diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c
index 6c75c83baf5a82a3eb1da0c7a5d5949bcf31e43b..2d2763ea1a68277eedf82f6e9c132be6f8706923 100644
--- a/drivers/gpio/gpio-104-idi-48.c
+++ b/drivers/gpio/gpio-104-idi-48.c
@@ -247,6 +247,7 @@ static int idi_48_probe(struct device *dev, unsigned int id)
 	idi48gpio->irq = irq[id];
 
 	spin_lock_init(&idi48gpio->lock);
+	spin_lock_init(&idi48gpio->ack_lock);
 
 	dev_set_drvdata(dev, idi48gpio);