Issue 623: merge tsc2007-gta4 into upstream tsc2007

Reported by Nikolaus Schaller, Jun 28, 2014

in small chunks:
1. swap/flip
2. dejitter algorithms (allow to choose through DT)
3. integrate ADC (ambient light sensor) - maybe poll only if 
separate /dev/input is opened
4. /sys status interface (poll only if needed)
unclear: fix for pressure

Comment 1 by Nikolaus Schaller, Aug 17, 2014

Status: Accepted

Comment 2 by Nikolaus Schaller, Aug 19, 2014

chunk 1 is done

Comment 3 by Nikolaus Schaller, Oct 24, 2015

chunk 2 is no longer needed (fuzz factor is good enough) and
chunk 3/4 has been solved by iio.
We only need to submit and discuss upstream.

Comment 4 by Nikolaus Schaller, Feb 13, 2016

Seems to work. But needs more review and it is not 100% clear if we 
should clip or report out of bounds coordinates. Android seems to 
expect the latter while X.org might get into problems.
So we might have to remove the clipping feature (and convert some 
code to signed temporary variables).

Comment 5 by Nikolaus Schaller, Nov 17, 2016

Version 8 is for review on LKML and almost done...

Comment 6 by Nikolaus Schaller, Apr 14, 2017

Unfortunatly, maintainers did accept not all features. Especially 
not our really simple pre-calibration.

Comment 7 by Nikolaus Schaller, Feb 16, 2019

Status: Ready

Letux Kernel