On Wed, 2015-02-04 at 17:27 +0000, Jonathan Cameron wrote: > On 30/01/15 04:03, Viorel Suman wrote: > > Hi, > > > > You might need more space in "values" buffer, for more details please check the > > "iio_push_to_buffers_with_timestamp" description and implementation. > Whilst that function is a little 'odd', this patch doesn't change the use > of buffer (simply how it if filled). The buffer is 16bytes long > (8 x s16) so should be fine (4 x 16 bit and 1 x 64 bit). > > More problematically, we have using a new smbus capability here > (to read it one transaction). It's one you can check for, so I'm guessing > we aren't guaranteed it is present. > I2C_FUNC_SMBUS_READ_I2C_BLOCK Good catch. We should add if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK) in probe and use this otherwise revert to old method. Thanks, Srinivas > > Jonathan > > > > Regards, > > Viorel > > > > > > On Thu, Jan 29, 2015 at 3:15 PM, Irina Tirdea <irina.tirdea@xxxxxxxxx <mailto:irina.tirdea@xxxxxxxxx>> wrote: > > > > 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 bmg160 driver does > > one i2c transfer for each axis. This has an impact on the frequency > > of the gyroscope at high sample rates due to additional delays > > introduced by the i2c bus at each transfer. > > > > Reading all axis values in one i2c transfer reduces the delays > > introduced by the i2c bus. > > > > Signed-off-by: Irina Tirdea <irina.tirdea@xxxxxxxxx <mailto:irina.tirdea@xxxxxxxxx>> > > Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx <mailto:srinivas.pandruvada@xxxxxxxxxxxxxxx>> > > --- > > drivers/iio/gyro/bmg160.c | 20 +++++++++++--------- > > 1 file changed, 11 insertions(+), 9 deletions(-) > > > > diff --git a/drivers/iio/gyro/bmg160.c b/drivers/iio/gyro/bmg160.c > > index 60451b3..814eb20 100644 > > --- a/drivers/iio/gyro/bmg160.c > > +++ b/drivers/iio/gyro/bmg160.c > > @@ -115,6 +115,7 @@ enum bmg160_axis { > > AXIS_X, > > AXIS_Y, > > AXIS_Z, > > + AXIS_MAX, > > }; > > > > static const struct { > > @@ -820,20 +821,21 @@ static irqreturn_t bmg160_trigger_handler(int irq, void *p) > > struct iio_dev *indio_dev = pf->indio_dev; > > struct bmg160_data *data = iio_priv(indio_dev); > > int bit, ret, i = 0; > > + s16 values[AXIS_MAX]; > > > > mutex_lock(&data->mutex); > > - for_each_set_bit(bit, indio_dev->buffer->scan_mask, > > - indio_dev->masklength) { > > - ret = i2c_smbus_read_word_data(data->client, > > - BMG160_AXIS_TO_REG(bit)); > > - if (ret < 0) { > > - mutex_unlock(&data->mutex); > > - goto err; > > - } > > - data->buffer[i++] = ret; > > + ret = i2c_smbus_read_i2c_block_data(data->client, BMG160_REG_XOUT_L, > > + sizeof(values), (u8 *) values); > > + if (ret < 0) { > > + mutex_unlock(&data->mutex); > > + goto err; > > } > > mutex_unlock(&data->mutex); > > > > + for_each_set_bit(bit, indio_dev->buffer->scan_mask, > > + indio_dev->masklength) > > + data->buffer[i++] = values[bit]; > > + > > iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, > > data->timestamp); > > err: > > -- > > 1.9.1 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx <mailto:majordomo@xxxxxxxxxxxxxxx> > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > ��.n��������+%������w��{.n�����{��(��)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
