From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Eugen Hristev , Maxime Ripard , Stable@vger.kernel.org, Jonathan Cameron , Sasha Levin Subject: [PATCH AUTOSEL 4.4 08/15] iio: adc: at91: fix acking DRDY irq on simple conversions Date: Sun, 4 Nov 2018 08:54:10 -0500 Message-Id: <20181104135417.88671-8-sashal@kernel.org> In-Reply-To: <20181104135417.88671-1-sashal@kernel.org> References: <20181104135417.88671-1-sashal@kernel.org> List-ID: From: Eugen Hristev [ Upstream commit bc1b45326223e7e890053cf6266357adfa61942d ] 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: 0e589d5fb ("ARM: AT91: IIO: Add AT91 ADC driver.") Cc: Maxime Ripard Signed-off-by: Eugen Hristev Acked-by: Ludovic Desroches Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/adc/at91_adc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c index d2a0d8a78df0..d83e5b75a37b 100644 --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -278,6 +278,8 @@ 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); } -- 2.17.1