power: supply: core: Add power_supply_prop_precharge

Battery chargers use POWER_SUPPLY_PROP_PRECHARGE_CURRENT
Clarify related item POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT
Signed-off-by: Liam Breck <kernel@networkimprov.net>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

Documentation/power/power_supply_class.txt

@@ -115,28 +115,33 @@ of charge when battery became full/empty". It also could mean "value of
 charge when battery considered full/empty at given conditions (temperature,
 age)". I.e. these attributes represents real thresholds, not design values.
 
+ENERGY_FULL, ENERGY_EMPTY - same as above but for energy.
+
 CHARGE_COUNTER - the current charge counter (in µAh).  This could easily
 be negative; there is no empty or full value.  It is only useful for
 relative, time-based measurements.
 
+PRECHARGE_CURRENT - the maximum charge current during precharge phase
+of charge cycle (typically 20% of battery capacity).
+CHARGE_TERM_CURRENT - Charge termination current. The charge cycle
+terminates when battery voltage is above recharge threshold, and charge
+current is below this setting (typically 10% of battery capacity).
+
 CONSTANT_CHARGE_CURRENT - constant charge current programmed by charger.
 CONSTANT_CHARGE_CURRENT_MAX - maximum charge current supported by the
 power supply object.
-INPUT_CURRENT_LIMIT - input current limit programmed by charger. Indicates
-the current drawn from a charging source.
-CHARGE_TERM_CURRENT - Charge termination current used to detect the end of charge
-condition.
-
-CALIBRATE - battery or coulomb counter calibration status
 
 CONSTANT_CHARGE_VOLTAGE - constant charge voltage programmed by charger.
 CONSTANT_CHARGE_VOLTAGE_MAX - maximum charge voltage supported by the
 power supply object.
 
+INPUT_CURRENT_LIMIT - input current limit programmed by charger. Indicates
+the current drawn from a charging source.
+
 CHARGE_CONTROL_LIMIT - current charge control limit setting
 CHARGE_CONTROL_LIMIT_MAX - maximum charge control limit setting
 
-ENERGY_FULL, ENERGY_EMPTY - same as above but for energy.
+CALIBRATE - battery or coulomb counter calibration status
 
 CAPACITY - capacity in percents.
 CAPACITY_ALERT_MIN - minimum capacity alert value in percents.

drivers/power/supply/power_supply_sysfs.c

@@ -242,6 +242,7 @@ static struct device_attribute power_supply_attrs[] = {
 	POWER_SUPPLY_ATTR(time_to_full_avg),
 	POWER_SUPPLY_ATTR(type),
 	POWER_SUPPLY_ATTR(scope),
+	POWER_SUPPLY_ATTR(precharge_current),
 	POWER_SUPPLY_ATTR(charge_term_current),
 	POWER_SUPPLY_ATTR(calibrate),
 	/* Properties of type `const char *' */

include/linux/power_supply.h

@@ -146,6 +146,7 @@ enum power_supply_property {
 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
 	POWER_SUPPLY_PROP_TYPE, /* use power_supply.type instead */
 	POWER_SUPPLY_PROP_SCOPE,
+	POWER_SUPPLY_PROP_PRECHARGE_CURRENT,
 	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
 	POWER_SUPPLY_PROP_CALIBRATE,
 	/* Properties of type `const char *' */
@@ -382,6 +383,8 @@ static inline bool power_supply_is_amp_property(enum power_supply_property psp)
 	case POWER_SUPPLY_PROP_CHARGE_NOW:
 	case POWER_SUPPLY_PROP_CHARGE_AVG:
 	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
+	case POWER_SUPPLY_PROP_PRECHARGE_CURRENT:
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
 	case POWER_SUPPLY_PROP_CURRENT_MAX: