diff --git a/drivers/slimbus/core.c b/drivers/slimbus/core.c
index 8ffdc9876223..b2f07d2043eb 100644
--- a/drivers/slimbus/core.c
+++ b/drivers/slimbus/core.c
@@ -274,6 +274,7 @@ int slim_register_controller(struct slim_controller *ctrl)
 	mutex_init(&ctrl->lock);
 	mutex_init(&ctrl->sched.m_reconf);
 	init_completion(&ctrl->sched.pause_comp);
+	spin_lock_init(&ctrl->txn_lock);
 
 	dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
 		ctrl->name, ctrl->dev);