drivers/rtc/rtc-mc13xxx.c: fix potential race condition

RTC drivers must not return an error after device registration.  This
patch makes RTC registration as the last action.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-mc13xxx.c

@@ -247,8 +247,6 @@ static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
 	struct mc13xxx_rtc *priv = dev;
 	struct mc13xxx *mc13xxx = priv->mc13xxx;
 
-	dev_dbg(&priv->rtc->dev, "Alarm\n");
-
 	rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
 
 	mc13xxx_irq_ack(mc13xxx, irq);
@@ -261,8 +259,6 @@ static irqreturn_t mc13xxx_rtc_update_handler(int irq, void *dev)
 	struct mc13xxx_rtc *priv = dev;
 	struct mc13xxx *mc13xxx = priv->mc13xxx;
 
-	dev_dbg(&priv->rtc->dev, "1HZ\n");
-
 	rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);
 
 	mc13xxx_irq_ack(mc13xxx, irq);
@@ -283,7 +279,6 @@ static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
 	struct mc13xxx_rtc *priv = dev;
 	struct mc13xxx *mc13xxx = priv->mc13xxx;
 
-	dev_warn(&priv->rtc->dev, "Contents of the RTC are no longer valid\n");
 	priv->valid = 0;
 
 	mc13xxx_irq_mask(mc13xxx, irq);
@@ -307,11 +302,6 @@ static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
-	priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
-					     &mc13xxx_rtc_ops, THIS_MODULE);
-	if (IS_ERR(priv->rtc))
-		return PTR_ERR(priv->rtc);
-
 	mc13xxx_lock(mc13xxx);
 
 	mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
@@ -319,24 +309,30 @@ static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
 	ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
 			mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
 	if (ret)
-		goto err_reset_irq_request;
+		goto err_irq_request;
 
 	ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_1HZ,
 			mc13xxx_rtc_update_handler, DRIVER_NAME, priv);
 	if (ret)
-		goto err_reset_irq_status;
+		goto err_irq_request;
 
 	ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
 			mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
-	if (!ret)
-		goto err_reset_irq_request;
+	if (ret)
+		goto err_irq_request;
 
-	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_1HZ, priv);
+	mc13xxx_unlock(mc13xxx);
+
+	priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
+					     &mc13xxx_rtc_ops, THIS_MODULE);
 
-err_reset_irq_status:
+	return 0;
+
+err_irq_request:
+	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
+	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_1HZ, priv);
 	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
 
-err_reset_irq_request:
 	mc13xxx_unlock(mc13xxx);
 
 	return ret;