Re: [RFC] Add Input IOCTL for accelerometer devices

Mohamed Ikbel Boulabiar
2009-05-16T04:20:06Z

On Fri, May 15, 2009 at 9:02 PM, Felipe Balbi <felipe.balbi@nokia.com> wrote:

> Yeah, let's try to define the best way to expose accelerometers with
> linux kernel and avoid a sysfs hell. Better sooner than later.

isn't the best way to add a thing like the one for battery for any input device
/proc/acpi/battery/CMB0/state
or even in /sys/input/devices/XXXX

and let any userspace application do what she wants with information ?

> The problem is that it doesn't really seem to me that all accelerometers
> will be doing hw monitoring. The ones used in laptops, for sure, trying
> to prevent the hd from drying during a fall. But imagine the
> accelerometers used in, say, wii-mote, or cellphones, or such stuff ?

Many of them are HID devices (99%), so can be treated the same way
according the standard.

> Say we wanna use the accelerometer for both screen rotation and gaming,
> that device isn't doing hw monitoring and still we _do_ want to set
> different thresholds and irq requests/types for different use cases,
> right ?

Another reason for preparing the interface I just cited.

> I'll grep around the Industrial IO patchset if that's supposed to a
> 'sensor fw' sorta thing. Hope it does report the devices as input
> devices. I'm pretty sure we're gonna fall into similar issues when
> dealing with magnetometers, for instance, what's the best way to expose
> those device with current linux frameworks ? It's not really user input
> data...
>
> Well, let's see where this discussion takes us. Willing to hear from
> Jonatha, Dmitry and all of you guys

Yes guys, I also wait for your comments :)

ikbel