Re: [PATCH v2 1/9] iio: imu: st_lsm6dsx: fix iio_chan_spec for sensors without event detection

Lorenzo Bianconi
2025-11-21T07:50:37Z

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> The st_lsm6dsx_acc_channels array of struct iio_chan_spec has a non-NULL
> event_spec field, indicating support for IIO events. However, event
> detection is not supported for all sensors, and if userspace tries to
> configure accelerometer wakeup events on a sensor device that does not
> support them (e.g. LSM6DS0), st_lsm6dsx_write_event() dereferences a NULL
> pointer when trying to write to the wakeup register.
> Define an additional struct iio_chan_spec array whose members have a NULL
> event_spec field, and use this array instead of st_lsm6dsx_acc_channels for
> sensors without event detection capability.
>
> Fixes: b5969abfa8b8 ("iio: imu: st_lsm6dsx: add motion events")
> Signed-off-by: Francesco Lavra <flavra@baylibre.com>

Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>

> ---
> drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> index 216160549b5a..a09df9d772dd 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -103,6 +103,13 @@ static const struct iio_chan_spec st_lsm6dsx_acc_channels[] = {
> IIO_CHAN_SOFT_TIMESTAMP(3),
> };
>
> +static const struct iio_chan_spec st_lsm6ds0_acc_channels[] = {
> + ST_LSM6DSX_CHANNEL(IIO_ACCEL, 0x28, IIO_MOD_X, 0),
> + ST_LSM6DSX_CHANNEL(IIO_ACCEL, 0x2a, IIO_MOD_Y, 1),
> + ST_LSM6DSX_CHANNEL(IIO_ACCEL, 0x2c, IIO_MOD_Z, 2),
> + IIO_CHAN_SOFT_TIMESTAMP(3),
> +};
> +
> static const struct iio_chan_spec st_lsm6dsx_gyro_channels[] = {
> ST_LSM6DSX_CHANNEL(IIO_ANGL_VEL, 0x22, IIO_MOD_X, 0),
> ST_LSM6DSX_CHANNEL(IIO_ANGL_VEL, 0x24, IIO_MOD_Y, 1),
> @@ -144,8 +151,8 @@ static const struct st_lsm6dsx_settings st_lsm6dsx_sensor_settings[] = {
> },
> .channels = {
> [ST_LSM6DSX_ID_ACC] = {
> - .chan = st_lsm6dsx_acc_channels,
> - .len = ARRAY_SIZE(st_lsm6dsx_acc_channels),
> + .chan = st_lsm6ds0_acc_channels,
> + .len = ARRAY_SIZE(st_lsm6ds0_acc_channels),
> },
> [ST_LSM6DSX_ID_GYRO] = {
> .chan = st_lsm6ds0_gyro_channels,
> @@ -1445,8 +1452,8 @@ static const struct st_lsm6dsx_settings st_lsm6dsx_sensor_settings[] = {
> },
> .channels = {
> [ST_LSM6DSX_ID_ACC] = {
> - .chan = st_lsm6dsx_acc_channels,
> - .len = ARRAY_SIZE(st_lsm6dsx_acc_channels),
> + .chan = st_lsm6ds0_acc_channels,
> + .len = ARRAY_SIZE(st_lsm6ds0_acc_channels),
> },
> [ST_LSM6DSX_ID_GYRO] = {
> .chan = st_lsm6dsx_gyro_channels,
> --
> 2.39.5
>

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