power_supply: Add MAX17042 Fuel Gauge Driver

The MAX17042 is a fuel gauge with an I2C interface for lithium-ion
betteries. Unlike its predecessor MAX17040, MAX17042 uses 16bit
registers. Besides, MAX17042 has much more features than MAX17040; e.g.,
a thermistor, current and current accumulation measurement, battery
internal resistance estimate, average values of measurement, and others.

This patch implements a driver for MAX17042.
In this initial release, we have implemented the most basic features of
a fuel gauge: measure the battery capacity and voltage.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 3216529..61bf5d7 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -136,6 +136,16 @@
 	  in handheld and portable equipment. The MAX17040 is configured
 	  to operate with a single lithium cell
 
+config BATTERY_MAX17042
+	tristate "Maxim MAX17042/8997/8966 Fuel Gauge"
+	depends on I2C
+	help
+	  MAX17042 is fuel-gauge systems for lithium-ion (Li+) batteries
+	  in handheld and portable equipment. The MAX17042 is configured
+	  to operate with a single lithium cell. MAX8997 and MAX8966 are
+	  multi-function devices that include fuel gauages that are compatible
+	  with MAX17042.
+
 config BATTERY_Z2
 	tristate "Z2 battery driver"
 	depends on I2C && MACH_ZIPIT2