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

[Hans de Goede]

Hi,

On 5/22/21 8:01 PM, Jonathan Cameron wrote:
> On Fri, 21 May 2021 19:14:10 +0200
> Hans de Goede <hdegoede at redhat.com> wrote:
> 
>> 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.
> 
> 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.

I'll do a v2 addressing a few minor things which Andy pointed out,
I'll also take care of the comment re-wrap in the v2.

> One side note, cc list includes a few random choices... Seems you've
> accidentally included alsa people as well as IIO ones. 

You're right, I accidentally included the address-list which I use
for ASoC patches. ASoc folks, sorry for the noise.

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(-)
>>
>