Re: [PATCH v2 1/2] iio: cros_ec: Add sign vector in core for backward compatibility

[Gwendal Grignou <gwendal@chromium.org>]

On Sat, Jun 22, 2019 at 1:54 AM Jonathan Cameron <jic23@kernel.org> wrote:
>
> On Thu, 20 Jun 2019 19:41:05 -0700
> Gwendal Grignou <gwendal@chromium.org> wrote:
>
> > To allow cros_ec iio core library to be used with legacy device, add a
> > vector to rotate sensor data if necessary: legacy devices are not
> > reporting data in HTML5/Android sensor referential.
> >
> > On veyron minnie, check chrome detect tablet mode and rotate
> > screen in tablet mode.
> >
> > Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
> I'm guessing that you have a whole pile of code that isn't using
> the mounting_matrix ABI and hence need the 'fixup' in kernel?
That's correct: cros EC normally presents sensors information in the
proper HTML5 matrix so it does not need to export "mount_matrix"
attribute.
Except for legacy sensors where the EC firmware used a different
matrix, Given we don't want to release a new firmware for these
machines, I indeed fix it up in the kernel.
>
> Otherwise this is fine, but I'd like to wait for Doug to have another
> look if he wants to (and ideally give a reviewed-by)
>
> Anyone else's input also welcome of course.
>
> Jonathan
>
> > ---
> >  drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c | 4 ++++
> >  include/linux/iio/common/cros_ec_sensors_core.h           | 1 +
> >  2 files changed, 5 insertions(+)
> >
> > diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> > index 719a0df5aeeb..e8a4d78659c8 100644
> > --- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> > +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> > @@ -66,6 +66,9 @@ int cros_ec_sensors_core_init(struct platform_device *pdev,
> >               }
> >               state->type = state->resp->info.type;
> >               state->loc = state->resp->info.location;
> > +
> > +             /* Set sign vector, only used for backward compatibility. */
> > +             memset(state->sign, 1, CROS_EC_SENSOR_MAX_AXIS);
> >       }
> >
> >       return 0;
> > @@ -254,6 +257,7 @@ static int cros_ec_sensors_read_data_unsafe(struct iio_dev *indio_dev,
> >               if (ret < 0)
> >                       return ret;
> >
> > +             *data *= st->sign[i];
> >               data++;
> >       }
> >
> > diff --git a/include/linux/iio/common/cros_ec_sensors_core.h b/include/linux/iio/common/cros_ec_sensors_core.h
> > index ce16445411ac..a1c85ad4df91 100644
> > --- a/include/linux/iio/common/cros_ec_sensors_core.h
> > +++ b/include/linux/iio/common/cros_ec_sensors_core.h
> > @@ -71,6 +71,7 @@ struct cros_ec_sensors_core_state {
> >       enum motionsensor_location loc;
> >
> >       s16 calib[CROS_EC_SENSOR_MAX_AXIS];
> > +     s8 sign[CROS_EC_SENSOR_MAX_AXIS];
> >
> >       u8 samples[CROS_EC_SAMPLE_SIZE];
> >
>