gpio: Add a function to get a pin number from mraa_gpio_context

Signed-off-by: Kenta Yonekura <yoneken@ieee.org>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa/gpio.h

@@ -192,6 +192,14 @@ mraa_result_t mraa_gpio_owner(mraa_gpio_context dev, mraa_boolean_t owner);
  */
 mraa_result_t mraa_gpio_use_mmaped(mraa_gpio_context dev, mraa_boolean_t mmap);
 
+/**
+ * Get a pin number of the gpio
+ *
+ * @param dev The Gpio context
+ * @return Pin number
+ */
+int mraa_gpio_get_pin(mraa_gpio_context dev);
+
 #ifdef __cplusplus
 }
 #endif

api/mraa/gpio.hpp

@@ -183,6 +183,14 @@ class Gpio {
         mraa_result_t useMmap(bool enable) {
             return mraa_gpio_use_mmaped(m_gpio, (mraa_boolean_t) enable);
         }
+        /**
+         * Get pin number of Gpio
+         *
+         * @return Pin number
+         */
+        int getPin() {
+            return mraa_gpio_get_pin(m_gpio);
+        }
     private:
         mraa_gpio_context m_gpio;
 };

src/gpio/gpio.c

@@ -573,3 +573,9 @@ mraa_gpio_use_mmaped(mraa_gpio_context dev, mraa_boolean_t mmap_en)
     syslog(LOG_ERR, "gpio: mmap not implemented on this platform");
     return MRAA_ERROR_FEATURE_NOT_IMPLEMENTED;
 }
+
+int
+mraa_gpio_get_pin(mraa_gpio_context dev)
+{
+    return dev->phy_pin;
+}