Re: [PATCH v4 3/3] iio: accel: bmc150: use guard(mutex) for mutex handling

On Mon, Aug 17, 2026 at 06:39:18PM +0300, Andy Shevchenko wrote:
> Not directly related to this change, but even in the original code what is
> protected here by the mutex? data->scan.channels?

Agreed it is out of scope for this cleanup, so I left the scope unchanged.

Honest answer: not much that is obvious. data->scan.channels does not need
it, since the triggered handler is the only writer and the core serializes
it. The accel one-shot read is already gated with -EBUSY while buffering, so
bmc150_accel_get_axis cannot race the handler. What is left sharing
data->mutex and still reachable during capture is the temperature read, the
bandwidth get/set and scale set, and the event config. But since the handler
is a single regmap_bulk_read and regmap already serializes the bus, it is not
clear the driver mutex guards a real invariant here, and it may well be
vestigial.

Dropping it is a behavioral change worth its own patch and testing rather
than something to fold into a lock-syntax cleanup. Happy to look into that
separately.

Thanks,
Gabriel