RE: [RFC PATCH 4/8] iio: core: Introduce pedometer STEP counter modifier

[Jonathan Cameron]

On October 6, 2014 2:50:13 PM GMT+01:00, "Tirdea, Irina" <irina.tirdea@xxxxxxxxx> wrote:
>> From: Jonathan Cameron [mailto:jic23@xxxxxxxxxx]
>> On 02/10/14 14:43, Daniel Baluta wrote:
>> > From: Irina Tirdea <irina.tirdea@xxxxxxxxx>
>> >
>> > One of the functionalities of a pedometer is a step counter.
>> > The step counter needs to be enabled and then it will count the
>steps
>> > in its hardware register. Whenever the applications need to check
>> > the step count, they will read the step counter register.
>> >
>> > To support this functionality we need a steps attribute that
>> > will export the number of steps.
>> >
>> I'm not keen on multiplexing different types of data onto a single
>activity type.
>> Steps is well enough defined on it's own to have it's own channel
>type.
>> 
>> in_steps_input would be fine by me.  I suppose steps might mean
>something else
>> though...
>> 
>
>Hi Jonathan,
>
>Thanks for the review.
>
>Moving the pedometer part to a new type sounds good to me.
>However, I would prefer to add a new type called pedometer and keep
>steps as a modifier, generating names like in_ped_steps_input for the
>attribute and in_ped_steps_instance_en for the event.
>The reason for this is that for supporting Freescale's MMA9553L we will
>need additional attributes (distance, speed, calories, height, weight)
>that we can add as modifiers to this pedometer type. To keep things
>simple, I did not add these additional attributes to the RFC series,
>but I could do that if you think it would be useful. For this device,
>the motion events (walking, running, jogging, still) also depend on the
>height attribute being set, but we intend to deal with this dependency
>in the driver (using the pedometer's height attribute).
>
>What do you think?
I think I would rather each of these was included as a type rather than a modifier.
There are lots of other ways to measure speed for starters and often user space
won't care where it comes from...

In_speed_raw etc...

Trick where possible is to think about what is measured rather than how. Tends to give
 more consistent interfaces.
>
>Thanks,
>Irina
>
>
>> > --- a/drivers/iio/industrialio-core.c
>> > +++ b/drivers/iio/industrialio-core.c
>> > @@ -96,6 +96,7 @@ static const char * const iio_modifier_names[] =
>{
>> >  	[IIO_MOD_JOGGING] = "jogging",
>> >  	[IIO_MOD_WALKING] = "walking",
>> >  	[IIO_MOD_STILL] = "still",
>> > +	[IIO_MOD_PED_STEPS] = "steps",
>> >  };
>> >
>> >  /* relies on pairs of these shared then separate */
>> > diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
>> > index 003638d..ae51780 100644
>> > --- a/include/linux/iio/types.h
>> > +++ b/include/linux/iio/types.h
>> > @@ -65,6 +65,7 @@ enum iio_modifier {
>> >  	IIO_MOD_JOGGING,
>> >  	IIO_MOD_WALKING,
>> >  	IIO_MOD_STILL,
>> > +	IIO_MOD_PED_STEPS,
>> >  };
>> >
>> >  enum iio_event_type {
>> >

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