iio: adc: at91: disable adc channel interrupt in timeout case (fe400daf) · Commits · e / devices / android_kernel_oneplus_sm8150

commit 09c6bdee51183a575bf7546890c8c137a75a2b44 upstream. Having a brief look at at91_adc_read_raw() it is obvious that in the case of a timeout the setting of AT91_ADC_CHDR and AT91_ADC_IDR registers is omitted. If 2 different channels are queried we can end up with a situation where two interrupts are enabled, but only one interrupt is cleared in the interrupt handler. Resulting in a interrupt loop and a system hang. Signed-off-by:

Georg Ottinger <g.ottinger@abatec.at> Acked-by:

Ludovic Desroches <ludovic.desroches@microchip.com> Cc: <Stable@vger.kernel.org> Signed-off-by:

Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/iio/adc/at91_adc.c

+17 −11

Original line number	Diff line number	Diff line
		@@ -705,23 +705,29 @@ static int at91_adc_read_raw(struct iio_dev *idev,
		ret = wait_event_interruptible_timeout(st->wq_data_avail,
		st->done,
		msecs_to_jiffies(1000));
		if (ret == 0)
		ret = -ETIMEDOUT;
		if (ret < 0) {
		mutex_unlock(&st->lock);
		return ret;
		}

		*val = st->last_value;

		/* Disable interrupts, regardless if adc conversion was
		* successful or not
		*/
		at91_adc_writel(st, AT91_ADC_CHDR,
		AT91_ADC_CH(chan->channel));
		at91_adc_writel(st, AT91_ADC_IDR, BIT(chan->channel));

		if (ret > 0) {
		/* a valid conversion took place */
		*val = st->last_value;
		st->last_value = 0;
		st->done = false;
		ret = IIO_VAL_INT;
		} else if (ret == 0) {
		/* conversion timeout */
		dev_err(&idev->dev, "ADC Channel %d timeout.\n",
		chan->channel);
		ret = -ETIMEDOUT;
		}

		mutex_unlock(&st->lock);
		return IIO_VAL_INT;
		return ret;

		case IIO_CHAN_INFO_SCALE:
		*val = st->vref_mv;