reef: battery: Revive batteries in soft-disconnect state

ESC+F3+Power+AC removal puts the battery into a soft-disconnect state
where is stops supplying current. Revive batteries in this state by
supplying a precharge current.

BUG=chrome-os-partner:55858
BRANCH=None
TEST=Manual on reef. Put battery into soft-disconnect state. Attach
charger and verify EC doesn't lose power and battery again supplies
current.

Change-Id: I9a772bf02a8bd40edc1db51de66de135f7299212
Signed-off-by: Rachel Nancollas <rachelsn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/365495
Commit-Ready: Rachel Nancollas <rachelsn@google.com>
Tested-by: Rachel Nancollas <rachelsn@google.com>
Reviewed-by: David Hendricks <dhendrix@chromium.org>

2 files changed, 61 insertions, 5 deletions

diff --git a/board/reef/battery.c b/board/reef/battery.c
index 38801bd4be..5227a4b556 100644
--- a/board/reef/battery.c
+++ b/board/reef/battery.c
@@ -10,6 +10,7 @@
 #include "charge_state.h"
 #include "console.h"
 #include "ec_commands.h"
+#include "extpower.h"
 #include "gpio.h"
 #include "i2c.h"
 #include "util.h"
@@ -21,10 +22,10 @@
 /* Battery info for BQ40Z55 */
 static const struct battery_info info = {
 	/* FIXME(dhendrix): where do these values come from? */
-	.voltage_max = 8700,        /* mV */
+	.voltage_max = 8700,	/* mV */
 	.voltage_normal = 7600,
 	.voltage_min = 6100,
-	.precharge_current = 256,   /* mA */
+	.precharge_current = 256,	/* mA */
 	.start_charging_min_c = 0,
 	.start_charging_max_c = 46,
 	.charging_min_c = 0,
@@ -58,6 +59,59 @@ int board_cut_off_battery(void)
 	return rv;
 }
 
+enum battery_disconnect_state battery_get_disconnect_state(void)
+{
+	uint8_t data[6];
+	int rv;
+
+	/*
+	 * Take note if we find that the battery isn't in disconnect state,
+	 * and always return NOT_DISCONNECTED without probing the battery.
+	 * This assumes the battery will not go to disconnect state during
+	 * runtime.
+	 */
+	static int not_disconnected;
+
+	if (not_disconnected)
+		return BATTERY_NOT_DISCONNECTED;
+
+	if (extpower_is_present()) {
+		/* Check if battery charging + discharging is disabled. */
+		rv = sb_write(SB_MANUFACTURER_ACCESS,
+			      PARAM_OPERATION_STATUS);
+		if (rv)
+			return BATTERY_DISCONNECT_ERROR;
+
+		rv = sb_read_string(I2C_PORT_BATTERY, BATTERY_ADDR,
+				    SB_ALT_MANUFACTURER_ACCESS, data, 6);
+
+		if (rv || (~data[3] & (BATTERY_DISCHARGING_DISABLED |
+				       BATTERY_CHARGING_DISABLED))) {
+			not_disconnected = 1;
+			return BATTERY_NOT_DISCONNECTED;
+		}
+
+		/*
+		 * Battery is neither charging nor discharging. Verify that
+		 * we didn't enter this state due to a safety fault.
+		 */
+		rv = sb_write(SB_MANUFACTURER_ACCESS, PARAM_SAFETY_STATUS);
+		if (rv)
+			return BATTERY_DISCONNECT_ERROR;
+
+		rv = sb_read_string(I2C_PORT_BATTERY, BATTERY_ADDR,
+				    SB_ALT_MANUFACTURER_ACCESS, data, 6);
+
+		if (rv || data[2] || data[3] || data[4] || data[5])
+			return BATTERY_DISCONNECT_ERROR;
+
+		/* No safety fault, battery is disconnected */
+		return BATTERY_DISCONNECTED;
+	}
+	not_disconnected = 1;
+	return BATTERY_NOT_DISCONNECTED;
+}
+
 #ifdef CONFIG_CHARGER_PROFILE_OVERRIDE
 
 static int fast_charging_allowed = 1;
@@ -70,6 +124,7 @@ static int fast_charging_allowed = 1;
  * Return the next poll period in usec, or zero to use the default (which is
  * state dependent).
  */
+
 int charger_profile_override(struct charge_state_data *curr)
 {
 	/* temp in 0.1 deg C */
@@ -225,12 +280,12 @@ static int command_fastcharge(int argc, char **argv)
 
 	return EC_SUCCESS;
 }
+
 DECLARE_CONSOLE_COMMAND(fastcharge, command_fastcharge,
 			"[on|off]",
-			"Get or set fast charging profile",
-			NULL);
+			"Get or set fast charging profile", NULL);
 
-#endif	/* CONFIG_CHARGER_PROFILE_OVERRIDE */
+#endif				/* CONFIG_CHARGER_PROFILE_OVERRIDE */
 
 #ifdef CONFIG_BATTERY_PRESENT_CUSTOM
 /*
diff --git a/board/reef/board.h b/board/reef/board.h
index bd06f25e25..40f9416335 100644
--- a/board/reef/board.h
+++ b/board/reef/board.h
@@ -20,6 +20,7 @@
 /* Battery */
 #define CONFIG_BATTERY_CUT_OFF
 #define CONFIG_BATTERY_PRESENT_CUSTOM
+#define CONFIG_BATTERY_REVIVE_DISCONNECT
 #define CONFIG_BATTERY_SMART
 
 /* Charger */