program to calculate the average of rssi values

Question

so here i a little code that I need to calculate the average of some rssi values:

#include <stdio.h>
#include <math.h>

int main (void)
{

    int8_t rssi_linear_sum;
    int8_t rssi_val;
    int8_t rssi_avg;
    int8_t rssi_num = 0;
    
    int8_t get_rssi(int8_t i)
    {
            return i;
    }
    /* rssi_get() in my actual code is a function that gets rssi 
    values through a bluetooth service, it returns an int8_t value, for the 
    sake of concision, I replaced it with a loop that 
    would return similar values to what I get.*/ 

    for (int8_t i = -100; i <-10; i+=10)
    { 
        rssi_val= get_rssi(i);
        rssi_linear_sum += powf(10, (float)rssi_val / 20);
        rssi_num ++;
    } 
    rssi_avg = 20 * log10f(rssi_linear_sum / rssi_num);

    printf("%d",rssi_avg );
}

so I know that to have a precise average to decibel values, you have to linear them first and then get the average. I am just not sure if my code expresses that perfectly. this is more of a logique question rather than a code question, but maybe you can introduce me to a function that does thi or verify that my logique does actually get me the average of values.