[PATCH] iio: magnetometer: tlv493d: fix magnetic field scale

[PATCH] iio: magnetometer: tlv493d: fix magnetic field scale

[Viral Patel]

The TLV493D-A1B6 datasheet specifies a magnetic resolution of
98 uT/LSB (0.098 mT/LSB). IIO reports magnetic field in Gauss
(1 mT = 10 G), so the scale should be 0.98 G/LSB.

The driver currently reports 98/1000 = 0.098 G/LSB, which
under-reports the magnetic field by a factor of 10. The comment
also gives the resolution as 0.0098 mT (9.8 uT), mixing up units.

Correct the scale value and the comment.

Fixes: 106511d280c7 ("iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor")
Signed-off-by: Viral Patel <viral8854@gmail.com>
---
Found while comparing this driver against the TLE493D-W2B6 register
map for a new driver I am working on. Compile-tested only; I do not
have TLV493D-A1B6 hardware.
---
 drivers/iio/magnetometer/tlv493d.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
index 03415cc2c9b3..234e3ce63ff7 100644
--- a/drivers/iio/magnetometer/tlv493d.c
+++ b/drivers/iio/magnetometer/tlv493d.c
@@ -299,11 +299,11 @@ static int tlv493d_read_raw(struct iio_dev *indio_dev,
 		switch (chan->type) {
 		case IIO_MAGN:
 			/*
-			 * Magnetic field scale: 0.0098 mTesla (i.e. 9.8 µT)
-			 * Magnetic field in Gauss: mT * 10 = 0.098.
+			 * Magnetic field scale: 0.098 mTesla (i.e. 98 µT) per LSB.
+			 * In Gauss (1 mT = 10 G): 0.98 G per LSB.
 			 */
 			*val = 98;
-			*val2 = 1000;
+			*val2 = 100;
 			return IIO_VAL_FRACTIONAL;
 		case IIO_TEMP:
 			/*

---
base-commit: ceb05f22e5cdc3f8bd3f7d5dcfc57843942191dd
change-id: 20261014-tlv493d-scale-fix-5a0b83b52d2a

Best regards,
-- 
Viral Patel <viral8854@gmail.com>

Re: [PATCH] iio: magnetometer: tlv493d: fix magnetic field scale

[Joshua Crofts]

On Wed, 14 Oct 2026 23:07:36 +0530
Viral Patel <viral8854@gmail.com> wrote:

> The TLV493D-A1B6 datasheet specifies a magnetic resolution of
> 98 uT/LSB (0.098 mT/LSB). IIO reports magnetic field in Gauss
> (1 mT = 10 G), so the scale should be 0.98 G/LSB.
> 
> The driver currently reports 98/1000 = 0.098 G/LSB, which
> under-reports the magnetic field by a factor of 10. The comment
> also gives the resolution as 0.0098 mT (9.8 uT), mixing up units.
> 
> Correct the scale value and the comment.
> 
> Fixes: 106511d280c7 ("iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor")
> Signed-off-by: Viral Patel <viral8854@gmail.com>
> ---

Good find.

Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>

-- 
Kind regards,
Joshua Crofts

Re: [PATCH] iio: magnetometer: tlv493d: fix magnetic field scale

[Jonathan Cameron]

On Wed, 14 Oct 2026 23:07:36 +0530
Viral Patel <viral8854@gmail.com> wrote:

> The TLV493D-A1B6 datasheet specifies a magnetic resolution of
> 98 uT/LSB (0.098 mT/LSB). IIO reports magnetic field in Gauss
> (1 mT = 10 G), so the scale should be 0.98 G/LSB.
> 
> The driver currently reports 98/1000 = 0.098 G/LSB, which
> under-reports the magnetic field by a factor of 10. The comment
> also gives the resolution as 0.0098 mT (9.8 uT), mixing up units.
> 
> Correct the scale value and the comment.
> 
> Fixes: 106511d280c7 ("iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor")
> Signed-off-by: Viral Patel <viral8854@gmail.com>

I'll give some time for Dixit to take a look at this.

Thanks,

Jonathan

> ---
> Found while comparing this driver against the TLE493D-W2B6 register
> map for a new driver I am working on. Compile-tested only; I do not
> have TLV493D-A1B6 hardware.
> ---
>  drivers/iio/magnetometer/tlv493d.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
> index 03415cc2c9b3..234e3ce63ff7 100644
> --- a/drivers/iio/magnetometer/tlv493d.c
> +++ b/drivers/iio/magnetometer/tlv493d.c
> @@ -299,11 +299,11 @@ static int tlv493d_read_raw(struct iio_dev *indio_dev,
>  		switch (chan->type) {
>  		case IIO_MAGN:
>  			/*
> -			 * Magnetic field scale: 0.0098 mTesla (i.e. 9.8 µT)
> -			 * Magnetic field in Gauss: mT * 10 = 0.098.
> +			 * Magnetic field scale: 0.098 mTesla (i.e. 98 µT) per LSB.
> +			 * In Gauss (1 mT = 10 G): 0.98 G per LSB.
>  			 */
>  			*val = 98;
> -			*val2 = 1000;
> +			*val2 = 100;
>  			return IIO_VAL_FRACTIONAL;
>  		case IIO_TEMP:
>  			/*
> 
> ---
> base-commit: ceb05f22e5cdc3f8bd3f7d5dcfc57843942191dd
> change-id: 20261014-tlv493d-scale-fix-5a0b83b52d2a
> 
> Best regards,

Re: [PATCH] iio: magnetometer: tlv493d: fix magnetic field scale

[Dixit Parmar]

LGTM. Good catch. There seem to be miscalculated Gauss scale due to
multiple conversion factor.

Reviewed-by: Dixit Parmar <dixitparmar19@gmail.com>

On Sun, Oct 18, 2026 at 9:22 PM Dixit Parmar <dixitparmar19@gmail.com> wrote:
>
> This change looks correct, the Gauss scale value seem to be miscalculated due to multiple conversations and different reference. Good catch.
>
> On Sunday, October 18, 2026, Jonathan Cameron <jic23@kernel.org> wrote:
>>
>> On Wed, 14 Oct 2026 23:07:36 +0530
>> Viral Patel <viral8854@gmail.com> wrote:
>>
>> > The TLV493D-A1B6 datasheet specifies a magnetic resolution of
>> > 98 uT/LSB (0.098 mT/LSB). IIO reports magnetic field in Gauss
>> > (1 mT = 10 G), so the scale should be 0.98 G/LSB.
>> >
>> > The driver currently reports 98/1000 = 0.098 G/LSB, which
>> > under-reports the magnetic field by a factor of 10. The comment
>> > also gives the resolution as 0.0098 mT (9.8 uT), mixing up units.
>> >
>> > Correct the scale value and the comment.
>> >
>> > Fixes: 106511d280c7 ("iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor")
>> > Signed-off-by: Viral Patel <viral8854@gmail.com>
>>
>> I'll give some time for Dixit to take a look at this.
>>
>> Thanks,
>>
>> Jonathan
>>
>> > ---
>> > Found while comparing this driver against the TLE493D-W2B6 register
>> > map for a new driver I am working on. Compile-tested only; I do not
>> > have TLV493D-A1B6 hardware.
>> > ---
>> >  drivers/iio/magnetometer/tlv493d.c | 6 +++---
>> >  1 file changed, 3 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
>> > index 03415cc2c9b3..234e3ce63ff7 100644
>> > --- a/drivers/iio/magnetometer/tlv493d.c
>> > +++ b/drivers/iio/magnetometer/tlv493d.c
>> > @@ -299,11 +299,11 @@ static int tlv493d_read_raw(struct iio_dev *indio_dev,
>> >               switch (chan->type) {
>> >               case IIO_MAGN:
>> >                       /*
>> > -                      * Magnetic field scale: 0.0098 mTesla (i.e. 9.8 µT)
>> > -                      * Magnetic field in Gauss: mT * 10 = 0.098.
>> > +                      * Magnetic field scale: 0.098 mTesla (i.e. 98 µT) per LSB.
>> > +                      * In Gauss (1 mT = 10 G): 0.98 G per LSB.
>> >                        */
>> >                       *val = 98;
>> > -                     *val2 = 1000;
>> > +                     *val2 = 100;
>> >                       return IIO_VAL_FRACTIONAL;
>> >               case IIO_TEMP:
>> >                       /*
>> >
>> > ---
>> > base-commit: ceb05f22e5cdc3f8bd3f7d5dcfc57843942191dd
>> > change-id: 20261014-tlv493d-scale-fix-5a0b83b52d2a
>> >
>> > Best regards,
>>

Re: [PATCH] iio: magnetometer: tlv493d: fix magnetic field scale

[Jonathan Cameron]

On Sun, 18 Oct 2026 21:29:49 +0530
Dixit Parmar <dixitparmar19@gmail.com> wrote:

> LGTM. Good catch. There seem to be miscalculated Gauss scale due to
> multiple conversion factor.
> 
> Reviewed-by: Dixit Parmar <dixitparmar19@gmail.com>
> 
Thanks for the fast response!

Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks,

Jonathan

> On Sun, Oct 18, 2026 at 9:22 PM Dixit Parmar <dixitparmar19@gmail.com> wrote:
> >
> > This change looks correct, the Gauss scale value seem to be miscalculated due to multiple conversations and different reference. Good catch.
> >
> > On Sunday, October 18, 2026, Jonathan Cameron <jic23@kernel.org> wrote:  
> >>
> >> On Wed, 14 Oct 2026 23:07:36 +0530
> >> Viral Patel <viral8854@gmail.com> wrote:
> >>  
> >> > The TLV493D-A1B6 datasheet specifies a magnetic resolution of
> >> > 98 uT/LSB (0.098 mT/LSB). IIO reports magnetic field in Gauss
> >> > (1 mT = 10 G), so the scale should be 0.98 G/LSB.
> >> >
> >> > The driver currently reports 98/1000 = 0.098 G/LSB, which
> >> > under-reports the magnetic field by a factor of 10. The comment
> >> > also gives the resolution as 0.0098 mT (9.8 uT), mixing up units.
> >> >
> >> > Correct the scale value and the comment.
> >> >
> >> > Fixes: 106511d280c7 ("iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor")
> >> > Signed-off-by: Viral Patel <viral8854@gmail.com>  
> >>
> >> I'll give some time for Dixit to take a look at this.
> >>
> >> Thanks,
> >>
> >> Jonathan
> >>  
> >> > ---
> >> > Found while comparing this driver against the TLE493D-W2B6 register
> >> > map for a new driver I am working on. Compile-tested only; I do not
> >> > have TLV493D-A1B6 hardware.
> >> > ---
> >> >  drivers/iio/magnetometer/tlv493d.c | 6 +++---
> >> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >> >
> >> > diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
> >> > index 03415cc2c9b3..234e3ce63ff7 100644
> >> > --- a/drivers/iio/magnetometer/tlv493d.c
> >> > +++ b/drivers/iio/magnetometer/tlv493d.c
> >> > @@ -299,11 +299,11 @@ static int tlv493d_read_raw(struct iio_dev *indio_dev,
> >> >               switch (chan->type) {
> >> >               case IIO_MAGN:
> >> >                       /*
> >> > -                      * Magnetic field scale: 0.0098 mTesla (i.e. 9.8 µT)
> >> > -                      * Magnetic field in Gauss: mT * 10 = 0.098.
> >> > +                      * Magnetic field scale: 0.098 mTesla (i.e. 98 µT) per LSB.
> >> > +                      * In Gauss (1 mT = 10 G): 0.98 G per LSB.
> >> >                        */
> >> >                       *val = 98;
> >> > -                     *val2 = 1000;
> >> > +                     *val2 = 100;
> >> >                       return IIO_VAL_FRACTIONAL;
> >> >               case IIO_TEMP:
> >> >                       /*
> >> >
> >> > ---
> >> > base-commit: ceb05f22e5cdc3f8bd3f7d5dcfc57843942191dd
> >> > change-id: 20261014-tlv493d-scale-fix-5a0b83b52d2a
> >> >
> >> > Best regards,  
> >>  
>