power: supply: sc27xx: Optimize the battery resistance with measuring temperature

Optimize the battery internal resistance in a certain temerature to
get a accurate battery internal resistance.
Signed-off-by: Yuanjiang Yu <yuanjiang.yu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/sc27xx_fuel_gauge.c

@@ -81,9 +81,11 @@
  * @max_volt: the maximum constant input voltage in millivolt
  * @min_volt: the minimum drained battery voltage in microvolt
  * @table_len: the capacity table length
+ * @resist_table_len: the resistance table length
  * @cur_1000ma_adc: ADC value corresponding to 1000 mA
  * @vol_1000mv_adc: ADC value corresponding to 1000 mV
  * @cap_table: capacity table with corresponding ocv
+ * @resist_table: resistance percent table with corresponding temperature
  */
 struct sc27xx_fgu_data {
 	struct regmap *regmap;
@@ -103,15 +105,18 @@ struct sc27xx_fgu_data {
 	int max_volt;
 	int min_volt;
 	int table_len;
+	int resist_table_len;
 	int cur_1000ma_adc;
 	int vol_1000mv_adc;
 	struct power_supply_battery_ocv_table *cap_table;
+	struct power_supply_resistance_temp_table *resist_table;
 };
 
 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, bool int_mode);
 static void sc27xx_fgu_adjust_cap(struct sc27xx_fgu_data *data, int cap);
+static int sc27xx_fgu_get_temp(struct sc27xx_fgu_data *data, int *temp);
 
 static const char * const sc27xx_charger_supply_name[] = {
 	"sc2731_charger",
@@ -434,7 +439,7 @@ static int sc27xx_fgu_get_current(struct sc27xx_fgu_data *data, int *val)
 
 static int sc27xx_fgu_get_vbat_ocv(struct sc27xx_fgu_data *data, int *val)
 {
-	int vol, cur, ret;
+	int vol, cur, ret, temp, resistance;
 
 	ret = sc27xx_fgu_get_vbat_vol(data, &vol);
 	if (ret)
@@ -444,8 +449,19 @@ static int sc27xx_fgu_get_vbat_ocv(struct sc27xx_fgu_data *data, int *val)
 	if (ret)
 		return ret;
 
+	resistance = data->internal_resist;
+	if (data->resist_table_len > 0) {
+		ret = sc27xx_fgu_get_temp(data, &temp);
+		if (ret)
+			return ret;
+
+		resistance = power_supply_temp2resist_simple(data->resist_table,
+						data->resist_table_len, temp);
+		resistance = data->internal_resist * resistance / 100;
+	}
+
 	/* Return the battery OCV in micro volts. */
-	*val = vol * 1000 - cur * data->internal_resist;
+	*val = vol * 1000 - cur * resistance;
 
 	return 0;
 }
@@ -929,6 +945,18 @@ static int sc27xx_fgu_hw_init(struct sc27xx_fgu_data *data)
 	if (!data->alarm_cap)
 		data->alarm_cap += 1;
 
+	data->resist_table_len = info.resist_table_size;
+	if (data->resist_table_len > 0) {
+		data->resist_table = devm_kmemdup(data->dev, info.resist_table,
+						  data->resist_table_len *
+						  sizeof(struct power_supply_resistance_temp_table),
+						  GFP_KERNEL);
+		if (!data->resist_table) {
+			power_supply_put_battery_info(data->battery, &info);
+			return -ENOMEM;
+		}
+	}
+
 	power_supply_put_battery_info(data->battery, &info);
 
 	ret = sc27xx_fgu_calibration(data);