Re: [PATCH 03/15] iio: accel: adxl367: don't stay in standby on -EINVAL

[Nuno Sá]

On Tue, Oct 27, 2026 at 05:19:07PM +0100, Greg Kroah-Hartman wrote:
> From: Josef Bacik <josef@xxxxxxxxxxxxxx>
> 
> adxl367_set_act_threshold() puts the sensor into standby, writes the
> threshold and switches the measurement on again.  A threshold above 8191 is
> refused in between, and the sensor stays in standby: no samples and no
> events until the next write that succeeds.
> 
> adxl367_set_range() has the same problem and a worse one.  It rescales both
> thresholds for the new range, times four from 8 g to 2 g.  If one no longer
> fits it returns -EINVAL with the sensor in standby, the new range in the
> chip, the old one in st->range and rescaled thresholds in the driver's
> state: from the next successful write on the samples are reported with the
> wrong scale.
> 
> Switch the measurement on again if the threshold is refused.  In
> adxl367_set_range() see whether the thresholds fit before anything is
> changed.
> 
> Fixes: cbab791c5e2a ("iio: accel: add ADXL367 driver")
> Cc: stable <stable@xxxxxxxxxx>
> Cc: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
> Cc: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
> Cc: "Nuno Sá" <nuno.sa@xxxxxxxxxx>
> Cc: Michael Hennerich <Michael.Hennerich@xxxxxxxxxx>
> Cc: David Lechner <dlechner@xxxxxxxxxxxx>
> Cc: Andy Shevchenko <andy@xxxxxxxxxx>
> Cc: Cosmin Tanislav <demonsingur@xxxxxxxxx>
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---

Why don't we use mul_frac() as in the next patch? Also don't love the
condition duplication (feels like some refactor would be worth it). But
for backporting purposes, seems reasonable like. With mul_frac()

Reviewed-by: Nuno Sá <nuno.sa@xxxxxxxxxx>

>  drivers/iio/accel/adxl367.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/adxl367.c b/drivers/iio/accel/adxl367.c
> index 026db73057c5..ba6e7423978f 100644
> --- a/drivers/iio/accel/adxl367.c
> +++ b/drivers/iio/accel/adxl367.c
> @@ -349,8 +349,11 @@ static int adxl367_set_act_threshold(struct adxl367_state *st,
>  		return ret;
>  
>  	ret = _adxl367_set_act_threshold(st, act, threshold);
> -	if (ret)
> +	if (ret) {
> +		/* Leave standby also if the value was refused */
> +		adxl367_set_measure_en(st, true);
>  		return ret;
> +	}
>  
>  	return adxl367_set_measure_en(st, true);
>  }
> @@ -483,6 +486,12 @@ static int adxl367_set_range(struct iio_dev *indio_dev,
>  
>  	guard(mutex)(&st->lock);
>  
> +	/* The thresholds are rescaled: see that they fit before any change */
> +	if (max(st->act_threshold, st->inact_threshold) *
> +	    adxl367_range_scale_factor_tbl[st->range] /
> +	    adxl367_range_scale_factor_tbl[range] > ADXL367_THRESH_MAX)
> +		return -EINVAL;
> +
>  	ret = adxl367_set_measure_en(st, false);
>  	if (ret)
>  		return ret;
> 
> -- 
> 2.56.0
>