reflow-oven-control-sw/stm-firmware/button.c

/* Reflow Oven Controller
*
* Copyright (C) 2020  Mario Hüttel <mario.huettel@gmx.net>
*
* This file is part of the Reflow Oven Controller Project.
*
* The reflow oven controller is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* The Reflow Oven Control Firmware is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the reflow oven controller project.
* If not, see <http://www.gnu.org/licenses/>.
*/

#include <stm32/stm32f4xx.h>
#include <reflow-controller/button.h>
#include <stm-periph/stm32-gpio-macros.h>
#include <stm-periph/rcc-manager.h>
#include <stdint.h>
#include <helper-macros/helper-macros.h>
#include <cmsis/core_cm4.h>
#include <reflow-controller/systick.h>

static volatile uint64_t IN_SECTION(.ccm.bss) to_active_timestamp;
static volatile enum button_state IN_SECTION(.ccm.bss) int_state;
static volatile enum button_state IN_SECTION(.ccm.bss) override_state;

void button_init()
{
	rcc_manager_enable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(BUTTON_RCC_MASK));
	rcc_manager_enable_clock(&RCC->APB2ENR, BITMASK_TO_BITNO(RCC_APB2ENR_SYSCFGEN));
	BUTTON_PORT->MODER &= MODER_DELETE(BUTTON_PIN);
	BUTTON_PORT->PUPDR &= PUPDR_DELETE(BUTTON_PIN);
	BUTTON_PORT->PUPDR |= PULLUP(BUTTON_PIN);

	to_active_timestamp = 0ULL;
	int_state = BUTTON_IDLE;
	override_state = BUTTON_IDLE;

	SYSCFG->EXTICR[1] |= 0x3;
	EXTI->IMR |= (1U<<4);
	EXTI->RTSR |= (1U<<4);
	EXTI->FTSR |= (1U<<4);
	NVIC_EnableIRQ(EXTI4_IRQn);
}

enum button_state button_read_event()
{
	uint64_t time_delta;
	enum button_state temp_state;

	if (override_state != BUTTON_IDLE) {
		temp_state = override_state;
		override_state = BUTTON_IDLE;
		return temp_state;
	}

	if (BUTTON_PORT->IDR & (1U<<BUTTON_PIN)) {
		temp_state = int_state;
		int_state = BUTTON_IDLE;
		return temp_state;
	} else {
		time_delta = systick_get_global_tick() - to_active_timestamp;
		if (time_delta >= BUTTON_LONG_ON_TIME_MS)
			return BUTTON_LONG;
		else if (time_delta >= BUTTON_SHORT_ON_TIME_MS)
			return BUTTON_SHORT;
		else
			return BUTTON_IDLE;
	}
}

void button_deinit()
{
	BUTTON_PORT->MODER &= MODER_DELETE(BUTTON_PIN);
	BUTTON_PORT->PUPDR &= PUPDR_DELETE(BUTTON_PIN);
	rcc_manager_disable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(BUTTON_RCC_MASK));
	EXTI->IMR &= ~(1U<<4);
	rcc_manager_disable_clock(&RCC->APB2ENR, BITMASK_TO_BITNO(RCC_APB2ENR_SYSCFGEN));
}

void EXTI4_IRQHandler(void)
{
	uint64_t time_delta;

	/* Clear interrupts */
	EXTI->PR = EXTI->PR;
	__DSB();

	if (BUTTON_PORT->IDR & (1U<<BUTTON_PIN)) {
		time_delta = systick_get_global_tick() - to_active_timestamp;
		if (time_delta >= BUTTON_SHORT_ON_TIME_MS && time_delta < BUTTON_LONG_ON_TIME_MS) {
			int_state = BUTTON_SHORT_RELEASED;
		} else if (time_delta >= BUTTON_LONG_ON_TIME_MS) {
			int_state = BUTTON_LONG_RELEASED;
		}
	} else {
		to_active_timestamp = systick_get_global_tick();
	}
}

void button_override_event(enum button_state state)
{
	override_state = state;
}