uart: add function mraa_uart_get_dev_path

Used for getting the path to the character device under linux for uart
device. i.e. "/dev/ttyS0"

Adds paths to existing platforms.
Closes #84

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>

src/x86/intel_de3815.c

@@ -140,6 +140,8 @@ mraa_intel_de3815()
     b->spi_bus[0].miso = 12;
     b->spi_bus[0].sclk = 13;
 
+    b->uart_dev_count = 0;
+
     return b;
 error:
     syslog(LOG_CRIT, "de3815: Platform failed to initialise");

src/x86/intel_edison_fab_c.c

@@ -40,6 +40,7 @@
 // Might not always be correct. First thing to check if mmap stops
 // working. Check the device for 0x1199 and Intel Vendor (0x8086)
 #define MMAP_PATH "/sys/devices/pci0000:00/0000:00:0c.0/resource0"
+#define UART_DEV_PATH "/dev/ttyMFD1"
 
 typedef struct {
     int sysfs;
@@ -1365,6 +1366,13 @@ mraa_intel_edison_fab_c()
     b->uart_dev[0].rx = 0;
     b->uart_dev[0].tx = 1;
 
+    int uart_path_length = strlen(UART_DEV_PATH) + 1;
+    b->uart_dev[0].device_path = (char*) malloc(sizeof(char) * uart_path_length);
+    if (b->uart_dev[0].device_path == NULL) {
+         goto error;
+    }
+    strncpy(b->uart_dev[0].device_path, UART_DEV_PATH, uart_path_length);
+
     int il;
     for (il =0; il < MRAA_INTEL_EDISON_PINCOUNT; il++) {
         pinmodes[il].gpio.sysfs = -1;

src/x86/intel_galileo_rev_d.c

@@ -405,11 +405,25 @@ mraa_intel_galileo_rev_d()
     b->spi_bus[0].miso = 12;
     b->spi_bus[0].sclk = 13;
 
+    int uart_path_length = strlen("/dev/ttyS0") + 1;
+
+    b->uart_dev_count = 2;
     b->def_uart_dev = 0;
     b->uart_dev[0].rx = 0;
     b->uart_dev[0].tx = 1;
+    b->uart_dev[0].device_path = (char*) malloc(sizeof(char) * uart_path_length);
+    if (b->uart_dev[0].device_path == NULL) {
+        goto error;
+    }
+    strncpy(b->uart_dev[0].device_path, "/dev/ttyS0", uart_path_length);
+
     b->uart_dev[1].rx = -1;
     b->uart_dev[1].tx = -1;
+    b->uart_dev[1].device_path = (char*) malloc(sizeof(char) * uart_path_length);
+    if (b->uart_dev[1].device_path == NULL) {
+        goto error;
+    }
+    strncpy(b->uart_dev[1].device_path, "/dev/ttyS1", uart_path_length);
 
     return b;
 error:

src/x86/intel_galileo_rev_g.c

@@ -746,10 +746,17 @@ mraa_intel_galileo_gen2()
     b->spi_bus[0].miso = 12;
     b->spi_bus[0].sclk = 13;
 
+    int uart_path_length = strlen("/dev/ttyS0") + 1;
+
     b->uart_dev_count = 1;
     b->def_uart_dev = 0;
     b->uart_dev[0].rx = 0;
     b->uart_dev[0].tx = 1;
+    b->uart_dev[0].device_path = (char*) malloc(sizeof(char) * uart_path_length);
+    if (b->uart_dev[0].device_path == NULL) {
+        goto error;
+    }
+    strncpy(b->uart_dev[0].device_path, "/dev/ttyS0", uart_path_length);
 
     return b;
 error:

src/x86/intel_minnow_max.c

@@ -181,6 +181,8 @@ mraa_intel_minnow_max()
     b->spi_bus[0].miso = 7;
     b->spi_bus[0].sclk = 11;
 
+    b->uart_dev_count = 0;
+
     return b;
 error:
     syslog(LOG_CRIT, "minnowmax: Platform failed to initialise");