GRTS_CH_PRESSURE
error = grts_map_channel(st, dev, GRTS_CH_PRESSURE, "pressure", true);
if (st->ch_map[GRTS_CH_PRESSURE] < GRTS_MAX_CHANNELS) {
if (st->ch_map[GRTS_CH_PRESSURE] < GRTS_MAX_CHANNELS) {
press = touch_info[st->ch_map[GRTS_CH_PRESSURE]];