Re: Sensors and the input layer (was Re: [RFC] [PATCH V2 1/2] input: CMA3000 Accelerometer driver)

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Mon, Aug 30, 2010 at 12:10:41PM -0500, Felipe Balbi wrote:
> Hi,
> 
> On Mon, 30 Aug 2010 09:28:56 -0700, Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> >> When we tried to push N900's accelerometer driver as an
> >> input device you commented you didn't want sensors such
> >> as accelerometers, magnetometers, proximity, etc on the
> >> input layer because "they are not user input", although
> >> I didn't fully agree with you, we had to modify the drivers
> >> and, I believe, one of them is sitting in staging under
> >> the industrial i/o subsystem.
> >> 
> >> Are you now accepting sensor drivers on the input layer ?
> >> that will make our life a lot easier but we need some
> >> definition to avoid having to re-work drivers when we
> >> want to push them to mainline.
> >> 
> > 
> > I got persuaded that 3-axis accelerometers are most often indended to be
> > used as input devices so I decided I should take these in (adxl134x is
> > there). I still think that sensor devices in general are better suited
> > to IIO subsystem and I hope it will get out of staging soon.
> > 
> > Once it is out of staging we may think about creating a IIO-to-input
> > bridge (copuld be either in kernel or a userspace solution based on
> > uinput) to route sensors that are indeed used as HIDs.
> > 
> > Hope this makes sense.
> 
> It kinda does, but such sensors will be more and more used as
> input devices, specially for gaming on mobile devices.
> 
> For example a proximity sensor might be used as the trigger
> button on a first person shooting game; accelerometers will
> be used to walk through the map and a magnetometer might be
> used to look behind you and a gyroscope to turn around your
> own axis.
> 
> In the end, the user is the one moving the device around and
> generating such events, so why not avoiding yet another
> subsystem if we will have to resort to solutions such as
> iio-to-input bridge, which smells like a hackish solution
> to get input events from sensors anyway.
> 
> I really hope I could convince you that, on mobile at least,
> sensors will be mostly used as HID devices and will give
> app developers new ways for them to allow users to interact
> with their app.
> 
> Take a look at how a gyroscope is used on iphone, for
> instance [1].
> 
> [1] http://www.youtube.com/watch?v=ORcu-c-qnjg
> 

My response to this - are gyroscopes will _only_ be used to turn around
in a game? Are proximity sensor is _only_ usable as a trigger in FPS?
Won't we ever see such chips controlling technological processes?

I do hope that answerrs are no, no and yes.

-- 
Dmitry