================================================
Misc sensors (fingerprint, hall, keyboard cover)
================================================

The small peripherals that don't carry enough register/protocol-level detail
to earn their own page: the fingerprint sensor, the hall-effect cover switch,
and the detachable keyboard cover's connector pins. All are DT-bound and
built into ``artifacts/kernel`` (:doc:`/boot/dtbo`); none of them needed
disassembly beyond confirming the binding. None of these are physical keys
you press — the power/volume buttons are in :doc:`/boot/keys`.

DT bindings
===========

.. list-table::
   :header-rows: 1
   :widths: 22 16 12 50

   * - Device
     - ``compatible``
     - Bus
     - GPIOs / notes
   * - **Fingerprint** (``fragment@57``)
     - ``fortsense,fortsense_fp`` /
       ``chipsailing_fp`` / ``microarray_fp``
     - SPI
     - three vendor drivers compiled in; the one whose chip answers is used
       (``cs-gpios``, ``onyx,rst_gpio``, ``onyx,irq_gpio``) — that
       selection-by-probe behavior is inferred from driver structure, not
       traced at runtime, see `Fingerprint`_ below. TA/firmware side:
       ``fpchips64`` in ``/vendor/firmware`` (:doc:`/trustzone/secure-world`)
   * - **Hall sensor** (``onyx_hall``)
     - onyx hall (``fragment@52``)
     - GPIO
     - ``irq-gpio`` — magnetic cover/case-close detection
   * - **Keyboard cover** (``onyx-keyboard``)
     - ``onyx,keyboard-ultra2``
     - —
     - ``vcc-ctrl``, ``id-gpio``, ``id-gpio2``, ``wake-gpio`` — pogo-pin
       *connector* pins (presence/wake detection); the keyboard's own keys
       are not something this DT node describes

The camera nodes (``qcom,cam-sensor@*``, ``qcom,eeprom@*``) in the overlay are
stock SM6350 reference-design entries with no populated sensor on this PCB — the
same reference-base pattern as the DSI/AMOLED panel names (:doc:`/display/panel`).

Fingerprint
===========

Three vendor drivers are compiled in and DT-described
(``fortsense,fortsense_fp``, ``chipsailing_fp``, ``microarray_fp``), all on SPI
with ``cs-gpios`` + reset/irq GPIOs; the driver whose chip is physically present
is inferred to bind (from the compiled-in-driver structure, not traced at
runtime) — the same "compile every candidate, whichever chip answers wins"
pattern as the pen/touch swappable suppliers (:doc:`/display/wacom-pen`,
:doc:`touchscreen`). The secure/enrolment side is handled off-CPU (the
``fpchips64`` firmware in ``/vendor/firmware`` and the TZ path,
:doc:`/trustzone/secure-world`).

Hall sensor
===========

``onyx_hall`` is a magnetic-field switch on an ``irq-gpio``, used to detect
the magnetic cover opening/closing (sleep/wake the panel). It reports a
proximity/field state, not a press — not a key.

Keyboard cover
===============

``onyx,keyboard-ultra2`` is the detachable pogo-pin keyboard cover, identified
by ``id-gpio``/``id-gpio2`` and woken via ``wake-gpio`` (kernel
``onyx_keyboard_connect`` path). This DT node only describes the *connector*
pins — presence detection and wake — not the keyboard's own individual keys,
which this dump has no register/protocol-level visibility into. The power and
volume buttons, which are physical keys, are documented in :doc:`/boot/keys`.

Sensors and charger (documented elsewhere)
===========================================

- **Sensors** (IMU, ALS, etc.) run on the ADSP via the SSC/QMI stack
  (``qcom,qmi-sensors``); there is no separate SLPI core on this SM6350 build
  (:doc:`/audio/dsp-firmware`).
- **Charger** is the PM7250B ``qcom,qpnp-smb5`` with the SMB1396/SMB1398 charge
  pumps (``qcom,smb1396-div2-cp-master`` / ``-slave`` / ``smb1398-pre-regulator``)
  for fast charging (:doc:`/soc/pmic`).

Provenance
==========

:Source: ``artifacts/dtbo_a/overlay_0.dts`` (all ``compatible`` bindings, SPI/GPIO
   assignments).
:Method: device-tree reading only — none of these devices carried enough
   register/protocol content to warrant static disassembly beyond confirming
   the DT binding. No code executed.
:Cross-refs: :doc:`/display/wacom-pen`, :doc:`touchscreen`,
   :doc:`/trustzone/secure-world`, :doc:`/audio/dsp-firmware`, :doc:`/soc/pmic`,
   :doc:`/boot/keys`, :doc:`/boot/dtbo`.