diff --git a/sound/atmel/ac97c.c b/sound/atmel/ac97c.c
index b310702..41b901b 100644
--- a/sound/atmel/ac97c.c
+++ b/sound/atmel/ac97c.c
@@ -971,7 +971,7 @@
 	chip->card = card;
 	chip->pclk = pclk;
 	chip->pdev = pdev;
-	chip->regs = ioremap(regs->start, regs->end - regs->start + 1);
+	chip->regs = ioremap(regs->start, resource_size(regs));
 
 	if (!chip->regs) {
 		dev_dbg(&pdev->dev, "could not remap register memory\n");