iio: initial API and enumeration of devices

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa/iio.h

@@ -59,7 +59,16 @@ mraa_iio_context mraa_iio_init(int device);
 
 /**
  */
-mraa_result_t mraa_iio_read(mraa_iio_context dev, uint32_t *data, int length);
+int mraa_iio_get_channel_count(mraa_iio_context dev);
+
+/**
+ */
+mraa_result_t mraa_iio_read(mraa_iio_context dev, int channel, const char* attribute, float* data);
+
+/**
+ *
+ */
+mraa_result_t mraa_iio_write(mraa_iio_context dev, int channel, const char* attribute);
 
 /**
  * De-inits an mraa_iio_context device

include/mraa_internal_types.h

@@ -134,6 +134,7 @@ struct _uart {
  */
 struct _iio {
     int num; /**< IIO device number */
+    char* name; /**< IIO device name */
 };
 
 /**
@@ -276,6 +277,8 @@ typedef struct _board_t {
     mraa_pininfo_t* pins;     /**< Pointer to pin array */
     mraa_adv_func_t* adv_func;    /**< Pointer to advanced function disptach table */
     struct _board_t* sub_platform;     /**< Pointer to sub platform */
+    struct _iio* iio_devices; /**< Pointer to IIO devices */
+    uint8_t iio_device_count; /**< IIO device count */
     /*@}*/
 } mraa_board_t;
 

src/iio/iio.c

@@ -28,20 +28,36 @@
 mraa_iio_context
 mraa_iio_init(int device)
 {
-    mraa_iio_context dev = (mraa_iio_context) calloc(1, sizeof(struct _iio));
-    if (dev == NULL) {
-        syslog(LOG_CRIT, "iio: Failed to allocate memory for context");
+    if (device > plat->iio_device_count) {
         return NULL;
     }
-
-    return dev;
+    return &plat->iio_devices[device];
 }
 
+int
+mraa_iio_get_channel_count(mraa_iio_context dev)
+{
+    return 1;
+}
 
 mraa_result_t
-mraa_iio_read(mraa_iio_context dev, uint32_t* data, int length)
+mraa_iio_read(mraa_iio_context dev, int channel, const char* attribute, float* data)
 {
-   return 0;
+    char buf[64];
+    snprintf(buf, 64, "/sys/bus/iio/devices/iio:device%d/in_voltage%d_%s", dev->num, channel, attribute);
+    int fd = open(buf, O_RDONLY);
+    if (fd != -1) {
+        int len = read(fd, &buf, 64);
+        *data = strtol(buf, NULL, 10);
+        return MRAA_SUCCESS;
+    }
+    return MRAA_ERROR_UNSPECIFIED;
+}
+
+mraa_result_t
+mraa_iio_write(mraa_iio_context dev, int channel, const char* attribute)
+{
+    return MRAA_ERROR_FEATURE_NOT_IMPLEMENTED;
 }
 
 mraa_result_t

src/mraa.c

@@ -52,6 +52,9 @@ mraa_board_t* plat = NULL;
 static char platform_name[MAX_PLATFORM_NAME_LENGTH];
 mraa_adv_func_t* advance_func;
 
+static int num_i2c_devices = 0;
+static int num_iio_devices = 0;
+
 const char*
 mraa_get_version()
 {
@@ -70,6 +73,17 @@ mraa_set_log_level(int level)
     return MRAA_ERROR_INVALID_PARAMETER;
 }
 
+static int
+mraa_count_iio_devices(const char* path, const struct stat* sb, int flag, struct FTW* ftwb)
+{
+    switch (sb->st_mode & S_IFMT) {
+        case S_IFLNK:
+            num_iio_devices++;
+            break;
+    }
+    return 0;
+}
+
 #if (defined SWIGPYTHON) || (defined SWIG)
 mraa_result_t
 #else
@@ -142,6 +156,30 @@ mraa_init()
     }
 #endif
 
+    // Now detect IIO devices, linux only
+    // find how many i2c buses we have if we haven't already
+    if (num_iio_devices == 0) {
+        if (nftw("/sys/bus/iio/devices", &mraa_count_iio_devices, 20, FTW_PHYS) == -1) {
+            return MRAA_ERROR_UNSPECIFIED;
+        }
+    }
+    char name[64], filepath[64];
+    int fd, len, i;
+    plat->iio_device_count = num_iio_devices;
+    plat->iio_devices = calloc(num_iio_devices, sizeof(struct _iio));
+    struct _iio* device;
+    for (i=0; i < num_iio_devices; i++) {
+        device = &plat->iio_devices[i];
+        device->num = i;
+        snprintf(filepath, 64, "/sys/bus/iio/devices/iio:device%d", i);
+        fd = open(filepath, O_RDONLY);
+        if (fd != -1) {
+            len = read(fd, &name, 64);
+            device->name = malloc((sizeof(char) * len) + sizeof(char));
+            strncpy(device->name, name, len);
+        }
+    }
+
     syslog(LOG_NOTICE, "libmraa initialised for platform '%s' of type %d", mraa_get_platform_name(), mraa_get_platform_type());
     return MRAA_SUCCESS;
 }
@@ -625,10 +663,8 @@ mraa_link_targets(const char* filename, const char* targetname)
     }
 }
 
-static int num_i2c_devices = 0;
-
 static int
-mraa_count_files(const char* path, const struct stat* sb, int flag, struct FTW* ftwb)
+mraa_count_i2c_files(const char* path, const struct stat* sb, int flag, struct FTW* ftwb)
 {
     switch (sb->st_mode & S_IFMT) {
         case S_IFLNK:
@@ -654,7 +690,7 @@ mraa_find_i2c_bus(const char* devname, int startfrom)
 
     // find how many i2c buses we have if we haven't already
     if (num_i2c_devices == 0) {
-        if (nftw("/sys/class/i2c-dev/", &mraa_count_files, 20, FTW_PHYS) == -1) {
+        if (nftw("/sys/class/i2c-dev/", &mraa_count_i2c_files, 20, FTW_PHYS) == -1) {
             return -1;
         }
     }
@@ -724,3 +760,22 @@ mraa_get_sub_platform_index(int pin_or_bus)
 {
     return pin_or_bus & (~MRAA_SUB_PLATFORM_MASK);
 }
+
+int
+mraa_get_iio_device_count()
+{
+    return plat->iio_device_count;
+}
+
+int
+mraa_find_iio_device(const char* devicename)
+{
+    int i = 0;
+    for (i; i < plat->iio_device_count; i++) {
+#if 0
+        if (!strcmp() {
+        }
+#endif
+    }
+    return 0;
+}