Improve doxygen documentation

include/sta/hal/gpio_pin.hpp

@@ -1,12 +1,27 @@
 /**
+ * @file
  * @brief Wrapper for HAL GPIO pins.
- *
- * Configuration:
- *     STA_HAL_GPIO_ENABLE: Enable module
  */
 #ifndef STA_HAL_GPIO_PIN_HPP
 #define STA_HAL_GPIO_PIN_HPP
 
+/**
+ * @defgroup halGPIO GPIO
+ * @ingroup hal
+ * @brief HAL GPIO module
+ */
+
+#ifdef DOXYGEN
+/**
+ * @def STA_HAL_GPIO_ENABLE
+ * @brief Enable module.
+ *
+ * @ingroup halBuildConfig
+ */
+#  define STA_HAL_GPIO_ENABLE
+#endif // DOXYGEN
+
+
 #include <sta/config.hpp>
 #ifdef STA_HAL_GPIO_ENABLE
 
@@ -18,6 +33,8 @@ namespace sta
 {
 	/**
 	 * @brief Container for HAL GPIO Pin objects.
+	 *
+	 * @ingroup halGPIO
 	 */
 	class HalGpioPin : public GpioPin
 	{
@@ -40,6 +57,8 @@ namespace sta
  * @brief Create HalGpioPin object from pin label.
  *
  * @param label     Pin label
+ *
+ * @ingroup halGPIO
  */
 #define STA_HAL_GPIO_PIN(label) sta::HalGpioPin{label##_GPIO_Port, label##_Pin}