Charge_state_v2: Always evaluate battery disconnect

Always evaluate the battery disconnect state when we know the battery is
physically present.

Otherwise, we may miss the battery coming out of disconnect if AC is
removed around the same time the battery becomes responsive.  This
causes us to remain in safe state with an active charge port offering
0mV/0mA.

Note this change adjusts the criteria for battery disconnect, counting
errors in assessing the battery disconnect state as disconnects.  This
should account for the fact that the check now runs before we've
verified battery communication is okay.

BRANCH=skyrim
BUG=b:276837557
TEST=on frostflow, ensure units don't show charging when AC is removed
after coming out of ship mode

Change-Id: Ie52c993005cf389dc2912c6ab9492483b60239a9
Signed-off-by: Diana Z <dzigterman@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4470067
Tested-by: SamSP Liu <samsp_liu2@compal.corp-partner.google.com>
Reviewed-by: Keith Short <keithshort@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
(cherry picked from commit 58d8fc6c170c69beb3d081d9e1f5bafb3dffe83d)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4472392
Tested-by: Chao Gui <chaogui@google.com>
Reviewed-by: Chao Gui <chaogui@google.com>
Commit-Queue: Chao Gui <chaogui@google.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/common/charge_state_v2.c b/common/charge_state_v2.c
index 59657318f5..e103f991ba 100644
--- a/common/charge_state_v2.c
+++ b/common/charge_state_v2.c
@@ -1809,6 +1809,17 @@ void charger_task(void *u)
 		}
 
 		/*
+		 * Always check the disconnect state if the battery is present.
+		 * This is because the battery disconnect state is one of the
+		 * items used to decide whether or not to leave safe mode.
+		 *
+		 * Note: For our purposes, an unresponsive battery is
+		 * considered to be disconnected
+		 */
+		battery_seems_disconnected = battery_get_disconnect_state() !=
+					     BATTERY_NOT_DISCONNECTED;
+
+		/*
 		 * If we had trouble talking to the battery or the charger, we
 		 * should probably do nothing for a bit, and if it doesn't get
 		 * better then flag it as an error.
@@ -1868,14 +1879,6 @@ void charger_task(void *u)
 		}
 		/* The battery is responding. Yay. Try to use it. */
 
-		/*
-		 * Always check the disconnect state.  This is because
-		 * the battery disconnect state is one of the items used
-		 * to decide whether or not to leave safe mode.
-		 */
-		battery_seems_disconnected = battery_get_disconnect_state() ==
-					     BATTERY_DISCONNECTED;
-
 		revive_battery(&need_static);
 
 		set_charge_state(ST_CHARGE);