Messages in this thread | | | Date | Tue, 26 Jan 2010 11:33:49 +0100 | From | Manuel Stahl <> | Subject | Re: [RFC] Staging:IIO: New ABI |
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Am 26.01.2010 11:25, schrieb Hennerich, Michael: >> From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com] >> On Tue, Jan 26, 2010 at 09:55:45AM +0000, Hennerich, Michael wrote: >>> >>> >>>> From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com] >>>> >>>> On Fri, Jan 22, 2010 at 04:31:12PM -0800, Greg KH wrote: >>>>> On Fri, Jan 22, 2010 at 04:14:15PM -0800, Dmitry Torokhov wrote: >>>>>> On Fri, Jan 22, 2010 at 12:47:18PM -0800, Greg KH wrote: >>>>>>> On Wed, Jan 20, 2010 at 04:53:21PM +0000, Jonathan Cameron > wrote: >>>>>>>> I am not aware of these. Could you direct me to the current > api? Also note that these >>>>>>>> aren't the actual alarms, merely a means of enabling the > relevant event on the related >>>>>>>> event character device. >>>>>>> >>>>>>> Hm, I thought we had an accelerator interface somewhere... >>>>>>> >>>>>> >>>>>> Nope. And I am also interested in this since I am sittign on a > bunch of >>>>>> accelerometers, magnetometers, etc drivers that are trying to > plug into >>>>>> input sysbsystem and quite unsure what to do with them. >>>>>> >>>>>> It was OK whch HDAPS and friends when they were using input for >>>>>> secondary, toyish purposes, but these new drivers trying to use > input >>>>>> devnts as primary API and I am unsure if it is the best > solution. >>>>>> Accelerometer might be used as an input device but not always an > input >>>>>> device. >>>>> >>>>> Yeah, I see it using a joystick interface, which might be > acceptable for >>>>> "toy" devices like you say. >>>>> >>>>> But for "real" ones, we should do something else. >>>>> >>>>> Maybe, for devices that are going to be used by x.org, like the > "toy" >>>>> ones, we stick with the current input interface, but for others, > we use >>>>> a "real" interface, probably through hwmon, so that users can get > the >>>>> real data out in a consistant manner. >>>>> >>>> >>>> I'd rather have all of them use real interface and then have a > bridge >>>> to input module to enable toyish mode (unless the device in question >>>> is really truly an input device). >>>> >>>> -- >>>> Dmitry >>> >> >>> I really don't see that hwmon provides facilities like input/evdev >>> does. Queuing of events with time stamping and multiple reader >>> support. >> >> I understand that using evdev might be very convenient but I still >> believe that input should be used for human interfaces, not for generic >> data acquisition. The idea is that userpsace consumers should be able > to >> query device's capabilities and based on those capabilities be able to >> classify and properly handle the device. Now it all breaks when we get >> random hardware using EV_ABS/ABS_* for delivering some datastream that >> has nothing to do with coordinates. > > Acceleration in X,Y,Z translates pretty well in what joysticks deliver.
But it's not only about accelerometers here. We also have gyros, magnetometers, pressure sensors and generic ADCs.
>>> The adxl34x accelerometer driver for example is really >>> intended to be a input device. Send EV_KEY for x,y,z_TAP detections, >>> send EV_KEY for 3D orientation sensing, and EV_ABS for acceleration. >>> With very minor platform data customization you can use this device >>> for game controls or GUI interaction. A few examples include digital >>> picture frames, ebook readers, etc. >>> >> >> I see. However, can it be reasonably used for other purposes? > > Well - it depends. Some applications for Accelerometers also include:
> Personal navigation devices (low to mid data rate)
> Hard disk drive (HDD) protection (only alerts)
> Safety (probably low data rate)
What we want with IIO is a common high performance interface to these devices. That's why we have ring buffers in the kernel. Possible applications are robotics, precise navigation, data aquisition, etc.
Regards, -- Dipl.-Inf. Manuel Stahl Fraunhofer-Institut für Integrierte Schaltungen IIS - Leistungsoptimierte Systeme - Nordostpark 93 Telefon +49 (0)911/58061-6419 90411 Nürnberg Fax +49 (0)911/58061-6398 http://www.iis.fraunhofer.de manuel.stahl@iis.fraunhofer.de begin:vcard fn:Manuel Stahl n:Stahl;Manuel email;internet:manuel.stahl@iis.fraunhofer.de tel;work:+49 911 58061-6419 x-mozilla-html:FALSE version:2.1 end:vcard
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