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 | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index 254df6a28cd8..c7663e5dd38a 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -310,10 +310,9 @@ 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) |
@@ -324,6 +323,7 @@ static int max1027_read_single_value(struct iio_dev *indio_dev,
if (ret < 0) {
dev_err(&indio_dev->dev,
"Failed to configure conversion register\n");
+ iio_device_release_direct_mode(indio_dev);
return ret;
}
@@ -336,6 +336,9 @@ static int max1027_read_single_value(struct iio_dev *indio_dev,
/* Read result */
ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);
+
+ iio_device_release_direct_mode(indio_dev);
+
if (ret < 0)
return ret;
--
2.27.0
