When hardware buffers are enabled (the cnvst pin being the trigger), one
should not mess with the device state by requesting a single channel
read.
There is already a iio_buffer_enabled() check in *_read_single_value()
to merely prevent this situation but the check is inconsistent since
buffers can be enabled after the if clause anyway. Instead, use the core
mutex by calling iio_device_claim/release_direct_mode().
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
---
drivers/iio/adc/max1027.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index f4cb5c75604b..57f62ea2d7aa 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -296,10 +296,9 @@ static int max1027_read_single_value(struct iio_dev *indio_dev,
int ret;
struct max1027_state *st = iio_priv(indio_dev);
- if (iio_buffer_enabled(indio_dev)) {
- dev_warn(&indio_dev->dev, "trigger mode already enabled");
- return -EBUSY;
- }
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
/* Configure conversion register with the requested chan */
st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) |
@@ -325,6 +324,8 @@ static int max1027_read_single_value(struct iio_dev *indio_dev,
if (ret < 0)
return ret;
+ iio_device_release_direct_mode(indio_dev);
+
*val = be16_to_cpu(st->buffer[0]);
return IIO_VAL_INT;
--
2.27.0
