Thread (42 messages) 42 messages, 12 authors, 2010-09-24

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

From: Pavel Machek <hidden>
Date: 2010-09-24 13:06:25
Also in: linux-omap, lkml

Hi!
quoted
So a voltmeter really makes no sense. It's not a set of keys and it
doesn't give X/Y/Z style readings. Nor does a camera. But a lot of things
do fit this to varying degrees.

I'm actually more dubious than Linus about ALS - because ALS tends not
produce 'events' but to be sampled, and there are significant power
implications to unnecessary polling.
That's very similar to analog joysticks, no?
quoted
And the more it's used the less special
code is needed in user or kernel space for PDAs and phones - instead they
just work.
OK, so let's say we start moving some of the devices into input. Which
ones we consider suitable for input? I guess some 3-digit
accelerometers, what else? Also, what new event types would we need?
Let's take GPS - I do not think that ABS_X and ABS_Y are the best events
to be used for such devices: I am trying to allow applications being
I'd not put GPS into input; yes, they do present 'x,y,z' in meters,
but that's not what users want. 'lat,lon,alt' is better, but it is
actually 'lat,lon,herror,alt,verror,time' and a lot of other
metadata...

Also, we already have driver for GPSes, its called gpsd. I'd leave
GPSes out of input.
Also, GPS, liek ALS, would probably be polling, no?
Normally, GPS just sends you position info once a second.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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