power: supply: add Huawei Matebook E Go psy driver

On the Huawei Matebook E Go tablet the EC provides access to the adapter
and battery status. Add the driver to read power supply status on the
tablet.

This driver is inspired by the following drivers:
        drivers/power/supply/lenovo_yoga_c630_battery.c
        drivers/platform/arm64/acer-aspire1-ec.c
        drivers/acpi/battery.c
        drivers/acpi/ac.c

base-commit: 613af58

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Link: https://lore.kernel.org/r/20250313103437.108772-1-mitltlatltl@gmail.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Author: right-0903

Documentation/ABI/testing/sysfs-class-power-gaokun

@@ -0,0 +1,27 @@
+What:		/sys/class/power_supply/gaokun-ec-battery/smart_charge_delay
+Date:		March 2025
+KernelVersion:	6.15
+Contact:	Pengyu Luo <mitltlatltl@gmail.com>
+Description:
+		This entry allows configuration of smart charging delay.
+
+		Smart charging behavior: when the power adapter is connected
+		for delay hours, battery charging will follow the rules of
+		charge_control_start_threshold and charge_control_end_threshold.
+		For more information about charge control, please refer to
+		sysfs-class-power.
+
+		Access: Read, Write
+
+		Valid values: In hours (non-negative)
+
+What:		/sys/class/power_supply/gaokun-ec-battery/battery_adaptive_charge
+Date:		March 2025
+KernelVersion:	6.15
+Contact:	Pengyu Luo <mitltlatltl@gmail.com>
+Description:
+		This entry allows enabling battery adaptive charging.
+
+		Access: Read, Write
+
+		Valid values: 0 (disabled) or 1 (enabled)

MAINTAINERS

@@ -10950,6 +10950,7 @@ M:	Pengyu Luo <mitltlatltl@gmail.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/platform/huawei,gaokun-ec.yaml
 F:	drivers/platform/arm64/huawei-gaokun-ec.c
+F:	drivers/power/supply/huawei-gaokun-battery.c
 F:	include/linux/platform_data/huawei-gaokun-ec.h
 
 HUGETLB SUBSYSTEM

drivers/power/supply/Kconfig

@@ -173,6 +173,16 @@ config BATTERY_DS2782
 	  Say Y here to enable support for the DS2782/DS2786 standalone battery
 	  gas-gauge.
 
+config BATTERY_HUAWEI_GAOKUN
+	tristate "Huawei Matebook E Go power supply"
+	depends on EC_HUAWEI_GAOKUN
+	help
+	  This driver enables battery and adapter support on the Huawei Matebook
+	  E Go, which is a sc8280xp-based 2-in-1 tablet.
+
+	  To compile the driver as a module, choose M here: the module will be
+	  called huawei-gaokun-battery.
+
 config BATTERY_LEGO_EV3
 	tristate "LEGO MINDSTORMS EV3 battery"
 	depends on OF && IIO && GPIOLIB && (ARCH_DAVINCI_DA850 || COMPILE_TEST)

drivers/power/supply/Makefile

@@ -32,6 +32,7 @@ obj-$(CONFIG_BATTERY_DS2781)	+= ds2781_battery.o
 obj-$(CONFIG_BATTERY_DS2782)	+= ds2782_battery.o
 obj-$(CONFIG_BATTERY_GAUGE_LTC2941)	+= ltc2941-battery-gauge.o
 obj-$(CONFIG_BATTERY_GOLDFISH)	+= goldfish_battery.o
+obj-$(CONFIG_BATTERY_HUAWEI_GAOKUN)	+= huawei-gaokun-battery.o
 obj-$(CONFIG_BATTERY_LEGO_EV3)	+= lego_ev3_battery.o
 obj-$(CONFIG_BATTERY_LENOVO_YOGA_C630) += lenovo_yoga_c630_battery.o
 obj-$(CONFIG_BATTERY_PMU)	+= pmu_battery.o