power.c

// see kucu.io for further details
#include "main.h"
#include "power.h"

#include <stdbool.h>

#include "FreeRTOS.h"
#include "task.h"

#include "stm32l4xx_ll_rtc.h"
#include "stm32l4xx_ll_pwr.h"


#define POWER_REQUIRED_TASK_COUNT_TO_STOP 2


static volatile bool can_stop = false;
static volatile int stop_enabler_count = 0;


void power_pre_sleep_processing() {
  if (can_stop) {
    LL_RCC_SetClkAfterWakeFromStop(LL_RCC_STOP_WAKEUPCLOCK_MSI);
    LL_PWR_SetPowerMode(LL_PWR_MODE_STOP2);
    LL_LPM_EnableDeepSleep();
    SysTick->CTRL &= ~SysTick_CTRL_TICKINT_Msk;
  }
}


void power_post_sleep_processing() {
  if (can_stop) {
    SysTick->CTRL  |= SysTick_CTRL_TICKINT_Msk;
    LL_LPM_EnableSleep();
  }
}


void power_deepsleep_allow() {
  portENTER_CRITICAL();
  stop_enabler_count++;
  can_stop = (stop_enabler_count == POWER_REQUIRED_TASK_COUNT_TO_STOP);
  portEXIT_CRITICAL();
}


void power_deepsleep_prevent() {
  portENTER_CRITICAL();
  stop_enabler_count--;
  can_stop = (stop_enabler_count == POWER_REQUIRED_TASK_COUNT_TO_STOP);
  portEXIT_CRITICAL();
}