Re: [PATCH] iio: imu: st_lsm6dsx: Fix selection of ST_LSM6DS3_ID

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 15 Dec 2019 17:23:42 +0000
Jonathan Cameron <jic23@kernel.org> wrote:

> On Mon,  9 Dec 2019 18:05:41 +0100
> Stephan Gerhold <stephan@gerhold.net> wrote:
> 
> > At the moment, attempting to probe a device with ST_LSM6DS3_ID
> > (e.g. using the st,lsm6ds3 compatible) fails with:
> > 
> >     st_lsm6dsx_i2c 1-006b: unsupported whoami [69]
> > 
> > ... even though 0x69 is the whoami listed for ST_LSM6DS3_ID.
> > 
> > This happens because st_lsm6dsx_check_whoami() also attempts
> > to match unspecified (zero-initialized) entries in the "id" array.
> > ST_LSM6DS3_ID = 0 will therefore match any entry in
> > st_lsm6dsx_sensor_settings (here: the first), because none of them
> > actually have all 12 entries listed in the "id" array.
> > 
> > Avoid this by additionally checking if "name" is set,
> > which is only set for valid entries in the "id" array.
> > 
> > Signed-off-by: Stephan Gerhold <stephan@gerhold.net>  
> Definitely sounds like this wants backporting. 
> 
> If you can figure out a fixes tag that would be great!
I've taken a stab at working out when this got introduced and
came up with:

81956a93b522 "iio: imu: st_lsm6dsx: get device name from st_lsm6dsx_sensor_settings"

If that's wrong please let me know asap.

Applied to the togreg branch of iio.git as we are near the merge
window opening and marked for stable.

Thanks,

Jonathan
> 
> Thanks,
> 
> Jonathan
> 
> > ---
> >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 3 ++-
> >  1 file changed, 2 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 a7d40c02ce6b..b921dd9e108f 100644
> > --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > @@ -1301,7 +1301,8 @@ static int st_lsm6dsx_check_whoami(struct st_lsm6dsx_hw *hw, int id,
> >  
> >  	for (i = 0; i < ARRAY_SIZE(st_lsm6dsx_sensor_settings); i++) {
> >  		for (j = 0; j < ST_LSM6DSX_MAX_ID; j++) {
> > -			if (id == st_lsm6dsx_sensor_settings[i].id[j].hw_id)
> > +			if (st_lsm6dsx_sensor_settings[i].id[j].name &&
> > +			    id == st_lsm6dsx_sensor_settings[i].id[j].hw_id)
> >  				break;
> >  		}
> >  		if (j < ST_LSM6DSX_MAX_ID)  
>