[PATCH] iio: adc: ti-ads131e08: Add iio_device_claim_direct() to protect buffered captures

[PATCH] iio: adc: ti-ads131e08: Add iio_device_claim_direct() to protect buffered captures

[Octávio Carneiro]

Add iio_device_claim_direct() to protect buffered captures. In
ads131e08_debugfs_reg_access and ads131e08_trigger_handler, data
reads are protected by the function call to avoid possible errors
caused by concurrent access.

Signed-off-by: Octávio Carneiro <ocarneiro1@gmail.com>
Co-developed-by: Fernando Lima <fernandolimabusiness@gmail.com>
Signed-off-by: Fernando Lima <fernandolimabusiness@gmail.com>
Co-developed-by: Lucas Eiji <eijiuchiyama@usp.br>
Signed-off-by: Lucas Eiji <eijiuchiyama@usp.br>
---
 drivers/iio/adc/ti-ads131e08.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ti-ads131e08.c b/drivers/iio/adc/ti-ads131e08.c
index c6096b646..00a7e6494 100644
--- a/drivers/iio/adc/ti-ads131e08.c
+++ b/drivers/iio/adc/ti-ads131e08.c
@@ -578,12 +578,16 @@ static int ads131e08_debugfs_reg_access(struct iio_dev *indio_dev,
 {
 	struct ads131e08_state *st = iio_priv(indio_dev);
 
+	if (!iio_device_claim_direct(indio_dev))
+		return -EBUSY;
+
 	if (readval) {
 		int ret = ads131e08_read_reg(st, reg);
 		*readval = ret;
 		return ret;
 	}
 
+	iio_device_release_direct(indio_dev);
 	return ads131e08_write_reg(st, reg, writeval);
 }
 
@@ -627,9 +631,11 @@ static irqreturn_t ads131e08_trigger_handler(int irq, void *private)
 	unsigned int num_bytes = ADS131E08_NUM_DATA_BYTES(st->data_rate);
 	u8 tweek_offset = num_bytes == 2 ? 1 : 0;
 
-	if (iio_trigger_using_own(indio_dev))
+	if (iio_trigger_using_own(indio_dev)) {
+		if (!iio_device_claim_direct(indio_dev))
+			return -EBUSY;
 		ret = ads131e08_read_data(st, st->readback_len);
-	else
+	} else
 		ret = ads131e08_pool_data(st);
 
 	if (ret)
@@ -670,6 +676,7 @@ static irqreturn_t ads131e08_trigger_handler(int irq, void *private)
 out:
 	iio_trigger_notify_done(indio_dev->trig);
 
+	iio_device_release_direct(indio_dev);
 	return IRQ_HANDLED;
 }
 
-- 
2.34.1