diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 8ce70cb..d21c24e 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -788,7 +788,7 @@
 	spin_lock_init(&as->lock);
 	INIT_LIST_HEAD(&as->queue);
 	as->pdev = pdev;
-	as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
+	as->regs = ioremap(regs->start, resource_size(regs));
 	if (!as->regs)
 		goto out_free_buffer;
 	as->irq = irq;