[PATCH 01/15] iio: adc: ad_sigma_delta: do not use internal iio_dev lock

Nuno Sá
2022-09-20T11:28:53Z

Drop 'mlock' usage by making use of iio_device_claim_direct_mode().
This change actually makes sure we cannot do a single conversion while
buffering is enable. Note there was a potential race in the previous
code since we were only acquiring the lock after checking if the bus is
enabled.

Fixes: af3008485ea0 ("iio:adc: Add common code for ADI Sigma Deltadevices")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
drivers/iio/adc/ad_sigma_delta.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index 261a9a6b45e1..d8570f620785 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -281,10 +281,10 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
unsigned int data_reg;
int ret = 0;

- if (iio_buffer_enabled(indio_dev))
- return -EBUSY;
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;

- mutex_lock(&indio_dev->mlock);
ad_sigma_delta_set_channel(sigma_delta, chan->address);

spi_bus_lock(sigma_delta->spi->master);
@@ -323,7 +323,7 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
sigma_delta->bus_locked = false;
spi_bus_unlock(sigma_delta->spi->master);
- mutex_unlock(&indio_dev->mlock);
+ iio_device_release_direct_mode(indio_dev);

if (ret)
return ret;
--
2.37.3