Re: [PATCH v3 2/3] iio: imu: inv_icm42600: drop the whoami check

[Conor Dooley]

On Sat, Aug 01, 2026 at 03:23:10AM +0100, Jonathan Cameron wrote:
> On Tue, 28 Jul 2026 20:43:50 +0200
> Jorijn van der Graaf <jorijnvdgraaf@xxxxxxxxxxxxx> wrote:
> 
> > A WHOAMI value differing from the one the compatible implies aborts
> > probe with -ENODEV, preventing a register-compatible part described
> > with a fallback compatible from probing at all.
> > 
> > The devicetree compatible is authoritative for which part is fitted:
> > drop the check, and with it the now-unused whoami definitions. No
> > warning replaces it, since probing via a fallback compatible is
> > legitimate use, not a condition to report. This changes the probe
> > outcome on mismatch for all parts the driver supports.
> > 
> > Tested via a backport to a Fairphone 6 running a 7.1-based kernel: its
> > ICM-42630 (WHOAMI 0x0C), described with an icm42631 fallback compatible
> > and matched as icm42631, probes silently, and accelerometer, gyroscope
> > and temperature reads work.
> > 
> > Suggested-by: Conor Dooley <conor@xxxxxxxxxx>
> > Link: https://lore.kernel.org/all/20260722-creature-volley-0f083b904c1d@spud/
> > Link: https://lore.kernel.org/all/20260728-extradite-yanking-42d918637f61@spud/
> > Assisted-by: Claude:claude-fable-5
> > Signed-off-by: Jorijn van der Graaf <jorijnvdgraaf@xxxxxxxxxxxxx>
> 
> Hi Jorijn,
> 
> I'm open to other opinions, particularly from those who are using
> this driver but I think dropping any form of hint that the device isn't
> the one we expect is too far when previous we just failed to probe.

FWIW, what I don't want is warning or error level printouts, so
something informational is tolerable to me.

> 
> We have a lot of drivers that issue such a print and my understanding
> is that has been useful.  If we want to make it non threatening we could
> phrase it as something like "Device ID XX is not the YY associate with the
> FW specified device, probably using a valid fallback compatible".  That
> would still provide the breadcrumb for anyone seeing an unexpected
> part change on their device vs the DT.
>

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