Add HAL API for GPIO pinmap

hal/gpio_api.h

@@ -22,6 +22,7 @@
 
 #include <stdint.h>
 #include "device.h"
+#include "pinmap.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -135,6 +136,18 @@ void gpio_init_out_ex(gpio_t *gpio, PinName pin, int value);
  */
 void gpio_init_inout(gpio_t *gpio, PinName pin, PinDirection direction, PinMode mode, int value);
 
+/** Get the pins that support all GPIO tests
+ *
+ * Return a PinMap array of pins that support GPIO. The
+ * array is terminated with {NC, NC, 0}.
+ *
+ * Targets should override the weak implementation of this
+ * function to provide the actual pinmap for GPIO testing.
+ *
+ * @return PinMap array
+ */
+const PinMap *gpio_pinmap(void);
+
 /**@}*/
 
 #ifdef __cplusplus

hal/mbed_gpio.c

@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 #include "hal/gpio_api.h"
+#include "platform/mbed_toolchain.h"
 
 static inline void _gpio_init_in(gpio_t *gpio, PinName pin, PinMode mode)
 {
@@ -66,3 +67,11 @@ void gpio_init_inout(gpio_t *gpio, PinName pin, PinDirection direction, PinMode
         _gpio_init_out(gpio, pin, mode, value);
     }
 }
+
+MBED_WEAK const PinMap *gpio_pinmap()
+{
+    static const PinMap empty_gpio_pinmap[] = {
+        {NC, NC, 0},
+    };
+    return empty_gpio_pinmap;
+}