power: supply: Add bd718(15/27/28/78) charger driver

Add charger driver for ROHM BD718(15/27/28/78) PMIC charger block.
Driver utilizes the simple-gauge for battery status / current polling,
CC correction and SOC estimation.

A version of driver which does not utilize simple-gauge can be seen
in ROHM venor specific Linux tree - comparison can visualize how
simple-gauge can simplify IC specific drivers.

https://github.com/RohmSemiconductor/Linux-Kernel-PMIC-Drivers/blob/stable-v5.4.6/drivers/power/supply/bd71827-power.c

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>

drivers/power/supply/Kconfig

@@ -791,6 +791,17 @@ config CHARGER_UCS1002
 	  Say Y to enable support for Microchip UCS1002 Programmable
 	  USB Port Power Controller with Charger Emulation.
 
+config CHARGER_BD71828
+	tristate "Power-supply driver for ROHM BD71828 and BD71815 PMIC"
+	depends on MFD_ROHM_BD71828
+	select POWER_SIMPLE_GAUGE
+	help
+	  Say Y here to enable support for charger, battery and fuel gauge
+	  in ROHM BD71815, BD71817, BD71827, ROHM BD71828 power management
+	  ICs. This driver gets various bits of information about battery
+	  and charger states and also implements fuel gauge based on
+	  coulomb counters on PMIC.
+
 config CHARGER_BD99954
 	tristate "ROHM bd99954 charger driver"
 	depends on I2C

drivers/power/supply/Makefile

@@ -99,6 +99,7 @@ obj-$(CONFIG_CHARGER_CROS_PCHG)	+= cros_peripheral_charger.o
 obj-$(CONFIG_CHARGER_SC2731)	+= sc2731_charger.o
 obj-$(CONFIG_FUEL_GAUGE_SC27XX)	+= sc27xx_fuel_gauge.o
 obj-$(CONFIG_CHARGER_UCS1002)	+= ucs1002_power.o
+obj-$(CONFIG_CHARGER_BD71828)	+= bd71827-power.o
 obj-$(CONFIG_CHARGER_BD99954)	+= bd99954-charger.o
 obj-$(CONFIG_CHARGER_WILCO)	+= wilco-charger.o
 obj-$(CONFIG_RN5T618_POWER)	+= rn5t618_power.o