#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/timer.h>

#include "libopencm3/stm32/common/timer_common_all.h"
#include "pinout.h"

#include "charge_pump.h"


void charge_pump_init(void)
{
	// set alternate function to Timer 1, channel 1 output
	gpio_set_af(CHARGE_PUMP_PORT, GPIO_AF2, CHARGE_PUMP_DRV_PIN);

	// set the GPIO to low until the charge pump is started
	gpio_clear(CHARGE_PUMP_PORT, CHARGE_PUMP_DRV_PIN);
	gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);

	// *** TIM1 ***
	// Configure channel 1 for PWM
	// Ch1 = charge pump output

	timer_set_mode(TIM1, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);

	// set up PWM channel
	timer_set_oc_mode(TIM1, TIM_OC1, TIM_OCM_PWM1);
	timer_enable_oc_output(TIM1, TIM_OC1);
	timer_enable_oc_preload(TIM1, TIM_OC1);
	timer_set_oc_polarity_high(TIM1, TIM_OC1);

	// prescaler
	timer_set_prescaler(TIM1, 48 - 1); // Timer runs at 1 MHz

	// auto-reload value
	timer_set_period(TIM1, 2000 - 1); // overflow every 2000 cycles = 500 Hz

	// output compare value
	timer_set_oc_value(TIM1, TIM_OC1, 100); // High for 100 cycles = 100 μs

	// only generate interrupt on overflow
	timer_update_on_overflow(TIM1);

	// enable main output
	timer_enable_break_main_output(TIM1);
}


void charge_pump_start(void)
{
	// start the timer
	timer_enable_counter(TIM1);

	// set mode to AF to pass through the PWM signal from the timer
	gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_AF, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
}


void charge_pump_stop(void)
{
	// stop the timer
	timer_disable_counter(TIM1);

	// set the output static low
	gpio_clear(CHARGE_PUMP_PORT, CHARGE_PUMP_DRV_PIN);
	gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
}