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

Add charger driver for ROHM BD718(15/28/78) PMIC charger block.
It is a stripped down version of the driver here:
https://lore.kernel.org/lkml/dbd97c1b0d715aa35a8b4d79741e433d97c562aa.1637061794.git.matti.vaittinen@fi.rohmeurope.com/

For the ease of review and to do a step-by-step approach remove all the
coloumb counter related stuff and do not sneak in BD71827 support. That
also avoids non-trivial rebasing of the above series.

Changes besides that:
Replace the custom property by a standard one and do not use megaohms
for the current sense resistor.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://patch.msgid.link/20250918-bd71828-charger-v5-2-851164839c28@kemnade.info
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/Kconfig

@@ -996,6 +996,15 @@ 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
+	help
+	  Say Y here to enable support for charger and battery
+	  in ROHM BD71815, BD71817, ROHM BD71828 power management
+	  ICs. This driver gets various bits of information about battery
+	  and charger states.
+
 config CHARGER_BD99954
 	tristate "ROHM bd99954 charger driver"
 	depends on I2C

drivers/power/supply/Makefile

@@ -116,6 +116,7 @@ obj-$(CONFIG_CHARGER_SC2731)	+= sc2731_charger.o
 obj-$(CONFIG_FUEL_GAUGE_SC27XX)	+= sc27xx_fuel_gauge.o
 obj-$(CONFIG_FUEL_GAUGE_STC3117)       += stc3117_fuel_gauge.o
 obj-$(CONFIG_CHARGER_UCS1002)	+= ucs1002_power.o
+obj-$(CONFIG_CHARGER_BD71828)	+= bd71828-power.o
 obj-$(CONFIG_CHARGER_BD99954)	+= bd99954-charger.o
 obj-$(CONFIG_CHARGER_WILCO)	+= wilco-charger.o
 obj-$(CONFIG_RN5T618_POWER)	+= rn5t618_power.o