The pedometer needs to filter out false steps that might be generated by tapping the foot, sitting, etc. To do that it computes the number of steps that occur in a given time and decides the user is moving only if this value is over a threshold. E.g.: the user starts moving only if he takes 4 steps in 3 seconds. This filter is applied only when the user starts moving.
A device that has such pedometer functionality is Freescale's MMA9553L: http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf. To export this feature, this patch introduces IIO_CHAN_INFO_FILTER_OUTLIERS_THRESH and IIO_CHAN_INFO_FILTER_OUTLIERS_PERIOD. For the pedometer, in_steps_filter_outlier_thresh will specify the number of steps that need to occur in in_steps_filter_outlier_period seconds so that the pedometer decides the user is moving. Signed-off-by: Irina Tirdea <[email protected]> --- Documentation/ABI/testing/sysfs-bus-iio | 21 +++++++++++++++++++++ drivers/iio/industrialio-core.c | 2 ++ include/linux/iio/iio.h | 2 ++ 3 files changed, 25 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio index c03a140..e009f49 100644 --- a/Documentation/ABI/testing/sysfs-bus-iio +++ b/Documentation/ABI/testing/sysfs-bus-iio @@ -1193,3 +1193,24 @@ Description: This attribute is used to read the current speed value of the user (which is the norm or magnitude of the velocity vector). Units after application of scale are m/s. + +What: /sys/.../iio:deviceX/in_steps_filter_outliers_period +KernelVersion: 3.20 +Contact: [email protected] +Description: + Specifies the number of seconds in which we compute the + values so we can decide if they are outlier values and + need to be filter out. These computed values are then + compared with in_steps_filter_outliers_thresh. E.g. for steps: + specifies number of seconds in which we compute the steps + that occur in order to decide if the consumer is making steps. + +What: /sys/.../iio:deviceX/in_steps_filter_outliers_thresh +KernelVersion: 3.20 +Contact: [email protected] +Description: + Specifies a threshold for filtering outlier values: if value + measured in in_steps_filter_outliers_period seconds is below + threshold, we filter it out. E.g. for steps: specifies number + of steps that must occur within in_steps_filter_outliers_period + for the pedometer to decide the consumer is making steps. diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 4ee6fdf..81678b3 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -126,6 +126,8 @@ static const char * const iio_chan_info_postfix[] = { [IIO_CHAN_INFO_ENABLE] = "en", [IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight", [IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight", + [IIO_CHAN_INFO_FILTER_OUTLIERS_THRESH] = "filter_outliers_thresh", + [IIO_CHAN_INFO_FILTER_OUTLIERS_PERIOD] = "filter_outliers_period", }; /** diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h index 752a929..b6b12ac 100644 --- a/include/linux/iio/iio.h +++ b/include/linux/iio/iio.h @@ -41,6 +41,8 @@ enum iio_chan_info_enum { IIO_CHAN_INFO_ENABLE, IIO_CHAN_INFO_CALIBHEIGHT, IIO_CHAN_INFO_CALIBWEIGHT, + IIO_CHAN_INFO_FILTER_OUTLIERS_THRESH, + IIO_CHAN_INFO_FILTER_OUTLIERS_PERIOD, }; enum iio_shared_by { -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
