[PATCH 3/4] power: supply: bq24190: Avoid rescheduling after cancelling work

[Krzysztof Kozlowski]

Driver initializes delayed work and then registers interrupt handler
with devm interface.  This means that device removal will not use a
reversed order, but first cancel pending work items and then, via devm
release handlers, free the interrupt.

The interrupt handler does not directly use/schedule work
items on the workqueue, however it updates the status of the battery
charger which might lead to calling power_supply_changed() and trigger
chain of calls leading to scheduling the work items.  If this happens
during short time window after cancel_delayed_work_sync() in remove()
callback, the work would be rescheduled.

Avoid this by using devm interface to initialize and cancel work item,
thus having exactly reverse order during remove() in respect to rest of
the probe/cleanup paths.  This is also more logical and readable code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
---
 drivers/power/supply/bq24190_charger.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/power/supply/bq24190_charger.c b/drivers/power/supply/bq24190_charger.c
index ed0ceae8d90b..55da91bacc3e 100644
--- a/drivers/power/supply/bq24190_charger.c
+++ b/drivers/power/supply/bq24190_charger.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
+#include <linux/devm-helpers.h>
 #include <linux/pm_runtime.h>
 #include <linux/power_supply.h>
 #include <linux/power/bq24190_charger.h>
@@ -2087,8 +2088,11 @@ static int bq24190_probe(struct i2c_client *client)
 	bdi->charge_type = POWER_SUPPLY_CHARGE_TYPE_FAST;
 	bdi->f_reg = 0;
 	bdi->ss_reg = BQ24190_REG_SS_VBUS_STAT_MASK; /* impossible state */
-	INIT_DELAYED_WORK(&bdi->input_current_limit_work,
-			  bq24190_input_current_limit_work);
+
+	ret = devm_delayed_work_autocancel(dev, &bdi->input_current_limit_work,
+					   bq24190_input_current_limit_work);
+	if (ret)
+		return ret;
 
 	i2c_set_clientdata(client, bdi);
 
@@ -2198,7 +2202,6 @@ static void bq24190_remove(struct i2c_client *client)
 	struct bq24190_dev_info *bdi = i2c_get_clientdata(client);
 	int error;
 
-	cancel_delayed_work_sync(&bdi->input_current_limit_work);
 	error = pm_runtime_resume_and_get(bdi->dev);
 	if (error < 0)
 		dev_warn(bdi->dev, "pm_runtime_get failed: %i\n", error);
-- 
2.51.0