Re: [PATCH 2/3] dt-bindings: iio: st,st-sensors: add st,fullscale-mg

[Linus Walleij]

On Fri, Jun 5, 2026 at 12:08 PM Herman van Hazendonk
<github.com@xxxxxxxxxx> wrote:

> Add an optional st,fullscale-mg property that selects the initial
> full-scale range of an ST MEMS sensor at probe time, expressed in
> milligauss for magnetometers (and analogous engineering units for
> other ST sensor families that may grow this property in the future).
>
> The property is purely additive: if absent, drivers fall back to
> their existing chip default, and if present but unsupported by the
> specific sensor the driver warns and falls back. No existing in-tree
> DTS is affected.
>
> The motivating case is the LSM303DLH magnetometer on the HP TouchPad
> (apq8060 / tenderloin) where the kernel's chip-default +/-1.3 G range
> saturates the X axis to the chip's 0xF000 overflow sentinel out of
> probe, because the chip is mounted close to surrounding power planes
> and picks up enough DC bias to exceed the smallest range. The driver
> core hardcodes fs_avl[0] as the starting range, so userspace cannot
> recover without racing the driver to write the in_magn_x_scale sysfs
> attribute after probe. st,fullscale-mg lets the device tree declare
> a wider initial range up-front and avoids the race entirely.
>
> Signed-off-by: Herman van Hazendonk <github.com@xxxxxxxxxx>

Makes sense to me.
Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>

Yours,
Linus Walleij