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In-Reply-To: <20211020183739.6a045ccc@jic23-huawei>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Wed, 20 Oct 2021 23:03:59 +0300
Message-ID: <CAHp75Vf=tXsDd_mDDGtNF-TD3SAK0BycvZonoKq---Ucp79s=Q@mail.gmail.com>
Subject: Re: BMI160 accelerometer on AyaNeo tablet
To:     Jonathan Cameron <jic23@kernel.org>
Cc:     Maxim Levitsky <maximlevitsky@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        linux-realtek-soc@lists.infradead.org,
        Oder Chiou <oder_chiou@realtek.com>,
        Ping-Ke Shih <pkshih@realtek.com>,
        nic_swsd <nic_swsd@realtek.com>,
        Derek Fang <derek.fang@realtek.com>,
        Hayes Wang <hayeswang@realtek.com>,
        Kailang Yang <kailang@realtek.com>,
        linux-iio <linux-iio@vger.kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        LKML <linux-kernel@vger.kernel.org>, info@ayaneo.com
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On Wed, Oct 20, 2021 at 8:33 PM Jonathan Cameron <jic23@kernel.org> wrote:
> On Tue, 19 Oct 2021 12:58:53 +0300
> Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > On Mon, Oct 18, 2021 at 11:42 PM Maxim Levitsky <maximlevitsky@gmail.com> wrote:
> > > On Mon, Oct 18, 2021 at 10:02 PM Andy Shevchenko
> > > <andy.shevchenko@gmail.com> wrote:
> > > > On Mon, Oct 18, 2021 at 09:02:40PM +0300, Maxim Levitsky wrote:

...

> > > > This is done by the commit 8a0672003421 ("iio: accel: bmc150: Get
> > > > mount-matrix from ACPI") which needs to be amended to take care about
> > > > more devices, somewhere in drivers/iio/industialio-acpi.c ? Jonathan,
> > > > Hans, what do you think?
> > >
> > > If you like to, I can probably volunteer to prepare a patch for this myself next
> > > weekend, using this pointer as a reference.
>
> Hmm. This isn't part of the ACPI spec but seems to be a microsoft addition.
> The webpage google feeds me says this is windows 10 mobile specific...
> https://docs.microsoft.com/en-us/windows-hardware/drivers/sensors/sensors-acpi-entries

So, it means it is at least a standard de facto on Windows machines.
We have to support it whether we want it or not. Same happened with
USB (wired) devices and many other things (SPCR, DBG2, CSRT, ...).

> Whilst I haven't been paying particularly close attention, I haven't noticed
> any attempt to add this to a future ACPI spec. If anyone happens to have
> convenient Microsoft contacts to verify the status of this method that would
> be a good step before we in any way imply it is standard.  Until then my inclination
> is to keep this in the few drivers in which we know it is useful.

-- 
With Best Regards,
Andy Shevchenko