charge_manager: Revisit charge supplier priority.stabilize-12206.B

According to USB-C spec 1.3 Table 4-17 "Precedence of power source
usage", the supplier's priority should be:
USB-C 3.0A/1.5A  >  BC1.2  >  USB-C under 1.5A.

This CL propose to raise the BC1.2 priority to fix that
charge_manager won't choose BC1.2 when the port reports it can
supply both TYPEC 500ma and BC1.2 supplier.  According to the
spec mentioned aboved, we should prefer BC1.2 rather than TYPEC.

Besdies, charge_manager is able to pick the supplier which provides
the higheste power.  The CL simplifies the supplier priority a bit by
taking advantage of the feature.

TEST=Charge kukui with 5V/2A charger and see it can drain 1.34A (DCP
     current bound of mt6370 is 1.5A) rather than 0.5A.
TEST=Charge kukui with Type-C 5V3A/CDP/DCP/SDP/PD charger randomly and see
     that the current it drains is reasonable.
TEST=Charge soraka with 'A', and plug another port with 'B',
     and see it can transist the sinking port from A to B.
     Here (A, B) are:
     1. (SDP 5V0.5A, Type-C 5V3A)
     2. (CDP 5V1.5A, PD)
     3. (SDP 5V0.5A, CDP 5V1.5A)
     4. (CDP 5V1.5A, Type-C 5V3A)
     5. (Type-C 5V3A, PD)

BUG=b:131126720
BRANCH=None

Change-Id: I46384e09d764aa926129358657d0593fca4923c2
Signed-off-by: Yilun Lin <yllin@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1581859
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Yilun Lin <yllin@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/board/host/board.h b/board/host/board.h
index 494edf5eb3..2d7c492238 100644
--- a/board/host/board.h
+++ b/board/host/board.h
@@ -50,6 +50,7 @@ enum {
 	CHARGE_SUPPLIER_TEST7,
 	CHARGE_SUPPLIER_TEST8,
 	CHARGE_SUPPLIER_TEST9,
+	CHARGE_SUPPLIER_TEST10,
 	CHARGE_SUPPLIER_TEST_COUNT
 };