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#include "main.h"
#include "gpio.h"


struct timeval startTime;   //Times needed for calculating Distance
struct timeval travelTime;

// IO Acces
struct bcm2835_peripheral {
    unsigned long addr_p;
    int mem_fd;
    void *map;
    volatile unsigned int *addr;
};
struct bcm2835_peripheral gpio = {GPIO_BASE};


//>> Create MMAP for GPIO
//------------------------------------------------------------------------------------------------------
int map_peripheral(struct bcm2835_peripheral *p)
{
   // Open /dev/mem
   if ((p->mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) {
      printf("Failed to open /dev/mem, try checking permissions.\n");
      return -1;
   }
   p->map = mmap(
      NULL,
      BLOCK_SIZE,
      PROT_READ|PROT_WRITE,
      MAP_SHARED,
      p->mem_fd,      
      p->addr_p      
   );
   if (p->map == MAP_FAILED) {
        perror("mmap");
        return -1;
   }
   p->addr = (volatile unsigned int *)p->map;
   return 0;
}
 
void unmap_peripheral(struct bcm2835_peripheral *p) {
    munmap(p->map, BLOCK_SIZE);
    close(p->mem_fd);
}

//>> Funktion for short buzzing Sound
//------------------------------------------------------------------------------------------------------
void buzzer_short(int seq){
        INP_GPIO(4);
        OUT_GPIO(4);
        for (int i = 0; i < seq; ++i)
        {
                if(seq > 1){usleep(50000);}
                GPIO_SET = 1 << 4;
                usleep(50000);
                GPIO_CLR = 1 << 4;
        }
}

//>> Calculate Distance with external sonar
//------------------------------------------------------------------------------------------------------
int calculate_distance(){
  int distanceTemp;
  int loopbreaker = 10000;        //Breaks the first loop in case it gets stuck (which happens from time to time if the Objekt facing the sensor is too close)
  GPIO_SET = 1 << ULTRA_TRIGGER;
  usleep(10);
  GPIO_CLR = 1 << ULTRA_TRIGGER;    

  while(!(GPIO_READ(ULTRA_ECHO)))
  {
    loopbreaker--;
    if(!loopbreaker){break;}
  }
  gettimeofday(&startTime, NULL);

  while((GPIO_READ(ULTRA_ECHO)))
  gettimeofday(&travelTime, NULL);

  loopbreaker = 0;
  distanceTemp = (travelTime.tv_usec - startTime.tv_usec) / 58;
  return distanceTemp;
}

//>> Initialize GPIO
//------------------------------------------------------------------------------------------------------
void gpio_init(){
  if(map_peripheral(&gpio) == -1)
    {
        printf("Failed to map the physical GPIO registers into the virtual memory space.\n");
    }

  INP_GPIO(ULTRA_ECHO);
  OUT_GPIO(ULTRA_TRIGGER);
  GPIO_CLR = 1 << ULTRA_TRIGGER;
  sleep(1);
}