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power_supply: Increment power supply use counter when obtaining references 

Increment the power_supply.use_cnt usage counter on:
 - power_supply_get_by_phandle()
 - power_supply_get_by_name()
and decrement it on power_supply_put() call.

This helps tracking of valid usage of power supply instance by
consumers. The usage counter itself also allows safe calling of
power_supply_get_property-like functions even when driver unregisters
this power supply.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
This commit is contained in:
Krzysztof Kozlowski 2015-03-12 08:44:13 +01:00 committed by Sebastian Reichel
parent 1a352462b5
commit 03e81acce5
1 changed files with 15 additions and 2 deletions
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17
drivers/power/power_supply_core.c
View File

@ -349,10 +349,16 @@ static int power_supply_match_device_by_name(struct device *dev, const void *dat
*/
struct power_supply *power_supply_get_by_name(const char *name)
{
struct power_supply *psy = NULL;
struct device *dev = class_find_device(power_supply_class, NULL, name,
power_supply_match_device_by_name);
return dev ? dev_get_drvdata(dev) : NULL;
if (dev) {
psy = dev_get_drvdata(dev);
atomic_inc(&psy->use_cnt);
}
return psy;
}
EXPORT_SYMBOL_GPL(power_supply_get_by_name);
@ -367,6 +373,7 @@ void power_supply_put(struct power_supply *psy)
{
might_sleep();
atomic_dec(&psy->use_cnt);
put_device(&psy->dev);
}
EXPORT_SYMBOL_GPL(power_supply_put);
@ -393,6 +400,7 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np,
const char *property)
{
struct device_node *power_supply_np;
struct power_supply *psy = NULL;
struct device *dev;
power_supply_np = of_parse_phandle(np, property, 0);
@ -404,7 +412,12 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np,
of_node_put(power_supply_np);
return dev ? dev_get_drvdata(dev) : NULL;
if (dev) {
psy = dev_get_drvdata(dev);
atomic_inc(&psy->use_cnt);
}
return psy;
}
EXPORT_SYMBOL_GPL(power_supply_get_by_phandle);
#endif /* CONFIG_OF */