On 10/19/23 21:21, Jagath Jog J wrote:
Hi Matti, On Thu, Oct 19, 2023 at 6:54 PM Matti Vaittinen <mazziesaccount@xxxxxxxxx> 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@xxxxxxxxx> Reported-by: Jagath Jog J <jagathjog1996@xxxxxxxxx> 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@xxxxxxxxx>
Thanks a ton for testing! May I ask which component did you use (or did you just use some 'simulated' regster values?)
Yours, -- Matti -- Matti Vaittinen Linux kernel developer at ROHM Semiconductors Oulu Finland ~~ When things go utterly wrong vim users can always type :help! ~~
