mraa.c: add a by-name lookup function also for UARTs

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

src/mraa.c

@@ -903,6 +903,27 @@ mraa_pwm_lookup(const char* pwm_name)
     return -1;
 }
 
+int
+mraa_uart_lookup(const char* uart_name)
+{
+    int i;
+
+    if (plat == NULL) {
+        return -1;
+    }
+
+    if (uart_name == NULL || strlen(uart_name) == 0) {
+        return -1;
+    }
+
+    for (i = 0; i < plat->uart_dev_count; i++) {
+         if (plat->uart_dev[i].name != NULL && strcmp(uart_name, plat->uart_dev[i].name) == 0) {
+             return plat->uart_dev[i].index;
+         }
+    }
+    return -1;
+}
+
 int
 mraa_get_default_i2c_bus(uint8_t platform_offset)
 {