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>

api/mraa/common.h

@@ -149,6 +149,7 @@ typedef struct {
     unsigned int index; /**< ID as exposed in the system */
     int rx; /**< uart rx */
     int tx; /**< uart tx */
+    char* device_path; /**< To store "/dev/ttyS1" for example */
     /*@}*/
 } mraa_uart_dev_t;
 

api/mraa/uart.h

@@ -54,6 +54,15 @@ typedef struct _uart* mraa_uart_context;
  */
 mraa_uart_context mraa_uart_init(int uart);
 
+/**
+ * Get Char pointer with tty device path within Linux
+ * For example. Could point to "/dev/ttyS0"
+ *
+ * @param dev uart context
+ * @return char pointer of device path
+ */
+char* mraa_uart_get_dev_path(mraa_uart_context dev);
+
 #ifdef __cplusplus
 }
 #endif

api/mraa/uart.hpp

@@ -55,6 +55,17 @@ class Uart {
         ~Uart() {
             return;
         }
+
+        /**
+         * Get string with tty device path within Linux
+         * For example. Could point to "/dev/ttyS0"
+         *
+         * @return char pointer of device path
+         */
+        std::string getDevicePath() {
+            std::string ret_val(mraa_uart_get_dev_path(m_uart));
+            return ret_val;
+        }
     private:
         mraa_uart_context m_uart;
 };

include/mraa_internal_types.h

@@ -91,5 +91,6 @@ struct _aio {
 struct _uart {
     /*@{*/
     int index; /**< the uart index, as known to the os. */
+    char* path; /**< the uart device path. */
     /*@}*/
 };

src/arm/raspberry_pi_b.c

@@ -28,6 +28,8 @@
 #include "common.h"
 #include "arm/raspberry_pi_b.h"
 
+#define UART_DEV_PATH "/dev/ttyAMA0"
+
 mraa_board_t*
 mraa_raspberry_pi_b()
 {
@@ -178,6 +180,17 @@ mraa_raspberry_pi_b()
     b->def_uart_dev = 0;
     b->uart_dev[0].rx = 10;
     b->uart_dev[0].tx = 8;
+    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);
 
     return b;
+
+error:
+    syslog(LOG_CRIT, "raspberry pi: board failed to initialise");
+    free(b);
+    return NULL;
 }

src/uart/uart.c

@@ -83,6 +83,7 @@ mraa_uart_init(int index)
     memset(dev, 0, sizeof(struct _uart));
 
     dev->index = index;
+    dev->path = plat->uart_dev[index].device_path;
     if (advance_func->uart_init_post != NULL) {
         mraa_result_t ret = advance_func->uart_init_post(dev);
         if (ret != MRAA_SUCCESS) {
@@ -93,3 +94,17 @@ mraa_uart_init(int index)
 
     return dev;
 }
+
+char*
+mraa_uart_get_dev_path(mraa_uart_context dev)
+{
+    if (dev == NULL) {
+        syslog(LOG_ERR, "uart: get_device_path failed, context is NULL");
+        return "ERROR:CONTEXT_IS_NULL";
+    }
+    if (dev->path == NULL) {
+        syslog(LOG_ERR, "uart: device path undefined");
+        return "ERROR:PATH_NOT_SET";
+    }
+    return dev->path;
+}

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");