rtc: rtc-davinci: use devm_ioremap_resource()

Use devm_ioremap_resource() in order to make the code simpler, and
remove redundant return value check of platform_get_resource() because
the value is checked by devm_ioremap_resource().

Signed-off-by: Jingoo Han <[e-mail]>
Cc: Kevin Hilman <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/rtc/rtc-davinci.c

···
 struct davinci_rtc {
 	struct rtc_device		*rtc;
 	void __iomem			*base;
-	resource_size_t			pbase;
-	size_t				base_size;
 	int				irq;
 };
 
···
 {
 	struct device *dev = &pdev->dev;
 	struct davinci_rtc *davinci_rtc;
-	struct resource *res, *mem;
+	struct resource *res;
 	int ret = 0;
 
 	davinci_rtc = devm_kzalloc(&pdev->dev, sizeof(struct davinci_rtc), GFP_KERNEL);
···
 	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res) {
-		dev_err(dev, "no mem resource\n");
-		return -EINVAL;
-	}
-
-	davinci_rtc->pbase = res->start;
-	davinci_rtc->base_size = resource_size(res);
-
-	mem = devm_request_mem_region(dev, davinci_rtc->pbase,
-				davinci_rtc->base_size, pdev->name);
-	if (!mem) {
-		dev_err(dev, "RTC registers at %08x are not free\n",
-			davinci_rtc->pbase);
-		return -EBUSY;
-	}
-
-	davinci_rtc->base = devm_ioremap(dev, davinci_rtc->pbase,
-					davinci_rtc->base_size);
-	if (!davinci_rtc->base) {
-		dev_err(dev, "unable to ioremap MEM resource\n");
-		return -ENOMEM;
-	}
+	davinci_rtc->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(davinci_rtc->base))
+		return PTR_ERR(davinci_rtc->base);
 
 	platform_set_drvdata(pdev, davinci_rtc);