[PATCH v2] iio: ti-ads7138: Disable STATS_EN bit while reading conversion results

[Paul Geurts]

The device might update channel data while it's read by the host,
providing a data race. Disable the update of the channel stats before
reading the values.

Signed-off-by: Paul Geurts <paul.geurts@xxxxxxxxxxxxxxxxxxxxxxxxx>
Fixes: 93a39542d3c3 ("iio: adc: Add driver for ADS7128 / ADS7138")
---

V1 -> V2: Checked return values and prefixed iio: in commit msg

v1: https://lore.kernel.org/all/20260619075646.4100193-1-paul.geurts@xxxxxxxxxxxxxxxxxxxxxxxxx/
---
 drivers/iio/adc/ti-ads7138.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iio/adc/ti-ads7138.c b/drivers/iio/adc/ti-ads7138.c
index ee5c1b8e3a8e..81380fd2badc 100644
--- a/drivers/iio/adc/ti-ads7138.c
+++ b/drivers/iio/adc/ti-ads7138.c
@@ -237,11 +237,21 @@ static int ads7138_read_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
+		/* Disable statistics update so the value is not updated mid read */
+		ret = ads7138_i2c_clear_bit(data->client, ADS7138_REG_GENERAL_CFG,
+					    ADS7138_GENERAL_CFG_STATS_EN);
+		if (ret)
+			return ret;
 		ret = ads7138_i2c_read_block(data->client,
 					     ADS7138_REG_RECENT_LSB_CH(chan->channel),
 					     values, ARRAY_SIZE(values));
 		if (ret)
 			return ret;
+		/* Enable statistics update after read */
+		ret = ads7138_i2c_set_bit(data->client, ADS7138_REG_GENERAL_CFG,
+					  ADS7138_GENERAL_CFG_STATS_EN);
+		if (ret)
+			return ret;
 
 		*val = get_unaligned_le16(values);
 		return IIO_VAL_INT;
-- 
2.39.2