poppy: Dynamically disable effect of SLP_S0# on all VRs

Just setting the global VRMODECTRL register is not enough to disable
the effect of SLP_S0# signal. Each VR control register needs to be set
correctly to ignore the effect as well. However, disabling VR decay on
SLP_S0# assertion by default results in additional power consumption
during S0ix. In order to prevent this, VR decay on SLP_S0# assertion
needs to be enabled and disabled dynamically as follows:

1. By default on EC boot, PMIC will be initialized to disable VR decay
on SLP_S0# assertion.
2. When host indicates intent to enter S0ix, EC will enable decay of
VRs on SLP_S0# assertion.
3. When host exits from S0ix and updates the intent to no longer enter
S0ix using host command, EC will disable decay of VRs on SLP_S0#
assertion.

 actual SLP_S0# assertion because PMIC seems to honor the setting only
 at SLP_S0# assertion and not if it is already asserted.

BUG=b:65732924
BRANCH=None
TEST=Verified with this change that the failing Lux device is stable
for a long time even with runtime S0ix.

Change-Id: I9c5afb408694b3b467e85dcea723f7574bc639c1
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/674034
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

0 files changed, 0 insertions, 0 deletions