power: supply: Add support for MAX1721x standalone fuel gauge

The MAX17211 monitor a single cell pack. The MAX17215 monitor and
balance a 2S or 3S pack or monitor a multiple-series cell pack.
Both device use 1-Wire interfce.
Signed-off-by: Alex A. Mihaylov <minimumlaw@rambler.ru>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

drivers/power/supply/Kconfig

@@ -313,6 +313,19 @@ config BATTERY_MAX17042
 	  with MAX17042. This driver also supports max17047/50 chips which are
 	  improved version of max17042.
 
+config BATTERY_MAX1721X
+	tristate "MAX17211/MAX17215 standalone gas-gauge"
+	depends on W1
+	select REGMAP_W1
+	help
+	  MAX1721x is fuel-gauge systems for lithium-ion (Li+) batteries
+	  in handheld and portable equipment. MAX17211 used with single cell
+	  battery. MAX17215 designed for muticell battery. Both them have
+	  OneWire (W1) host interface.
+
+	  Say Y here to enable support for the MAX17211/MAX17215 standalone
+	  battery gas-gauge.
+
 config BATTERY_Z2
 	tristate "Z2 battery driver"
 	depends on I2C && MACH_ZIPIT2

drivers/power/supply/Makefile

@@ -44,6 +44,7 @@ obj-$(CONFIG_CHARGER_DA9150)	+= da9150-charger.o
 obj-$(CONFIG_BATTERY_DA9150)	+= da9150-fg.o
 obj-$(CONFIG_BATTERY_MAX17040)	+= max17040_battery.o
 obj-$(CONFIG_BATTERY_MAX17042)	+= max17042_battery.o
+obj-$(CONFIG_BATTERY_MAX1721X)	+= max1721x_battery.o
 obj-$(CONFIG_BATTERY_Z2)	+= z2_battery.o
 obj-$(CONFIG_BATTERY_RT5033)	+= rt5033_battery.o
 obj-$(CONFIG_CHARGER_RT9455)	+= rt9455_charger.o