diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c
index 080d7970a377..5971b5cb290a 100644
--- a/drivers/mfd/omap-usb-tll.c
+++ b/drivers/mfd/omap-usb-tll.c
@@ -237,8 +237,7 @@ static int usbtll_omap_probe(struct platform_device *pdev)
 		break;
 	}
 
-	tll = devm_kzalloc(dev, sizeof(*tll) + sizeof(tll->ch_clk[nch]),
-			   GFP_KERNEL);
+	tll = devm_kzalloc(dev, struct_size(tll, ch_clk, nch), GFP_KERNEL);
 	if (!tll) {
 		pm_runtime_put_sync(dev);
 		pm_runtime_disable(dev);