Ayaneo devices support charge inhibition via the EC. This inhibition
only works while the device is powered on, and resets between restarts.
However, it is maintained across suspend/resume cycles.

The EC does not support charge threshold control. Instead, userspace
software on Windows manually toggles charge inhibition depending on
battery level.

Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
---
 drivers/platform/x86/Kconfig     |   1 +
 drivers/platform/x86/ayaneo-ec.c | 112 +++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index e19850bd2609..b049c55057b7 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -320,6 +320,7 @@ config AYANEO_EC
 	tristate "Ayaneo EC platform control"
 	depends on DMI
 	depends on ACPI_EC
+	depends on ACPI_BATTERY
 	depends on HWMON
 	help
 	  Enables support for the platform EC of Ayaneo devices. This
diff --git a/drivers/platform/x86/ayaneo-ec.c b/drivers/platform/x86/ayaneo-ec.c
index 86d4eed49f42..69901ac335eb 100644
--- a/drivers/platform/x86/ayaneo-ec.c
+++ b/drivers/platform/x86/ayaneo-ec.c
@@ -15,6 +15,8 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <acpi/battery.h>
 
 #define AYANEO_PWM_ENABLE_REG	 0x4A
 #define AYANEO_PWM_REG		 0x4B
@@ -23,17 +25,27 @@
 
 #define AYANEO_FAN_REG		 0x76
 
+#define EC_CHARGE_CONTROL_BEHAVIOURS                         \
+	(BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO) |           \
+	 BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE))
+#define AYANEO_CHARGE_REG		0x1e
+#define AYANEO_CHARGE_VAL_AUTO		0xaa
+#define AYANEO_CHARGE_VAL_INHIBIT	0x55
+
 struct ayaneo_ec_quirk {
 	bool has_fan_control;
+	bool has_charge_control;
 };
 
 struct ayaneo_ec_platform_data {
 	struct platform_device *pdev;
 	struct ayaneo_ec_quirk *quirks;
+	struct acpi_battery_hook battery_hook;
 };
 
 static const struct ayaneo_ec_quirk quirk_ayaneo3 = {
 	.has_fan_control = true,
+	.has_charge_control = true,
 };
 
 static const struct dmi_system_id dmi_table[] = {
@@ -164,11 +176,102 @@ static const struct hwmon_chip_info ayaneo_ec_chip_info = {
 	.info = ayaneo_ec_sensors,
 };
 
+static int ayaneo_psy_ext_get_prop(struct power_supply *psy,
+				   const struct power_supply_ext *ext,
+				   void *data,
+				   enum power_supply_property psp,
+				   union power_supply_propval *val)
+{
+	int ret;
+	u8 tmp;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
+		ret = ec_read(AYANEO_CHARGE_REG, &tmp);
+		if (ret)
+			return ret;
+
+		if (tmp == AYANEO_CHARGE_VAL_INHIBIT)
+			val->intval = POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE;
+		else
+			val->intval = POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ayaneo_psy_ext_set_prop(struct power_supply *psy,
+				   const struct power_supply_ext *ext,
+				   void *data,
+				   enum power_supply_property psp,
+				   const union power_supply_propval *val)
+{
+	u8 raw_val;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
+		switch (val->intval) {
+		case POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO:
+			raw_val = AYANEO_CHARGE_VAL_AUTO;
+			break;
+		case POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE:
+			raw_val = AYANEO_CHARGE_VAL_INHIBIT;
+			break;
+		default:
+			return -EINVAL;
+		}
+		return ec_write(AYANEO_CHARGE_REG, raw_val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ayaneo_psy_prop_is_writeable(struct power_supply *psy,
+					const struct power_supply_ext *ext,
+					void *data,
+					enum power_supply_property psp)
+{
+	return true;
+}
+
+static const enum power_supply_property ayaneo_psy_ext_props[] = {
+	POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR,
+};
+
+static const struct power_supply_ext ayaneo_psy_ext = {
+	.name			= "ayaneo-charge-control",
+	.properties		= ayaneo_psy_ext_props,
+	.num_properties		= ARRAY_SIZE(ayaneo_psy_ext_props),
+	.charge_behaviours	= EC_CHARGE_CONTROL_BEHAVIOURS,
+	.get_property		= ayaneo_psy_ext_get_prop,
+	.set_property		= ayaneo_psy_ext_set_prop,
+	.property_is_writeable	= ayaneo_psy_prop_is_writeable,
+};
+
+static int ayaneo_add_battery(struct power_supply *battery,
+			      struct acpi_battery_hook *hook)
+{
+	struct ayaneo_ec_platform_data *data =
+		container_of(hook, struct ayaneo_ec_platform_data, battery_hook);
+
+	return power_supply_register_extension(battery, &ayaneo_psy_ext,
+					       &data->pdev->dev, NULL);
+}
+
+static int ayaneo_remove_battery(struct power_supply *battery,
+				 struct acpi_battery_hook *hook)
+{
+	power_supply_unregister_extension(battery, &ayaneo_psy_ext);
+	return 0;
+}
+
 static int ayaneo_ec_probe(struct platform_device *pdev)
 {
 	const struct dmi_system_id *dmi_entry;
 	struct ayaneo_ec_platform_data *data;
 	struct device *hwdev;
+	int ret;
 
 	dmi_entry = dmi_first_match(dmi_table);
 	if (!dmi_entry)
@@ -189,6 +292,15 @@ static int ayaneo_ec_probe(struct platform_device *pdev)
 			return PTR_ERR(hwdev);
 	}
 
+	if (data->quirks->has_charge_control) {
+		data->battery_hook.add_battery = ayaneo_add_battery;
+		data->battery_hook.remove_battery = ayaneo_remove_battery;
+		data->battery_hook.name = "Ayaneo Battery";
+		ret = devm_battery_hook_register(&pdev->dev, &data->battery_hook);
+		if (ret)
+			return ret;
+	}
+
 	return 0;
 }
 
-- 
2.52.0