power: supply: Introduces bypass charging property

Adds a POWER_SUPPLY_CHARGE_TYPE_BYPASS option to the POWER_SUPPLY_PROP_CHARGE_TYPE
property to facilitate bypass charging operation.

In bypass charging operation, the charger bypasses the charging path around the
integrated converter allowing for a "smart" wall adaptor to perform the power
conversion externally.

This operational mode is critical for the USB PPS standard of power adaptors and is
becoming a common feature in modern charging ICs such as:

- BQ25980
- BQ25975
- BQ25960
- LN8000
- LN8410

Signed-off-by: Ricardo Rivera-Matos <rriveram@opensource.cirrus.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/ABI/testing/sysfs-class-power

@@ -380,13 +380,16 @@ Description:
 		algorithm to adjust the charge rate dynamically, without
 		any user configuration required. "Custom" means that the charger
 		uses the charge_control_* properties as configuration for some
-		different algorithm.
+		different algorithm. "Bypass" means the charger bypasses the
+		charging path around the integrated converter allowing for a
+		"smart" wall adaptor to perform the power conversion
+		externally.
 
 		Access: Read, Write
 
 		Valid values:
 			      "Unknown", "N/A", "Trickle", "Fast", "Standard",
-			      "Adaptive", "Custom"
+			      "Adaptive", "Custom", "Bypass"
 
 What:		/sys/class/power_supply/<supply_name>/charge_term_current
 Date:		July 2014

drivers/power/supply/power_supply_sysfs.c

@@ -89,6 +89,7 @@ static const char * const POWER_SUPPLY_CHARGE_TYPE_TEXT[] = {
 	[POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE]	= "Adaptive",
 	[POWER_SUPPLY_CHARGE_TYPE_CUSTOM]	= "Custom",
 	[POWER_SUPPLY_CHARGE_TYPE_LONGLIFE]	= "Long Life",
+	[POWER_SUPPLY_CHARGE_TYPE_BYPASS]	= "Bypass",
 };
 
 static const char * const POWER_SUPPLY_HEALTH_TEXT[] = {

include/linux/power_supply.h

@@ -49,6 +49,7 @@ enum {
 	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 */
+	POWER_SUPPLY_CHARGE_TYPE_BYPASS,	/* bypassing the charger */
 };
 
 enum {