When doing simple conversions, the driver did not acknowledge the DRDY irq. If this irq is not acked, it will be left pending, and as soon as a trigger is enabled, the irq handler will be called, it doesn't know why this irq has occurred because no channel is pending, and then we will have irq loop and board will hang.
Fixes 0e589d5fb ("ARM: AT91: IIO: Add AT91 ADC driver.") Cc: Maxime Ripard maxime.ripard@bootlin.com Cc: stable@vger.kernel.org Signed-off-by: Eugen Hristev eugen.hristev@microchip.com --- drivers/iio/adc/at91_adc.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c index 44b5168..e85f859 100644 --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -712,6 +712,11 @@ static int at91_adc_read_raw(struct iio_dev *idev, at91_adc_writel(st, AT91_ADC_CHDR, AT91_ADC_CH(chan->channel)); at91_adc_writel(st, AT91_ADC_IDR, BIT(chan->channel)); + /* + * we need to ack the DRDY irq, otherwise it will be + * left pending and irq handler will be confused + */ + at91_adc_readl(st, AT91_ADC_LCDR);
st->last_value = 0; st->done = false;