power: supply: core: fix charge_behaviour formatting

This property is documented to have a special format which exposes all
available behaviours and the currently active one at the same time. For
this special format some helpers are provided.

When the charge_behaviour property was added in
1b0b6cc ("power: supply: add charge_behaviour attributes"), it did
not update the default logic in in power_supply_sysfs.c to use the
format helpers. Thus by default only the currently active behaviour
is printed. This fixes the default logic to follow the documented
format.

There is currently only one in-tree drivers exposing charge behaviours -
thinkpad_acpi, which is not affected by the change, as it directly uses
the helpers and does not use the power_supply_sysfs.c logic.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20240303-power_supply-charge_behaviour_prop-v2-3-8ebb0a7c2409@weissschuh.net
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Author: t-8ch

drivers/power/supply/power_supply_sysfs.c

@@ -271,6 +271,23 @@ static ssize_t power_supply_show_usb_type(struct device *dev,
 	return count;
 }
 
+static ssize_t power_supply_show_charge_behaviour(struct device *dev,
+						  struct power_supply *psy,
+						  union power_supply_propval *value,
+						  char *buf)
+{
+	int ret;
+
+	ret = power_supply_get_property(psy,
+					POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR,
+					value);
+	if (ret < 0)
+		return ret;
+
+	return power_supply_charge_behaviour_show(dev, psy->desc->charge_behaviours,
+						  value->intval, buf);
+}
+
 static ssize_t power_supply_show_property(struct device *dev,
 					  struct device_attribute *attr,
 					  char *buf) {
@@ -303,6 +320,9 @@ static ssize_t power_supply_show_property(struct device *dev,
 		ret = power_supply_show_usb_type(dev, psy->desc,
 						&value, buf);
 		break;
+	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
+		ret = power_supply_show_charge_behaviour(dev, psy, &value, buf);
+		break;
 	case POWER_SUPPLY_PROP_MODEL_NAME ... POWER_SUPPLY_PROP_SERIAL_NUMBER:
 		ret = sysfs_emit(buf, "%s\n", value.strval);
 		break;

include/linux/power_supply.h

@@ -242,6 +242,7 @@ struct power_supply_config {
 struct power_supply_desc {
 	const char *name;
 	enum power_supply_type type;
+	u8 charge_behaviours;
 	const enum power_supply_usb_type *usb_types;
 	size_t num_usb_types;
 	const enum power_supply_property *properties;