Re: [PATCH v9 6/6] iio: imu: st_lsm6dsx: Add support for rotation sensor

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 25 Mar 2026 14:55:26 +0000
Jonathan Cameron <jonathan.cameron@huawei.com> wrote:

> On Tue, 24 Mar 2026 09:48:07 +0100
> Francesco Lavra <flavra@baylibre.com> wrote:
> 
> > Some IMU chips in the LSM6DSX family have sensor fusion features that
> > combine data from the accelerometer and gyroscope. One of these features
> > generates rotation vector data and makes it available in the hardware
> > FIFO as a quaternion (more specifically, the X, Y and Z components of the
> > quaternion vector, expressed as 16-bit half-precision floating-point
> > numbers).
> > 
> > Add support for a new sensor instance that allows receiving sensor fusion
> > data, by defining a new struct st_lsm6dsx_fusion_settings (which contains
> > chip-specific details for the sensor fusion functionality), and adding this
> > struct as a new field in struct st_lsm6dsx_settings. In st_lsm6dsx_core.c,
> > populate this new struct for the LSM6DSV and LSM6DSV16X chips, and add the
> > logic to initialize an additional IIO device if this struct is populated
> > for the hardware type being probed.
> > Note: a new IIO device is being defined (as opposed to adding channels to
> > an existing device) because the rate at which sensor fusion data is
> > generated may not match the data rate from any of the existing devices.
> > 
> > Tested on LSM6DSV16X.
> > 
> > Signed-off-by: Francesco Lavra <flavra@baylibre.com>
> > Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>  
> One trivial thing. But don't resend for that. Assuming nothing else comes
> up I'll tweak it whilst applying.  Same for Andy's line wrap comment.
> 

Ah. I tried to pick up the series but we have a dependency on a fix
that hasn't quite made it upstream yet and I don't want the complexity
of merging my own fixes branch in until I know that made it upstream.

Sorry, I don't think I can get this merged this cycle unless we go
to rc8. Will get it queued from start of next cycle.

Jonathan

> thanks,
> 
> Jonathan
> 
> > diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_fusion.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_fusion.c
> > new file mode 100644
> > index 000000000000..9fb3e19e4a55
> > --- /dev/null
> > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_fusion.c
> > @@ -0,0 +1,243 @@  
> 
> > +
> > +int st_lsm6dsx_fusion_set_odr(struct st_lsm6dsx_sensor *sensor, bool enable)
> > +{
> > +	struct st_lsm6dsx_hw *hw = sensor->hw;
> > +	int err;
> > +
> > +	guard(mutex)(&hw->page_lock);
> > +
> > +	err = st_lsm6dsx_fusion_page_enable(hw);
> > +	if (err)
> > +		return err;
> > +
> > +	err = st_lsm6dsx_fusion_set_odr_locked(sensor, enable);
> > +	if (err) {
> > +		st_lsm6dsx_fusion_page_disable(hw);
> > +		return err;
> > +	}
> > +
> > +	return st_lsm6dsx_fusion_page_disable(hw);
> > +
> > +out:  
> Stray.  If nothing else comes up I'll drop this whilst applying.
> 
> > +}