#pragma once
#include <cdefs.h>
#include <stdint.h>

/**
 * A Simple Driver for the Sonata's GPIO.
 *
 * Documentation source can be found at:
 * https://github.com/lowRISC/sonata-system/blob/1a59633d2515d4fe186a07d53e49ff95c18d9bbf/doc/ip/gpio.md
 *
 * Rendered documentation is served from:
 * https://lowrisc.org/sonata-system/doc/ip/gpio.html
 */
struct SonataGPIO
{
	uint32_t output;
	uint32_t input;
	uint32_t debouncedInput;
	uint32_t debouncedThreshold;
	uint32_t raspberryPiHeader;
	uint32_t raspberryPiMask;
	uint32_t arduinoShieldHeader;
	uint32_t arduinoShieldMask;

	/**
	 * The index of the first GPIO pin connected to a LED.
	 */
	static constexpr uint32_t FirstLED = 4;
	/**
	 * The index of the last GPIO pin connected to a LED.
	 */
	static constexpr uint32_t LastLED = 11;
	/**
	 * The number of GPIO pins used for LEDs.
	 */
	static constexpr uint32_t LEDCount = LastLED - FirstLED + 1;
	/**
	 * The mask covering the GPIO pins used for LEDs.
	 */
	static constexpr uint32_t LEDMask = ((1 << LEDCount) - 1) << FirstLED;

	constexpr static uint32_t led_bit(uint32_t index)
	{
		return (1 << (index + FirstLED)) & LEDMask;
	}

	void led_on(uint32_t index) volatile
	{
		output = output | led_bit(index);
	}

	void led_off(uint32_t index) volatile
	{
		output = output & ~led_bit(index);
	}

	void led_toggle(uint32_t index) volatile
	{
		output = output ^ led_bit(index);
	}
};