charger v2: Don't set charger current limit if capability is unknown

If charge_manager has not decided on a current limit, don't set a
minimum current limit, since we may brown-out in the no / low-battery
case.

BUG=chrome-os-partner:56139
BRANCH=None
TEST=Manual on kevin, attach cut-off battery, attach OEM charger, verify
system doesn't brown-out due to OC.

Change-Id: Id53eb32c4a8ac9c6d9a0d3f1d700f089a50fcb0f
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/386793
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>

5 files changed, 21 insertions, 15 deletions

diff --git a/board/kevin/board.c b/board/kevin/board.c
index fb134c31e4..ff070f1167 100644
--- a/board/kevin/board.c
+++ b/board/kevin/board.c
@@ -208,8 +208,8 @@ int board_set_active_charge_port(int charge_port)
 	 */
 	if (!initialized &&
 	    charge_port == CHARGE_PORT_NONE &&
-	    charge_get_percent() < 2) {
-		CPRINTS("Battery critical, don't disable charging");
+	    charge_get_percent() < CONFIG_CHARGER_MIN_BAT_PCT_FOR_POWER_ON) {
+		CPRINTS("Bat critical, don't stop charging");
 		return -1;
 	}
 
@@ -244,7 +244,7 @@ void board_set_charge_limit(int port, int supplier, int charge_ma, int max_ma)
 	 */
 	if (supplier == CHARGE_SUPPLIER_PD &&
 	    charge_ma < 1500 &&
-	    charge_get_percent() < 2) {
+	    charge_get_percent() < CONFIG_CHARGER_MIN_BAT_PCT_FOR_POWER_ON) {
 		CPRINTS("Using max ilim %d", max_ma);
 		charge_ma = max_ma;
 	}
diff --git a/board/kevin/board.h b/board/kevin/board.h
index 1b190e0a07..85b2cfeda3 100644
--- a/board/kevin/board.h
+++ b/board/kevin/board.h
@@ -63,8 +63,8 @@
 #define CONFIG_CHARGER_INPUT_CURRENT 512
 #define CONFIG_CHARGER_NARROW_VDC
 #define CONFIG_CHARGER_V2
-#define CONFIG_CHARGER_MIN_BAT_PCT_FOR_POWER_ON 1
-#define CONFIG_CHARGER_LIMIT_POWER_THRESH_BAT_PCT 1
+#define CONFIG_CHARGER_MIN_BAT_PCT_FOR_POWER_ON 2
+#define CONFIG_CHARGER_LIMIT_POWER_THRESH_BAT_PCT 2
 #define CONFIG_CHARGER_LIMIT_POWER_THRESH_CHG_MW 15000
 #define CONFIG_USB_CHARGER
 #define CONFIG_USB_MUX_VIRTUAL
diff --git a/common/charge_manager.c b/common/charge_manager.c
index eeac1211fb..eeae350f10 100644
--- a/common/charge_manager.c
+++ b/common/charge_manager.c
@@ -889,8 +889,7 @@ int charge_manager_get_active_charge_port(void)
  */
 int charge_manager_get_charger_current(void)
 {
-	return (charge_current != CHARGE_CURRENT_UNINITIALIZED) ?
-		charge_current : 0;
+	return charge_current;
 }
 
 /**
diff --git a/common/charge_state_v2.c b/common/charge_state_v2.c
index 611f60b2a1..8ff268709c 100644
--- a/common/charge_state_v2.c
+++ b/common/charge_state_v2.c
@@ -571,13 +571,15 @@ void charger_init(void)
 }
 DECLARE_HOOK(HOOK_INIT, charger_init, HOOK_PRIO_DEFAULT);
 
-int get_desired_input_current(enum battery_present batt_present,
-			      const struct charger_info * const info)
+static int get_desired_input_current(enum battery_present batt_present,
+				     const struct charger_info * const info)
 {
 	if (batt_present == BP_YES || system_is_locked()) {
 #ifdef CONFIG_CHARGE_MANAGER
-		return MAX(CONFIG_CHARGER_INPUT_CURRENT,
-			charge_manager_get_charger_current());
+		int ilim = charge_manager_get_charger_current();
+		return ilim == CHARGE_CURRENT_UNINITIALIZED ?
+			CHARGE_CURRENT_UNINITIALIZED :
+			MAX(CONFIG_CHARGER_INPUT_CURRENT, ilim);
 #else
 		return CONFIG_CHARGER_INPUT_CURRENT;
 #endif
@@ -640,8 +642,10 @@ void charger_task(void)
 				if (rv != EC_SUCCESS) {
 					problem(PR_POST_INIT, rv);
 				} else {
-					rv = charger_set_input_current(
-						curr.desired_input_current);
+					if (curr.desired_input_current !=
+					    CHARGE_CURRENT_UNINITIALIZED)
+						rv = charger_set_input_current(
+						    curr.desired_input_current);
 					if (rv != EC_SUCCESS)
 						problem(PR_SET_INPUT_CURR, rv);
 					else
@@ -666,7 +670,10 @@ void charger_task(void)
 
 			curr.desired_input_current =
 				get_desired_input_current(prev_bp, info);
-			charger_set_input_current(curr.desired_input_current);
+			if (curr.desired_input_current !=
+			    CHARGE_CURRENT_UNINITIALIZED)
+				charger_set_input_current(
+					curr.desired_input_current);
 			hook_notify(HOOK_BATTERY_SOC_CHANGE);
 		}
 
diff --git a/include/charge_manager.h b/include/charge_manager.h
index 3623bc1635..51007f3d7b 100644
--- a/include/charge_manager.h
+++ b/include/charge_manager.h
@@ -83,7 +83,7 @@ int charge_manager_get_active_charge_port(void);
 /* Return the power limit (uW) set by charge manager. */
 int charge_manager_get_power_limit_uw(void);
 
-/* Return the charger current (mA) value. */
+/* Return the charger current (mA) value or CHARGE_CURRENT_UNINITIALIZED. */
 int charge_manager_get_charger_current(void);
 
 #ifdef CONFIG_USB_PD_LOGGING