Commit 4f9b80ae authored by William Breathitt Gray's avatar William Breathitt Gray Committed by Jonathan Cameron
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iio: addac: stx104: Fix race condition when converting analog-to-digital 



The ADC conversion procedure requires several device I/O operations
performed in a particular sequence. If stx104_read_raw() is called
concurrently, the ADC conversion procedure could be clobbered. Prevent
such a race condition by utilizing a mutex.

Fixes: 4075a283 ("iio: stx104: Add IIO support for the ADC channels")
Signed-off-by: default avatarWilliam Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/2ae5e40eed5006ca735e4c12181a9ff5ced65547.1680790580.git.william.gray@linaro.org


Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 97408274

drivers/iio/addac/stx104.c

+4 −0
Original line number Diff line number Diff line
@@ -117,6 +117,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, 
			return IIO_VAL_INT;

		}



		mutex_lock(&priv->lock);



		/* select ADC channel */

		iowrite8(chan->channel | (chan->channel << 4), &reg->achan);
@@ -127,6 +129,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, 
		while (ioread8(&reg->cir_asr) & BIT(7));



		*val = ioread16(&reg->ssr_ad);



		mutex_unlock(&priv->lock);

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_OFFSET:

		/* get ADC bipolar/unipolar configuration */