Optimize the Spreadtrum SC27xx fuel gauge

index 24895cc..2fe97ae 100644
@@ -587,6 +587,10 @@ static int sc27xx_fgu_get_property(struct power_supply *psy,
 		val->intval = value * 1000;
 		break;
 
+	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
+		val->intval = data->total_cap * 1000;
+		break;
+
 	default:
 		ret = -EINVAL;
 		break;

@@ -644,6 +648,7 @@ static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
 	POWER_SUPPLY_PROP_CURRENT_NOW,
 	POWER_SUPPLY_PROP_CURRENT_AVG,
 	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
+	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
 };
 
 static const struct power_supply_desc sc27xx_fgu_desc = {

index 2fe97ae..ca7b73e 100644
@@ -1098,7 +1098,8 @@ static int sc27xx_fgu_suspend(struct device *dev)
 	 * If we are charging, then no need to enable the FGU interrupts to
 	 * adjust the battery capacity.
 	 */
-	if (status != POWER_SUPPLY_STATUS_NOT_CHARGING)
+	if (status != POWER_SUPPLY_STATUS_NOT_CHARGING &&
+	    status != POWER_SUPPLY_STATUS_DISCHARGING)
 		return 0;
 
 	ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_EN,

index ca7b73e..ab3afa1 100644
@@ -326,8 +326,6 @@ static int sc27xx_fgu_set_clbcnt(struct sc27xx_fgu_data *data, int clbcnt)
 {
 	int ret;
 
-	clbcnt *= SC27XX_FGU_SAMPLE_HZ;
-
 	ret = regmap_update_bits(data->regmap,
 				 data->base + SC27XX_FGU_CLBCNT_SETL,
 				 SC27XX_FGU_CLBCNT_MASK, clbcnt);

@@ -362,7 +360,6 @@ static int sc27xx_fgu_get_clbcnt(struct sc27xx_fgu_data *data, int *clb_cnt)
 
 	*clb_cnt = ccl & SC27XX_FGU_CLBCNT_MASK;
 	*clb_cnt |= (cch & SC27XX_FGU_CLBCNT_MASK) << SC27XX_FGU_CLBCNT_SHIFT;
-	*clb_cnt /= SC27XX_FGU_SAMPLE_HZ;
 
 	return 0;
 }

@@ -380,10 +377,10 @@ static int sc27xx_fgu_get_capacity(struct sc27xx_fgu_data *data, int *cap)
 
 	/*
 	 * Convert coulomb counter to delta capacity (mAh), and set multiplier
-	 * as 100 to improve the precision.
+	 * as 10 to improve the precision.
 	 */
-	temp = DIV_ROUND_CLOSEST(delta_clbcnt, 360);
-	temp = sc27xx_fgu_adc_to_current(data, temp);
+	temp = DIV_ROUND_CLOSEST(delta_clbcnt * 10, 36 * SC27XX_FGU_SAMPLE_HZ);
+	temp = sc27xx_fgu_adc_to_current(data, temp / 1000);
 
 	/*
 	 * Convert to capacity percent of the battery total capacity,

@@ -790,7 +787,7 @@ static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity)
 	 * Convert current capacity (mAh) to coulomb counter according to the
 	 * formula: 1 mAh =3.6 coulomb.
 	 */
-	return DIV_ROUND_CLOSEST(cur_cap * 36 * data->cur_1000ma_adc, 10);
+	return DIV_ROUND_CLOSEST(cur_cap * 36 * data->cur_1000ma_adc * SC27XX_FGU_SAMPLE_HZ, 10);
 }
 
 static int sc27xx_fgu_calibration(struct sc27xx_fgu_data *data)

index ab3afa1..f670131 100644
@@ -109,6 +109,8 @@ struct sc27xx_fgu_data {
 };
 
 static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity);
+static void sc27xx_fgu_capacity_calibration(struct sc27xx_fgu_data *data,
+					    int cap, int int_mode);
 
 static const char * const sc27xx_charger_supply_name[] = {
 	"sc2731_charger",

@@ -389,6 +391,9 @@ static int sc27xx_fgu_get_capacity(struct sc27xx_fgu_data *data, int *cap)
 	delta_cap = DIV_ROUND_CLOSEST(temp * 100, data->total_cap);
 	*cap = delta_cap + data->init_cap;
 
+	/* Calibrate the battery capacity in a normal range. */
+	sc27xx_fgu_capacity_calibration(data, *cap, false);
+
 	return 0;
 }
 

@@ -661,50 +666,62 @@ static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
 
 static void sc27xx_fgu_adjust_cap(struct sc27xx_fgu_data *data, int cap)
 {
+	int ret;
+
 	data->init_cap = cap;
-	data->init_clbcnt = sc27xx_fgu_cap_to_clbcnt(data, data->init_cap);
+	ret = sc27xx_fgu_get_clbcnt(data, &data->init_clbcnt);
+	if (ret)
+		dev_err(data->dev, "failed to get init coulomb counter\n");
 }
 
-static irqreturn_t sc27xx_fgu_interrupt(int irq, void *dev_id)
+static void sc27xx_fgu_capacity_calibration(struct sc27xx_fgu_data *data,
+					    int cap, int int_mode)
 {
-	struct sc27xx_fgu_data *data = dev_id;
-	int ret, cap, ocv, adc;
-	u32 status;
-
-	mutex_lock(&data->lock);
+	int ret, ocv, chg_sts, adc;
 
-	ret = regmap_read(data->regmap, data->base + SC27XX_FGU_INT_STS,
-			  &status);
-	if (ret)
-		goto out;
+	ret = sc27xx_fgu_get_vbat_ocv(data, &ocv);
+	if (ret) {
+		dev_err(data->dev, "get battery ocv error.\n");
+		return;
+	}
 
-	ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_CLR,
-				 status, status);
-	if (ret)
-		goto out;
+	ret = sc27xx_fgu_get_status(data, &chg_sts);
+	if (ret) {
+		dev_err(data->dev, "get charger status error.\n");
+		return;
+	}
 
 	/*
-	 * When low overload voltage interrupt happens, we should calibrate the
-	 * battery capacity in lower voltage stage.
+	 * If we are in charging mode, then we do not need to calibrate the
+	 * lower capacity.
 	 */
-	if (!(status & SC27XX_FGU_LOW_OVERLOAD_INT))
-		goto out;
+	if (chg_sts == POWER_SUPPLY_STATUS_CHARGING)
+		return;
 
-	ret = sc27xx_fgu_get_capacity(data, &cap);
-	if (ret)
-		goto out;
-
-	ret = sc27xx_fgu_get_vbat_ocv(data, &ocv);
-	if (ret)
-		goto out;
-
-	/*
-	 * If current OCV value is less than the minimum OCV value in OCV table,
-	 * which means now battery capacity is 0%, and we should adjust the
-	 * inititial capacity to 0.
-	 */
-	if (ocv <= data->cap_table[data->table_len - 1].ocv) {
+	if ((ocv > data->cap_table[0].ocv && cap < 100) || cap > 100) {
+		/*
+		 * If current OCV value is larger than the max OCV value in
+		 * OCV table, or the current capacity is larger than 100,
+		 * we should force the inititial capacity to 100.
+		 */
+		sc27xx_fgu_adjust_cap(data, 100);
+	} else if (ocv <= data->cap_table[data->table_len - 1].ocv) {
+		/*
+		 * If current OCV value is leass than the minimum OCV value in
+		 * OCV table, we should force the inititial capacity to 0.
+		 */
 		sc27xx_fgu_adjust_cap(data, 0);
+	} else if ((ocv > data->cap_table[data->table_len - 1].ocv && cap <= 0) ||
+		   (ocv > data->min_volt && cap <= data->alarm_cap)) {
+		/*
+		 * If current OCV value is not matchable with current capacity,
+		 * we should re-calculate current capacity by looking up the
+		 * OCV table.
+		 */
+		int cur_cap = power_supply_ocv2cap_simple(data->cap_table,
+							  data->table_len, ocv);
+
+		sc27xx_fgu_adjust_cap(data, cur_cap);
 	} else if (ocv <= data->min_volt) {
 		/*
 		 * If current OCV value is less than the low alarm voltage, but

@@ -713,7 +730,7 @@ static irqreturn_t sc27xx_fgu_interrupt(int irq, void *dev_id)
 		 */
 		if (cap > data->alarm_cap) {
 			sc27xx_fgu_adjust_cap(data, data->alarm_cap);
-		} else if (cap <= 0) {
+		} else {
 			int cur_cap;
 
 			/*

@@ -728,15 +745,55 @@ static irqreturn_t sc27xx_fgu_interrupt(int irq, void *dev_id)
 			sc27xx_fgu_adjust_cap(data, cur_cap);
 		}
 
+		if (!int_mode)
+			return;
+
 		/*
 		 * After adjusting the battery capacity, we should set the
 		 * lowest alarm voltage instead.
 		 */
 		data->min_volt = data->cap_table[data->table_len - 1].ocv;
+		data->alarm_cap = power_supply_ocv2cap_simple(data->cap_table,
+							      data->table_len,
+							      data->min_volt);
+
 		adc = sc27xx_fgu_voltage_to_adc(data, data->min_volt / 1000);
-		regmap_update_bits(data->regmap, data->base + SC27XX_FGU_LOW_OVERLOAD,
+		regmap_update_bits(data->regmap,
+				   data->base + SC27XX_FGU_LOW_OVERLOAD,
 				   SC27XX_FGU_LOW_OVERLOAD_MASK, adc);
 	}
+}
+
+static irqreturn_t sc27xx_fgu_interrupt(int irq, void *dev_id)
+{
+	struct sc27xx_fgu_data *data = dev_id;
+	int ret, cap;
+	u32 status;
+
+	mutex_lock(&data->lock);
+
+	ret = regmap_read(data->regmap, data->base + SC27XX_FGU_INT_STS,
+			  &status);
+	if (ret)
+		goto out;
+
+	ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_CLR,
+				 status, status);
+	if (ret)
+		goto out;
+
+	/*
+	 * When low overload voltage interrupt happens, we should calibrate the
+	 * battery capacity in lower voltage stage.
+	 */
+	if (!(status & SC27XX_FGU_LOW_OVERLOAD_INT))
+		goto out;
+
+	ret = sc27xx_fgu_get_capacity(data, &cap);
+	if (ret)
+		goto out;
+
+	sc27xx_fgu_capacity_calibration(data, cap, true);
 
 out:
 	mutex_unlock(&data->lock);

index f670131..fa85f40 100644
@@ -915,6 +915,8 @@ static int sc27xx_fgu_hw_init(struct sc27xx_fgu_data *data)
 	data->alarm_cap = power_supply_ocv2cap_simple(data->cap_table,
 						      data->table_len,
 						      data->min_volt);
+	if (!data->alarm_cap)
+		data->alarm_cap += 1;
 
 	power_supply_put_battery_info(data->battery, &info);
 

index fa85f40..6363c48 100644
@@ -111,6 +111,7 @@ struct sc27xx_fgu_data {
 static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity);
 static void sc27xx_fgu_capacity_calibration(struct sc27xx_fgu_data *data,
 					    int cap, int int_mode);
+static void sc27xx_fgu_adjust_cap(struct sc27xx_fgu_data *data, int cap);
 
 static const char * const sc27xx_charger_supply_name[] = {
 	"sc2731_charger",

@@ -610,17 +611,25 @@ static int sc27xx_fgu_set_property(struct power_supply *psy,
 	struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
 	int ret;
 
-	if (psp != POWER_SUPPLY_PROP_CAPACITY)
-		return -EINVAL;
-
 	mutex_lock(&data->lock);
 
-	ret = sc27xx_fgu_save_last_cap(data, val->intval);
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CAPACITY:
+		ret = sc27xx_fgu_save_last_cap(data, val->intval);
+		if (ret < 0)
+			dev_err(data->dev, "failed to save battery capacity\n");
+		break;
 
-	mutex_unlock(&data->lock);
+	case POWER_SUPPLY_PROP_CALIBRATE:
+		sc27xx_fgu_adjust_cap(data, val->intval);
+		ret = 0;
+		break;
 
-	if (ret < 0)
-		dev_err(data->dev, "failed to save battery capacity\n");
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&data->lock);
 
 	return ret;
 }

@@ -635,7 +644,8 @@ static void sc27xx_fgu_external_power_changed(struct power_supply *psy)
 static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
 					    enum power_supply_property psp)
 {
-	return psp == POWER_SUPPLY_PROP_CAPACITY;
+	return psp == POWER_SUPPLY_PROP_CAPACITY ||
+		psp == POWER_SUPPLY_PROP_CALIBRATE;
 }
 
 static enum power_supply_property sc27xx_fgu_props[] = {

@@ -651,6 +661,7 @@ static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
 	POWER_SUPPLY_PROP_CURRENT_AVG,
 	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
 	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
+	POWER_SUPPLY_PROP_CALIBRATE,
 };
 
 static const struct power_supply_desc sc27xx_fgu_desc = {