power: supply: cpcap-battery: Add a battery driver

On the CPCAP PMIC we can use the ADCs for monitoring the battery,
and there is also a coulomb counter. So let's add basic support for
the battery driver.

I did not add any capacity prediction as that should probably be
done in the user space. Or at least user space should tell the kernel
some battery statistics and then the kernel driver could display the
capacity based on that.

Cc: devicetree@vger.kernel.org
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Michael Scott <michael.scott@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

drivers/power/supply/Kconfig

@@ -82,6 +82,14 @@ config BATTERY_ACT8945A
 	  Say Y here to enable support for power supply provided by
 	  Active-semi ActivePath ACT8945A charger.
 
+config BATTERY_CPCAP
+	tristate "Motorola CPCAP PMIC battery driver"
+	depends on MFD_CPCAP && IIO
+	default MFD_CPCAP
+	help
+	  Say Y here to enable support for battery on Motorola
+	  phones and tablets such as droid 4.
+
 config BATTERY_DS2760
 	tristate "DS2760 battery driver (HP iPAQ & others)"
 	depends on W1 && W1_SLAVE_DS2760

drivers/power/supply/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_BATTERY_88PM860X)	+= 88pm860x_battery.o
 obj-$(CONFIG_BATTERY_ACT8945A)	+= act8945a_charger.o
 obj-$(CONFIG_BATTERY_AXP20X)	+= axp20x_battery.o
 obj-$(CONFIG_CHARGER_AXP20X)	+= axp20x_ac_power.o
+obj-$(CONFIG_BATTERY_CPCAP)	+= cpcap-battery.o
 obj-$(CONFIG_BATTERY_DS2760)	+= ds2760_battery.o
 obj-$(CONFIG_BATTERY_DS2780)	+= ds2780_battery.o
 obj-$(CONFIG_BATTERY_DS2781)	+= ds2781_battery.o