patch "iio: imu: st_lsm6dsx: Set buffer sampling frequency for accelerometer" added to char-misc-linus

This is a note to let you know that I've just added the patch titled

iio: imu: st_lsm6dsx: Set buffer sampling frequency for accelerometer

to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 679c04c10d65d32a3f269e696b22912ff0a001b9 Mon Sep 17 00:00:00 2001
From: Francesco Lavra <[email protected]>
Date: Wed, 25 Feb 2026 11:06:01 +0100
Subject: iio: imu: st_lsm6dsx: Set buffer sampling frequency for accelerometer
only

The st_lsm6dsx_hwfifo_odr_store() function, which is called when userspace writes the buffer sampling frequency sysfs attribute, calls st_lsm6dsx_check_odr(), which accesses the odr_table array at index sensor->id; since this array is only 2 entries long, an access for any sensor type other than accelerometer or gyroscope is an out-of-bounds access.

The motivation for being able to set a buffer frequency different from the sensor sampling frequency is to support use cases that need accurate event detection (which requires a high sampling frequency) while retrieving sensor data at low frequency. Since all the supported event types are generated from acceleration data only, do not create the buffer sampling frequency attribute for sensor types other than the accelerometer.

---
 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

index 1ee2fc5f5f1f..5b28a3ffcc3d 100644
@@ -862,12 +862,21 @@ int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw)
 	int i, ret;
 
 	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+		const struct iio_dev_attr **attrs;
+
 		if (!hw->iio_devs[i])
 			continue;
 
+		/*
+		 * For the accelerometer, allow setting FIFO sampling frequency
+		 * values different from the sensor sampling frequency, which
+		 * may be needed to keep FIFO data rate low while sampling
+		 * acceleration data at high rates for accurate event detection.
+		 */
+		attrs = i == ST_LSM6DSX_ID_ACC ? st_lsm6dsx_buffer_attrs : NULL;
 		ret = devm_iio_kfifo_buffer_setup_ext(hw->dev, hw->iio_devs[i],
 						      &st_lsm6dsx_buffer_ops,
-						      st_lsm6dsx_buffer_attrs);
+						      attrs);
 		if (ret)
 			return ret;
 	}

2.53.0