From: Daniel Baluta <daniel.baluta@intel.com>
To: Jonathan Cameron <jic23@kernel.org>
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
Date: Mon, 06 Oct 2014 17:17:24 +0300 [thread overview]
Message-ID: <5432A474.7000700@intel.com> (raw)
In-Reply-To: <542FF252.1020206@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 <daniel.baluta@intel.com>
>> Signed-off-by: Irina Tirdea <irina.tirdea@intel.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@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
next prev parent reply other threads:[~2014-10-06 14:11 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-02 13:43 [RFC PATCH] iio: Introduce activity channel Daniel Baluta
2014-10-02 13:43 ` [RFC PATCH 1/8] iio: dummy: Introduce virtual registers for dummy device Daniel Baluta
2014-10-04 12:48 ` Jonathan Cameron
2014-10-06 11:17 ` Daniel Baluta
2014-10-09 19:28 ` Jonathan Cameron
2014-10-19 20:30 ` Hartmut Knaack
2014-10-19 20:39 ` Daniel Baluta
2014-10-02 13:43 ` [RFC PATCH 2/8] iio: core: Introduce IIO_ACTIVITY channel Daniel Baluta
2014-10-04 13:00 ` Jonathan Cameron
2014-10-02 13:43 ` [RFC PATCH 3/8] iio: core: Introduce new MOTION event Daniel Baluta
2014-10-04 13:12 ` Jonathan Cameron
2014-10-06 14:17 ` Daniel Baluta [this message]
2014-10-09 19:31 ` Jonathan Cameron
2014-10-11 9:47 ` Daniel Baluta
2014-10-13 9:46 ` Karol Wrona
2014-10-07 10:48 ` Daniel Baluta
2014-10-09 19:37 ` Jonathan Cameron
2014-10-02 13:43 ` [RFC PATCH 4/8] iio: core: Introduce pedometer STEP counter modifier Daniel Baluta
2014-10-04 12:53 ` Jonathan Cameron
2014-10-06 13:50 ` Tirdea, Irina
2014-10-06 16:31 ` Jonathan Cameron
2014-10-07 13:54 ` Tirdea, Irina
2014-10-02 13:43 ` [RFC PATCH 5/8] iio: core: Introduce ENABLE channel info mask Daniel Baluta
2014-10-02 13:43 ` [RFC PATCH 6/8] iio: core: Introduce new STEP_DETECT event Daniel Baluta
2014-10-04 12:56 ` Jonathan Cameron
2014-10-02 13:43 ` [RFC PATCH 7/8] iio: dummy: Demonstrate the usage of activity channel Daniel Baluta
2014-10-02 13:43 ` [RFC PATCH 8/8] iio: event_monitor: Add support for " Daniel Baluta
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