Commit b7e95f41 authored Sep 24, 2018 by Eugen Hristev Committed by Greg Kroah-Hartman Nov 13, 2018

iio: adc: at91: fix acking DRDY irq on simple conversions



commit bc1b45326223e7e890053cf6266357adfa61942d upstream.

When doing simple conversions, the driver did not acknowledge the DRDY irq.
If this irq status 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 status has occurred because no channel is pending, and then it will go
int a irq loop and board will hang.
To avoid this situation, read the LCDR after a raw conversion is done.

Fixes: 0e589d5f ("ARM: AT91: IIO: Add AT91 ADC driver.")
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
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>

parent f809deba

drivers/iio/adc/at91_adc.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -279,6 +279,8 @@ static void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
		iio_trigger_poll(idev->trig);
		} else {
		st->last_value = at91_adc_readl(st, AT91_ADC_CHAN(st, st->chnb));
		/* Needed to ACK the DRDY interruption */
		at91_adc_readl(st, AT91_ADC_LCDR);
		st->done = true;
		wake_up_interruptible(&st->wq_data_avail);
		}