chgmgr: Allow charge_manager_update_charge to accept NULL

Currently, charge_manager_update_charge does not handle NULL pointer
for struct charge_port_info any differently. It's not sanity-checked
either (thus memory access violation can occur).

This patch will make charge_manager_update_charge accept NULL pointer
and set available current and voltage to zero.

This also helps callers' intentions be clear because callers can
explicitly specify NULL (instead of passing a pointer to chg = {0},
which is initialized somewhere else).

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

BUG=none
BRANCH=none
TEST=buildall

Change-Id: I518662ab6a3a07f93da5d34cf62a6f856884f67d
Reviewed-on: https://chromium-review.googlesource.com/1236851
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Tested-by: Daisuke Nojiri <dnojiri@chromium.org>
Commit-Queue: Daisuke Nojiri <dnojiri@chromium.org>

8 files changed, 33 insertions, 49 deletions

diff --git a/board/fizz/board.c b/board/fizz/board.c
index f8de83b255..0de6ff12b7 100644
--- a/board/fizz/board.c
+++ b/board/fizz/board.c
@@ -750,13 +750,12 @@ static void setup_bj(void)
 static void board_charge_manager_init(void)
 {
 	enum charge_port port;
-	struct charge_port_info cpi = { 0 };
 	int i, j;
 
 	/* Initialize all charge suppliers to 0 */
 	for (i = 0; i < CHARGE_PORT_COUNT; i++) {
 		for (j = 0; j < CHARGE_SUPPLIER_COUNT; j++)
-			charge_manager_update_charge(j, i, &cpi);
+			charge_manager_update_charge(j, i, NULL);
 	}
 
 	port = gpio_get_level(GPIO_ADP_IN_L) ?
diff --git a/board/glkrvp_ite/chg_usb_pd.c b/board/glkrvp_ite/chg_usb_pd.c
index 5ef8d7a77e..0b1a188081 100644
--- a/board/glkrvp_ite/chg_usb_pd.c
+++ b/board/glkrvp_ite/chg_usb_pd.c
@@ -166,13 +166,11 @@ DECLARE_HOOK(HOOK_AC_CHANGE, board_dc_jack_handle, HOOK_PRIO_FIRST);
 static void board_charge_init(void)
 {
 	int port, supplier;
-	struct charge_port_info charge_init = {0};
 
 	/* Initialize all charge suppliers to seed the charge manager */
 	for (port = 0; port < CHARGE_PORT_COUNT; port++) {
 		for (supplier = 0; supplier < CHARGE_SUPPLIER_COUNT; supplier++)
-			charge_manager_update_charge(supplier, port,
-				&charge_init);
+			charge_manager_update_charge(supplier, port, NULL);
 	}
 
 	board_dc_jack_handle();
diff --git a/common/charge_manager.c b/common/charge_manager.c
index 76c9d4e436..5120944007 100644
--- a/common/charge_manager.c
+++ b/common/charge_manager.c
@@ -912,6 +912,9 @@ void charge_manager_update_charge(int supplier,
 				  int port,
 				  const struct charge_port_info *charge)
 {
+	struct charge_port_info zero = {0};
+	if (!charge)
+		charge = &zero;
 	charge_manager_make_change(CHANGE_CHARGE, supplier, port, charge);
 }
 
diff --git a/common/usb_charger.c b/common/usb_charger.c
index 1b88adb444..7a35d0f4b9 100644
--- a/common/usb_charger.c
+++ b/common/usb_charger.c
@@ -17,6 +17,7 @@
 #include "console.h"
 #include "gpio.h"
 #include "hooks.h"
+#include "stddef.h"
 #include "task.h"
 #include "usb_charge.h"
 #include "usb_pd.h"
@@ -80,25 +81,19 @@ void usb_charger_vbus_change(int port, int vbus_level)
 static void usb_charger_init(void)
 {
 	int i;
-	struct charge_port_info charge_none = {0};
 
 	/* Initialize all charge suppliers */
 	for (i = 0; i < CONFIG_USB_PD_PORT_COUNT; i++) {
 		charge_manager_update_charge(CHARGE_SUPPLIER_PROPRIETARY,
-					     i,
-					     &charge_none);
+					     i, NULL);
 		charge_manager_update_charge(CHARGE_SUPPLIER_BC12_CDP,
-					     i,
-					     &charge_none);
+					     i, NULL);
 		charge_manager_update_charge(CHARGE_SUPPLIER_BC12_DCP,
-					     i,
-					     &charge_none);
+					     i, NULL);
 		charge_manager_update_charge(CHARGE_SUPPLIER_BC12_SDP,
-					     i,
-					     &charge_none);
+					     i, NULL);
 		charge_manager_update_charge(CHARGE_SUPPLIER_OTHER,
-					     i,
-					     &charge_none);
+					     i, NULL);
 		/* Initialize VBUS supplier based on whether VBUS is present. */
 		update_vbus_supplier(i, pd_is_vbus_present(i));
 	}
diff --git a/driver/bc12/bq24392.c b/driver/bc12/bq24392.c
index 8f97ad704f..c06f8746a0 100644
--- a/driver/bc12/bq24392.c
+++ b/driver/bc12/bq24392.c
@@ -96,7 +96,7 @@ static void power_down_ic(const int port)
 	gpio_set_level(pin_tbl[port].chip_enable_l, 1);
 
 	/* Let charge manager know there's no more charge available. */
-	charge_manager_update_charge(CHARGE_SUPPLIER_OTHER, port, &no_chg);
+	charge_manager_update_charge(CHARGE_SUPPLIER_OTHER, port, NULL);
 }
 
 /**
diff --git a/driver/bc12/pi3usb9281.c b/driver/bc12/pi3usb9281.c
index 9bdf875468..f1bd3ce8d4 100644
--- a/driver/bc12/pi3usb9281.c
+++ b/driver/bc12/pi3usb9281.c
@@ -289,7 +289,6 @@ void usb_charger_set_switches(int port, enum usb_switch setting)
 static void bc12_detect(int port)
 {
 	int device_type, charger_status;
-	struct charge_port_info charge = {0};
 	int type;
 
 	if (usb_charger_port_is_sourcing_vbus(port)) {
@@ -351,6 +350,7 @@ static void bc12_detect(int port)
 
 	/* Attachment: decode + update available charge */
 	if (device_type || PI3USB9281_CHG_STATUS_ANY(charger_status)) {
+		struct charge_port_info chg;
 		if (PI3USB9281_CHG_STATUS_ANY(charger_status))
 			type = CHARGE_SUPPLIER_PROPRIETARY;
 		else if (device_type & PI3USB9281_TYPE_CDP)
@@ -362,31 +362,21 @@ static void bc12_detect(int port)
 		else
 			type = CHARGE_SUPPLIER_OTHER;
 
-		charge.voltage = USB_CHARGER_VOLTAGE_MV;
-		charge.current = pi3usb9281_get_ilim(device_type,
-						     charger_status);
-		charge_manager_update_charge(type, port, &charge);
-	} else { /* Detachment */
-		charge_manager_update_charge(
-					CHARGE_SUPPLIER_PROPRIETARY,
-					port,
-					&charge);
-		charge_manager_update_charge(
-					CHARGE_SUPPLIER_BC12_CDP,
-					port,
-					&charge);
-		charge_manager_update_charge(
-					CHARGE_SUPPLIER_BC12_DCP,
-					port,
-					&charge);
-		charge_manager_update_charge(
-					CHARGE_SUPPLIER_BC12_SDP,
-					port,
-					&charge);
-		charge_manager_update_charge(
-					CHARGE_SUPPLIER_OTHER,
-					port,
-					&charge);
+		chg.voltage = USB_CHARGER_VOLTAGE_MV;
+		chg.current = pi3usb9281_get_ilim(device_type, charger_status);
+		charge_manager_update_charge(type, port, &chg);
+	} else {
+		/* Detachment */
+		charge_manager_update_charge(CHARGE_SUPPLIER_PROPRIETARY,
+					     port, NULL);
+		charge_manager_update_charge(CHARGE_SUPPLIER_BC12_CDP,
+					     port, NULL);
+		charge_manager_update_charge(CHARGE_SUPPLIER_BC12_DCP,
+					     port, NULL);
+		charge_manager_update_charge(CHARGE_SUPPLIER_BC12_SDP,
+					     port, NULL);
+		charge_manager_update_charge(CHARGE_SUPPLIER_OTHER,
+					     port, NULL);
 	}
 }
 
diff --git a/driver/charger/bd9995x.c b/driver/charger/bd9995x.c
index 4fb5e9a347..65c72e65bd 100644
--- a/driver/charger/bd9995x.c
+++ b/driver/charger/bd9995x.c
@@ -407,10 +407,8 @@ static int bd9995x_bc12_check_type(int port)
 
 static void bd9995x_bc12_detach(int port, int type)
 {
-	struct charge_port_info charge = {0};
-
 	/* Update charge manager */
-	charge_manager_update_charge(type, port, &charge);
+	charge_manager_update_charge(type, port, NULL);
 
 	/* Disable charging trigger by BC1.2 detection */
 	bd9995x_bc12_enable_charging(port, 0);
diff --git a/include/charge_manager.h b/include/charge_manager.h
index 984d119319..54253d66c7 100644
--- a/include/charge_manager.h
+++ b/include/charge_manager.h
@@ -57,9 +57,10 @@ struct charge_port_info {
 /**
  * Called by charging tasks to update their available charge.
  *
- * @param supplier		Charge supplier to update.
- * @param port			Charge port to update.
- * @param charge		Charge port current / voltage.
+ * @param supplier	Charge supplier to update.
+ * @param port		Charge port to update.
+ * @param charge	Charge port current / voltage. If NULL, current = 0
+ * 			voltage = 0 will be used.
  */
 void charge_manager_update_charge(int supplier,
 				  int port,