staging:iio:Documentation: Rewrite example for new abi.
authorJonathan Cameron <jic23@cam.ac.uk>
Tue, 4 May 2010 13:43:13 +0000 (14:43 +0100)
committerGreg Kroah-Hartman <gregkh@suse.de>
Tue, 11 May 2010 18:36:06 +0000 (11:36 -0700)
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/staging/iio/Documentation/iio_utils.h
drivers/staging/iio/Documentation/lis3l02dqbuffersimple.c

index d24006aedd5a2ddd6aae79541e9b6a462acd4639..a4555e6f133f0f4cca98924a6085aa8b7f0b6ad0 100644 (file)
  * the Free Software Foundation.
  */
 
+/* Made up value to limit allocation sizes */
+#include <string.h>
+#include <stdlib.h>
+
+#define IIO_MAX_NAME_LENGTH 30
+
 #define IIO_EVENT_CODE_RING_50_FULL 200
 #define IIO_EVENT_CODE_RING_75_FULL 201
 #define IIO_EVENT_CODE_RING_100_FULL 202
 
+const char *iio_dir = "/sys/bus/iio/devices/";
+
 struct iio_event_data {
        int id;
        __s64 timestamp;
 };
 
-
-inline char *find_ring_subelement(const char *directory, const char *subelement)
-{
-       DIR *dp;
-       const struct dirent *ent;
-       int pos;
-       char temp[100];
-       char *returnstring;
-       dp = opendir(directory);
-       if (dp == NULL) {
-               printf("could not directory: %s\n", directory);
-               return NULL;
-       }
-       while (ent = readdir(dp), ent != NULL) {
-               if (strcmp(ent->d_name, ".") != 0 &&
-                   strcmp(ent->d_name, "..") != 0)  {
-                       if (strncmp(ent->d_name, subelement, strlen(subelement)) == 0) {
-                               int length = sprintf(temp, "%s%s%s", directory, ent->d_name, "/");
-                               returnstring = malloc(length+1);
-                               strncpy(returnstring, temp, length+1);
-                               return returnstring;
-
-                       }
-               }
-       }
-       return 0;
-}
-
-
-char *find_type_by_name(const char *name, const char *type)
+/**
+ * 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 char *iio_dir = "/sys/bus/iio/devices/";
        const struct dirent *ent;
-       int cnt, pos, pos2;
+       int number, numstrlen;
 
        FILE *nameFile;
        DIR *dp;
-       char thisname[100];
-       char temp[100];
-
-       char *returnstring = NULL;
+       char thisname[IIO_MAX_NAME_LENGTH];
+       char *filename;
        struct stat Stat;
-       pos = sprintf(temp, "%s", iio_dir);
+
        dp = opendir(iio_dir);
        if (dp == NULL) {
                printf("No industrialio devices available");
-               return NULL;
+               return -ENODEV;
        }
+
        while (ent = readdir(dp), ent != NULL) {
-               cnt++;
-               /*reject . and .. */
                if (strcmp(ent->d_name, ".") != 0 &&
-                   strcmp(ent->d_name, "..") != 0)  {
-                       /*make sure it isn't a trigger!*/
-                       if (strncmp(ent->d_name, type, strlen(type)) == 0) {
-                               /* build full path to new file */
-                               pos2 = pos + sprintf(temp + pos, "%s/", ent->d_name);
-                               sprintf(temp + pos2, "name");
-                               printf("search location %s\n", temp);
-                               nameFile = fopen(temp, "r");
-                               if (!nameFile) {
-                                       sprintf(temp + pos2, "modalias", ent->d_name);
-                                       nameFile = fopen(temp, "r");
-                                       if (!nameFile) {
-                                               printf("Failed to find a name for device\n");
-                                               return NULL;
-                                       }
-                               }
+                       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)
+                                               + 1
+                                               + numstrlen
+                                               + 1);
+                               if (filename == NULL)
+                                       return -ENOMEM;
+                               sprintf(filename, "%s%s%d/name",
+                                       iio_dir,
+                                       type,
+                                       number);
+                               nameFile = fopen(filename, "r");
+                               if (!nameFile)
+                                       continue;
+                               free(filename);
                                fscanf(nameFile, "%s", thisname);
-                               if (strcmp(name, thisname) == 0) {
-                                       returnstring = malloc(strlen(temp) + 1);
-                                       sprintf(temp + pos2, "");
-                                       strcpy(returnstring, temp);
-                                       return returnstring;
-                               }
+                               if (strcmp(name, thisname) == 0)
+                                       return number;
                                fclose(nameFile);
-
                        }
                }
        }
+       return -ENODEV;
 }
 
-int write_sysfs_int(char *filename, char *basedir, int val)
+inline int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
 {
        int ret;
-       FILE  *sysfsfp;
-       char temp[100];
-       sprintf(temp, "%s%s", basedir, filename);
+       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)
-               return -1;
+       if (sysfsfp == NULL) {
+               printf("failed to open %s\n", temp);
+               ret = -errno;
+               goto error_free;
+       }
        fprintf(sysfsfp, "%d", val);
        fclose(sysfsfp);
-       return 0;
+       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);
+               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;
        FILE  *sysfsfp;
-       char temp[100];
-       int test;
-
-       sprintf(temp, "%s%s", basedir, filename);
+       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)
-               return -1;
-       fprintf(sysfsfp, "%d", val);
+       if (sysfsfp == NULL) {
+               printf("Could not open %s\n", temp);
+               ret = -errno;
+               goto error_free;
+       }
+       fprintf(sysfsfp, "%s", val);
        fclose(sysfsfp);
-
-       sysfsfp = fopen(temp, "r");
-       if (sysfsfp == NULL)
-               return -1;
-       fscanf(sysfsfp, "%d", &test);
-       if (test != val) {
-               printf("Possible failure in int write %d to %s%s\n",
-                      val,
-                      basedir,
-                      filename);
-               return -1;
+       if (verify) {
+               sysfsfp = fopen(temp, "r");
+               if (sysfsfp == NULL) {
+                       ret = -errno;
+                       goto error_free;
+               }
+               fscanf(sysfsfp, "%s", temp);
+               if (strcmp(temp, val) != 0) {
+                       printf("Possible failure in string write of %s "
+                               "Should be %s "
+                               "writen to %s\%s\n",
+                               temp,
+                               val,
+                               basedir,
+                               filename);
+                       ret = -1;
+               }
        }
+error_free:
+       free(temp);
 
-       return 0;
+       return ret;
 }
-
 /**
  * write_sysfs_string_and_verify() - string write, readback and verify
  * @filename: name of file to write to
@@ -149,40 +182,54 @@ int write_sysfs_int_and_verify(char *filename, char *basedir, int val)
  **/
 int write_sysfs_string_and_verify(char *filename, char *basedir, char *val)
 {
-       int ret;
-       FILE  *sysfsfp;
-       char temp[100];
-       sprintf(temp, "%s%s", basedir, filename);
-       sysfsfp = fopen(temp, "w");
-       if (sysfsfp == NULL)
-               return -1;
-       fprintf(sysfsfp, "%s", val);
-       fclose(sysfsfp);
+       return _write_sysfs_string(filename, basedir, val, 1);
+}
 
-       sysfsfp = fopen(temp, "r");
-       if (sysfsfp == NULL)
-               return -1;
-       fscanf(sysfsfp, "%s", temp);
-       if (strcmp(temp, val) != 0) {
-               printf("Possible failure in string write %s to %s%s \n",
-                      val,
-                      basedir,
-                      filename);
-               return -1;
-       }
-       return 0;
+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[100];
-       sprintf(temp, "%s%s", basedir, filename);
+       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)
-               return -1;
+       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;
 }
index 08e012fa8460368bf7951a0bf511d8329c8a90e5..3a580284020cb95b2fcd85d5fcbafb817392724a 100644 (file)
@@ -1,4 +1,4 @@
-/* Industrialio test ring buffer with a lis3l02dq acceleromter
+/* Industrialio ring buffer with a lis3l02dq accelerometer
  *
  * Copyright (c) 2008 Jonathan Cameron
  *
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  *
- * Assumes suitable udev rules are used to create the dev nodes as named here.
+ * This program is primarily intended as an example application.
  */
 
 #include <dirent.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <errno.h>
-#include <stdint.h>
-#include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/dir.h>
-
 #include <linux/types.h>
 #include "iio_utils.h"
 
-static const char *ring_access = "/dev/iio/lis3l02dq_ring_access";
-static const char *ring_event = "/dev/iio/lis3l02dq_ring_event";
-static const char *device_name = "lis3l02dq";
-static const char *trigger_name = "lis3l02dq-dev0";
-static int NumVals = 3;
-static int scan_ts = 1;
-static int RingLength = 128;
+const char *device_name = "lis3l02dq";
+const char *trigger_name_base = "lis3l02dq-dev";
+const int num_vals = 3;
+const int scan_ts = 1;
+const int buf_len = 128;
+const int num_loops = 10;
 
 /*
  * Could get this from ring bps, but only after starting the ring
- * which is a bit late for it to be useful
+ * which is a bit late for it to be useful.
+ *
+ * Todo: replace with much more generic version based on scan_elements
+ * directory.
  */
-int size_from_scanmode(int numVals, int timestamp)
+int size_from_scanmode(int num_vals, int timestamp)
 {
-       if (numVals && timestamp)
+       if (num_vals && timestamp)
                return 16;
        else if (timestamp)
                return 8;
        else
-               return numVals*2;
+               return num_vals*2;
 }
 
 int main(int argc, char **argv)
 {
+       int ret;
        int i, j, k, toread;
        FILE *fp_ev;
        int fp;
+
+       char *trigger_name, *dev_dir_name, *buf_dir_name;
        char *data;
        size_t read_size;
        struct iio_event_data dat;
+       int dev_num, trig_num;
+
+       char *buffer_access, *buffer_event;
+       const char *iio_dir = "/sys/bus/iio/devices/";
+       int scan_size;
+       float gain = 1;
 
-       char    *BaseDirectoryName,
-               *TriggerDirectoryName,
-               *RingBufferDirectoryName;
 
-       BaseDirectoryName = find_type_by_name(device_name, "device");
-       if (BaseDirectoryName == NULL) {
-               printf("Failed to find the %s \n", device_name);
-               return -1;
+       /* Find out which iio device is the accelerometer. */
+       dev_num = find_type_by_name(device_name, "device");
+       if (dev_num < 0) {
+               printf("Failed to find the %s\n", device_name);
+               ret = -ENODEV;
+               goto error_ret;
        }
-       TriggerDirectoryName = find_type_by_name(trigger_name, "trigger");
-       if (TriggerDirectoryName == NULL) {
+       printf("iio device number being used is %d\n", dev_num);
+       asprintf(&dev_dir_name, "%sdevice%d", iio_dir, dev_num);
+
+       /*
+        * Build the trigger name.
+        * In this case we want the lis3l02dq's data ready trigger
+        * for this lis3l02dq. The naming is lis3l02dq_dev[n], where
+        * n matches the device number found above.
+        */
+       ret = asprintf(&trigger_name, "%s%d", trigger_name_base, dev_num);
+       if (ret < 0) {
+               ret = -ENOMEM;
+               goto error_free_dev_dir_name;
+       }
+
+       /*
+        * Find the trigger by name.
+        * This is techically unecessary here as we only need to
+        * refer to the trigger by name and that name is already
+        * known.
+        */
+       trig_num = find_type_by_name(trigger_name, "trigger");
+       if (trig_num < 0) {
                printf("Failed to find the %s\n", trigger_name);
-               return -1;
+               ret = -ENODEV;
+               goto error_free_triggername;
        }
-       RingBufferDirectoryName = find_ring_subelement(BaseDirectoryName,
-                                                      "ring_buffer");
-       if (RingBufferDirectoryName == NULL) {
-               printf("Failed to find ring buffer\n");
-               return -1;
+       printf("iio trigger number being used is %d\n", trig_num);
+
+       /*
+        * Read in the scale value - in a more generic case, first
+        * check for accel_scale, then the indivual channel scales
+        */
+       ret = read_sysfs_float("accel_scale", dev_dir_name, &gain);
+       if (ret)
+               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, "%sdevice%d:buffer0", iio_dir, dev_num);
+       if (ret < 0) {
+               ret = -ENOMEM;
+               goto error_free_triggername;
        }
-
-       if (write_sysfs_string_and_verify("trigger/current_trigger",
-                                         BaseDirectoryName,
-                                         (char *)trigger_name) < 0) {
-               printf("Failed to write current_trigger file \n");
-               return -1;
+       /* Set the device trigger to be the data rdy 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 */
-       if (write_sysfs_int("length", RingBufferDirectoryName,
-                           RingLength) < 0) {
-               printf("Failed to open the ring buffer length file \n");
-               return -1;
-       }
+       ret = write_sysfs_int("length", buf_dir_name, buf_len);
+       if (ret < 0)
+               goto error_free_buf_dir_name;
 
-       /* Enable the ring buffer */
-       if (write_sysfs_int("ring_enable", RingBufferDirectoryName, 1) < 0) {
-               printf("Failed to open the ring buffer control file \n");
-               return -1;
-       };
+       /* Enable the buffer */
+       ret = write_sysfs_int("ring_enable", buf_dir_name, 1);
+       if (ret < 0)
+               goto error_free_buf_dir_name;
 
-       data = malloc(size_from_scanmode(NumVals, scan_ts)*RingLength);
+       data = malloc(size_from_scanmode(num_vals, scan_ts)*buf_len);
        if (!data) {
-               printf("Could not allocate space for usespace data store\n");
-               return -1;
+               ret = -ENOMEM;
+               goto error_free_buf_dir_name;
+       }
+
+       ret = asprintf(&buffer_access,
+                      "/dev/device%d:buffer0:access0",
+                      dev_num);
+       if (ret < 0) {
+               ret = -ENOMEM;
+               goto error_free_data;
        }
 
+       ret = asprintf(&buffer_event, "/dev/device%d:buffer0:event0", dev_num);
+       if (ret < 0) {
+               ret = -ENOMEM;
+               goto error_free_data;
+       }
        /* Attempt to open non blocking the access dev */
-       fp = open(ring_access, O_RDONLY | O_NONBLOCK);
+       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", ring_access);
-               return -1;
+               printf("Failed to open %s\n", buffer_access);
+               ret = -errno;
+               goto error_free_buffer_event;
        }
        /* Attempt to open the event access dev (blocking this time) */
-       fp_ev = fopen(ring_event, "rb");
+       fp_ev = fopen(buffer_event, "rb");
        if (fp_ev == NULL) {
-               printf("Failed to open %s\n", ring_event);
-               return -1;
+               printf("Failed to open %s\n", buffer_event);
+               ret = -errno;
+               goto error_close_buffer_access;
        }
 
        /* Wait for events 10 times */
-       for (j = 0; j < 10; j++) {
+       for (j = 0; j < num_loops; j++) {
                read_size = fread(&dat, 1, sizeof(struct iio_event_data),
                                  fp_ev);
                switch (dat.id) {
                case IIO_EVENT_CODE_RING_100_FULL:
-                       toread = RingLength;
+                       toread = buf_len;
                        break;
                case IIO_EVENT_CODE_RING_75_FULL:
-                       toread = RingLength*3/4;
+                       toread = buf_len*3/4;
                        break;
                case IIO_EVENT_CODE_RING_50_FULL:
-                       toread = RingLength/2;
+                       toread = buf_len/2;
                        break;
                default:
                        printf("Unexpecteded event code\n");
@@ -132,39 +188,51 @@ int main(int argc, char **argv)
                }
                read_size = read(fp,
                                 data,
-                                toread*size_from_scanmode(NumVals, scan_ts));
+                                toread*size_from_scanmode(num_vals, scan_ts));
                if (read_size == -EAGAIN) {
-                       printf("nothing available \n");
+                       printf("nothing available\n");
                        continue;
                }
-
-               for (i = 0;
-                    i < read_size/size_from_scanmode(NumVals, scan_ts);
-                    i++) {
-                       for (k = 0; k < NumVals; k++) {
-                               __s16 val = *(__s16 *)(&data[i*size_from_scanmode(NumVals, scan_ts)
+               scan_size = size_from_scanmode(num_vals, scan_ts);
+               for (i = 0; i < read_size/scan_size; i++) {
+                       for (k = 0; k < num_vals; k++) {
+                               __s16 val = *(__s16 *)(&data[i*scan_size
                                                             + (k)*2]);
-                               printf("%05d ", val);
+                               printf("%05f ", (float)val*gain);
                        }
                        printf(" %lld\n",
-                              *(__s64 *)(&data[(i+1)*size_from_scanmode(NumVals, scan_ts)
+                              *(__s64 *)(&data[(i + 1)
+                                               *size_from_scanmode(num_vals,
+                                                                   scan_ts)
                                                - sizeof(__s64)]));
                }
        }
 
        /* Stop the ring buffer */
-       if (write_sysfs_int("ring_enable", RingBufferDirectoryName, 0) < 0) {
-               printf("Failed to open the ring buffer control file \n");
-               return -1;
-       };
-
-       /* Disconnect from the trigger - writing something that doesn't exist.*/
-       write_sysfs_string_and_verify("trigger/current_trigger",
-                                     BaseDirectoryName, "NULL");
-       free(BaseDirectoryName);
-       free(TriggerDirectoryName);
-       free(RingBufferDirectoryName);
+       ret = write_sysfs_int("ring_enable", buf_dir_name, 0);
+       if (ret < 0)
+               goto error_close_buffer_event;
+
+       /* Disconnect from the trigger - just write a dummy name.*/
+       write_sysfs_string("trigger/current_trigger",
+                       dev_dir_name, "NULL");
+
+error_close_buffer_event:
+       fclose(fp_ev);
+error_close_buffer_access:
+       close(fp);
+error_free_data:
        free(data);
-
-       return 0;
+error_free_buffer_access:
+       free(buffer_access);
+error_free_buffer_event:
+       free(buffer_event);
+error_free_buf_dir_name:
+       free(buf_dir_name);
+error_free_triggername:
+       free(trigger_name);
+error_free_dev_dir_name:
+       free(dev_dir_name);
+error_ret:
+       return ret;
 }