[PATCH 0/8] iio: accel: bmc150: Add support for yoga's with dual accelerometers with an ACPI HID of DUAL250E

[Jonathan Cameron]

On Sat, 22 May 2021 21:03:02 +0300
Andy Shevchenko <andy.shevchenko at gmail.com> wrote:

> On Sat, May 22, 2021 at 9:00 PM Jonathan Cameron <jic23 at kernel.org> wrote:
> 
> > On Fri, 21 May 2021 19:14:10 +0200
> > Hans de Goede <hdegoede at redhat.com> wrote:  
> 
> > > Some 360 degree hinges (yoga) style 2-in-1 devices use 2 bmc150 accels
> > > to allow the OS to determine the angle between the display and the base
> > > of the device, so that the OS can determine if the 2-in-1 is in laptop
> > > or in tablet-mode.
> > >
> > > We already support this setup on devices using a single ACPI node
> > > with a HID of "BOSC0200" to describe both accelerometers. This patch
> > > set extends this support to also support the same setup but then
> > > using a HID of "DUAL250E".
> > >
> > > While testing this I found some crashes on rmmod, patches 1-2
> > > fix those patches, patch 3 does some refactoring and patch 4
> > > adds support for the "DUAL250E" HID.
> > >
> > > Unfortunately we need some more special handling though, which the
> > > rest of the patches are for.
> > >
> > > On Windows both accelerometers are read (polled) by a special service
> > > and this service calls a DSM (Device Specific Method), which in turn
> > > translates the angles to one of laptop/tablet/tent/stand mode and then
> > > notifies the EC about the new mode and the EC then enables or disables
> > > the builtin keyboard and touchpad based in the mode.
> > >
> > > When the 2-in-1 is powered-on or resumed folded in tablet mode the
> > > EC senses this independent of the DSM by using a HALL effect sensor
> > > which senses that the keyboard has been folded away behind the display.
> > >
> > > At power-on or resume the EC disables the keyboard based on this and
> > > the only way to get the keyboard to work after this is to call the
> > > DSM to re-enable it (similar to how we also need to call a special
> > > DSM in the kxcjk-1013.c accel driver to re-enable the keyboard).
> > >
> > > Patches 5-7 deal with the DSM mess and patch 8 adds labels to the
> > > 2 accelerometers specifying which one is which.  
> >
> > Given only thing I'm planning to do is tweak the line wrapping, I'm
> > happy to pick this series up.
> >
> > The two fixes will slow things down a bit though as we should probably
> > get those upstream this cycle.
> >
> > I'm going to leave this on list for a few days before I take anything
> > though, to give others time to take a look.  
> 
> You are, guys, too fast :-)

One day did seem a bit short for a series doing as much as this one :)


> 
> I have few (minor) comments on a few patches, in general they are okay!
> So, after settling on the comments,
> Reviewed-by: Andy Shevchenko <andy.shevchenko at gmail.com>
> for the entire series.
> 
> Thanks, Hans, for doing this!
> 
> > One side note, cc list includes a few random choices... Seems you've
> > accidentally included alsa people as well as IIO ones.  
> 
>