mraa: add a function that returns the number of uarts available

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

api/mraa/common.h

@@ -201,6 +201,13 @@ int mraa_get_platform_combined_type();
  */
 unsigned int mraa_get_pin_count();
 
+/**
+ * Get the number of usable UARTs, board must be initialised.
+ *
+ * @return number of usable UARTs on the platform, returns -1 on failure.
+ */
+int mraa_get_uart_count(void);
+
 /**
  * Get platform usable I2C bus count, board must be initialised.
  *

api/mraa/common.hpp

@@ -178,6 +178,18 @@ getPinCount()
     return mraa_get_pin_count();
 }
 
+/**
+ * Get platform usable UART count, board must be initialised.
+ *
+ * @return number of usable UARTs on the current platform. Function will
+ * return -1 on failure
+ */
+inline int
+getUartCount()
+{
+    return mraa_get_uart_count();
+}
+
 /**
  * Get platform usable I2C bus count, board must be initialised.
  *

src/mraa.c

@@ -750,6 +750,15 @@ mraa_get_platform_version(int platform_offset)
     }
 }
 
+int
+mraa_get_uart_count(void)
+{
+    if (plat == NULL) {
+        return -1;
+    }
+    return plat->uart_dev_count;
+}
+
 int
 mraa_get_i2c_bus_count()
 {