power_supply: allow a power supply to explicitly point to powered device

If a power supply has a scope of "Device", then allow the power supply
to indicate what device it actually powers. This is represented in the
power supply's sysfs directory as a symlink named "powers", which points to
the sysfs directory of the powered device.

If the device has children, then the sub-devices are also powered by
the same power supply.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Richard Hughes <richard@hughsie.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index 329b46b..b10c121 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -147,6 +147,12 @@ struct power_supply *power_supply_get_by_name(char *name)
 }
 EXPORT_SYMBOL_GPL(power_supply_get_by_name);
 
+int power_supply_powers(struct power_supply *psy, struct device *dev)
+{
+	return sysfs_create_link_nowarn(&psy->dev->kobj, &dev->kobj, "powers");
+}
+EXPORT_SYMBOL_GPL(power_supply_powers);
+
 static void power_supply_dev_release(struct device *dev)
 {
 	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
@@ -202,6 +208,7 @@ EXPORT_SYMBOL_GPL(power_supply_register);
 void power_supply_unregister(struct power_supply *psy)
 {
 	cancel_work_sync(&psy->changed_work);
+	sysfs_remove_link(&psy->dev->kobj, "powers");
 	power_supply_remove_triggers(psy);
 	device_unregister(psy->dev);
 }