Add GPIO pin interface

include/sta/gpio_pin.hpp

@@ -0,0 +1,32 @@
+#ifndef STA_GPIO_PIN_HPP
+#define STA_GPIO_PIN_HPP
+
+
+namespace sta
+{
+	/**
+	 * @brief GPIO pin state
+	 */
+	enum class GpioPinState
+	{
+		LOW,
+		HIGH
+	};
+
+	/**
+	 * @brief Interface for GPIO pins.
+	 */
+	class GpioPin
+	{
+	public:
+		/**
+		 * @brief Set pin output state.
+		 *
+		 * @param state     Output state
+		 */
+		virtual void setState(GpioPinState state) = 0;
+	};
+} // namespace sta
+
+
+#endif // STA_GPIO_PIN_HPP