> > Some i2c busses (e.g.: Synopsys DesignWare I2C adapter) need to
> > enable/disable the bus at each i2c transfer and must wait for
> > the enable/disable to happen before sending the data.
> >
> > When reading data in the trigger handler, the bmc150 accel driver does
should refer to bmg160
> > one bus transfer for each axis. This has an impact on the frequency
> > of the accelerometer at high sample rates due to additional delays
> > introduced by the bus at each transfer.
> >
> > Reading all axis values in one bus transfer reduces the delays
> > introduced by the bus.
> >
> > Signed-off-by: Irina Tirdea <irina.tir...@intel.com>
> I forgot to highlight on the earlier driver that there is also 'technically'
> a bit of an ABI change here because we are now exporting as LE rather than CPU
> order. However, I 'hope' anyone actually accessing the buffered data is
> either
> doing it through a nice library or hasn't hacked the endian unwinding out of
> the generic_buffer example!
the patch takes away the possibility to do buffered reads on individual
channels (not sure if this is useful per se)
this optimizes for the common case, ok;
wondering if adding
.endianness = IIO_LE
is actually an unrelated fix
> Again, fingers crossed this doesn't break anything significant.
>
> Applied,
>
> Thanks,
>
> Jonathan
> > ---
> > drivers/iio/gyro/bmg160_core.c | 17 ++++++-----------
> > 1 file changed, 6 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/iio/gyro/bmg160_core.c b/drivers/iio/gyro/bmg160_core.c
> > index 8d6e5b1..43570b8 100644
> > --- a/drivers/iio/gyro/bmg160_core.c
> > +++ b/drivers/iio/gyro/bmg160_core.c
> > @@ -734,6 +734,7 @@ static const struct iio_event_spec bmg160_event = {
> > .sign = 's', \
> > .realbits = 16, \
> > .storagebits = 16, \
> > + .endianness = IIO_LE, \
> > }, \
> > .event_spec = &bmg160_event, \
> > .num_event_specs = 1 \
> > @@ -773,20 +774,14 @@ static irqreturn_t bmg160_trigger_handler(int irq,
> > void *p)
> > struct iio_poll_func *pf = p;
> > struct iio_dev *indio_dev = pf->indio_dev;
> > struct bmg160_data *data = iio_priv(indio_dev);
> > - int bit, ret, i = 0;
> > - unsigned int val;
> > + int ret;
> >
> > mutex_lock(&data->mutex);
> > - for (bit = 0; bit < AXIS_MAX; bit++) {
> > - ret = regmap_bulk_read(data->regmap, BMG160_AXIS_TO_REG(bit),
> > - &val, 2);
> > - if (ret < 0) {
> > - mutex_unlock(&data->mutex);
> > - goto err;
> > - }
> > - data->buffer[i++] = ret;
> > - }
> > + ret = regmap_bulk_read(data->regmap, BMG160_REG_XOUT_L,
> > + data->buffer, AXIS_MAX * 2);
> > mutex_unlock(&data->mutex);
> > + if (ret < 0)
> > + goto err;
> >
> > iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
> > pf->timestamp);
> >
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
