zinger: optimize idle current
zinger: optimize idle current

Force enabling STOP mode when we have a power contract etablished but
the sink is consuming a low current (<500mA).
As a side effect, when the STOP mode is on,  the fast OCP is no longer
reacting fast because the analog watchdog ADC conversion will only
happen on the next wake-up (dozens of milliseconds).

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=samus
BUG=none
TEST=run on Zinger with the UART RX used as debug GPIO to record STOP
mode entry/exit.

Reviewed-on: https://chromium-review.googlesource.com/230341
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
Commit-Queue: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
(cherry picked from commit bacd096372e22d87d7b98d9afc9ae9db91d4e0b9)
Signed-off-by: Duncan Laurie <70662b43bc1a20b57ded72a2b08be88dd0da4841@chromium.org>

Change-Id: If78b2651862782cee45cfcdb22425b94f1eee678
Reviewed-on: https://chromium-review.googlesource.com/230880
Tested-by: Duncan Laurie <70662b43bc1a20b57ded72a2b08be88dd0da4841@chromium.org>
Reviewed-by: Duncan Laurie <70662b43bc1a20b57ded72a2b08be88dd0da4841@chromium.org>
Commit-Queue: Duncan Laurie <70662b43bc1a20b57ded72a2b08be88dd0da4841@chromium.org>

thehobn/ec,thehobn/ec,thehobn/ec,thehobn/ec