[RFC PATCH] power: supply: fix circular dependency with cooling device

[Caleb Connolly <caleb.connolly@linaro.org>]

A recent change in thermal/core means it now calls the cooling device
->get_max_state() callback during __thermal_cooling_device_register().
This creates a circular dependency as it attempts to fetch a power
supply property before the psy is initialised. Move this call later to
break the dependency.

Fixes: c408b3d1d9bb ("thermal: Validate new state in cur_state_store()")
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
---
 drivers/power/supply/power_supply_core.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index 7c790c41e2fe..c921111ff26a 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -1354,10 +1354,6 @@ __power_supply_register(struct device *parent,
 	if (rc)
 		goto register_thermal_failed;
 
-	rc = psy_register_cooler(psy);
-	if (rc)
-		goto register_cooler_failed;
-
 	rc = power_supply_create_triggers(psy);
 	if (rc)
 		goto create_triggers_failed;
@@ -1378,17 +1374,27 @@ __power_supply_register(struct device *parent,
 	atomic_inc(&psy->use_cnt);
 	psy->initialized = true;
 
+	/* This has to be done after updating use_cnt and initialized
+	 * otherwise when __thermal_cooling_device_register calls back
+	 * to ->get_max_state() the psy core will return -EAGAIN..
+	 */
+	rc = psy_register_cooler(psy);
+	if (rc)
+		goto register_cooler_failed;
+
 	queue_delayed_work(system_power_efficient_wq,
 			   &psy->deferred_register_work,
 			   POWER_SUPPLY_DEFERRED_REGISTER_TIME);
 
 	return psy;
 
+register_cooler_failed:
+	power_supply_remove_hwmon_sysfs(psy);
+	psy->initialized = false;
+	atomic_dec(&psy->use_cnt);
 add_hwmon_sysfs_failed:
 	power_supply_remove_triggers(psy);
 create_triggers_failed:
-	psy_unregister_cooler(psy);
-register_cooler_failed:
 	psy_unregister_thermal(psy);
 register_thermal_failed:
 wakeup_init_failed:
-- 
2.39.0