--- /dev/null
+/* Industrialio buffer test code.
+ *
+ * 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.
+ *
+ * This program is primarily intended as an example application.
+ * Reads the current buffer setup from sysfs and starts a short capture
+ * from the specified device, pretty printing the result after appropriate
+ * conversion.
+ *
+ * Command line parameters
+ * generic_buffer -n <device_name> -t <trigger_name>
+ * If trigger name is not specified the program assumes you want a dataready
+ * trigger associated with the device and goes looking for it.
+ *
+ */
+
+#define _GNU_SOURCE
+
+#include <unistd.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/dir.h>
+#include <linux/types.h>
+#include <string.h>
+#include <poll.h>
+#include <endian.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include "iio_utils.h"
+
+/**
+ * size_from_channelarray() - calculate the storage size of a scan
+ * @channels: the channel info array
+ * @num_channels: number of channels
+ *
+ * Has the side effect of filling the channels[i].location values used
+ * in processing the buffer output.
+ **/
+int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
+{
+ int bytes = 0;
+ int i = 0;
+ while (i < num_channels) {
+ if (bytes % channels[i].bytes == 0)
+ channels[i].location = bytes;
+ else
+ channels[i].location = bytes - bytes%channels[i].bytes
+ + channels[i].bytes;
+ bytes = channels[i].location + channels[i].bytes;
+ i++;
+ }
+ return bytes;
+}
+
+void print2byte(int input, struct iio_channel_info *info)
+{
+ /* First swap if incorrect endian */
+ if (info->be)
+ input = be16toh((uint16_t)input);
+ else
+ input = le16toh((uint16_t)input);
+
+ /*
+ * Shift before conversion to avoid sign extension
+ * of left aligned data
+ */
+ input = input >> info->shift;
+ if (info->is_signed) {
+ int16_t val = input;
+ val &= (1 << info->bits_used) - 1;
+ val = (int16_t)(val << (16 - info->bits_used)) >>
+ (16 - info->bits_used);
+ printf("%05f ", ((float)val + info->offset)*info->scale);
+ } else {
+ uint16_t val = input;
+ val &= (1 << info->bits_used) - 1;
+ printf("%05f ", ((float)val + info->offset)*info->scale);
+ }
+}
+/**
+ * process_scan() - print out the values in SI units
+ * @data: pointer to the start of the scan
+ * @channels: information about the channels. Note
+ * size_from_channelarray must have been called first to fill the
+ * location offsets.
+ * @num_channels: number of channels
+ **/
+void process_scan(char *data,
+ struct iio_channel_info *channels,
+ int num_channels)
+{
+ int k;
+ for (k = 0; k < num_channels; k++)
+ switch (channels[k].bytes) {
+ /* only a few cases implemented so far */
+ case 2:
+ print2byte(*(uint16_t *)(data + channels[k].location),
+ &channels[k]);
+ break;
+ case 4:
+ if (!channels[k].is_signed) {
+ uint32_t val = *(uint32_t *)
+ (data + channels[k].location);
+ printf("%05f ", ((float)val +
+ channels[k].offset)*
+ channels[k].scale);
+
+ }
+ break;
+ case 8:
+ if (channels[k].is_signed) {
+ int64_t val = *(int64_t *)
+ (data +
+ channels[k].location);
+ if ((val >> channels[k].bits_used) & 1)
+ val = (val & channels[k].mask) |
+ ~channels[k].mask;
+ /* special case for timestamp */
+ if (channels[k].scale == 1.0f &&
+ channels[k].offset == 0.0f)
+ printf("%" PRId64 " ", val);
+ else
+ printf("%05f ", ((float)val +
+ channels[k].offset)*
+ channels[k].scale);
+ }
+ break;
+ default:
+ break;
+ }
+ printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+ unsigned long num_loops = 2;
+ unsigned long timedelay = 1000000;
+ unsigned long buf_len = 128;
+
+ int ret, c, i, j, toread;
+ int fp;
+
+ int num_channels;
+ char *trigger_name = NULL, *device_name = NULL;
+ char *dev_dir_name, *buf_dir_name;
+
+ int datardytrigger = 1;
+ char *data;
+ ssize_t read_size;
+ int dev_num, trig_num;
+ char *buffer_access;
+ int scan_size;
+ int noevents = 0;
+ char *dummy;
+
+ struct iio_channel_info *channels;
+
+ while ((c = getopt(argc, argv, "l:w:c:et:n:")) != -1) {
+ switch (c) {
+ case 'n':
+ device_name = optarg;
+ break;
+ case 't':
+ trigger_name = optarg;
+ datardytrigger = 0;
+ break;
+ case 'e':
+ noevents = 1;
+ break;
+ case 'c':
+ num_loops = strtoul(optarg, &dummy, 10);
+ break;
+ case 'w':
+ timedelay = strtoul(optarg, &dummy, 10);
+ break;
+ case 'l':
+ buf_len = strtoul(optarg, &dummy, 10);
+ break;
+ case '?':
+ return -1;
+ }
+ }
+
+ if (device_name == NULL)
+ return -1;
+
+ /* Find the device requested */
+ dev_num = find_type_by_name(device_name, "iio:device");
+ if (dev_num < 0) {
+ printf("Failed to find the %s\n", device_name);
+ ret = -ENODEV;
+ goto error_ret;
+ }
+ printf("iio device number being used is %d\n", dev_num);
+
+ asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
+ if (trigger_name == NULL) {
+ /*
+ * Build the trigger name. If it is device associated its
+ * name is <device_name>_dev[n] where n matches the device
+ * number found above
+ */
+ ret = asprintf(&trigger_name,
+ "%s-dev%d", device_name, dev_num);
+ if (ret < 0) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ }
+
+ /* Verify the trigger exists */
+ trig_num = find_type_by_name(trigger_name, "trigger");
+ if (trig_num < 0) {
+ printf("Failed to find the trigger %s\n", trigger_name);
+ ret = -ENODEV;
+ goto error_free_triggername;
+ }
+ printf("iio trigger number being used is %d\n", trig_num);
+
+ /*
+ * Parse the files in scan_elements to identify what channels are
+ * present
+ */
+ ret = build_channel_array(dev_dir_name, &channels, &num_channels);
+ if (ret) {
+ printf("Problem reading scan element information\n");
+ printf("diag %s\n", dev_dir_name);
+ goto error_free_triggername;
+ }
+
+ /*
+ * Construct the directory name for the associated buffer.
+ * As we know that the lis3l02dq has only one buffer this may
+ * be built rather than found.
+ */
+ ret = asprintf(&buf_dir_name,
+ "%siio:device%d/buffer", iio_dir, dev_num);
+ if (ret < 0) {
+ ret = -ENOMEM;
+ goto error_free_triggername;
+ }
+ printf("%s %s\n", dev_dir_name, trigger_name);
+ /* Set the device trigger to be the data ready trigger found above */
+ ret = write_sysfs_string_and_verify("trigger/current_trigger",
+ dev_dir_name,
+ trigger_name);
+ if (ret < 0) {
+ printf("Failed to write current_trigger file\n");
+ goto error_free_buf_dir_name;
+ }
+
+ /* Setup ring buffer parameters */
+ ret = write_sysfs_int("length", buf_dir_name, buf_len);
+ if (ret < 0)
+ goto error_free_buf_dir_name;
+
+ /* Enable the buffer */
+ ret = write_sysfs_int("enable", buf_dir_name, 1);
+ if (ret < 0)
+ goto error_free_buf_dir_name;
+ scan_size = size_from_channelarray(channels, num_channels);
+ data = malloc(scan_size*buf_len);
+ if (!data) {
+ ret = -ENOMEM;
+ goto error_free_buf_dir_name;
+ }
+
+ ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
+ if (ret < 0) {
+ ret = -ENOMEM;
+ goto error_free_data;
+ }
+
+ /* Attempt to open non blocking the access dev */
+ fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
+ if (fp == -1) { /* If it isn't there make the node */
+ printf("Failed to open %s\n", buffer_access);
+ ret = -errno;
+ goto error_free_buffer_access;
+ }
+
+ /* Wait for events 10 times */
+ for (j = 0; j < num_loops; j++) {
+ if (!noevents) {
+ struct pollfd pfd = {
+ .fd = fp,
+ .events = POLLIN,
+ };
+
+ poll(&pfd, 1, -1);
+ toread = buf_len;
+
+ } else {
+ usleep(timedelay);
+ toread = 64;
+ }
+
+ read_size = read(fp,
+ data,
+ toread*scan_size);
+ if (read_size == -EAGAIN) {
+ printf("nothing available\n");
+ continue;
+ }
+ for (i = 0; i < read_size/scan_size; i++)
+ process_scan(data + scan_size*i,
+ channels,
+ num_channels);
+ }
+
+ /* Stop the buffer */
+ ret = write_sysfs_int("enable", buf_dir_name, 0);
+ if (ret < 0)
+ goto error_close_buffer_access;
+
+ /* Disconnect the trigger - just write a dummy name. */
+ write_sysfs_string("trigger/current_trigger",
+ dev_dir_name, "NULL");
+
+error_close_buffer_access:
+ close(fp);
+error_free_data:
+ free(data);
+error_free_buffer_access:
+ free(buffer_access);
+error_free_buf_dir_name:
+ free(buf_dir_name);
+error_free_triggername:
+ if (datardytrigger)
+ free(trigger_name);
+error_ret:
+ return ret;
+}
--- /dev/null
+/* 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 <ctype.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <dirent.h>
+#include <errno.h>
+
+/* Made up value to limit allocation sizes */
+#define IIO_MAX_NAME_LENGTH 30
+
+#define FORMAT_SCAN_ELEMENTS_DIR "%s/scan_elements"
+#define FORMAT_TYPE_FILE "%s_type"
+
+const char *iio_dir = "/sys/bus/iio/devices/";
+
+/**
+ * iioutils_break_up_name() - extract generic name from full channel name
+ * @full_name: the full channel name
+ * @generic_name: the output generic channel name
+ **/
+inline int iioutils_break_up_name(const char *full_name,
+ char **generic_name)
+{
+ char *current;
+ char *w, *r;
+ char *working;
+ current = strdup(full_name);
+ working = strtok(current, "_\0");
+ w = working;
+ r = working;
+
+ while (*r != '\0') {
+ if (!isdigit(*r)) {
+ *w = *r;
+ w++;
+ }
+ r++;
+ }
+ *w = '\0';
+ *generic_name = strdup(working);
+ free(current);
+
+ return 0;
+}
+
+/**
+ * struct iio_channel_info - information about a given channel
+ * @name: channel name
+ * @generic_name: general name for channel type
+ * @scale: scale factor to be applied for conversion to si units
+ * @offset: offset to be applied for conversion to si units
+ * @index: the channel index in the buffer output
+ * @bytes: number of bytes occupied in buffer output
+ * @mask: a bit mask for the raw output
+ * @is_signed: is the raw value stored signed
+ * @enabled: is this channel enabled
+ **/
+struct iio_channel_info {
+ char *name;
+ char *generic_name;
+ float scale;
+ float offset;
+ unsigned index;
+ unsigned bytes;
+ unsigned bits_used;
+ unsigned shift;
+ uint64_t mask;
+ unsigned be;
+ unsigned is_signed;
+ unsigned enabled;
+ unsigned location;
+};
+
+/**
+ * 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
+ * @mask: output a bit mask for the raw data
+ * @be: big endian
+ * @device_dir: the iio device directory
+ * @name: the channel name
+ * @generic_name: the channel type name
+ **/
+inline 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) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ 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 == NULL) {
+ ret = -errno;
+ goto error_free_builtname_generic;
+ }
+ while (ent = readdir(dp), ent != NULL)
+ /*
+ * Do we allow devices to override a generic name with
+ * a specific one?
+ */
+ 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 == NULL) {
+ printf("failed to open %s\n", filename);
+ ret = -errno;
+ goto error_free_filename;
+ }
+
+ ret = fscanf(sysfsfp,
+ "%ce:%c%u/%u>>%u",
+ &endianchar,
+ &signchar,
+ bits_used,
+ &padint, shift);
+ if (ret < 0) {
+ printf("failed to pass scan type description\n");
+ ret = -errno;
+ goto error_close_sysfsfp;
+ }
+ *be = (endianchar == 'b');
+ *bytes = padint / 8;
+ if (*bits_used == 64)
+ *mask = ~0;
+ else
+ *mask = (1 << *bits_used) - 1;
+ if (signchar == 's')
+ *is_signed = 1;
+ else
+ *is_signed = 0;
+ fclose(sysfsfp);
+ free(filename);
+
+ filename = 0;
+ sysfsfp = 0;
+ }
+error_close_sysfsfp:
+ if (sysfsfp)
+ fclose(sysfsfp);
+error_free_filename:
+ if (filename)
+ free(filename);
+error_closedir:
+ closedir(dp);
+error_free_builtname_generic:
+ free(builtname_generic);
+error_free_builtname:
+ free(builtname);
+error_free_scan_el_dir:
+ free(scan_el_dir);
+error_ret:
+ return ret;
+}
+
+inline 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) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ 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 == NULL) {
+ ret = -errno;
+ goto error_free_builtname_generic;
+ }
+ while (ent = readdir(dp), ent != NULL)
+ 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;
+ }
+ fscanf(sysfsfp, "%f", output);
+ break;
+ }
+error_free_filename:
+ if (filename)
+ free(filename);
+error_closedir:
+ closedir(dp);
+error_free_builtname_generic:
+ free(builtname_generic);
+error_free_builtname:
+ free(builtname);
+error_ret:
+ return ret;
+}
+
+/**
+ * bsort_channel_array_by_index() - reorder so that the array is in index order
+ *
+ **/
+
+inline 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
+ * @
+ **/
+inline int build_channel_array(const char *device_dir,
+ struct iio_channel_info **ci_array,
+ int *counter)
+{
+ DIR *dp;
+ FILE *sysfsfp;
+ int count, 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) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ dp = opendir(scan_el_dir);
+ if (dp == NULL) {
+ ret = -errno;
+ goto error_free_name;
+ }
+ while (ent = readdir(dp), ent != NULL)
+ 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 == NULL) {
+ ret = -errno;
+ free(filename);
+ goto error_close_dir;
+ }
+ fscanf(sysfsfp, "%u", &ret);
+ if (ret == 1)
+ (*counter)++;
+ fclose(sysfsfp);
+ free(filename);
+ }
+ *ci_array = malloc(sizeof(**ci_array) * (*counter));
+ if (*ci_array == NULL) {
+ ret = -ENOMEM;
+ goto error_close_dir;
+ }
+ seekdir(dp, 0);
+ count = 0;
+ while (ent = readdir(dp), ent != NULL) {
+ if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
+ "_en") == 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 == NULL) {
+ free(filename);
+ ret = -errno;
+ goto error_cleanup_array;
+ }
+ fscanf(sysfsfp, "%u", ¤t->enabled);
+ fclose(sysfsfp);
+
+ 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 == NULL) {
+ free(filename);
+ ret = -ENOMEM;
+ goto error_cleanup_array;
+ }
+ /* Get the generic and specific name elements */
+ ret = iioutils_break_up_name(current->name,
+ ¤t->generic_name);
+ if (ret) {
+ free(filename);
+ 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");
+ fscanf(sysfsfp, "%u", ¤t->index);
+ fclose(sysfsfp);
+ free(filename);
+ /* Find the scale */
+ ret = iioutils_get_param_float(¤t->scale,
+ "scale",
+ device_dir,
+ current->name,
+ current->generic_name);
+ if (ret < 0)
+ goto error_cleanup_array;
+ ret = iioutils_get_param_float(¤t->offset,
+ "offset",
+ device_dir,
+ current->name,
+ current->generic_name);
+ if (ret < 0)
+ goto error_cleanup_array;
+ ret = iioutils_get_type(¤t->is_signed,
+ ¤t->bytes,
+ ¤t->bits_used,
+ ¤t->shift,
+ ¤t->mask,
+ ¤t->be,
+ device_dir,
+ current->name,
+ current->generic_name);
+ }
+ }
+
+ closedir(dp);
+ /* 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);
+error_close_dir:
+ closedir(dp);
+error_free_name:
+ free(scan_el_dir);
+error_ret:
+ return ret;
+}
+
+/**
+ * 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 sort
+ *
+ * Typical types this is used for are device and trigger.
+ **/
+inline int find_type_by_name(const char *name, const char *type)
+{
+ const struct dirent *ent;
+ int number, numstrlen;
+
+ FILE *nameFile;
+ DIR *dp;
+ char thisname[IIO_MAX_NAME_LENGTH];
+ char *filename;
+
+ dp = opendir(iio_dir);
+ if (dp == NULL) {
+ printf("No industrialio devices available\n");
+ return -ENODEV;
+ }
+
+ while (ent = readdir(dp), ent != NULL) {
+ 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) {
+ numstrlen = sscanf(ent->d_name + strlen(type),
+ "%d",
+ &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 == NULL) {
+ closedir(dp);
+ return -ENOMEM;
+ }
+ sprintf(filename, "%s%s%d/name",
+ iio_dir,
+ type,
+ number);
+ nameFile = fopen(filename, "r");
+ if (!nameFile) {
+ free(filename);
+ continue;
+ }
+ free(filename);
+ fscanf(nameFile, "%s", thisname);
+ fclose(nameFile);
+ if (strcmp(name, thisname) == 0) {
+ closedir(dp);
+ return number;
+ }
+ }
+ }
+ }
+ closedir(dp);
+ return -ENODEV;
+}
+
+inline int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
+{
+ int ret;
+ FILE *sysfsfp;
+ int test;
+ char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+ if (temp == NULL)
+ return -ENOMEM;
+ sprintf(temp, "%s/%s", basedir, filename);
+ sysfsfp = fopen(temp, "w");
+ if (sysfsfp == NULL) {
+ printf("failed to open %s\n", temp);
+ ret = -errno;
+ goto error_free;
+ }
+ fprintf(sysfsfp, "%d", val);
+ fclose(sysfsfp);
+ if (verify) {
+ sysfsfp = fopen(temp, "r");
+ if (sysfsfp == NULL) {
+ printf("failed to open %s\n", temp);
+ ret = -errno;
+ goto error_free;
+ }
+ fscanf(sysfsfp, "%d", &test);
+ fclose(sysfsfp);
+ if (test != val) {
+ printf("Possible failure in int write %d to %s%s\n",
+ val,
+ basedir,
+ filename);
+ ret = -1;
+ }
+ }
+error_free:
+ free(temp);
+ return ret;
+}
+
+int write_sysfs_int(char *filename, char *basedir, int val)
+{
+ return _write_sysfs_int(filename, basedir, val, 0);
+}
+
+int write_sysfs_int_and_verify(char *filename, char *basedir, int val)
+{
+ return _write_sysfs_int(filename, basedir, val, 1);
+}
+
+int _write_sysfs_string(char *filename, char *basedir, char *val, int verify)
+{
+ int ret = 0;
+ FILE *sysfsfp;
+ char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+ if (temp == NULL) {
+ printf("Memory allocation failed\n");
+ return -ENOMEM;
+ }
+ sprintf(temp, "%s/%s", basedir, filename);
+ sysfsfp = fopen(temp, "w");
+ if (sysfsfp == NULL) {
+ printf("Could not open %s\n", temp);
+ ret = -errno;
+ goto error_free;
+ }
+ fprintf(sysfsfp, "%s", val);
+ fclose(sysfsfp);
+ if (verify) {
+ sysfsfp = fopen(temp, "r");
+ if (sysfsfp == NULL) {
+ printf("could not open file to verify\n");
+ ret = -errno;
+ goto error_free;
+ }
+ fscanf(sysfsfp, "%s", temp);
+ fclose(sysfsfp);
+ if (strcmp(temp, val) != 0) {
+ printf("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
+ **/
+int write_sysfs_string_and_verify(char *filename, char *basedir, char *val)
+{
+ return _write_sysfs_string(filename, basedir, val, 1);
+}
+
+int write_sysfs_string(char *filename, char *basedir, char *val)
+{
+ return _write_sysfs_string(filename, basedir, val, 0);
+}
+
+int read_sysfs_posint(char *filename, char *basedir)
+{
+ int ret;
+ FILE *sysfsfp;
+ char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+ if (temp == NULL) {
+ printf("Memory allocation failed");
+ return -ENOMEM;
+ }
+ sprintf(temp, "%s/%s", basedir, filename);
+ sysfsfp = fopen(temp, "r");
+ if (sysfsfp == NULL) {
+ ret = -errno;
+ goto error_free;
+ }
+ fscanf(sysfsfp, "%d\n", &ret);
+ fclose(sysfsfp);
+error_free:
+ free(temp);
+ return ret;
+}
+
+int read_sysfs_float(char *filename, char *basedir, float *val)
+{
+ float ret = 0;
+ FILE *sysfsfp;
+ char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+ if (temp == NULL) {
+ printf("Memory allocation failed");
+ return -ENOMEM;
+ }
+ sprintf(temp, "%s/%s", basedir, filename);
+ sysfsfp = fopen(temp, "r");
+ if (sysfsfp == NULL) {
+ ret = -errno;
+ goto error_free;
+ }
+ fscanf(sysfsfp, "%f\n", val);
+ fclose(sysfsfp);
+error_free:
+ free(temp);
+ return ret;
+}
--- /dev/null
+This is a userspace application which accesses the adc via /dev/iio in continuous sampling mode.
+
+The application scans the scan_elements folder in /dev/iio/devices/iio:deviceX/scan_elements for enabled channels.
+
+Creates a data structure.
+
+Sets the buffer size. Enables the buffer. And reads from the dev file for the driver.
+
+The source code is located under kernel sources "drivers/staging/iio/Documentation/generic_buffer.c".
+
+How to compile:
+
+arm-arago-linux-gnueabi-gcc --static generic_buffer.c -o generic_buffer
+
+or
+
+-gcc --static generic_buffer.c -o generic_buffer
+
+
+SOURCE: https://github.com/ZubairLK/adc-iio-continuous-sampling-userspace
\ No newline at end of file
--- /dev/null
+echo 1 > /sys/bus/iio/devices/iio_sysfs_trigger/add_trigger
+echo 1 > /sys/bus/iio/devices/iio\:device0/scan_elements/in_voltage7_en
+echo 1 > /sys/bus/iio/devices/iio\:device0/scan_elements/in_voltage5_en
+generic_buffer -n TI-am335x-adc -t sysfstrig1 -l 128
+
--- /dev/null
+echo 1 > /sys/bus/iio/devices/trigger0/trigger_now
--- /dev/null
+//Code to blink an LED - just to illustrate that it's pretty easy
+//Only important thing is which name to address the LED by
+
+#include <stdio.h>
+#include <unistd.h>
+
+using namespace std;
+
+int main(int argc, char** argv) {
+ FILE *LEDHandle = NULL;
+ char *LEDBrightness = "/sys/class/leds/beaglebone:green:usr0/brightness";
+ printf("\nStarting LED blink program wooo!\n");
+ while(1){
+ if((LEDHandle = fopen(LEDBrightness, "r+")) != NULL){
+ fwrite("1", sizeof(char), 1, LEDHandle);
+ fclose(LEDHandle);
+ }
+ sleep(1);
+ if((LEDHandle = fopen(LEDBrightness, "r+")) != NULL){
+ fwrite("0", sizeof(char), 1, LEDHandle);
+ fclose(LEDHandle);
+ }
+ sleep(1);
+ }
+ return 0;
+}
+
+//Sample code that should read a pressure sensor pin (conversion factors
+//are just random numbers). Again pretty simple.
+
+#include STUFF
+
+double pressure(char *string) {
+ int value = atoi(string);
+ double millivolts = (value / 4096.0) * 1800; //convert input to volts
+ double pressure = (millivolts - 500.0) / 10.0; //convert volts to pressure
+ return pressure;
+}
+
+void main() {
+ int fd = open("/sys/devices/platform/tsc/ain2", O_RDONLY); //open pin signal
+ while (1) {
+ char buffer[1024];
+ int ret = read(fd, buffer, sizeof(buffer)); //get data
+ if (ret != -1) {
+ buffer[ret] = NULL;
+ double kpa = pressure(buffer);
+ printf("digital value: %s kilopascals: %f\n", buffer, kpa);
+ lseek(fd, 0, 0);
+ }
+ sleep(1);
+ }
+ close(fd);
+}
\ No newline at end of file
--- /dev/null
+/*
+ * SimpleGPIO.cpp
+ *
+ * Modifications by Derek Molloy, School of Electronic Engineering, DCU
+ * www.eeng.dcu.ie/~molloyd/
+ * Almost entirely based on Software by RidgeRun:
+ *
+ * Copyright (c) 2011, RidgeRun
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the RidgeRun.
+ * 4. Neither the name of the RidgeRun nor the
+ * names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RIDGERUN ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL RIDGERUN BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "SimpleGPIO.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <poll.h>
+
+/****************************************************************
+ * gpio_export
+ ****************************************************************/
+int gpio_export(unsigned int gpio)
+{
+ int fd, len;
+ char buf[MAX_BUF];
+
+ fd = open(SYSFS_GPIO_DIR "/export", O_WRONLY);
+ if (fd < 0) {
+ perror("gpio/export");
+ return fd;
+ }
+
+ len = snprintf(buf, sizeof(buf), "%d", gpio);
+ write(fd, buf, len);
+ close(fd);
+
+ return 0;
+}
+
+/****************************************************************
+ * gpio_unexport
+ ****************************************************************/
+int gpio_unexport(unsigned int gpio)
+{
+ int fd, len;
+ char buf[MAX_BUF];
+
+ fd = open(SYSFS_GPIO_DIR "/unexport", O_WRONLY);
+ if (fd < 0) {
+ perror("gpio/export");
+ return fd;
+ }
+
+ len = snprintf(buf, sizeof(buf), "%d", gpio);
+ write(fd, buf, len);
+ close(fd);
+ return 0;
+}
+
+/****************************************************************
+ * gpio_set_dir
+ ****************************************************************/
+int gpio_set_dir(unsigned int gpio, PIN_DIRECTION out_flag)
+{
+ int fd;
+ char buf[MAX_BUF];
+
+ snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/direction", gpio);
+
+ fd = open(buf, O_WRONLY);
+ if (fd < 0) {
+ perror("gpio/direction");
+ return fd;
+ }
+
+ if (out_flag == OUTPUT_PIN)
+ write(fd, "out", 4);
+ else
+ write(fd, "in", 3);
+
+ close(fd);
+ return 0;
+}
+
+/****************************************************************
+ * gpio_set_value
+ ****************************************************************/
+int gpio_set_value(unsigned int gpio, PIN_VALUE value)
+{
+ int fd;
+ char buf[MAX_BUF];
+
+ snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value", gpio);
+
+ fd = open(buf, O_WRONLY);
+ if (fd < 0) {
+ perror("gpio/set-value");
+ return fd;
+ }
+
+ if (value==LOW)
+ write(fd, "0", 2);
+ else
+ write(fd, "1", 2);
+
+ close(fd);
+ return 0;
+}
+
+/****************************************************************
+ * gpio_get_value
+ ****************************************************************/
+int gpio_get_value(unsigned int gpio, unsigned int *value)
+{
+ int fd;
+ char buf[MAX_BUF];
+ char ch;
+
+ snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value", gpio);
+
+ fd = open(buf, O_RDONLY);
+ if (fd < 0) {
+ perror("gpio/get-value");
+ return fd;
+ }
+
+ read(fd, &ch, 1);
+
+ if (ch != '0') {
+ *value = 1;
+ } else {
+ *value = 0;
+ }
+
+ close(fd);
+ return 0;
+}
+
+
+/****************************************************************
+ * gpio_set_edge
+ ****************************************************************/
+
+int gpio_set_edge(unsigned int gpio, char *edge)
+{
+ int fd;
+ char buf[MAX_BUF];
+
+ snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/edge", gpio);
+
+ fd = open(buf, O_WRONLY);
+ if (fd < 0) {
+ perror("gpio/set-edge");
+ return fd;
+ }
+
+ write(fd, edge, strlen(edge) + 1);
+ close(fd);
+ return 0;
+}
+
+/****************************************************************
+ * gpio_fd_open
+ ****************************************************************/
+
+int gpio_fd_open(unsigned int gpio)
+{
+ int fd;
+ char buf[MAX_BUF];
+
+ snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value", gpio);
+
+ fd = open(buf, O_RDONLY | O_NONBLOCK );
+ if (fd < 0) {
+ perror("gpio/fd_open");
+ }
+ return fd;
+}
+
+/****************************************************************
+ * gpio_fd_close
+ ****************************************************************/
+
+int gpio_fd_close(int fd)
+{
+ return close(fd);
+}
+
+
+/****************************************************************
+ * gpio_omap_mux_setup - Allow us to setup the omap mux mode for a pin
+ ****************************************************************/
+int gpio_omap_mux_setup(const char *omap_pin0_name, const char *mode)
+{
+ int fd;
+ char buf[MAX_BUF];
+ snprintf(buf, sizeof(buf), SYSFS_OMAP_MUX_DIR "%s", omap_pin0_name);
+ fd = open(buf, O_WRONLY);
+ if (fd < 0) {
+ perror("failed to open OMAP_MUX");
+ return fd;
+ }
+ write(fd, mode, strlen(mode) + 1);
+ close(fd);
+ return 0;
+}
\ No newline at end of file
--- /dev/null
+/*
+ * SimpleGPIO.h
+ *
+ * Copyright Derek Molloy, School of Electronic Engineering, Dublin City University
+ * www.eeng.dcu.ie/~molloyd/
+ *
+ * Based on Software by RidgeRun
+ * Copyright (c) 2011, RidgeRun
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the RidgeRun.
+ * 4. Neither the name of the RidgeRun nor the
+ * names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RIDGERUN ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL RIDGERUN BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef SIMPLEGPIO_H_
+#define SIMPLEGPIO_H_
+
+ /****************************************************************
+ * Constants
+ ****************************************************************/
+
+#define SYSFS_GPIO_DIR "/sys/class/gpio"
+#define POLL_TIMEOUT (3 * 1000) /* 3 seconds */
+#define MAX_BUF 64
+#define SYSFS_OMAP_MUX_DIR "/sys/kernel/debug/omap_mux/"
+
+enum PIN_DIRECTION{
+ INPUT_PIN=0,
+ OUTPUT_PIN=1
+};
+
+enum PIN_VALUE{
+ LOW=0,
+ HIGH=1
+};
+
+/****************************************************************
+ * gpio_export
+ ****************************************************************/
+int gpio_export(unsigned int gpio);
+int gpio_unexport(unsigned int gpio);
+int gpio_set_dir(unsigned int gpio, PIN_DIRECTION out_flag);
+int gpio_set_value(unsigned int gpio, PIN_VALUE value);
+int gpio_get_value(unsigned int gpio, unsigned int *value);
+int gpio_set_edge(unsigned int gpio, char *edge);
+int gpio_fd_open(unsigned int gpio);
+int gpio_fd_close(int fd);
+int gpio_omap_mux_setup(const char *omap_pin0_name, const char *mode);
+
+#endif /* SIMPLEGPIO_H_ */
\ No newline at end of file