rtc: omap: switch to rtc_register_device

This removes a possible race condition and crash and allows for further
improvement of the driver.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-omap.c

@@ -797,13 +797,14 @@ static int omap_rtc_probe(struct platform_device *pdev)
 
 	device_init_wakeup(&pdev->dev, true);
 
-	rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
-			&omap_rtc_ops, THIS_MODULE);
+	rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(rtc->rtc)) {
 		ret = PTR_ERR(rtc->rtc);
 		goto err;
 	}
 
+	rtc->rtc->ops = &omap_rtc_ops;
+
 	/* handle periodic and alarm irqs */
 	ret = devm_request_irq(&pdev->dev, rtc->irq_timer, rtc_irq, 0,
 			dev_name(&rtc->rtc->dev), rtc);
@@ -834,6 +835,10 @@ static int omap_rtc_probe(struct platform_device *pdev)
 		goto err;
 	}
 
+	ret = rtc_register_device(rtc->rtc);
+	if (ret)
+		goto err;
+
 	return 0;
 
 err: