Nami: Report error for disconnected battery on Sona

On Sona, when a battery is cutoff, the gas gauge does not clear
BATTERY_DISCHARGING_DISABLED or BATTERY_CHARGING_DISABLED until a
precharge current is supplied.

This patch makes battery_is_present return BP_NOT_SURE for the first
5 seconds after the battery is found electrically disconnected. After
5 seconds, it reports BP_NO as it normally does.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>

BUG=b:112292720
BRANCH=nami
TEST=Verify the battery wakes up from cutoff mode. Verify a bad battery
eventually stops being charged.

Change-Id: I4d0e9e5ed0e9631b7bbf8565ce62c17da8a0a848
Reviewed-on: https://chromium-review.googlesource.com/1171259
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Commit-Queue: Daisuke Nojiri <dnojiri@chromium.org>
Tested-by: Daisuke Nojiri <dnojiri@chromium.org>
(cherry picked from commit 4363e098c546f09cdfcc9c10de09b0c517d52e63)
Reviewed-on: https://chromium-review.googlesource.com/1177721
Commit-Ready: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

1 files changed, 36 insertions, 2 deletions

diff --git a/board/nami/battery.c b/board/nami/battery.c
index b34c5e18e8..d32a1b74ff 100644
--- a/board/nami/battery.c
+++ b/board/nami/battery.c
@@ -213,6 +213,19 @@ static int battery_init(void)
 		!!(batt_status & STATUS_INITIALIZED);
 }
 
+enum battery_disconnect_grace_period {
+	BATTERY_DISCONNECT_GRACE_PERIOD_OFF,
+	BATTERY_DISCONNECT_GRACE_PERIOD_ON,
+	BATTERY_DISCONNECT_GRACE_PERIOD_OVER,
+};
+static enum battery_disconnect_grace_period disconnect_grace_period;
+
+static void battery_disconnect_timer(void)
+{
+	disconnect_grace_period = BATTERY_DISCONNECT_GRACE_PERIOD_OVER;
+}
+DECLARE_DEFERRED(battery_disconnect_timer);
+
 /*
  * Check for case where both XCHG and XDSG bits are set indicating that even
  * though the FG can be read from the battery, the battery is not able to be
@@ -238,8 +251,29 @@ static int battery_check_disconnect_ti_bq40z50(void)
 
 	if ((data[3] & (BATTERY_DISCHARGING_DISABLED |
 			BATTERY_CHARGING_DISABLED)) ==
-	    (BATTERY_DISCHARGING_DISABLED | BATTERY_CHARGING_DISABLED))
-		return BATTERY_DISCONNECTED;
+	    (BATTERY_DISCHARGING_DISABLED | BATTERY_CHARGING_DISABLED)) {
+		if (oem != PROJECT_SONA)
+			return BATTERY_DISCONNECTED;
+		/*
+		 * For Sona, we need a workaround to wake up a battery from
+		 * cutoff. We return DISCONNECT_ERROR for the 5 seconds after
+		 * the first call BP_NOT_SURE is reported to chgstv2. It will
+		 * supply precharge current and wakes up the battery from
+		 * cutoff. If the battery is good, we won't come back here.
+		 * If not, after 5 seconds, we will return DISCONNECTED to
+		 * stop charging and avoid damaging the battery.
+		 */
+		if (disconnect_grace_period ==
+				BATTERY_DISCONNECT_GRACE_PERIOD_OVER)
+			return BATTERY_DISCONNECTED;
+		if (disconnect_grace_period ==
+				BATTERY_DISCONNECT_GRACE_PERIOD_OFF)
+			hook_call_deferred(&battery_disconnect_timer_data,
+					   5 * SECOND);
+		ccprintf("Battery disconnect grace period\n");
+		disconnect_grace_period = BATTERY_DISCONNECT_GRACE_PERIOD_ON;
+		return BATTERY_DISCONNECT_ERROR;
+	}
 
 	return BATTERY_NOT_DISCONNECTED;
 }