--- zzzz-none-000/linux-3.10.107/drivers/rtc/rtc-ds1742.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/rtc/rtc-ds1742.c	2021-02-04 17:41:59.000000000 +0000
@@ -13,12 +13,13 @@
  */
 
 #include <linux/bcd.h>
-#include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/gfp.h>
 #include <linux/delay.h>
 #include <linux/jiffies.h>
 #include <linux/rtc.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -52,11 +53,9 @@
 #define RTC_BATT_FLAG		0x80
 
 struct rtc_plat_data {
-	struct rtc_device *rtc;
 	void __iomem *ioaddr_nvram;
 	void __iomem *ioaddr_rtc;
 	size_t size_nvram;
-	size_t size;
 	unsigned long last_jiffies;
 	struct bin_attribute nvram_attr;
 };
@@ -117,11 +116,7 @@
 	/* year is 1900 + tm->tm_year */
 	tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
 
-	if (rtc_valid_tm(tm) < 0) {
-		dev_err(dev, "retrieved date/time is not valid.\n");
-		rtc_time_to_tm(0, tm);
-	}
-	return 0;
+	return rtc_valid_tm(tm);
 }
 
 static const struct rtc_class_ops ds1742_rtc_ops = {
@@ -139,7 +134,7 @@
 	void __iomem *ioaddr = pdata->ioaddr_nvram;
 	ssize_t count;
 
-	for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
+	for (count = 0; count < size; count++)
 		*buf++ = readb(ioaddr + pos++);
 	return count;
 }
@@ -154,7 +149,7 @@
 	void __iomem *ioaddr = pdata->ioaddr_nvram;
 	ssize_t count;
 
-	for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
+	for (count = 0; count < size; count++)
 		writeb(*buf++, ioaddr + pos++);
 	return count;
 }
@@ -168,22 +163,17 @@
 	void __iomem *ioaddr;
 	int ret = 0;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res)
-		return -ENODEV;
 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		return -ENOMEM;
-	pdata->size = resource_size(res);
-	if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
-		pdev->name))
-		return -EBUSY;
-	ioaddr = devm_ioremap(&pdev->dev, res->start, pdata->size);
-	if (!ioaddr)
-		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ioaddr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ioaddr))
+		return PTR_ERR(ioaddr);
 
 	pdata->ioaddr_nvram = ioaddr;
-	pdata->size_nvram = pdata->size - RTC_SIZE;
+	pdata->size_nvram = resource_size(res) - RTC_SIZE;
 	pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
 
 	sysfs_bin_attr_init(&pdata->nvram_attr);
@@ -212,11 +202,13 @@
 				  &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, "Unable to create sysfs entry: %s\n",
+			pdata->nvram_attr.attr.name);
 
-	return ret;
+	return 0;
 }
 
 static int ds1742_rtc_remove(struct platform_device *pdev)
@@ -227,12 +219,18 @@
 	return 0;
 }
 
+static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
+	{ .compatible = "maxim,ds1742", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
+
 static struct platform_driver ds1742_rtc_driver = {
 	.probe		= ds1742_rtc_probe,
 	.remove		= ds1742_rtc_remove,
 	.driver		= {
 		.name	= "rtc-ds1742",
-		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(ds1742_rtc_of_match),
 	},
 };