[PATCH 2/5] power: supply: core: add function to get supplies from fwnode

Amit Sunil Dhamne via B4 Relay
2025-03-12T23:43:20Z

From: Amit Sunil Dhamne <amitsd@google.com>

Add a new helper function power_supply_get_by_fwnode_reference_array()
to retrieve a list of power_supplies associated with the fwnode's
property. The property can contain multiple nodes where each node is
associated with a power_supply. The list of power_supply objects will be
stored in an array supplied by the caller and the return value will
indicate the size of the resulting array.

Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
---
drivers/power/supply/power_supply_core.c | 60 ++++++++++++++++++++++++++++++++
include/linux/power_supply.h | 5 +++
2 files changed, 65 insertions(+)

diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index 76c340b38015af0a67a0d91305e6242a8646bf53..df1a52f85125748c4fdcb10687aa7ed2f626ded1 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -593,6 +593,66 @@ struct power_supply *devm_power_supply_get_by_phandle(struct device *dev,
EXPORT_SYMBOL_GPL(devm_power_supply_get_by_phandle);
#endif /* CONFIG_OF */

+static int power_supply_match_fwnode(struct device *dev, const void *data)
+{
+ return dev && dev->parent && dev->parent->fwnode == data;
+}
+
+/**
+ * power_supply_get_by_fwnode_reference_array() - Returns an array of power
+ * supply objects associated with each fwnode reference present in the property
+ * @fwnode: Pointer to fwnode to lookup property
+ * @property: Name of property holding references
+ * @psy: Resulting array of power_supply pointers. To be provided by the caller.
+ * @size: size of power_supply pointer array.
+ *
+ * If power supply was found, it increases reference count for the
+ * internal power supply's device. The user should power_supply_put()
+ * after usage.
+ *
+ * Return: On success returns the number of power supply objects filled
+ * in the @psy array.
+ * -EOVERFLOW when size of @psy array is not suffice.
+ * -EINVAL when @psy is NULL or @size is 0.
+ * -ENODATA when fwnode does not contain the given property
+ */
+int power_supply_get_by_fwnode_reference_array(struct fwnode_handle *fwnode,
+ const char *property,
+ struct power_supply **psy,
+ ssize_t size)
+{
+ int ret, index, count = 0;
+ struct fwnode_reference_args args;
+ struct device *dev;
+
+ if (!psy || !size)
+ return -EINVAL;
+
+ for (index = 0; index < size &&
+ !(ret = fwnode_property_get_reference_args(fwnode, property, NULL,
+ 0, index, &args));
+ ++index) {
+ dev = class_find_device(&power_supply_class, NULL, args.fwnode,
+ power_supply_match_fwnode);
+ fwnode_handle_put(args.fwnode);
+ if (!dev)
+ continue;
+
+ if (count > size)
+ return -EOVERFLOW;
+
+ psy[count] = dev_get_drvdata(dev);
+ atomic_inc(&psy[count]->use_cnt);
+ ++count;
+ }
+
+ if (ret != -ENOENT)
+ return ret;
+
+ return index ? count : -ENODATA;
+}
+EXPORT_SYMBOL_GPL(power_supply_get_by_fwnode_reference_array);
+
int power_supply_get_battery_info(struct power_supply *psy,
struct power_supply_battery_info **info_out)
{
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 6ed53b292162469d7b357734d5589bff18a201d0..3f062607e5cd7c7f04384e34128ae0953e25d981 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -820,6 +820,11 @@ devm_power_supply_get_by_phandle(struct device *dev, const char *property)
{ return NULL; }
#endif /* CONFIG_OF */

+extern int
+power_supply_get_by_fwnode_reference_array(struct fwnode_handle *fwnode,
+ const char *property,
+ struct power_supply **psy,
+ ssize_t size);
extern const enum power_supply_property power_supply_battery_info_properties[];
extern const size_t power_supply_battery_info_properties_size;
extern int power_supply_get_battery_info(struct power_supply *psy,

--
2.49.0.rc0.332.g42c0ae87b1-goog