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author | Georg Ottinger <g.ottinger@abatec.at> | 2019-01-30 14:42:02 +0100 |
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committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2019-03-09 16:55:07 +0000 |
commit | 09c6bdee51183a575bf7546890c8c137a75a2b44 (patch) | |
tree | aeba77f046513e9ccbd1d53adce1dff6b76ceeb3 /drivers/iio | |
parent | 409a51e0a4a5f908763191fae2c29008632eb712 (diff) | |
download | linux-09c6bdee51183a575bf7546890c8c137a75a2b44.tar.gz linux-09c6bdee51183a575bf7546890c8c137a75a2b44.tar.bz2 linux-09c6bdee51183a575bf7546890c8c137a75a2b44.zip |
iio: adc: at91: disable adc channel interrupt in timeout case
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>
Diffstat (limited to 'drivers/iio')
-rw-r--r-- | drivers/iio/adc/at91_adc.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c index 75d2f73582a3..596841a3c4db 100644 --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -704,23 +704,29 @@ 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)); - st->last_value = 0; - st->done = false; + 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; |