power: supply: max1720x correct capacity computation

From the datasheet of the MAX17201/17205, the LSB should be "5.0μVh/RSENSE".
The current computation sets it at 0.5mAh=5.0μVh/10mOhm, which does not take
into account the value of rsense (which is in 10µV steps) which can be
different from 10mOhm.

Change the computation to fit the specs.

Fixes: 479b6d0 ("power: supply: add support for MAX1720x standalone fuel gauge")
Signed-off-by: Thomas Antoine <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sebastian Reichel <[email protected]>

Author: Thomas Antoine

drivers/power/supply/max1720x_battery.c

@@ -288,9 +288,10 @@ static int max172xx_voltage_to_ps(unsigned int reg)
 	return reg * 1250;	/* in uV */
 }
 
-static int max172xx_capacity_to_ps(unsigned int reg)
+static int max172xx_capacity_to_ps(unsigned int reg,
+				   struct max1720x_device_info *info)
 {
-	return reg * 500;	/* in uAh */
+	return reg * (500000 / info->rsense);	/* in uAh */
 }
 
 /*
@@ -394,11 +395,11 @@ static int max1720x_battery_get_property(struct power_supply *psy,
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 		ret = regmap_read(info->regmap, MAX172XX_DESIGN_CAP, &reg_val);
-		val->intval = max172xx_capacity_to_ps(reg_val);
+		val->intval = max172xx_capacity_to_ps(reg_val, info);
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_AVG:
 		ret = regmap_read(info->regmap, MAX172XX_REPCAP, &reg_val);
-		val->intval = max172xx_capacity_to_ps(reg_val);
+		val->intval = max172xx_capacity_to_ps(reg_val, info);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
 		ret = regmap_read(info->regmap, MAX172XX_TTE, &reg_val);
@@ -422,7 +423,7 @@ static int max1720x_battery_get_property(struct power_supply *psy,
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL:
 		ret = regmap_read(info->regmap, MAX172XX_FULL_CAP, &reg_val);
-		val->intval = max172xx_capacity_to_ps(reg_val);
+		val->intval = max172xx_capacity_to_ps(reg_val, info);
 		break;
 	case POWER_SUPPLY_PROP_MODEL_NAME:
 		ret = regmap_read(info->regmap, MAX172XX_DEV_NAME, &reg_val);