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

From: Dmitry Torokhov
Date: Mon Aug 30 2010 - 16:50:33 EST


On Mon, Aug 30, 2010 at 01:52:18PM -0500, Felipe Balbi wrote:
> Hi,
>
> On Mon, 30 Aug 2010 10:21:44 -0700, Dmitry Torokhov
> <dmitry.torokhov@xxxxxxxxx> wrote:
> > 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?
>
> similarly, will accelerometers always be used as input devices ?
> of course not, they have been used e.g. to spin down hard disks
> on laptops when they are shaken too hard. Still they have quite a
> fair bit of usage as input devices; you've seen it yourself,
> right ?
>

This is a fair point. I was told that the main purpose for the chips in
question (specifically 3-axis accelerometers) is to be used as HIDs.
But it could be that I should not have merged adxl and instead waited
for IIO.

> in the end of the day, when you put those on mobile devices
> like e.g. cellphones, app developers will be really keen on
> creating new ways for interacting with apps (be it a game
> or not) using those devices, so I will agree with Jonathan
> that, maybe, having two separate drivers for different
> purposes would make sense, although that might cause a bit
> of trouble if user ends up enabling the wrong driver when
> building custom kernel for his device.

No, I do not believe that maintaining 2 separate devices for the same
hardware with the only difference is how data is presented to userspace
is a viable option.

>
> My hope is that we can make use of a well known and uniform
> API for all input devices in a device, be it a keypad,
> touchscreen, accelerometer, magnetometer, gyro, or whatever.
>

If only we could agree what input devices are...

--
Dmitry
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