| Message ID | ZTEt7NqfDHPOkm8j@dc78bmyyyyyyyyyyyyydt-3.rev.dnainternet.fi (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | iio: kx022a: Fix acceleration value scaling | expand |
Hi Matti, On Thu, Oct 19, 2023 at 6:54 PM Matti Vaittinen <mazziesaccount@gmail.com> wrote: > > The IIO ABI mandates acceleration values from accelerometer to be > emitted in m/s^2. The KX022A was emitting values in micro m/s^2. > > Fix driver to report the correct scale values. > > Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> > Reported-by: Jagath Jog J <jagathjog1996@gmail.com> > Fixes: 7c1d1677b322 ("iio: accel: Support Kionix/ROHM KX022A accelerometer") > > --- > The fix is somewhat crude and just crops the last 3 digits (rounds) of the > scale while using IIO_VAL_INT_PLUS_NANO. I played with a thought of using > IIO_VAL_FRACTIONAL, which could have modelled the computation > G_range * g * scaling / (2^16 * scaling) - where scaling 10000 would > have allowed using g value 980665. > > This would have worked fine for reporting scale and available scales - > but would be somewhat tricky when converting the user-supplied scale to > register values in write_raw(). > > Well, the g varies from 9.832 (poles) to 9.780 (equator) according to > some website - no proper source check done but this sounds about right - > so maybe the loss of accuracy is acceptable. > > I did only very quick testing on KX022A and iio_generic_buffer. After > the patch the values seemed to be correct order of magnitude. Further > testing is appreciated :) Values are correct with this change, Thank you for fixing. Tested-by: Jagath Jog J <jagathjog1996@gmail.com> Regards Jagath > > --- > drivers/iio/accel/kionix-kx022a.c | 37 ++++++++++++++++++++++--------- > 1 file changed, 26 insertions(+), 11 deletions(-) > > diff --git a/drivers/iio/accel/kionix-kx022a.c b/drivers/iio/accel/kionix-kx022a.c > index 4ea3c6718ed4..971fc60efef0 100644 > --- a/drivers/iio/accel/kionix-kx022a.c > +++ b/drivers/iio/accel/kionix-kx022a.c > @@ -273,17 +273,17 @@ static const unsigned int kx022a_odrs[] = { > * (range / 2^bits) * g = (range / 2^bits) * 9.80665 m/s^2 > * => KX022A uses 16 bit (HiRes mode - assume the low 8 bits are zeroed > * in low-power mode(?) ) > - * => +/-2G => 4 / 2^16 * 9,80665 * 10^6 (to scale to micro) > - * => +/-2G - 598.550415 > - * +/-4G - 1197.10083 > - * +/-8G - 2394.20166 > - * +/-16G - 4788.40332 > + * => +/-2G => 4 / 2^16 * 9,80665 > + * => +/-2G - 0.000598550415 > + * +/-4G - 0.00119710083 > + * +/-8G - 0.00239420166 > + * +/-16G - 0.00478840332 > */ > static const int kx022a_scale_table[][2] = { > - { 598, 550415 }, > - { 1197, 100830 }, > - { 2394, 201660 }, > - { 4788, 403320 }, > + { 0, 598550 }, > + { 0, 1197101 }, > + { 0, 2394202 }, > + { 0, 4788403 }, > }; > > static int kx022a_read_avail(struct iio_dev *indio_dev, > @@ -302,7 +302,7 @@ static int kx022a_read_avail(struct iio_dev *indio_dev, > *vals = (const int *)kx022a_scale_table; > *length = ARRAY_SIZE(kx022a_scale_table) * > ARRAY_SIZE(kx022a_scale_table[0]); > - *type = IIO_VAL_INT_PLUS_MICRO; > + *type = IIO_VAL_INT_PLUS_NANO; > return IIO_AVAIL_LIST; > default: > return -EINVAL; > @@ -366,6 +366,20 @@ static int kx022a_turn_on_unlock(struct kx022a_data *data) > return ret; > } > > +static int kx022a_write_raw_get_fmt(struct iio_dev *idev, > + struct iio_chan_spec const *chan, > + long mask) > +{ > + switch (mask) { > + case IIO_CHAN_INFO_SCALE: > + return IIO_VAL_INT_PLUS_NANO; > + case IIO_CHAN_INFO_SAMP_FREQ: > + return IIO_VAL_INT_PLUS_MICRO; > + default: > + return -EINVAL; > + } > +} > + > static int kx022a_write_raw(struct iio_dev *idev, > struct iio_chan_spec const *chan, > int val, int val2, long mask) > @@ -510,7 +524,7 @@ static int kx022a_read_raw(struct iio_dev *idev, > > kx022a_reg2scale(regval, val, val2); > > - return IIO_VAL_INT_PLUS_MICRO; > + return IIO_VAL_INT_PLUS_NANO; > } > > return -EINVAL; > @@ -712,6 +726,7 @@ static int kx022a_fifo_flush(struct iio_dev *idev, unsigned int samples) > static const struct iio_info kx022a_info = { > .read_raw = &kx022a_read_raw, > .write_raw = &kx022a_write_raw, > + .write_raw_get_fmt = &kx022a_write_raw_get_fmt, > .read_avail = &kx022a_read_avail, > > .validate_trigger = iio_validate_own_trigger, > -- > 2.41.0 > > > -- > Matti Vaittinen, Linux device drivers > ROHM Semiconductors, Finland SWDC > Kiviharjunlenkki 1E > 90220 OULU > FINLAND > > ~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~ > Simon says - in Latin please. > ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~ > Thanks to Simon Glass for the translation =]
On 10/19/23 21:21, Jagath Jog J wrote: > Hi Matti, > > On Thu, Oct 19, 2023 at 6:54 PM Matti Vaittinen > <mazziesaccount@gmail.com> wrote: >> >> The IIO ABI mandates acceleration values from accelerometer to be >> emitted in m/s^2. The KX022A was emitting values in micro m/s^2. >> >> Fix driver to report the correct scale values. >> >> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> >> Reported-by: Jagath Jog J <jagathjog1996@gmail.com> >> Fixes: 7c1d1677b322 ("iio: accel: Support Kionix/ROHM KX022A accelerometer") >> >> --- >> The fix is somewhat crude and just crops the last 3 digits (rounds) of the >> scale while using IIO_VAL_INT_PLUS_NANO. I played with a thought of using >> IIO_VAL_FRACTIONAL, which could have modelled the computation >> G_range * g * scaling / (2^16 * scaling) - where scaling 10000 would >> have allowed using g value 980665. >> >> This would have worked fine for reporting scale and available scales - >> but would be somewhat tricky when converting the user-supplied scale to >> register values in write_raw(). >> >> Well, the g varies from 9.832 (poles) to 9.780 (equator) according to >> some website - no proper source check done but this sounds about right - >> so maybe the loss of accuracy is acceptable. >> >> I did only very quick testing on KX022A and iio_generic_buffer. After >> the patch the values seemed to be correct order of magnitude. Further >> testing is appreciated :) > > Values are correct with this change, Thank you for fixing. > Tested-by: Jagath Jog J <jagathjog1996@gmail.com> Thanks a ton for testing! May I ask which component did you use (or did you just use some 'simulated' regster values?) Yours, -- Matti
On Fri, Oct 20, 2023 at 5:39 PM Matti Vaittinen <mazziesaccount@gmail.com> wrote: > > On 10/19/23 21:21, Jagath Jog J wrote: > > Hi Matti, > > > > On Thu, Oct 19, 2023 at 6:54 PM Matti Vaittinen > > <mazziesaccount@gmail.com> wrote: > >> > >> I did only very quick testing on KX022A and iio_generic_buffer. After > >> the patch the values seemed to be correct order of magnitude. Further > >> testing is appreciated :) > > > > Values are correct with this change, Thank you for fixing. > > Tested-by: Jagath Jog J <jagathjog1996@gmail.com> > > Thanks a ton for testing! May I ask which component did you use (or did > you just use some 'simulated' regster values?) Hi Matti, I just simulated with the register values, Should the 'tested-by' tag only be provided after hardware testing? I referred to this driver because it's the most recent accelerometer driver that was merged. Regards Jagath
On Thu, 19 Oct 2023 16:23:56 +0300 Matti Vaittinen <mazziesaccount@gmail.com> wrote: > The IIO ABI mandates acceleration values from accelerometer to be > emitted in m/s^2. The KX022A was emitting values in micro m/s^2. > > Fix driver to report the correct scale values. > > Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> > Reported-by: Jagath Jog J <jagathjog1996@gmail.com> > Fixes: 7c1d1677b322 ("iio: accel: Support Kionix/ROHM KX022A accelerometer") > > --- > The fix is somewhat crude and just crops the last 3 digits (rounds) of the > scale while using IIO_VAL_INT_PLUS_NANO. I played with a thought of using > IIO_VAL_FRACTIONAL, which could have modelled the computation > G_range * g * scaling / (2^16 * scaling) - where scaling 10000 would > have allowed using g value 980665. > > This would have worked fine for reporting scale and available scales - > but would be somewhat tricky when converting the user-supplied scale to > register values in write_raw(). > > Well, the g varies from 9.832 (poles) to 9.780 (equator) according to > some website - no proper source check done but this sounds about right - > so maybe the loss of accuracy is acceptable. MEMS accelerometers tend to be pretty inaccurate. So I'd not worry too much about this loss of accuracy at all. The 0 point according to the datasheet I just looked at is +- 25mg and if I read the sensitivity numbers right part to part variation in scale is well above 5%. For 2G mode, it lists acceptable 1G values of min=15401, typical=16384, max=17367 So if anyone actually wants to do precision measurement they need to calibrate their particular device + deal with the variation due to temperature etc which makes this even more fun. Applied to my local fixes-togreg branch of iio.git, but I've just sent a pull request so this may not go out until after the 6.7 merge window. Jonathan > > I did only very quick testing on KX022A and iio_generic_buffer. After > the patch the values seemed to be correct order of magnitude. Further > testing is appreciated :) > > --- > drivers/iio/accel/kionix-kx022a.c | 37 ++++++++++++++++++++++--------- > 1 file changed, 26 insertions(+), 11 deletions(-) > > diff --git a/drivers/iio/accel/kionix-kx022a.c b/drivers/iio/accel/kionix-kx022a.c > index 4ea3c6718ed4..971fc60efef0 100644 > --- a/drivers/iio/accel/kionix-kx022a.c > +++ b/drivers/iio/accel/kionix-kx022a.c > @@ -273,17 +273,17 @@ static const unsigned int kx022a_odrs[] = { > * (range / 2^bits) * g = (range / 2^bits) * 9.80665 m/s^2 > * => KX022A uses 16 bit (HiRes mode - assume the low 8 bits are zeroed > * in low-power mode(?) ) > - * => +/-2G => 4 / 2^16 * 9,80665 * 10^6 (to scale to micro) > - * => +/-2G - 598.550415 > - * +/-4G - 1197.10083 > - * +/-8G - 2394.20166 > - * +/-16G - 4788.40332 > + * => +/-2G => 4 / 2^16 * 9,80665 > + * => +/-2G - 0.000598550415 > + * +/-4G - 0.00119710083 > + * +/-8G - 0.00239420166 > + * +/-16G - 0.00478840332 > */ > static const int kx022a_scale_table[][2] = { > - { 598, 550415 }, > - { 1197, 100830 }, > - { 2394, 201660 }, > - { 4788, 403320 }, > + { 0, 598550 }, > + { 0, 1197101 }, > + { 0, 2394202 }, > + { 0, 4788403 }, > }; > > static int kx022a_read_avail(struct iio_dev *indio_dev, > @@ -302,7 +302,7 @@ static int kx022a_read_avail(struct iio_dev *indio_dev, > *vals = (const int *)kx022a_scale_table; > *length = ARRAY_SIZE(kx022a_scale_table) * > ARRAY_SIZE(kx022a_scale_table[0]); > - *type = IIO_VAL_INT_PLUS_MICRO; > + *type = IIO_VAL_INT_PLUS_NANO; > return IIO_AVAIL_LIST; > default: > return -EINVAL; > @@ -366,6 +366,20 @@ static int kx022a_turn_on_unlock(struct kx022a_data *data) > return ret; > } > > +static int kx022a_write_raw_get_fmt(struct iio_dev *idev, > + struct iio_chan_spec const *chan, > + long mask) > +{ > + switch (mask) { > + case IIO_CHAN_INFO_SCALE: > + return IIO_VAL_INT_PLUS_NANO; > + case IIO_CHAN_INFO_SAMP_FREQ: > + return IIO_VAL_INT_PLUS_MICRO; > + default: > + return -EINVAL; > + } > +} > + > static int kx022a_write_raw(struct iio_dev *idev, > struct iio_chan_spec const *chan, > int val, int val2, long mask) > @@ -510,7 +524,7 @@ static int kx022a_read_raw(struct iio_dev *idev, > > kx022a_reg2scale(regval, val, val2); > > - return IIO_VAL_INT_PLUS_MICRO; > + return IIO_VAL_INT_PLUS_NANO; > } > > return -EINVAL; > @@ -712,6 +726,7 @@ static int kx022a_fifo_flush(struct iio_dev *idev, unsigned int samples) > static const struct iio_info kx022a_info = { > .read_raw = &kx022a_read_raw, > .write_raw = &kx022a_write_raw, > + .write_raw_get_fmt = &kx022a_write_raw_get_fmt, > .read_avail = &kx022a_read_avail, > > .validate_trigger = iio_validate_own_trigger,
On 10/20/23 19:48, Jagath Jog J wrote: > On Fri, Oct 20, 2023 at 5:39 PM Matti Vaittinen > <mazziesaccount@gmail.com> wrote: >> >> On 10/19/23 21:21, Jagath Jog J wrote: >>> Hi Matti, >>> >>> On Thu, Oct 19, 2023 at 6:54 PM Matti Vaittinen >>> <mazziesaccount@gmail.com> wrote: >>>> > >>>> I did only very quick testing on KX022A and iio_generic_buffer. After >>>> the patch the values seemed to be correct order of magnitude. Further >>>> testing is appreciated :) >>> >>> Values are correct with this change, Thank you for fixing. >>> Tested-by: Jagath Jog J <jagathjog1996@gmail.com> >> >> Thanks a ton for testing! May I ask which component did you use (or did >> you just use some 'simulated' regster values?) > > Hi Matti, > > I just simulated with the register values, Should the 'tested-by' tag only be > provided after hardware testing? I am not sure TBH. I didn't have a problem with your tag though, I was merely curious to hear about the IC usage :) Now that you mentioned the tested-by tag usage, I started to wonder it as well. From pure SW/driver point of view the register value simulation is sufficient - but in practice we are not interested in whether the code works "in theory" - but whether the products do really work. This is something which includes handling of potential HW quircks and oddities - which are not always documented or known. If we assume a case where someone is developing new gizmo and hits a bug which is in reality caused by some undocumented HW hiccup - then fixes with "tested-by" tags which are not actually tested on HW having this hiccup but using SW simulation - may be misleading. The above is just some overall pondering - I am not too concerned on your tested-by tag :) Besides, it's cool you did the testing! I appreciate that! However, I wonder if there is some wider consensus whether the tests should be ran using real HW when tested-by tag is given. Jonathan, do you have any educated opinion on this? > I referred to this driver because it's > the most recent accelerometer driver that was merged. Makes sense :) Thanks for replying! Yours, -- Matti
diff --git a/drivers/iio/accel/kionix-kx022a.c b/drivers/iio/accel/kionix-kx022a.c index 4ea3c6718ed4..971fc60efef0 100644 --- a/drivers/iio/accel/kionix-kx022a.c +++ b/drivers/iio/accel/kionix-kx022a.c @@ -273,17 +273,17 @@ static const unsigned int kx022a_odrs[] = { * (range / 2^bits) * g = (range / 2^bits) * 9.80665 m/s^2 * => KX022A uses 16 bit (HiRes mode - assume the low 8 bits are zeroed * in low-power mode(?) ) - * => +/-2G => 4 / 2^16 * 9,80665 * 10^6 (to scale to micro) - * => +/-2G - 598.550415 - * +/-4G - 1197.10083 - * +/-8G - 2394.20166 - * +/-16G - 4788.40332 + * => +/-2G => 4 / 2^16 * 9,80665 + * => +/-2G - 0.000598550415 + * +/-4G - 0.00119710083 + * +/-8G - 0.00239420166 + * +/-16G - 0.00478840332 */ static const int kx022a_scale_table[][2] = { - { 598, 550415 }, - { 1197, 100830 }, - { 2394, 201660 }, - { 4788, 403320 }, + { 0, 598550 }, + { 0, 1197101 }, + { 0, 2394202 }, + { 0, 4788403 }, }; static int kx022a_read_avail(struct iio_dev *indio_dev, @@ -302,7 +302,7 @@ static int kx022a_read_avail(struct iio_dev *indio_dev, *vals = (const int *)kx022a_scale_table; *length = ARRAY_SIZE(kx022a_scale_table) * ARRAY_SIZE(kx022a_scale_table[0]); - *type = IIO_VAL_INT_PLUS_MICRO; + *type = IIO_VAL_INT_PLUS_NANO; return IIO_AVAIL_LIST; default: return -EINVAL; @@ -366,6 +366,20 @@ static int kx022a_turn_on_unlock(struct kx022a_data *data) return ret; } +static int kx022a_write_raw_get_fmt(struct iio_dev *idev, + struct iio_chan_spec const *chan, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_SCALE: + return IIO_VAL_INT_PLUS_NANO; + case IIO_CHAN_INFO_SAMP_FREQ: + return IIO_VAL_INT_PLUS_MICRO; + default: + return -EINVAL; + } +} + static int kx022a_write_raw(struct iio_dev *idev, struct iio_chan_spec const *chan, int val, int val2, long mask) @@ -510,7 +524,7 @@ static int kx022a_read_raw(struct iio_dev *idev, kx022a_reg2scale(regval, val, val2); - return IIO_VAL_INT_PLUS_MICRO; + return IIO_VAL_INT_PLUS_NANO; } return -EINVAL; @@ -712,6 +726,7 @@ static int kx022a_fifo_flush(struct iio_dev *idev, unsigned int samples) static const struct iio_info kx022a_info = { .read_raw = &kx022a_read_raw, .write_raw = &kx022a_write_raw, + .write_raw_get_fmt = &kx022a_write_raw_get_fmt, .read_avail = &kx022a_read_avail, .validate_trigger = iio_validate_own_trigger,
The IIO ABI mandates acceleration values from accelerometer to be emitted in m/s^2. The KX022A was emitting values in micro m/s^2. Fix driver to report the correct scale values. Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> Reported-by: Jagath Jog J <jagathjog1996@gmail.com> Fixes: 7c1d1677b322 ("iio: accel: Support Kionix/ROHM KX022A accelerometer") --- The fix is somewhat crude and just crops the last 3 digits (rounds) of the scale while using IIO_VAL_INT_PLUS_NANO. I played with a thought of using IIO_VAL_FRACTIONAL, which could have modelled the computation G_range * g * scaling / (2^16 * scaling) - where scaling 10000 would have allowed using g value 980665. This would have worked fine for reporting scale and available scales - but would be somewhat tricky when converting the user-supplied scale to register values in write_raw(). Well, the g varies from 9.832 (poles) to 9.780 (equator) according to some website - no proper source check done but this sounds about right - so maybe the loss of accuracy is acceptable. I did only very quick testing on KX022A and iio_generic_buffer. After the patch the values seemed to be correct order of magnitude. Further testing is appreciated :) --- drivers/iio/accel/kionix-kx022a.c | 37 ++++++++++++++++++++++--------- 1 file changed, 26 insertions(+), 11 deletions(-)