battery: don't talk to battery after cut-off

Add a shortcut in smart battery driver and i2c passthru. Once
the battery cut-off order is submitted (in the factory line),
the EC will no longer talk to battery.

BUG=chrome-os-partner:28248
BRANCH=tot,nyan
TEST=See below
> remove AC, cutoff: expect system is off.
> cutoff, then remove AC: expect system is off.
> cutoff, wait for 1 min, then remove AC: expect system is off.

Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>

Change-Id: Ied963c19d17d581ce99e4543469cf2fa165f0439
Reviewed-on: https://chromium-review.googlesource.com/196657
Tested-by: Yung-chieh Lo <yjlou@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Commit-Queue: Yung-chieh Lo <yjlou@chromium.org>

3 files changed, 51 insertions, 4 deletions

diff --git a/common/battery.c b/common/battery.c
index 19ad2e49b8..b6e79bb383 100644
--- a/common/battery.c
+++ b/common/battery.c
@@ -9,12 +9,18 @@
 #include "charge_state.h"
 #include "common.h"
 #include "console.h"
+#include "extpower.h"
 #include "gpio.h"
+#include "hooks.h"
 #include "host_command.h"
 #include "timer.h"
 #include "util.h"
 #include "watchdog.h"
 
+#ifdef CONFIG_BATTERY_CUT_OFF
+static int is_cut_off;
+#endif
+
 #ifdef CONFIG_BATTERY_PRESENT_GPIO
 #ifdef CONFIG_BATTERY_PRESENT_CUSTOM
 #error "Don't define both CONFIG_BATTERY_PRESENT_CUSTOM and" \
@@ -252,19 +258,44 @@ DECLARE_CONSOLE_COMMAND(battery, command_battery,
 
 
 #ifdef CONFIG_BATTERY_CUT_OFF
-int battery_command_cut_off(struct host_cmd_handler_args *args)
+int battery_is_cut_off(void)
+{
+	return is_cut_off;
+}
+
+static void clean_cut_off(void)
+{
+	if (extpower_is_present())
+		is_cut_off = 0;
+}
+DECLARE_HOOK(HOOK_AC_CHANGE, clean_cut_off, HOOK_PRIO_DEFAULT);
+
+static int battery_command_cut_off(struct host_cmd_handler_args *args)
 {
-	return board_cut_off_battery();
+	int rv = board_cut_off_battery();
+	if (!rv)
+		is_cut_off = 1;
+
+	return rv;
 }
 DECLARE_HOST_COMMAND(EC_CMD_BATTERY_CUT_OFF, battery_command_cut_off,
 		EC_VER_MASK(0));
 
 static int command_cutoff(int argc, char **argv)
 {
-	return board_cut_off_battery();
+	int rv = board_cut_off_battery();
+	if (!rv)
+		is_cut_off = 1;
+
+	return rv;
 }
 DECLARE_CONSOLE_COMMAND(cutoff, command_cutoff,
 		"",
 		"Cut off the battery output",
 		NULL);
+#else
+int battery_is_cut_off(void)
+{
+	return 0;  /* Always return NOT cut off */
+}
 #endif  /* CONFIG_BATTERY_CUT_OFF */
diff --git a/common/charge_state_v2.c b/common/charge_state_v2.c
index 36addbe332..a5a621da8b 100644
--- a/common/charge_state_v2.c
+++ b/common/charge_state_v2.c
@@ -620,12 +620,19 @@ wait_for_it:
 		/* Charger only accpets request when AC is on. */
 		if (curr.ac) {
 			/*
+			 * Some batteries would wake up after cut-off if we keep
+			 * charging it. Thus, we only charge when AC is on and
+			 * battery is not cut off yet.
+			 */
+			if (battery_is_cut_off())
+				charge_request(0, 0);
+			/*
 			 * As a safety feature, some chargers will stop
 			 * charging if we don't communicate with it frequently
 			 * enough. In manual mode, we'll just tell it what it
 			 * knows.
 			 */
-			if (manual_mode) {
+			else if (manual_mode) {
 				charge_request(curr.chg.voltage,
 					       curr.chg.current);
 			} else {
diff --git a/common/i2c.c b/common/i2c.c
index f5ce577aa2..8667bff1cf 100644
--- a/common/i2c.c
+++ b/common/i2c.c
@@ -5,6 +5,7 @@
 
 /* I2C cross-platform code for Chrome EC */
 
+#include "battery.h"
 #include "clock.h"
 #include "console.h"
 #include "host_command.h"
@@ -492,6 +493,14 @@ static int i2c_command_passthru(struct host_cmd_handler_args *args)
 		return EC_RES_ACCESS_DENIED;
 #endif
 
+#ifdef CONFIG_BATTERY_CUT_OFF
+	/*
+	 * Some batteries would wake up after cut-off if we talk to it.
+	 */
+	if (battery_is_cut_off())
+		return EC_RES_ACCESS_DENIED;
+#endif
+
 	ret = check_i2c_params(args);
 	if (ret)
 		return ret;