Re: [RFC PATCH v2 2/7] iio: core: Introduce IIO_ACTIVITY channel and TRANSITION event

[Jonathan Cameron <jic23@kernel.org>]

On 09/10/14 13:39, Daniel Baluta wrote:
> This channel will be used for exposing information about
> activity composite sensors. Activities supported so far:
> 	* running
> 	* jogging
> 	* walking
> 	* still
>
> TRANSITION event is used to signal a change in the activity
> state.
>
> We associate a confidence interval for each activity expressed
> as a percentage from 0 to 100.
>   * 0, means the sensor IS NOT reporting that activity.
>   * 100, means the sensor IS reporting that activity.
>
> Users of this interface have two possibile means to gather
> information about the ongoing activities.
>
> 1. Event based, via event file descriptor
>   * sensor may report an event when ENTERING an activity or LEAVING
>     an activity based on a threshold value.
>   * drivers will wake up applications waiting data on the event fd
>
> 2. Polling, by reading the sysfs associated attribute files:
>   * /sys/bus/iio/devices/iio:device0/in_activity_running_input
> expressed as percentage confidence value from 0 to 100.
>
> This will offer an interface for Android significant motion
> composite sensor defined here:
> http://source.android.com/devices/sensors/composite_sensors.html
>
> Activities listed above are supported by Freescale's MMA9553 sensor:
> http://freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf
>
> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>

I don't see why we need the transition event.  A transition is simply
a threshold rising (or falling) event much like any other - just
on a confidence interval.

So it would be possible to be interested in the confidence that are not
sitting rising above 20% on the basis that some other sensor needs enabling.

See below for resulting suggestions.

Other than that little point this looks good to me.
> ---
>  Documentation/ABI/testing/sysfs-bus-iio | 44 +++++++++++++++++++++++++++++++++
>  drivers/iio/industrialio-core.c         |  5 ++++
>  drivers/iio/industrialio-event.c        |  1 +
>  include/linux/iio/types.h               |  8 +++++-
>  4 files changed, 57 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> index d760b02..12d0385 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -776,6 +776,40 @@ Description:
>  		met before an event is generated. If direction is not
>  		specified then this period applies to both directions.
>
> +What:		/sys/.../events/in_activity_still_transition_rising_en
What:   /sys/.../events/in_activity_threshold_rising_en
> +What:		/sys/.../events/in_activity_still_transition_falling_en
What:   /sys/.../events/in_activity_threshold_falling_en
etc
> +What:		/sys/.../events/in_activity_walking_transition_rising_en
> +What:		/sys/.../events/in_activity_walking_transition_falling_en
> +What:		/sys/.../events/in_activity_jogging_transition_rising_en
> +What:		/sys/.../events/in_activity_jogging_transition_falling_en
> +What:		/sys/.../events/in_activity_running_transition_rising_en
> +What:		/sys/.../events/in_activity_running_transition_falling_en
> +KernelVersion:	3.19
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Enables or disables activitity events. Depending on direction
> +		an event is generated when sensor ENTERS or LEAVES a given state.
> +
> +What:		/sys/.../events/in_activity_still_transition_rising_value
What: /sys/.../events/in_activity_still_threshold_rising_value etc
> +What:		/sys/.../events/in_activity_still_transition_falling_value
> +What:		/sys/.../events/in_activity_walking_transition_rising_value
> +What:		/sys/.../events/in_activity_walking_transition_falling_value
> +What:		/sys/.../events/in_activity_jogging_transition_rising_value
> +What:		/sys/.../events/in_activity_jogging_transition_falling_value
> +What:		/sys/.../events/in_activity_running_transition_rising_value
> +What:		/sys/.../events/in_activity_running_transition_falling_value
> +KernelVersion:	3.19
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Confidence value (in units as percentage) to be used
> +		for deciding when an event should be generated. E.g for
> +		running: If the confidence value reported by the sensor
> +		is greater then in_activity_running_transition_rising_value
> +		then the sensor ENTERS running state. Conversely, if the
> +		confidence value reported by the sensor is lower than
> +		in_activity_running_transition_rising_value then the sensor
> +		is LEAVING running state.
> +
>  What:		/sys/.../iio:deviceX/events/in_accel_mag_en
>  What:		/sys/.../iio:deviceX/events/in_accel_mag_rising_en
>  What:		/sys/.../iio:deviceX/events/in_accel_mag_falling_en
> @@ -942,6 +976,16 @@ Description:
>  		and the relevant _type attributes to establish the data storage
>  		format.
>
> +What:		/sys/.../iio:deviceX/in_activity_still_input
> +What:		/sys/.../iio:deviceX/in_activity_walking_input
> +What:		/sys/.../iio:deviceX/in_activity_jogging_input
> +What:		/sys/.../iio:deviceX/in_activity_running_input
> +KernelVersion:	3.19
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		This attribute is used to read the confidence for an activity
> +		expressed in units as percentage.
> +
>  What:		/sys/.../iio:deviceX/in_anglvel_z_quadrature_correction_raw
>  KernelVersion:	2.6.38
>  Contact:	linux-iio@vger.kernel.org
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index af3e76d..e453ef9 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -70,6 +70,7 @@ static const char * const iio_chan_type_name_spec[] = {
>  	[IIO_CCT] = "cct",
>  	[IIO_PRESSURE] = "pressure",
>  	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
> +	[IIO_ACTIVITY] = "activity",
>  };
>
>  static const char * const iio_modifier_names[] = {
> @@ -91,6 +92,10 @@ static const char * const iio_modifier_names[] = {
>  	[IIO_MOD_NORTH_TRUE] = "from_north_true",
>  	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
>  	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
> +	[IIO_MOD_RUNNING] = "running",
> +	[IIO_MOD_JOGGING] = "jogging",
> +	[IIO_MOD_WALKING] = "walking",
> +	[IIO_MOD_STILL] = "still",
>  };
>
>  /* relies on pairs of these shared then separate */
> diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
> index 0c1e37e..afcf154 100644
> --- a/drivers/iio/industrialio-event.c
> +++ b/drivers/iio/industrialio-event.c
> @@ -197,6 +197,7 @@ static const char * const iio_ev_type_text[] = {
>  	[IIO_EV_TYPE_ROC] = "roc",
>  	[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
>  	[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
> +	[IIO_EV_TYPE_TRANSITION] = "transition",
>  };
>
>  static const char * const iio_ev_dir_text[] = {
> diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
> index 4a2af8a..a08ee6c 100644
> --- a/include/linux/iio/types.h
> +++ b/include/linux/iio/types.h
> @@ -30,6 +30,7 @@ enum iio_chan_type {
>  	IIO_CCT,
>  	IIO_PRESSURE,
>  	IIO_HUMIDITYRELATIVE,
> +	IIO_ACTIVITY,
>  };
>
>  enum iio_modifier {
> @@ -59,7 +60,11 @@ enum iio_modifier {
>  	IIO_MOD_NORTH_MAGN,
>  	IIO_MOD_NORTH_TRUE,
>  	IIO_MOD_NORTH_MAGN_TILT_COMP,
> -	IIO_MOD_NORTH_TRUE_TILT_COMP
> +	IIO_MOD_NORTH_TRUE_TILT_COMP,
> +	IIO_MOD_RUNNING,
> +	IIO_MOD_JOGGING,
> +	IIO_MOD_WALKING,
> +	IIO_MOD_STILL,
>  };
>
>  enum iio_event_type {
> @@ -68,6 +73,7 @@ enum iio_event_type {
>  	IIO_EV_TYPE_ROC,
>  	IIO_EV_TYPE_THRESH_ADAPTIVE,
>  	IIO_EV_TYPE_MAG_ADAPTIVE,
> +	IIO_EV_TYPE_TRANSITION,
>  };
>
>  enum iio_event_info {
>