AT91_ADC_CHAN
st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, chan->channel));
st->last_value = at91_adc_readl(st, AT91_ADC_CHAN(st, st->chnb));
st->ts_prev_absx = at91_adc_readl(st, AT91_ADC_CHAN(st, 3))
st->ts_prev_absx /= at91_adc_readl(st, AT91_ADC_CHAN(st, 2));
st->ts_prev_absy = at91_adc_readl(st, AT91_ADC_CHAN(st, 1))
st->ts_prev_absy /= at91_adc_readl(st, AT91_ADC_CHAN(st, 0));