Re: [PATCH 1/2] iio: imu: st_lsm6dsx: add dts property to disable sensor-hub

[Lorenzo Bianconi <lorenzo.bianconi@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 1890 bytes --]

> On Wed, 10 Nov 2021 15:42:32 +0100
> Lorenzo Bianconi <lorenzo@kernel.org> wrote:
> 
> > Introduce the capability to disable sensorhub through a device-tree
> > property since there are some configurations where users want to
> > explicitly disable sensor-hub auto-probing at bootstrap.
> > A typical configuration is when the sensorhub clock/data lines are connected
> > to a pull-up resistor since no slave sensors are connected to the i2c master.
> > If SDO/SA0 line is connected to the same pull-up resistor, when the driver
> > tries to probe slave devices connected on sensor-hub, it will force SDO/SA0
> > line to low, modifying the device i2c address.
> 
> That's some 'interesting' wiring...
> 
> My only suggestion here is perhaps expand on shub as disable-sensor-hub
> would be easier for people not familiar with the abbreviation?

ack, sure. I will fix it in v2.

Regards,
Lorenzo

> 
> Jonathan
> 
> > 
> > Tested-by: Mario Tesi <mario.tesi@st.com>
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > index f2cbbc756459..82ac6c59ca03 100644
> > --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > @@ -2244,7 +2244,9 @@ int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id,
> >  		return err;
> >  
> >  	hub_settings = &hw->settings->shub_settings;
> > -	if (hub_settings->master_en.addr) {
> > +	if (hub_settings->master_en.addr &&
> > +	    (!dev_fwnode(dev) ||
> > +	     !device_property_read_bool(dev, "st,disable-shub"))) {
> >  		err = st_lsm6dsx_shub_probe(hw, name);
> >  		if (err < 0)
> >  			return err;
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]