Re: [PATCH] IIO: hid-sensor-prox: add missing scale attribute

[srinivas pandruvada <srinivas.pandruvada@linux.intel.com>]

On Thu, 2022-12-22 at 13:07 +0100, Philipp Jungkamp wrote:
> The hid-sensor-prox returned an empty string on sysfs
> in_proximity_scale
> read. This is due to the the drivers reporting it's scale from an
> internal value which is never changed from zero.
> 
> Try to query the scale of the HID sensor using
> hid_sensor_format_scale.

By spec there is no unit for this attribute:

"
An application-level or physical collection that identifies
a device that detects human presence (Boolean yes or no).
"

There is no use of calling hid_sensor_format_scale() as there is no
conversion. With the call this is setting scale_pre_decml to 1.

Better to set scale_pre_decml to 1 instead of calling
hid_sensor_format_scale(), which gives wrong impression that we are
converting to some scale.

Thanks,
Srinivas

> 
> Signed-off-by: Philipp Jungkamp <p.jungkamp@gmx.net>
> ---
> Hello,
> 
> While trying to utilize hid_sensor_prox driver I noticed this
> problem.
> Should this be part of the branch created for the other patch series
> I
> have submitted?
> See:
> https://lore.kernel.org/linux-iio/nycvar.YFH.7.76.2212201525010.9000@cbobk.fhfr.pm/T/#u
> 
> Regards,
> Philipp Jungkamp
> 
>  drivers/iio/light/hid-sensor-prox.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iio/light/hid-sensor-prox.c
> b/drivers/iio/light/hid-sensor-prox.c
> index f10fa2abfe72..3322f8e56f41 100644
> --- a/drivers/iio/light/hid-sensor-prox.c
> +++ b/drivers/iio/light/hid-sensor-prox.c
> @@ -222,6 +222,9 @@ static int prox_parse_report(struct
> platform_device *pdev,
>         dev_dbg(&pdev->dev, "prox %x:%x\n", st->prox_attr.index,
>                         st->prox_attr.report_id);
> 
> +       st->scale_precision = hid_sensor_format_scale(usage_id, &st-
> >prox_attr,
> +                               &st->scale_pre_decml, &st-
> >scale_post_decml);
> +
>         return ret;
>  }
> 
> --
> 2.39.0
>