Add battery charge state machine and task

This CL adds a charge state machine for SMB compliant battery pack.
Vendor specific charge constraints can be applied through function
call, defined in battery_pack.h .

BUG=chrome-os-partner:7526
TEST=Attach EC serial console
  Unplug AC adapter: state ==> "discharge"
  Plug AC adapter:   state ==> "charge"
  Battery full:      state ==> "idle"
  Unplug battery:    state ==> "error"

Change-Id: Iabff0988a6067d37c17c11b060bbb7e66505c118

1 files changed, 86 insertions, 0 deletions

diff --git a/common/battery_atl706486.c b/common/battery_atl706486.c
new file mode 100644
index 0000000000..1bf973a7c7
--- /dev/null
+++ b/common/battery_atl706486.c
@@ -0,0 +1,86 @@
+/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Battery pack vendor provided charging profile for ATL706486
+ */
+
+#include "battery_pack.h"
+
+/* Convert Celsius degree to Deci Kelvin degree */
+static inline int celsius_to_deci_kelvin(int degree_c)
+{
+	return degree_c * 10 + 2731;
+}
+
+static inline void limit_value(int *val, int limit)
+{
+	if (*val > limit)
+		*val = limit;
+}
+
+/* Vendor provided parameters for battery charging */
+void battery_vendor_params(struct batt_params *batt)
+{
+	/* Designed capacity
+	 *   Battery capacity = 8400 mAh
+	 *   1C = 8400 mA
+	 */
+	const int C = 8400;
+	const int C_01 = C * 0.1;
+	const int C_02 = C * 0.2;
+	const int C_05 = C * 0.5;
+	const int C_07 = C * 0.7;
+
+	/* Designed voltage
+	 *   max    = 8.4V
+	 *   normal = 7.4V
+	 */
+	const int V_max = 8400;
+
+	/* Operation temperation range
+	 *   0   <= T_charge    <= 45
+	 *   -20 <= T_discharge <= 60
+	 */
+	const int T_charge_min = 0;
+	const int T_charge_max = 45;
+
+	int *desired_current = &batt->desired_current;
+
+	/* Hard limits
+	 *  - charging voltage < 8.4V
+	 *  - charging temperature range 0 ~ 45 degree Celcius
+	 *  */
+	if (batt->desired_voltage > V_max)
+		batt->desired_voltage = V_max;
+	if (batt->temperature >= celsius_to_deci_kelvin(T_charge_max) ||
+	    batt->temperature <= celsius_to_deci_kelvin(T_charge_min)) {
+		batt->desired_voltage = 0;
+		batt->desired_current = 0;
+	}
+
+	/* Vendor provided charging method
+	 *      temp  :    I - V   ,   I - V
+	 *  -  0 ~ 10 : 0.2C - 8.0V, 0.1C to 8.4V
+	 *  - 10 ~ 23 : 0.5C - 8.0V, 0.2C to 8.4V
+	 *  - 23 ~ 45 : 0.7C - 8.0V, 0.2C to 8.4V
+	 */
+	if (batt->temperature <= celsius_to_deci_kelvin(10)) {
+		if (batt->voltage < 8000)
+			limit_value(desired_current, C_02);
+		else
+			limit_value(desired_current, C_01);
+	} else if (batt->temperature <= celsius_to_deci_kelvin(23)) {
+		if (batt->voltage < 8000)
+			limit_value(desired_current, C_05);
+		else
+			limit_value(desired_current, C_02);
+	} else {
+		if (batt->voltage < 8000)
+			limit_value(desired_current, C_07);
+		else
+			limit_value(desired_current, C_02);
+	}
+}
+
+