On 19/06/14 12:20, Bastien Nocera wrote:
On Wed, 2014-06-18 at 16:45 -0700, Srinivas Pandruvada wrote:
On 06/18/2014 04:31 PM, Reyad Attiyat wrote:
Hello Bastien Nocera,
I'm not the best person to answer your questions but I will try and
help. The best people to talk to would be Jonathan Cameron, the IIO
maintainer, and Srinivas Pandruvada, the author of the hid-sensor-hub
device drivers. I have CC'ed them for you to hopefully get a better
response than what I can offer.
Your device uses the same sensor hub, over usb, as my device does. I
have a Microsoft Surface and it also uses many of the sensors found on
the Lenovo Yoga.
So, my question regarding the IIO user-space API is:
is it possible to make the IIO accelerometer send out a kevent when the
orientation changes in a major way (using triggers?) or does user-space
need to poll the device instead?
You can check a program called generic_buffer.c in
"drivers/staging/iio/Documentation". I have used this as a reference to
port to Android.
You don't need to poll, you can also check
"https://github.com/pfps/yoga-laptop/sensors " developed by Peter F.
Patel-Schneider.
I've read this code, and in fact, I mentioned it in my original mail. I
fail to see how this code isn't polling. It's also much more complicated
than doing the same thing for a evdev accelerometer.
Just to throw it in there. There is an out of tree bridge driver from
IIO to input. It's only out of tree because I haven't had a chance to
tidy it up (anyone else is welcome to take this on if they like!)
Google for iio_input.c to find it.
The intent of that was to allow general accelerometer drivers and similar
in IIO to work in conjunction with iio-input to provide input style interfaces.
This came about after previous debates on where the 'right' place for
accelerometers was in the kernel. I believe that at least in principle,
Dmitry was happy with this concept.
Jonathan
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