platform/x86: ayaneo-ec: Add charge control support

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>
Link: https://patch.msgid.link/20251119174505.597218-4-lkml@antheas.dev
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: antheas

drivers/platform/x86/Kconfig

@@ -315,6 +315,7 @@ 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

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;
 }