qmk-firmware/keyboards/rotr/rotr.c

#include "rotr.h"

bool encoder_update_kb(uint8_t index, bool clockwise) {
    if (!encoder_update_user(index, clockwise)) return false;
    if (clockwise) {
        tap_code(KC_VOLU);
    } else {
        tap_code(KC_VOLD);
    }
    return true;
}