From: Val Packett <val@packett.cool>
To: Aleksandrs Vinarskis <alex@vinarskis.com>,
Bjorn Andersson <andersson@kernel.org>,
Konrad Dybcio <konradybcio@kernel.org>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>
Cc: laurentiu.tudor1@dell.com, linux-arm-msm@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Subject: Re: [PATCH v2] arm64: dts: qcom: x1e80100-dell-xps13-9345: enable onboard accelerometers
Date: Tue, 31 Mar 2026 14:04:56 -0300 [thread overview]
Message-ID: <33c0a723-7748-4199-9623-7ed3eed8bfa0@packett.cool> (raw)
In-Reply-To: <20260331-dell-xps-9345-accel-v2-1-7dacbd24b43d@vinarskis.com>
On 3/31/26 10:36 AM, Aleksandrs Vinarskis wrote:
> Particular laptop comes with two sets of sensors:
> 1. Motherboard: accelerometer
> 2. Display/Camera module: accelerometer, ambient ligth (and more)
> sensor
>
> Both i2c busses are bound to Snapdragon Sensor Core (SSC) and are
> typically controlled by (A)DSP thus allowing for great power
> efficiency. This however requires DSP libraries matching ADSP firmware,
> sensors descriptions (must be extracted from Windows) and other
> potentially closed-source libraries. Opensource tooling includes
> `libssc` and `hexagonrpcd`, but they were not verified to be working.
>
> Until SSC support for X1E lands, bitbang both i2c busses to enable
> accelerometer functionality. In the future if/when sensors on this
> platform can be used from DSP directly, this commit can be reverted.
>
> [..]
WDYM by "support lands"? It's a userspace setup thing, nothing new
should be required in the kernel.
It is amazing that this bitbanging works here, I don't think it was
expected to ever work on anything newer than msm89x7 o.0
But this is likely inefficient… and "stealing" GPIOs from ADSP like this
sounds rather scary. And would definitely break SSC initialization for
anyone wanting to bring up hexagonrpcd/iio-sensor-proxy.
~val
next prev parent reply other threads:[~2026-03-31 17:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-31 13:36 Aleksandrs Vinarskis
2026-03-31 17:04 ` Val Packett [this message]
2026-03-31 17:28 ` Aleksandrs Vinarskis
2026-04-14 14:15 ` Konrad Dybcio
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