power: supply: wilco_ec: Add long life charging mode

This is a long life mode set in the factory for extended warranty
battery, the power charging rate is customized so that battery at
work last longer.

Presently switching to a different battery charging mode is through
EC PID 0x0710 to configure the battery firmware, this operation will
be blocked by EC with failure code 0x01 when PLL mode is already
in use.

Signed-off-by: Crag Wang <crag.wang@dell.com>
Reviewed-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/ABI/testing/sysfs-class-power-wilco

@@ -14,6 +14,10 @@ Description:
 			Charging begins when level drops below
 			charge_control_start_threshold, and ceases when
 			level is above charge_control_end_threshold.
+		Long Life: Customized charge rate for last longer battery life.
+			On Wilco device this mode is pre-configured in the factory
+			through EC's private PID. Swiching to a different mode will
+			be denied by Wilco EC when Long Life mode is enabled.
 
 What:		/sys/class/power_supply/wilco-charger/charge_control_start_threshold
 Date:		April 2019

drivers/power/supply/power_supply_sysfs.c

@@ -87,6 +87,7 @@ static const char * const POWER_SUPPLY_CHARGE_TYPE_TEXT[] = {
 	[POWER_SUPPLY_CHARGE_TYPE_STANDARD]	= "Standard",
 	[POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE]	= "Adaptive",
 	[POWER_SUPPLY_CHARGE_TYPE_CUSTOM]	= "Custom",
+	[POWER_SUPPLY_CHARGE_TYPE_LONGLIFE]	= "Long Life",
 };
 
 static const char * const POWER_SUPPLY_HEALTH_TEXT[] = {

drivers/power/supply/wilco-charger.c

@@ -27,6 +27,7 @@ enum charge_mode {
 	CHARGE_MODE_AC = 3,	/* Mostly AC use, used for Trickle */
 	CHARGE_MODE_AUTO = 4,	/* Used for Adaptive */
 	CHARGE_MODE_CUSTOM = 5,	/* Used for Custom */
+	CHARGE_MODE_LONGLIFE = 6, /* Used for Long Life */
 };
 
 #define CHARGE_LOWER_LIMIT_MIN	50
@@ -48,6 +49,8 @@ static int psp_val_to_charge_mode(int psp_val)
 		return CHARGE_MODE_AUTO;
 	case POWER_SUPPLY_CHARGE_TYPE_CUSTOM:
 		return CHARGE_MODE_CUSTOM;
+	case POWER_SUPPLY_CHARGE_TYPE_LONGLIFE:
+		return CHARGE_MODE_LONGLIFE;
 	default:
 		return -EINVAL;
 	}
@@ -67,6 +70,8 @@ static int charge_mode_to_psp_val(enum charge_mode mode)
 		return POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE;
 	case CHARGE_MODE_CUSTOM:
 		return POWER_SUPPLY_CHARGE_TYPE_CUSTOM;
+	case CHARGE_MODE_LONGLIFE:
+		return POWER_SUPPLY_CHARGE_TYPE_LONGLIFE;
 	default:
 		return -EINVAL;
 	}

include/linux/power_supply.h

@@ -48,6 +48,7 @@ enum {
 	POWER_SUPPLY_CHARGE_TYPE_STANDARD,	/* normal speed */
 	POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE,	/* dynamically adjusted speed */
 	POWER_SUPPLY_CHARGE_TYPE_CUSTOM,	/* use CHARGE_CONTROL_* props */
+	POWER_SUPPLY_CHARGE_TYPE_LONGLIFE,	/* slow speed, longer life */
 };
 
 enum {