In dead battery mode, we can find ANX7688 will pull the CC to Rp in the beginning;
some of the adapters will drop the VBUS since this should be treated as a
disconnection, hence the whole system lost the only power source and cannot boot up.
According to chrome-os-partner:58283, there's a chance for ANX7688 to be in an
abnormal state if the system provides it with 3.3V first but RESET_N and PWR_EN
are still in an unstable level. To prevent this situation, we try to enable the
3.3V only after RESET_N and PWR_EN are in their initial state.
BRANCH=none
BUG=chrome-os-partner:58283
TEST=plug in the adapter, check ANX7688 does not pull CC to Rp in the beginning,
and boot up system in dead battery mode
Change-Id: Ibb81a33a7dd957d3bdc6c54bb7723cc9ffdcfd26
Signed-off-by: Milton Chiang <milton.chiang@mediatek.com>
Reviewed-on: https://chromium-review.googlesource.com/394408
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
0fd106fbf4