using monotonic clok for timstamping

[Gregor Boirie <gregor.boirie@parrot.com>]

Dear  all,

Our application relies on precise and monotonic timestamping of IMU 
samples (and other sensors).
I am wondering what reasons / use cases led to the choice of realtime 
clock to implement
iio_get_time_ns (not to mention time gaps that may be seen after wake up 
from sleep states).

As a dirty hack, I simply rewrote iio_get_time_ns on our platform. But I 
suspect it would be usefull as
a long term solution, to give userland the ability to choose a 
particular posix clock (realtime, monotonic,
etc...) on a per device and / or driver basis through a sysfs attribute 
for example.

I'd be glad to hear your suggestions. Best regards,
Grégor.