[PATCH 0/1] iio: light: isl29018: cover-glass gain compensation via DT

[Herman van Hazendonk]

The ISL29018/ISL29023 is commonly mounted behind a tinted or coated
cover glass on consumer devices (HP TouchPad being one example). In
that configuration the visible-light photodiode reads roughly 1/100th
of actual ambient lux, causing downstream consumers (brightness daemons,
display managers) to permanently classify the environment as near-dark
and pin the backlight at a fraction of its range.

The driver already exposes in_illuminance0_calibscale for runtime
compensation, but that requires udev rules or userspace re-application
after every reboot.  The optical loss is a board-level hardware constant
and belongs in firmware.

This series adds an "isil,cover-comp-gain" DT property that seeds
calibscale at probe time, following the precedent established by
tsl2563.c (amstaos,cover-comp-gain) for the same class of problem.
The default stays 1 so existing systems are unaffected, and userspace
can still override the value through sysfs afterwards.

A follow-up DTS patch enabling this for the HP TouchPad will be sent
separately to the ARM/DTS tree once this driver change is upstream.

Herman van Hazendonk (1):
  iio: light: isl29018: support cover-glass gain compensation via DT

 .../devicetree/bindings/iio/light/isl29018.yaml     | 13 +++++++++++++
 drivers/iio/light/isl29018.c                        |  9 +++++++++
 2 files changed, 22 insertions(+)

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2.43.0