diff --git a/drivers/usb/gadget/atmel_usba_udc.c b/drivers/usb/gadget/atmel_usba_udc.c
index 4e970cf0e29a..976822f50c70 100644
--- a/drivers/usb/gadget/atmel_usba_udc.c
+++ b/drivers/usb/gadget/atmel_usba_udc.c
@@ -1914,14 +1914,14 @@ static int __init usba_udc_probe(struct platform_device *pdev)
 	udc->vbus_pin = -ENODEV;
 
 	ret = -ENOMEM;
-	udc->regs = ioremap(regs->start, regs->end - regs->start + 1);
+	udc->regs = ioremap(regs->start, resource_size(regs));
 	if (!udc->regs) {
 		dev_err(&pdev->dev, "Unable to map I/O memory, aborting.\n");
 		goto err_map_regs;
 	}
 	dev_info(&pdev->dev, "MMIO registers at 0x%08lx mapped at %p\n",
 		 (unsigned long)regs->start, udc->regs);
-	udc->fifo = ioremap(fifo->start, fifo->end - fifo->start + 1);
+	udc->fifo = ioremap(fifo->start, resource_size(fifo));
 	if (!udc->fifo) {
 		dev_err(&pdev->dev, "Unable to map FIFO, aborting.\n");
 		goto err_map_fifo;