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Date:   Thu, 17 Sep 2020 10:06:56 +0200
From:   Lorenzo Bianconi <lorenzo@kernel.org>
To:     Mario Tesi <martepisa@gmail.com>
Cc:     lorenzo.bianconi83@gmail.com, jic23@kernel.org, knaack.h@gmx.de,
        lars@metafoo.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org, mario.tesi@st.com
Subject: Re: [PATCH] iio: imu: st_lsm6dsx: Scaling factor type set to
 IIO_VAL_INT_PLUS_NANO
Message-ID: <20200917080656.GA22982@lore-desk>
References: <1600274660-29143-1-git-send-email-martepisa@gmail.com>
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> From: Mario Tesi <mario.tesi@st.com>
>=20
> Scaling factor values for Acc lead to an unacceptable rounding of the
> full scale (FS) calculated by some SensorHAL on Android devices. For exam=
ples
> setting FS to 4g the in_accel_x_scale, in_accel_y_scale and in_accel_z_sc=
ale
> are 0.001196 on 6 decimal digits and the FS is
> 0.001196 =C3=97 ((2^15) =E2=88=92 1) ~=3D 39.1893 m/s^2.
>=20
> Android CTS R10 SensorParameterRangeTest test expects a value greater than
> 39.20 m/s^2 so this test fails (ACCELEROMETER_MAX_RANGE =3D 4 * 9.80).
>=20
> Using 9 decimal digits the new scale factor is 0.001196411 and the FS now
> is 0.001196411 =C3=97 ((2^15)=E2=88=921) ~=3D 39.2028 m/s^2.
>=20
> This patch extends to IIO_VAL_INT_PLUS_NANO type the scaling factor to all
> IMU devices where SensorParameterRangeTest CTS test fails.
>=20
> Signed-off-by: Mario Tesi <mario.tesi@st.com>

Hi Mario,

just a minor comment inline. Fixing it:

Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>

> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 136 ++++++++++++++++-----=
------
>  1 file changed, 79 insertions(+), 57 deletions(-)
>=20

[...]

>  	fs_table =3D &hw->settings->fs_table[sensor->id];
>  	for (i =3D 0; i < fs_table->fs_len; i++)
> -		len +=3D scnprintf(buf + len, PAGE_SIZE - len, "0.%06u ",
> +		len +=3D scnprintf(buf + len, PAGE_SIZE - len, "0.%09u ",
>  				 fs_table->fs_avl[i].gain);
>  	buf[len - 1] =3D '\n';
> =20
>  	return len;
>  }
> =20
> +static int st_lsm6dsx_write_raw_get_fmt(struct iio_dev *indio_dev,
> +					struct iio_chan_spec const *chan,
> +					long mask)
> +{
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +		case IIO_ACCEL:
> +			return IIO_VAL_INT_PLUS_NANO;
> +		default:
> +			return IIO_VAL_INT_PLUS_MICRO;
> +		}
> +	default:
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	}
> +
> +	return -EINVAL;

you can remove this

> +}
> +
>  static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(st_lsm6dsx_sysfs_sampling_frequency_=
avail);
>  static IIO_DEVICE_ATTR(in_accel_scale_available, 0444,
>  		       st_lsm6dsx_sysfs_scale_avail, NULL, 0);
> @@ -1868,6 +1888,7 @@ static const struct iio_info st_lsm6dsx_acc_info =
=3D {
>  	.read_event_config =3D st_lsm6dsx_read_event_config,
>  	.write_event_config =3D st_lsm6dsx_write_event_config,
>  	.hwfifo_set_watermark =3D st_lsm6dsx_set_watermark,
> +	.write_raw_get_fmt =3D st_lsm6dsx_write_raw_get_fmt,
>  };
> =20
>  static struct attribute *st_lsm6dsx_gyro_attributes[] =3D {
> @@ -1885,6 +1906,7 @@ static const struct iio_info st_lsm6dsx_gyro_info =
=3D {
>  	.read_raw =3D st_lsm6dsx_read_raw,
>  	.write_raw =3D st_lsm6dsx_write_raw,
>  	.hwfifo_set_watermark =3D st_lsm6dsx_set_watermark,
> +	.write_raw_get_fmt =3D st_lsm6dsx_write_raw_get_fmt,
>  };
> =20
>  static int st_lsm6dsx_get_drdy_pin(struct st_lsm6dsx_hw *hw, int *drdy_p=
in)
> --=20
> 2.7.4
>=20

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