api: Added mraa_has_sub_platform() function

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

api/mraa/common.h

@@ -188,6 +188,14 @@ char* mraa_get_pin_name(int pin);
  */
 int mraa_get_default_2c_bus();
 
+/**
+ * Detect presence of sub platform.
+ *
+ * @return mraa_boolean_t 1 if sub platform is present and initialized, 0 otherwise
+ */
+mraa_boolean_t mraa_has_sub_platform();
+
+
 /**
  * Select main platform for platform info calls.
  *

src/mraa.c

@@ -260,6 +260,13 @@ mraa_result_print(mraa_result_t result)
 }
 
 
+mraa_boolean_t 
+mraa_has_sub_platform()
+{
+    return (plat != NULL) && (plat->sub_platform != NULL);
+}
+
+
 mraa_boolean_t
 mraa_select_main_platform()
 {