On Wed, Mar 16, 2016 at 12:09 PM, Clément VUCHENER
[off-list ref] wrote:

2016-03-16 16:26 GMT+01:00 David Herrmann [off-list ref]:

quoted

Hi

On Wed, Mar 16, 2016 at 4:10 PM, Bastien Nocera [off-list ref] wrote:

quoted

On Tue, 2016-03-15 at 17:17 -0700, Roderick Colenbrander wrote:

quoted

Hi Bastien,

Thanks for providing this suggestion. I can see this approach work
for
situations like screen rotation on tablets. The device I'm involved
with is an input device, which needs a high poll rate for
acceleration
/ velocity and needs to be paired with the button / axes data. Evdev
would be most appropriate.

So more like a Wiimote than a builtin sensor. What will consume events
in user-space? A specialised application?

I really think evdev is the right place to put any of those devices.
The real problem is that the current set of ABS types is very limited
and strongly overloaded. We didn't do this for other types, but
somehow ABS turned out that way.

In general, Dmitry was ok with introducing new ABS types, properly
representing those types. I sent an RFC some years ago, which also
introduces gyro and accelerometer types (see patch #4):

https://lists.freedesktop.org/archives/input-tools/2013-December/000612.html

The problem is, however, that the current ABS_* namespace is
exhausted. That is, we have to introduce some new way to add new ABS
types (the series introduced ABS2 for that). No-one continued that
effort so far, so we are stuck with the current ABS types. Feel free
to pick this up. It might be a lengthy effort, though. You might be
better off doing it the wiimote way: pick you ABS types and make
user-space recognize them depending on the device name/etc.

Hi.

I am writing a user-space driver for the steam controller and I was
wondering how that would fit. The steam controller reports its
absolute gyro data as a quaternion instead of three angles. Although,
in the case of the steam controller, this data is meant to emulate
other kind of devices from the driver, if applications started to use
such an interface, it would be nice that the steam controller supports
it.

quoted

Thanks
David

I haven't with the SteamController yet. Based on iFixit it has a
3-axis gyro and 3-axis accelerometer. I guess the microcontroller
could be doing the quaternion calculations. Are you sure it is gyro
data and not maybe orientation data derived from gyro + accel? Try
spinning it around an axis and integrate the output in a script
(provided you knew the resolution in units per deg/s or rad/s).

Some devices may use 1D or 2D sensors, so if for those just ABS_GYRO_X
/ _Y for them, for a 4th dimension _W would make sense I guess.
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