power: supply: core: Add new "charge_types" property

Add a new "charge_types" property, this is identical to "charge_type" but
reading returns a list of supported charge-types with the currently active
type surrounded by square brackets, e.g.:

Fast [Standard] "Long_Life"

This has the advantage over the existing "charge_type" property that this
allows userspace to find out which charge-types are supported for writable
charge_type properties.

Drivers which already support "charge_type" can easily add support for
this by setting power_supply_desc.charge_types to a bitmask representing
valid charge_type values. The existing "charge_type" get_property() and
set_property() code paths can be re-used for "charge_types".

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20241211174451.355421-3-hdegoede@redhat.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/Documentation/ABI/testing/sysfs-class-power b/Documentation/ABI/testing/sysfs-class-power
index 45180b62d42686c8999eda54f38435cb6c74a879..74050dfb5fc01019b2d85926b83172edd88eb3b3 100644 (file)
--- a/Documentation/ABI/testing/sysfs-class-power
+++ b/Documentation/ABI/testing/sysfs-class-power
@@ -407,10 +407,30 @@ Description:
 
                Access: Read, Write
 
+               Reading this returns the current active value, e.g. 'Standard'.
+               Check charge_types to get the values supported by the battery.
+
                Valid values:
                              "Unknown", "N/A", "Trickle", "Fast", "Standard",
                              "Adaptive", "Custom", "Long Life", "Bypass"
 
+What:          /sys/class/power_supply/<supply_name>/charge_types
+Date:          December 2024
+Contact:       linux-pm@vger.kernel.org
+Description:
+               Identical to charge_type but reading returns a list of supported
+               charge-types with the currently active type surrounded by square
+               brackets, e.g.: "Fast [Standard] Long_Life".
+
+               power_supply class devices may support both charge_type and
+               charge_types for backward compatibility. In this case both will
+               always have the same active value and the active value can be
+               changed by writing either property.
+
+               Note charge-types which contain a space such as "Long Life" will
+               have the space replaced by a '_' resulting in e.g. "Long_Life".
+               When writing charge-types both variants are accepted.
+
 What:          /sys/class/power_supply/<supply_name>/charge_term_current
 Date:          July 2014
 Contact:       linux-pm@vger.kernel.org

diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index 9b604a1bcd17ff1a1d8e06ba8dcdac7c4bf76744..e18f1ee53f2107c0d7a4ede829e57032c5f8b76e 100644 (file)
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -182,6 +182,8 @@ static struct power_supply_attr power_supply_attrs[] __ro_after_init = {
        POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
        POWER_SUPPLY_ATTR(CHARGE_CONTROL_END_THRESHOLD),
        POWER_SUPPLY_ENUM_ATTR(CHARGE_BEHAVIOUR),
+       /* Same enum value texts as "charge_type" without the 's' at the end */
+       _POWER_SUPPLY_ENUM_ATTR(CHARGE_TYPES, POWER_SUPPLY_CHARGE_TYPE_TEXT),
        POWER_SUPPLY_ATTR(INPUT_CURRENT_LIMIT),
        POWER_SUPPLY_ATTR(INPUT_VOLTAGE_LIMIT),
        POWER_SUPPLY_ATTR(INPUT_POWER_LIMIT),
@@ -339,6 +341,12 @@ static ssize_t power_supply_format_property(struct device *dev,
                ret = power_supply_charge_behaviour_show(dev, psy->desc->charge_behaviours,
                                                         value.intval, buf);
                break;
+       case POWER_SUPPLY_PROP_CHARGE_TYPES:
+               if (uevent) /* no possible values in uevents */
+                       goto default_format;
+               ret = power_supply_charge_types_show(dev, psy->desc->charge_types,
+                                                    value.intval, buf);
+               break;
        case POWER_SUPPLY_PROP_MODEL_NAME ... POWER_SUPPLY_PROP_SERIAL_NUMBER:
                ret = sysfs_emit(buf, "%s\n", value.strval);
                break;
@@ -556,3 +564,31 @@ int power_supply_charge_behaviour_parse(unsigned int available_behaviours, const
        return -EINVAL;
 }
 EXPORT_SYMBOL_GPL(power_supply_charge_behaviour_parse);
+
+ssize_t power_supply_charge_types_show(struct device *dev,
+                                      unsigned int available_types,
+                                      enum power_supply_charge_type current_type,
+                                      char *buf)
+{
+       return power_supply_show_enum_with_available(
+                               dev, POWER_SUPPLY_CHARGE_TYPE_TEXT,
+                               ARRAY_SIZE(POWER_SUPPLY_CHARGE_TYPE_TEXT),
+                               available_types, current_type, buf);
+}
+EXPORT_SYMBOL_GPL(power_supply_charge_types_show);
+
+int power_supply_charge_types_parse(unsigned int available_types, const char *buf)
+{
+       int i = power_supply_match_string(POWER_SUPPLY_CHARGE_TYPE_TEXT,
+                                         ARRAY_SIZE(POWER_SUPPLY_CHARGE_TYPE_TEXT),
+                                         buf);
+
+       if (i < 0)
+               return i;
+
+       if (available_types & BIT(i))
+               return i;
+
+       return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(power_supply_charge_types_parse);

diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 17fc383785bf5705ef3dbe5fdebf90843684b715..0d96657d1a2bcf9ce8a81e553aca7794406ac57e 100644 (file)
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -40,7 +40,7 @@ enum {
 };
 
 /* What algorithm is the charger using? */
-enum {
+enum power_supply_charge_type {
        POWER_SUPPLY_CHARGE_TYPE_UNKNOWN = 0,
        POWER_SUPPLY_CHARGE_TYPE_NONE,
        POWER_SUPPLY_CHARGE_TYPE_TRICKLE,       /* slow speed */
@@ -99,6 +99,7 @@ enum power_supply_property {
        /* Properties of type `int' */
        POWER_SUPPLY_PROP_STATUS = 0,
        POWER_SUPPLY_PROP_CHARGE_TYPE,
+       POWER_SUPPLY_PROP_CHARGE_TYPES,
        POWER_SUPPLY_PROP_HEALTH,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_ONLINE,
@@ -245,6 +246,7 @@ struct power_supply_desc {
        const char *name;
        enum power_supply_type type;
        u8 charge_behaviours;
+       u32 charge_types;
        u32 usb_types;
        const enum power_supply_property *properties;
        size_t num_properties;
@@ -946,6 +948,11 @@ ssize_t power_supply_charge_behaviour_show(struct device *dev,
                                           char *buf);
 
 int power_supply_charge_behaviour_parse(unsigned int available_behaviours, const char *buf);
+ssize_t power_supply_charge_types_show(struct device *dev,
+                                      unsigned int available_types,
+                                      enum power_supply_charge_type current_type,
+                                      char *buf);
+int power_supply_charge_types_parse(unsigned int available_types, const char *buf);
 #else
 static inline
 ssize_t power_supply_charge_behaviour_show(struct device *dev,
@@ -961,6 +968,20 @@ static inline int power_supply_charge_behaviour_parse(unsigned int available_beh
 {
        return -EOPNOTSUPP;
 }
+
+static inline
+ssize_t power_supply_charge_types_show(struct device *dev,
+                                      unsigned int available_types,
+                                      enum power_supply_charge_type current_type,
+                                      char *buf)
+{
+       return -EOPNOTSUPP;
+}
+
+static inline int power_supply_charge_types_parse(unsigned int available_types, const char *buf)
+{
+       return -EOPNOTSUPP;
+}
 #endif
 
 #endif /* __LINUX_POWER_SUPPLY_H__ */