan_el_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				goto error_close_dir;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				free(filename);
+				goto error_close_dir;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%i", &ret) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				if (fclose(sysfsfp))
+					perror("build_channel_array(): Failed to close file");
+
+				free(filename);
+				goto error_close_dir;
+			}
+			if (ret == 1)
+				(*counter)++;
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				goto error_close_dir;
+			}
+
+			free(filename);
+		}
+
+	*ci_array = malloc(sizeof(**ci_array) * (*counter));
+	if (!*ci_array) {
+		ret = -ENOMEM;
+		goto error_close_dir;
+	}
+
+	seekdir(dp, 0);
+	while (ent = readdir(dp), ent) {
+		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
+			   "_en") == 0) {
+			int current_enabled = 0;
+
+			current = &(*ci_array)[count++];
+			ret = asprintf(&filename,
+				       "%s/%s", scan_el_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				/* decrement count to avoid freeing name */
+				count--;
+				goto error_cleanup_array;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			if (!current_enabled) {
+				free(filename);
+				count--;
+				continue;
+			}
+
+			current->scale = 1.0;
+			current->offset = 0;
+			current->name = strndup(ent->d_name,
+						strlen(ent->d_name) -
+						strlen("_en"));
+			if (!current->name) {
+				free(filename);
+				ret = -ENOMEM;
+				count--;
+				goto error_cleanup_array;
+			}
+
+			/* Get the generic and specific name elements */
+			ret = iioutils_break_up_name(current->name,
+						     &current->generic_name);
+			if (ret) {
+				free(filename);
+				free(current->name);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			ret = asprintf(&filename,
+				       "%s/%s_index",
+				       scan_el_dir,
+				       current->name);
+			if (ret < 0) {
+				free(filename);
+				ret = -ENOMEM;
+				goto error_cleanup_array;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				fprintf(stderr, "failed to open %s\n",
+					filename);
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%u", &current->index) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				if (fclose(sysfsfp))
+					perror("build_channel_array(): Failed to close file");
+
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			free(filename);
+			/* Find the scale */
+			ret = iioutils_get_param_float(&current->scale,
+						       "scale",
+						       device_dir,
+						       current->name,
+						       current->generic_name);
+			if ((ret < 0) && (ret != -ENOENT))
+				goto error_cleanup_array;
+
+			ret = iioutils_get_param_float(&current->offset,
+						       "offset",
+						       device_dir,
+						       current->name,
+						       current->generic_name);
+			if ((ret < 0) && (ret != -ENOENT))
+				goto error_cleanup_array;
+
+			ret = iioutils_get_type(&current->is_signed,
+						&current->bytes,
+						&current->bits_used,
+						&current->shift,
+						&current->mask,
+						&current->be,
+						device_dir,
+						current->name,
+						current->generic_name);
+			if (ret < 0)
+				goto error_cleanup_array;
+		}
+	}
+
+	if (closedir(dp) == -1) {
+		ret = -errno;
+		goto error_cleanup_array;
+	}
+
+	free(scan_el_dir);
+	/* reorder so that the array is in index order */
+	bsort_channel_array_by_index(*ci_array, *counter);
+
+	return 0;
+
+error_cleanup_array:
+	for (i = count - 1;  i >= 0; i--) {
+		free((*ci_array)[i].name);
+		free((*ci_array)[i].generic_name);
+	}
+	free(*ci_array);
+	*ci_array = NULL;
+	*counter = 0;
+error_close_dir:
+	if (dp)
+		if (closedir(dp) == -1)
+			perror("build_channel_array(): Failed to close dir");
+
+error_free_name:
+	free(scan_el_dir);
+
+	return ret;
+}
+
+static int calc_digits(int num)
+{
+	int count = 0;
+
+	while (num != 0) {
+		num /= 10;
+		count++;
+	}
+
+	return count;
+}
+
+/**
+ * find_type_by_name() - function to match top level types by name
+ * @name: top level type instance name
+ * @type: the type of top level instance being searched
+ *
+ * Returns the device number of a matched IIO device on success, otherwise a
+ * negative error code.
+ * Typical types this is used for are device and trigger.
+ **/
+int find_type_by_name(const char *name, const char *type)
+{
+	const struct dirent *ent;
+	int number, numstrlen, ret;
+
+	FILE *namefp;
+	DIR *dp;
+	char thisname[IIO_MAX_NAME_LENGTH];
+	char *filename;
+
+	dp = opendir(iio_dir);
+	if (!dp) {
+		fprintf(stderr, "No industrialio devices available\n");
+		return -ENODEV;
+	}
+
+	while (ent = readdir(dp), ent) {
+		if (strcmp(ent->d_name, ".") != 0 &&
+		    strcmp(ent->d_name, "..") != 0 &&
+		    strlen(ent->d_name) > strlen(type) &&
+		    strncmp(ent->d_name, type, strlen(type)) == 0) {
+			errno = 0;
+			ret = sscanf(ent->d_name + strlen(type), "%d", &number);
+			if (ret < 0) {
+				ret = -errno;
+				fprintf(stderr,
+					"failed to read element number\n");
+				goto error_close_dir;
+			} else if (ret != 1) {
+				ret = -EIO;
+				fprintf(stderr,
+					"failed to match element number\n");
+				goto error_close_dir;
+			}
+
+			numstrlen = calc_digits(number);
+			/* verify the next character is not a colon */
+			if (strncmp(ent->d_name + strlen(type) + numstrlen,
+			    ":", 1) != 0) {
+				filename = malloc(strlen(iio_dir) + strlen(type)
+						  + numstrlen + 6);
+				if (!filename) {
+					ret = -ENOMEM;
+					goto error_close_dir;
+				}
+
+				ret = sprintf(filename, "%s%s%d/name", iio_dir,
+					      type, number);
+				if (ret < 0) {
+					free(filename);
+					goto error_close_dir;
+				}
+
+				namefp = fopen(filename, "r");
+				if (!namefp) {
+					free(filename);
+					continue;
+				}
+
+				free(filename);
+				errno = 0;
+				if (fscanf(namefp, "%s", thisname) != 1) {
+					ret = errno ? -errno : -ENODATA;
+					goto error_close_dir;
+				}
+
+				if (fclose(namefp)) {
+					ret = -errno;
+					goto error_close_dir;
+				}
+
+				if (strcmp(name, thisname) == 0) {
+					if (closedir(dp) == -1)
+						return -errno;
+
+					return number;
+				}
+			}
+		}
+	}
+	if (closedir(dp) == -1)
+		return -errno;
+
+	return -ENODEV;
+
+error_close_dir:
+	if (closedir(dp) == -1)
+		perror("find_type_by_name(): Failed to close directory");
+
+	return ret;
+}
+
+static int _write_sysfs_int(const char *filename, const char *basedir, int val,
+			    int verify)
+{
+	int ret = 0;
+	FILE *sysfsfp;
+	int test;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp)
+		return -ENOMEM;
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "w");
+	if (!sysfsfp) {
+		ret = -errno;
+		fprintf(stderr, "failed to open %s\n", temp);
+		goto error_free;
+	}
+
+	ret = fprintf(sysfsfp, "%d", val);
+	if (ret < 0) {
+		if (fclose(sysfsfp))
+			perror("_write_sysfs_int(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp)) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	if (verify) {
+		sysfsfp = fopen(temp, "r");
+		if (!sysfsfp) {
+			ret = -errno;
+			fprintf(stderr, "failed to open %s\n", temp);
+			goto error_free;
+		}
+
+		if (fscanf(sysfsfp, "%d", &test) != 1) {
+			ret = errno ? -errno : -ENODATA;
+			if (fclose(sysfsfp))
+				perror("_write_sysfs_int(): Failed to close dir");
+
+			goto error_free;
+		}
+
+		if (fclose(sysfsfp)) {
+			ret = -errno;
+			goto error_free;
+		}
+
+		if (test != val) {
+			fprintf(stderr,
+				"Possible failure in int write %d to %s/%s\n",
+				val, basedir, filename);
+			ret = -1;
+		}
+	}
+
+error_free:
+	free(temp);
+	return ret;
+}
+
+/**
+ * write_sysfs_int() - write an integer value to a sysfs file
+ * @filename: name of the file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: integer value to write to file
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_int(const char *filename, const char *basedir, int val)
+{
+	return _write_sysfs_int(filename, basedir, val, 0);
+}
+
+/**
+ * write_sysfs_int_and_verify() - write an integer value to a sysfs file
+ *				  and verify
+ * @filename: name of the file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: integer value to write to file
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_int_and_verify(const char *filename, const char *basedir,
+			       int val)
+{
+	return _write_sysfs_int(filename, basedir, val, 1);
+}
+
+static int _write_sysfs_string(const char *filename, const char *basedir,
+			       const char *val, int verify)
+{
+	int ret = 0;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed\n");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "w");
+	if (!sysfsfp) {
+		ret = -errno;
+		fprintf(stderr, "Could not open %s\n", temp);
+		goto error_free;
+	}
+
+	ret = fprintf(sysfsfp, "%s", val);
+	if (ret < 0) {
+		if (fclose(sysfsfp))
+			perror("_write_sysfs_string(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp)) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	if (verify) {
+		sysfsfp = fopen(temp, "r");
+		if (!sysfsfp) {
+			ret = -errno;
+			fprintf(stderr, "Could not open file to verify\n");
+			goto error_free;
+		}
+
+		if (fscanf(sysfsfp, "%s", temp) != 1) {
+			ret = errno ? -errno : -ENODATA;
+			if (fclose(sysfsfp))
+				perror("_write_sysfs_string(): Failed to close dir");
+
+			goto error_free;
+		}
+
+		if (fclose(sysfsfp)) {
+			ret = -errno;
+			goto error_free;
+		}
+
+		if (strcmp(temp, val) != 0) {
+			fprintf(stderr,
+				"Possible failure in string write of %s "
+				"Should be %s written to %s/%s\n", temp, val,
+				basedir, filename);
+			ret = -1;
+		}
+	}
+
+error_free:
+	free(temp);
+
+	return ret;
+}
+
+/**
+ * write_sysfs_string_and_verify() - string write, readback and verify
+ * @filename: name of file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: the string to write
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_string_and_verify(const char *filename, const char *basedir,
+				  const char *val)
+{
+	return _write_sysfs_string(filename, basedir, val, 1);
+}
+
+/**
+ * write_sysfs_string() - write string to a sysfs file
+ * @filename: name of file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: the string to write
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_string(const char *filename, const char *basedir,
+		       const char *val)
+{
+	return _write_sysfs_string(filename, basedir, val, 0);
+}
+
+/**
+ * read_sysfs_posint() - read an integer value from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ *
+ * Returns the read integer value >= 0 on success, otherwise a negative error
+ * code.
+ **/
+int read_sysfs_posint(const char *filename, const char *basedir)
+{
+	int ret;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "r");
+	if (!sysfsfp) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_posint(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
+error_free:
+	free(temp);
+
+	return ret;
+}
+
+/**
+ * read_sysfs_float() - read a float value from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: output the read float value
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int read_sysfs_float(const char *filename, const char *basedir, float *val)
+{
+	int ret = 0;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "r");
+	if (!sysfsfp) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%f\n", val) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_float(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
+error_free:
+	free(temp);
+
+	return ret;
+}
+
+/**
+ * read_sysfs_string() - read a string from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ * @str: output the read string
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int read_sysfs_string(const char *filename, const char *basedir, char *str)
+{
+	int ret = 0;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "r");
+	if (!sysfsfp) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%s\n", str) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_string(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
+error_free:
+	free(temp);
+
+	return ret;
+}