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Date: Mon, 13 Oct 2014 11:46:45 +0200 From: Karol Wrona <k.wrona@...sung.com> To: Daniel Baluta <daniel.baluta@...el.com>, Jonathan Cameron <jic23@...nel.org> Cc: linux-iio@...r.kernel.org, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, irina.tirdea@...el.com Subject: Re: [RFC PATCH 3/8] iio: core: Introduce new MOTION event On 10/11/2014 11:47 AM, Daniel Baluta wrote: > On Thu, Oct 9, 2014 at 10:31 PM, Jonathan Cameron <jic23@...nel.org> wrote: >> On 06/10/14 15:17, Daniel Baluta wrote: >>> >>> On 10/04/2014 04:12 PM, Jonathan Cameron wrote: >>>> On 02/10/14 14:43, Daniel Baluta wrote: >>>>> This is to be used by drivers to signal detection of motion. We also >>>>> add some possible values for motion as IIO events modifiers: >>>>> * running >>>>> * jogging >>>>> * walking >>>>> * still >>>>> >>>>> These values are supported by Frescale's MMA9553 sensor: >>>>> >>>>> http://freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf >>>>> >>>>> Signed-off-by: Daniel Baluta <daniel.baluta@...el.com> >>>>> Signed-off-by: Irina Tirdea <irina.tirdea@...el.com> >>>> Hmm.. This is the interesting one. >>>> Not immediately obvious how best to represent this stuff. >>>>> --- >>>>> Documentation/ABI/testing/sysfs-bus-iio | 7 +++++++ >>>>> drivers/iio/industrialio-core.c | 4 ++++ >>>>> drivers/iio/industrialio-event.c | 1 + >>>>> include/linux/iio/types.h | 7 ++++++- >>>>> 4 files changed, 18 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio >>>>> b/Documentation/ABI/testing/sysfs-bus-iio >>>>> index d760b02..070346d 100644 >>>>> --- a/Documentation/ABI/testing/sysfs-bus-iio >>>>> +++ b/Documentation/ABI/testing/sysfs-bus-iio >>>>> @@ -808,6 +808,13 @@ Description: >>>>> number or direction is not specified, applies to all channels of >>>>> this type. >>>>> >>>>> +What: /sys/.../events/in_activity_motion_either_en >>>>> +KernelVersion: 3.17 >>>>> +Contact: linux-iio@...r.kernel.org >>>>> +Description: >>>>> + Enables or disables motion detection. Each time motion is detected an >>>>> + event of this type will be generated. >>>>> + >>>> The either bit seems a bit random but I can see there is no particularly obvious >>>> alternative. >>> I wonder if introducing a new IIO_EV_DIR_NONE event direction type would make >>> sense. In this case the sysfs attribute will drop event direction text from its >>> name (e.g /sys/.../events/in_activity_motion_en) >>> >>>> We really need a clean way of representing a multilevel 'state change' like this. >>>> >>>> Looking at the event code, I almost wonder if we would be better using the >>>> direction element for running, walking etc rather than a modifier. >>> When pushing events code to userspace the modifier seemed to be the only option. >>> >>>> Having said that we will probably also get devices where this is polled rather >>>> than >>>> event. 'What activity is currently going on?' >>> Adding IIO_EV_INFO_VALUE bit, would create an attribute >>> /sys/.../events/in_activity_motion_either_value that could expose the current >>> activity going on. >>> >>>> If we take that view modifiers make sense as it becomes >>>> 'Is the user running?' Perhaps even offering a confidence interval, e.g units as >>>> percentage >>>> in_activity_running_input 0..100 >>>> in_activity_walking_input 0..100 >>>> etc >>>> >>>> Then our event becomes a state change event (yup we'll need to add that) >>>> >>>> /events/in_activity_walking_rising_en will then cause events when the percentage >>>> confidence on a state rises above the provided threshold or goes above it >>>> (default of 50% perhaps on devices which only report one state). >>>> >>>> /events/in_activity_walking_falling_en will do the leaving case. >>> This is a very nice idea and it will also offer more flexibility. I am not sure >>> about the use case of confidence interval but using 0 and 100 will do the trick >>> for us. >> Sure, feel free to propose something else. We could define a confidence interval >> that counts as 'we think it is this'. Basically just use values of 0 or 100 when >> there is no explicit indication of the confidence available. Not sure what >> you do get ;) >>> We will use this interface for implementation of significant motion in Android's >>> HAL. [1] >>> >>> I will experiment more with how IIO attributes work and I will send a v2 >>> using direction instead of modifier for activity type (running, walking etc). >>> >>> >>>> Note these are just some quick initial thoughts on alternative methods. >>>> I'll want to think on this more and get responses from more interested >>>> parties! >>> Thanks a lot for your time! >> You are welcome. Funnily enough I rather enjoy trying to think of ways to >> handle new 'weird' hardware in a consistent fashion :) > We have already sent a second proposal :). > > http://marc.info/?l=linux-iio&m=141285801717857&w=2 > > We are also hoping to get more opinions from other parties. > CC'ing Karol from Samsung :). > > Daniel. > Thanks for the info. In my case I have to figure out what is really needed between hw and driver first. The existing android driver has given a data blob to user space as concerns new sensor classes. Please, give a few days. Karol -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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