Add generic evdev support to touchscreen part of ti_adc: two absolute
coordinates + button touch to indicate pen position. Pressure value
reporting is not implemented yet.
Tested on: Beaglebone Black + 4DCAPE-43T + tslib
Split ADC driver in two halves: ADC(analog ot digital) and
TSC(touchscreen). Touchscreen driver is fully functional
up to the point of reporting samples. This part will be added
once FreeBSD has API for touchscreen.
Tested on: Beaglebone Black + 4DCAPE-43T
Reviewed by: loos
Differential Revision: https://reviews.freebsd.org/D5847
through a voltage divisor (R163 and R164 on page 4 of BBB schematic).
Add a note about this on ti_adc(4) man page. The ti_adc(4) man page will
first appear on 10.1-RELEASE.
MFC after: 1 week
Suggested by: Sulev-Madis Silber (ketas)
Manual page reviewed by: brueffer (D127)
The ADC has a 12bit resolution and its raw output can be read via sysctl(8)
interface.
The driver allows the setup of ADC clock, samples average and open delay
(the number of clock cycles to wait before start the conversion).
The TSC_ADC module is set in the general purpose mode (no touchscreen
support).
Tested on Beaglebone-black.
Written based on AM335x TRM.
Reviewed by: rpaulo
Approved by: adrian (mentor)
Tested by: me, Brian J. McGovern, Sulev-Madis Silber (ketas)
