rtc: rtc-ds1742: use devm_rtc_device_register()

devm_rtc_device_register() is device managed and makes cleanup
paths simpler.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-ds1742.c

@@ -208,17 +208,14 @@ static int ds1742_rtc_probe(struct platform_device *pdev)
 
 	pdata->last_jiffies = jiffies;
 	platform_set_drvdata(pdev, pdata);
-	rtc = rtc_device_register(pdev->name, &pdev->dev,
+	rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 				  &ds1742_rtc_ops, THIS_MODULE);
 	if (IS_ERR(rtc))
 		return PTR_ERR(rtc);
 	pdata->rtc = rtc;
 
 	ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
-	if (ret) {
-		dev_err(&pdev->dev, "creating nvram file in sysfs failed\n");
-		rtc_device_unregister(rtc);
-	}
+
 	return ret;
 }
 
@@ -227,7 +224,6 @@ static int ds1742_rtc_remove(struct platform_device *pdev)
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 
 	sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
-	rtc_device_unregister(pdata->rtc);
 	return 0;
 }