From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752805AbaJFOLU (ORCPT ); Mon, 6 Oct 2014 10:11:20 -0400 Received: from mga14.intel.com ([192.55.52.115]:39317 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752662AbaJFOLT (ORCPT ); Mon, 6 Oct 2014 10:11:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="396050796" Message-ID: <5432A474.7000700@intel.com> Date: Mon, 06 Oct 2014 17:17:24 +0300 From: Daniel Baluta User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Jonathan Cameron CC: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, irina.tirdea@intel.com Subject: Re: [RFC PATCH 3/8] iio: core: Introduce new MOTION event References: <1412257439-15683-1-git-send-email-daniel.baluta@intel.com> <1412257439-15683-4-git-send-email-daniel.baluta@intel.com> <542FF252.1020206@kernel.org> In-Reply-To: <542FF252.1020206@kernel.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >> Signed-off-by: Irina Tirdea > 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@vger.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. 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! Daniel. [1] https://source.android.com/devices/sensors/composite_sensors.html