Long press button

How do I implement a long press button event?

I currently have the following and coming from an arduino environment I would normally use millis() to time the button presses.

static void user_app_button_press_cb(void) { uint8_t next_btn_event = 0; // Read button state if(GPIO_GetPinStatus(GPIO_BUTTON_PORT, GPIO_BUTTON_PIN)) { app_sleep_env.custs1_btn_state = CUSTS1_BTN_STATE_RELEASED; next_btn_event = WKUPCT_PIN_POLARITY_LOW; } else { app_sleep_env.custs1_btn_state = CUSTS1_BTN_STATE_PRESSED; next_btn_event = WKUPCT_PIN_POLARITY_HIGH; } // Update button characteristic struct custs1_val_ntf_ind_req *req = KE_MSG_ALLOC_DYN(CUSTS1_VAL_NTF_REQ, prf_get_task_from_id(TASK_ID_CUSTS1), TASK_APP, custs1_val_ntf_ind_req, DEF_SVC1_BUTTON_STATE_CHAR_LEN); req->conidx = app_env->conidx; req->notification = true; req->handle = SVC1_IDX_BUTTON_STATE_VAL; req->length = DEF_SVC1_BUTTON_STATE_CHAR_LEN; req->value[0] = app_sleep_env.custs1_btn_state; ke_msg_send(req); // Configure next button event user_app_set_button_event(next_btn_event); }