Re: [PATCH v2] iio: st_sensors: make scale channels also shared by type

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 26 Apr 2020 13:19:09 +0200
Bastien Nocera <hadess@hadess.net> wrote:

> On Sat, 2020-04-25 at 18:13 +0100, Jonathan Cameron wrote:
> > On Thu, 23 Apr 2020 14:17:15 +0200
> > Gaëtan André <rvlander@gaetanandre.eu> wrote:
> >   
> > > Scale channels are available by axis. For example for
> > > accelerometers,
> > > in_accel_x_scale, in_accel_y_scale and in_accel_z_scale are
> > > available.
> > > 
> > > However, they should be shared by type as documented in
> > > Documentation/ABI/testing/sysfs-bus-iio.
> > > 
> > > For each sensor (acceleros, gyros and magnetos) only one value is
> > > specified
> > > for all the axes.
> > > 
> > > Existing, by axis, entries are preserved in order to to leave the
> > > old ABI
> > > untouched.  
> > As I mentioned in v1, there isn't a strict ABI rule that says that we
> > must
> > do the shared form
> > 
> > +CC'd Bastien for comment on what userspace is assuming and whether
> > we should
> > push this back to stable or not.  
> 
> I have no idea what the effects of this would be on the ABI, and how
> this would impact iio-sensor-proxy.

There goes me being lazy ;)

> 
> Code is here though, so it might be best to test it:
> https://gitlab.freedesktop.org/hadess/iio-sensor-proxy/-/tree/master/src
> 
> And we accept merge requests :)

Only looks at scale and in_accel_scale

Easy enough to fix...

Note that for some older accelerometers it has to do per channel scales btw.
It used to be hard to have the same range out of the plane of the silicon
than within it, so was common to have sensors with different ranges and hence
scales in z direction from x and y.

I'll apply the kernel patch but good to fix up iio-sensor-proxy as well.

I would ideally like Denis to give this a quick sanity check though as I'd
like to give it a stable tag and don't want any unexpected breakage.

Thanks,

Jonathan

>