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

[Hans de Goede]

Hi All,

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.

Regards,

Hans


Hans de Goede (8):
  iio: accel: bmc150: Fix dereferencing the wrong pointer in
    bmc150_get/set_second_device
  iio: accel: bmc150: Don't make the remove function of the second
    accelerometer unregister itself
  iio: accel: bmc150: Move check for second ACPI device into a separate
    function
  iio: accel: bmc150: Add support for dual-accelerometers with a
    DUAL250E HID
  iio: accel: bmc150: Move struct bmc150_accel_data definition to
    bmc150-accel.h
  iio: accel: bmc150: Remove bmc150_set/get_second_device() accessor
    functions
  iio: accel: bmc150: Add support for DUAL250E ACPI DSM for setting the
    hinge angle
  iio: accel: bmc150: Set label based on accel-location for ACPI
    DUAL250E fwnodes

 drivers/iio/accel/bmc150-accel-core.c |  87 ++----------
 drivers/iio/accel/bmc150-accel-i2c.c  | 192 +++++++++++++++++++++-----
 drivers/iio/accel/bmc150-accel.h      |  66 ++++++++-
 3 files changed, 239 insertions(+), 106 deletions(-)

-- 
2.31.1