Re: [RFC PATCH v1 3/3] iio:imu:mpu6050: enhance mounting matrix support

[Gregor Boirie <gregor.boirie-ITF29qwbsa/QT0dZR+AlfA@public.gmane.org>]

On Mon, Apr 11, 2016 at 02:12:12PM -0500, Rob Herring wrote:
> On Fri, Apr 08, 2016 at 04:12:05PM +0200, Gregor Boirie wrote:
> > Add a new rotation matrix sysfs attribute compliant with IIO core
> > mounting matrix API.
> > Matrix is retrieved from "in_anglvel_mount_matrix" and
> > "in_accel_mount_matrix" sysfs attributes. It is declared into mpu6050 DTS
> > entry as a "mount-matrix" property.
> 
> We have a common DT property, but can't have common sysfs interface?
Agreed. Original driver was structured that way. In fact, a single matrix is
enought for this sensor: AFAIK, reference frames are the same for gyro and
accelero.
I suppose that having a DTS and sysfs attribute per type of sample /
"sub-device" ensure better userspace API consistency across drivers.
Jonathan ?

> 
> BTW, sysfs interfaces also have to be documented.
Ok

> 
> > 
> > Old interface is kept for backward userspace compatibility and may be
> > retrieved from legacy platform_data mechanism only.
> > 
> > Signed-off-by: Gregor Boirie <gregor.boirie-ITF29qwbsa/QT0dZR+AlfA@public.gmane.org>
> > ---
> >  .../devicetree/bindings/iio/imu/inv_mpu6050.txt    | 13 +++++
> >  drivers/iio/imu/inv_mpu6050/inv_mpu_core.c         | 56 ++++++++++++++++++++--
> >  drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h          |  4 +-
> >  include/linux/platform_data/invensense_mpu6050.h   |  5 +-
> >  4 files changed, 72 insertions(+), 6 deletions(-)