2 files changed, 62 insertions, 1 deletions

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index a21e36ed8d41..583dece8845b 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -314,7 +314,9 @@ EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);
 
 int power_supply_set_battery_charged(struct power_supply *psy)
 {
-        if (psy->type == POWER_SUPPLY_TYPE_BATTERY && psy->set_charged) {
+        if (atomic_read(&psy->use_cnt) >= 0 &&
+                        psy->type == POWER_SUPPLY_TYPE_BATTERY &&
+                        psy->set_charged) {
                 psy->set_charged(psy);
                 return 0;
         }
@@ -366,6 +368,47 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np,
 EXPORT_SYMBOL_GPL(power_supply_get_by_phandle);
 #endif /* CONFIG_OF */
 
+int power_supply_get_property(struct power_supply *psy,
+                            enum power_supply_property psp,
+                            union power_supply_propval *val)
+{
+        if (atomic_read(&psy->use_cnt) <= 0)
+                return -ENODEV;
+
+        return psy->get_property(psy, psp, val);
+}
+EXPORT_SYMBOL_GPL(power_supply_get_property);
+
+int power_supply_set_property(struct power_supply *psy,
+                            enum power_supply_property psp,
+                            const union power_supply_propval *val)
+{
+        if (atomic_read(&psy->use_cnt) <= 0 || !psy->set_property)
+                return -ENODEV;
+
+        return psy->set_property(psy, psp, val);
+}
+EXPORT_SYMBOL_GPL(power_supply_set_property);
+
+int power_supply_property_is_writeable(struct power_supply *psy,
+                                        enum power_supply_property psp)
+{
+        if (atomic_read(&psy->use_cnt) <= 0 || !psy->property_is_writeable)
+                return -ENODEV;
+
+        return psy->property_is_writeable(psy, psp);
+}
+EXPORT_SYMBOL_GPL(power_supply_property_is_writeable);
+
+void power_supply_external_power_changed(struct power_supply *psy)
+{
+        if (atomic_read(&psy->use_cnt) <= 0 || !psy->external_power_changed)
+                return;
+
+        psy->external_power_changed(psy);
+}
+EXPORT_SYMBOL_GPL(power_supply_external_power_changed);
+
 int power_supply_powers(struct power_supply *psy, struct device *dev)
 {
         return sysfs_create_link(&psy->dev->kobj, &dev->kobj, "powers");
@@ -555,6 +598,7 @@ static int __power_supply_register(struct device *parent,
         dev->release = power_supply_dev_release;
         dev_set_drvdata(dev, psy);
         psy->dev = dev;
+        atomic_inc(&psy->use_cnt);
         if (cfg) {
                 psy->drv_data = cfg->drv_data;
                 psy->of_node = cfg->of_node;
@@ -676,6 +720,7 @@ EXPORT_SYMBOL_GPL(devm_power_supply_register_no_ws);
 
 void power_supply_unregister(struct power_supply *psy)
 {
+        WARN_ON(atomic_dec_return(&psy->use_cnt));
         cancel_work_sync(&psy->changed_work);
         sysfs_remove_link(&psy->dev->kobj, "powers");
         power_supply_remove_triggers(psy);
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 0d7c95f634a5..7ae60346465f 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -199,6 +199,12 @@ struct power_supply {
         size_t num_supplies;
         struct device_node *of_node;
 
+        /*
+         * Functions for drivers implementing power supply class.
+         * These shouldn't be called directly by other drivers for accessing
+         * this power supply. Instead use power_supply_*() functions (for
+         * example power_supply_get_property()).
+         */
         int (*get_property)(struct power_supply *psy,
                             enum power_supply_property psp,
                             union power_supply_propval *val);
@@ -227,6 +233,7 @@ struct power_supply {
         struct work_struct changed_work;
         spinlock_t changed_lock;
         bool changed;
+        atomic_t use_cnt;
 #ifdef CONFIG_THERMAL
         struct thermal_zone_device *tzd;
         struct thermal_cooling_device *tcd;
@@ -287,6 +294,15 @@ extern int power_supply_is_system_supplied(void);
 static inline int power_supply_is_system_supplied(void) { return -ENOSYS; }
 #endif
 
+extern int power_supply_get_property(struct power_supply *psy,
+                            enum power_supply_property psp,
+                            union power_supply_propval *val);
+extern int power_supply_set_property(struct power_supply *psy,
+                            enum power_supply_property psp,
+                            const union power_supply_propval *val);
+extern int power_supply_property_is_writeable(struct power_supply *psy,
+                                        enum power_supply_property psp);
+extern void power_supply_external_power_changed(struct power_supply *psy);
 extern int power_supply_register(struct device *parent,
                                  struct power_supply *psy,
                                  const struct power_supply_config *cfg);