Re: [PATCH v4 4/7] iio: core: Introduce STEPS channel, ENABLE mask and INSTANCE event

[Jonathan Cameron <jic23@kernel.org>]

On 10/11/14 12:45, Daniel Baluta wrote:
> From: Irina Tirdea <irina.tirdea@intel.com>
> 
> These changes are needed to support the functionality of a pedometer.
> A pedometer has two basic functionalities: step counter and step detector.
> 
> The step counter needs to be enabled and then it will count the steps
> in its hardware register. Whenever the application needs to check
> the step count, it will read the step counter register. To support the
> step counter a new channel type STEPS is added. Since the pedometer needs
> to be enabled first so that the hardware can count and store the steps,
> we need a specific ENABLE channel info mask.
> 
> The step detector will generate an interrupt each time a step is detected.
> To support this functionality we add a new event type INSTANCE.
> 
> For more information on the Android requirements for step counter and step
> detector see:
> http://source.android.com/devices/sensors/composite_sensors.html#counter
> and http://source.android.com/devices/sensors/composite_sensors.html#detector.
> 
> A device that has the pedometer functionality this interface needs to
> support is Freescale's MMA9553L:
> http://www.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>
Still a little dubious about the specific enable interface - perhaps
we might think about renaming it 'start' or something like that and making
the semantics that it always zeros the counter.  Then I guess we'd also
need stop to turn it off and it all gets uggly.

Lets go with enable for now and perhaps revisit when a real driver comes
along and we can see how it is being used in anger.

Applied to the togreg branch of iio.git - initially pushed out as testing.

Thanks

Jonathan
> ---
>  Documentation/ABI/testing/sysfs-bus-iio | 22 ++++++++++++++++++++++
>  drivers/iio/industrialio-core.c         |  2 ++
>  drivers/iio/industrialio-event.c        |  1 +
>  include/linux/iio/iio.h                 |  1 +
>  include/linux/iio/types.h               |  2 ++
>  5 files changed, 28 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> index 7bf49ad..c60b0a1 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -856,6 +856,13 @@ Description:
>  		number or direction is not specified, applies to all channels of
>  		this type.
>  
> +What:		/sys/.../events/in_steps_instance_en
> +KernelVersion:	3.19
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Enables or disables step detection. Each time the user takes a step an
> +		event of this type will be generated.
> +
>  What:		/sys/bus/iio/devices/iio:deviceX/trigger/current_trigger
>  KernelVersion:	2.6.35
>  Contact:	linux-iio@vger.kernel.org
> @@ -1095,3 +1102,18 @@ Description:
>  		after application of scale and offset. If no offset or scale is
>  		present, output should be considered as processed with the
>  		unit in milliamps.
> +
> +What:		/sys/.../iio:deviceX/in_steps_en
> +KernelVersion:	3.19
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Activates the step counter. After activation, the number of steps
> +		taken by the user will be counted in hardware and exported through
> +		in_steps_input.
> +
> +What:		/sys/.../iio:deviceX/in_steps_input
> +KernelVersion:	3.19
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		This attribute is used to read the number of steps taken by the user
> +		since the last reboot while activated.
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index e453ef9..1e060f3 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -71,6 +71,7 @@ static const char * const iio_chan_type_name_spec[] = {
>  	[IIO_PRESSURE] = "pressure",
>  	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
>  	[IIO_ACTIVITY] = "activity",
> +	[IIO_STEPS] = "steps",
>  };
>  
>  static const char * const iio_modifier_names[] = {
> @@ -118,6 +119,7 @@ static const char * const iio_chan_info_postfix[] = {
>  	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
>  	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
>  	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
> +	[IIO_CHAN_INFO_ENABLE] = "en",
>  };
>  
>  /**
> diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
> index 1290290..3f5cee0 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_INSTANCE] = "instance",
>  };
>  
>  static const char * const iio_ev_dir_text[] = {
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 3642ce7..f45a400 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -38,6 +38,7 @@ enum iio_chan_info_enum {
>  	IIO_CHAN_INFO_HARDWAREGAIN,
>  	IIO_CHAN_INFO_HYSTERESIS,
>  	IIO_CHAN_INFO_INT_TIME,
> +	IIO_CHAN_INFO_ENABLE,
>  };
>  
>  enum iio_shared_by {
> diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
> index 52cb532..904dcbb 100644
> --- a/include/linux/iio/types.h
> +++ b/include/linux/iio/types.h
> @@ -31,6 +31,7 @@ enum iio_chan_type {
>  	IIO_PRESSURE,
>  	IIO_HUMIDITYRELATIVE,
>  	IIO_ACTIVITY,
> +	IIO_STEPS,
>  };
>  
>  enum iio_modifier {
> @@ -73,6 +74,7 @@ enum iio_event_type {
>  	IIO_EV_TYPE_ROC,
>  	IIO_EV_TYPE_THRESH_ADAPTIVE,
>  	IIO_EV_TYPE_MAG_ADAPTIVE,
> +	IIO_EV_TYPE_INSTANCE,
>  };
>  
>  enum iio_event_info {
>