diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 65896a3..08b69fd 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -307,8 +307,12 @@
 		device_init_wakeup(&pdev->dev, 1);
 
 	platform_set_drvdata(pdev, rtc);
-	rtc->rtt = (void __force __iomem *) (AT91_VA_BASE_SYS - AT91_BASE_SYS);
-	rtc->rtt += r->start;
+	rtc->rtt = ioremap(r->start, resource_size(r));
+	if (!rtc->rtt) {
+		dev_err(&pdev->dev, "failed to map registers, aborting.\n");
+		ret = -ENOMEM;
+		goto fail;
+	}
 
 	mr = rtt_readl(rtc, MR);
 
@@ -326,7 +330,7 @@
 				&at91_rtc_ops, THIS_MODULE);
 	if (IS_ERR(rtc->rtcdev)) {
 		ret = PTR_ERR(rtc->rtcdev);
-		goto fail;
+		goto fail_register;
 	}
 
 	/* register irq handler after we know what name we'll use */
@@ -351,6 +355,8 @@
 
 	return 0;
 
+fail_register:
+	iounmap(rtc->rtt);
 fail:
 	platform_set_drvdata(pdev, NULL);
 	kfree(rtc);
@@ -371,6 +377,7 @@
 
 	rtc_device_unregister(rtc->rtcdev);
 
+	iounmap(rtc->rtt);
 	platform_set_drvdata(pdev, NULL);
 	kfree(rtc);
 	return 0;