On 19-1-2017 13:36, Lior David wrote:

On 1/19/2017 2:24 PM, Valo, Kalle wrote:

quoted

Maya Erez [off-list ref] writes:

quoted

From: Lior David <redacted>

In fine timing measurements, the calculation is affected by
2 parts: timing of packets over the air, which is platform
independent, and platform-specific delays, which are dependent
on things like antenna cable length and type.
Add a sysfs file which allows to get/set these platform specific
delays, separated into the TX and RX components.
There are 2 key scenarios where the file can be used:
1. Calibration - start with some initial values (for example,
the default values at startup), make measurements at a known
distance, then iteratively change the values until the
measurement results match the known distance.
2. Adjust the delays when platform starts up, based on known
values.

Signed-off-by: Lior David <redacted>
Signed-off-by: Maya Erez <redacted>

Can't this go via nl80211? sysfs is not really supposed to be used for
something like this.

There is no nl80211 API for this (yet?).

So come up with one...?

Will it be ok to put this in debugfs? Normally this will be in the board
file (as part of RF configuration) but it will be useful to play
with these values for debugging/diagnostics.

What is doing the FTM measurements? Is it all done in user-space? That
would mean you also need measurement data exported to user-space. How is
that done? Intel has a FTM api proposal, but it has not been submitted
upstream (yet?).

Regards,
Arend