diff --git a/drivers/usb/host/ehci-atmel.c b/drivers/usb/host/ehci-atmel.c
index 87c1b7c..51bd0ed 100644
--- a/drivers/usb/host/ehci-atmel.c
+++ b/drivers/usb/host/ehci-atmel.c
@@ -149,7 +149,7 @@
 		goto fail_request_resource;
 	}
 	hcd->rsrc_start = res->start;
-	hcd->rsrc_len = res->end - res->start + 1;
+	hcd->rsrc_len = resource_size(res);
 
 	if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len,
 				driver->description)) {