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power: supply: Add helpers to get and put arrays of power supply handles

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Add power_supply_get_system_batteries() to allow drivers to obtain
a list of registered battery type power supply references in the
system. Also add power_supply_put_system_batteries() to perform
cleanup after the former function is called.

Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
Reviewed-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Link: https://patch.msgid.link/20260714-batt-status-v5-1-9de4aa900b69@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Amit Sunil Dhamne 2026-07-14 21:10:52 +00:00 committed by Greg Kroah-Hartman
parent 1e6be4bd53
commit 3b17c8d8d6
2 changed files with 168 additions and 0 deletions
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153
drivers/power/supply/power_supply_core.c
View File

@ -477,6 +477,159 @@ struct power_supply *power_supply_get_by_name(const char *name)
}
EXPORT_SYMBOL_GPL(power_supply_get_by_name);
static bool power_supply_is_system_battery(struct power_supply *psy)
{
union power_supply_propval val;
if (psy->desc->type != POWER_SUPPLY_TYPE_BATTERY)
return false;
if (!power_supply_get_property_direct(psy, POWER_SUPPLY_PROP_SCOPE,
&val))
if (val.intval == POWER_SUPPLY_SCOPE_DEVICE)
return false;
return true;
}
static int __power_supply_get_num_system_batteries(struct power_supply *epsy,
void *data)
{
int *count = data;
if (power_supply_is_system_battery(epsy))
(*count)++;
return 0;
}
static int power_supply_get_num_system_batteries(struct device *dev)
{
int ret, count = 0;
ret = power_supply_for_each_psy(&count,
__power_supply_get_num_system_batteries);
dev_dbg(dev, "%s: count: %d ret %d\n", __func__, count, ret);
if (ret)
return ret;
return count;
}
struct psy_get_supplies_data {
int cnt;
int size;
struct power_supply **psys;
};
static int
__power_supply_populate_system_batteries_array(struct power_supply *epsy,
void *_data)
{
struct psy_get_supplies_data *data = _data;
if (power_supply_is_system_battery(epsy)) {
if (data->size <= data->cnt)
return -EOVERFLOW;
get_device(&epsy->dev);
data->psys[data->cnt] = epsy;
atomic_inc(&epsy->use_cnt);
data->cnt++;
}
return 0;
}
static int
power_supply_populate_system_batteries_array(struct device *dev, int size,
struct power_supply **batteries)
{
int ret;
struct psy_get_supplies_data data = {
.cnt = 0,
.size = size,
.psys = batteries,
};
ret = power_supply_for_each_psy(&data,
__power_supply_populate_system_batteries_array);
dev_dbg(dev, "%s Found %d batteries with array size %d ret %d\n",
__func__, data.cnt, data.size, ret);
if (ret < 0 || !data.cnt) {
power_supply_put_system_batteries(batteries, data.cnt);
return ret;
}
return data.cnt;
}
/**
* power_supply_get_system_batteries() - Fetches references to battery type
* power supplies in the system.
* @dev: Pointer to device requesting the power supply refs.
* @psys: Pointer to an array of power supply refs.
*
* Helper function to get handles to battery type power supplies in the system.
* If acquiring a ref to a power supply fails, then the search for battery type
* power supplies will abort and the acquired power supply references will be
* released.
*
* Return: Indicates the number of battery type power supplies returned on
* success or a negative error code on failure.
*
* Call power_supply_put_system_batteries() after use to cleanup resources.
*/
int __must_check power_supply_get_system_batteries(struct device *dev,
struct power_supply ***psys)
{
int ret;
if (!psys)
return -EINVAL;
ret = power_supply_get_num_system_batteries(dev);
if (ret <= 0) {
*psys = NULL;
return ret;
}
*psys = kzalloc_objs(**psys, ret);
if (!*psys)
return -ENOMEM;
ret = power_supply_populate_system_batteries_array(dev, ret, *psys);
if (ret <= 0)
*psys = NULL;
return ret;
}
EXPORT_SYMBOL_GPL(power_supply_get_system_batteries);
/**
* power_supply_put_system_batteries() - Cleanup resources allocated by
* power_supply_get_system_batteries()
* @psys: Array of power supply references to release and free.
* @count: Number of elements in the array.
*/
void power_supply_put_system_batteries(struct power_supply **psys, int count)
{
int i;
for (i = 0; i < count; i++) {
if (psys[i])
power_supply_put(psys[i]);
}
kfree(psys);
}
EXPORT_SYMBOL_GPL(power_supply_put_system_batteries);
/**
* power_supply_put() - Drop reference obtained with power_supply_get_by_name
* @psy: Reference to put

15
include/linux/power_supply.h
View File

@ -806,11 +806,26 @@ extern int power_supply_reg_notifier(struct notifier_block *nb);
extern void power_supply_unreg_notifier(struct notifier_block *nb);
#if IS_ENABLED(CONFIG_POWER_SUPPLY)
extern struct power_supply *power_supply_get_by_name(const char *name);
extern int __must_check power_supply_get_system_batteries(struct device *dev,
struct power_supply ***psys);
extern void power_supply_put_system_batteries(struct power_supply **psys, int count);
extern void power_supply_put(struct power_supply *psy);
#else
static inline void power_supply_put(struct power_supply *psy) {}
static inline struct power_supply *power_supply_get_by_name(const char *name)
{ return NULL; }
static inline int __must_check power_supply_get_system_batteries(struct device *dev,
struct power_supply ***psys)
{
if (psys)
*psys = NULL;
return 0;
}
static inline void power_supply_put_system_batteries(struct power_supply **psys,
int count)
{
}
#endif
extern struct power_supply *power_supply_get_by_reference(struct fwnode_handle *fwnode,
const char *property);