diff --git a/drivers/watchdog/adx_wdt.c b/drivers/watchdog/adx_wdt.c
index 9c65944..9d7d155 100644
--- a/drivers/watchdog/adx_wdt.c
+++ b/drivers/watchdog/adx_wdt.c
@@ -242,14 +242,14 @@
 	}
 
 	res = devm_request_mem_region(&pdev->dev, res->start,
-			res->end - res->start + 1, res->name);
+			resource_size(res), res->name);
 	if (!res) {
 		dev_err(&pdev->dev, "cannot request I/O memory region\n");
 		return -ENXIO;
 	}
 
 	wdt->base = devm_ioremap_nocache(&pdev->dev, res->start,
-			res->end - res->start + 1);
+			resource_size(res));
 	if (!wdt->base) {
 		dev_err(&pdev->dev, "cannot remap I/O memory region\n");
 		return -ENXIO;
diff --git a/drivers/watchdog/at32ap700x_wdt.c b/drivers/watchdog/at32ap700x_wdt.c
index e8ae638..0378479 100644
--- a/drivers/watchdog/at32ap700x_wdt.c
+++ b/drivers/watchdog/at32ap700x_wdt.c
@@ -326,7 +326,7 @@
 		return -ENOMEM;
 	}
 
-	wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
+	wdt->regs = ioremap(regs->start, resource_size(regs));
 	if (!wdt->regs) {
 		ret = -ENOMEM;
 		dev_dbg(&pdev->dev, "could not map I/O memory\n");
diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
index 9d7520fa..887136d 100644
--- a/drivers/watchdog/davinci_wdt.c
+++ b/drivers/watchdog/davinci_wdt.c
@@ -221,7 +221,7 @@
 		return -ENOENT;
 	}
 
-	size = res->end - res->start + 1;
+	size = resource_size(res);
 	wdt_mem = request_mem_region(res->start, size, pdev->name);
 
 	if (wdt_mem == NULL) {
diff --git a/drivers/watchdog/mpcore_wdt.c b/drivers/watchdog/mpcore_wdt.c
index 83fa34b..a2dc07c 100644
--- a/drivers/watchdog/mpcore_wdt.c
+++ b/drivers/watchdog/mpcore_wdt.c
@@ -350,7 +350,7 @@
 		ret = -ENXIO;
 		goto err_free;
 	}
-	wdt->base = ioremap(res->start, res->end - res->start + 1);
+	wdt->base = ioremap(res->start, resource_size(res));
 	if (!wdt->base) {
 		ret = -ENOMEM;
 		goto err_free;
diff --git a/drivers/watchdog/mv64x60_wdt.c b/drivers/watchdog/mv64x60_wdt.c
index acf589d..a51dbe4 100644
--- a/drivers/watchdog/mv64x60_wdt.c
+++ b/drivers/watchdog/mv64x60_wdt.c
@@ -275,7 +275,7 @@
 	if (!r)
 		return -ENODEV;
 
-	mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
+	mv64x60_wdt_regs = ioremap(r->start, resource_size(r));
 	if (mv64x60_wdt_regs == NULL)
 		return -ENOMEM;
 
diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
index 429ea99..c6aaf28 100644
--- a/drivers/watchdog/omap_wdt.c
+++ b/drivers/watchdog/omap_wdt.c
@@ -277,8 +277,7 @@
 		goto err_busy;
 	}
 
-	mem = request_mem_region(res->start, res->end - res->start + 1,
-				 pdev->name);
+	mem = request_mem_region(res->start, resource_size(res), pdev->name);
 	if (!mem) {
 		ret = -EBUSY;
 		goto err_busy;
@@ -306,7 +305,7 @@
 		goto err_clk;
 	}
 
-	wdev->base = ioremap(res->start, res->end - res->start + 1);
+	wdev->base = ioremap(res->start, resource_size(res));
 	if (!wdev->base) {
 		ret = -ENOMEM;
 		goto err_ioremap;
@@ -358,7 +357,7 @@
 	kfree(wdev);
 
 err_kzalloc:
-	release_mem_region(res->start, res->end - res->start + 1);
+	release_mem_region(res->start, resource_size(res));
 
 err_busy:
 err_get_resource:
@@ -383,7 +382,7 @@
 		return -ENOENT;
 
 	misc_deregister(&(wdev->omap_wdt_miscdev));
-	release_mem_region(res->start, res->end - res->start + 1);
+	release_mem_region(res->start, resource_size(res));
 	platform_set_drvdata(pdev, NULL);
 
 	clk_put(wdev->ick);
diff --git a/drivers/watchdog/pnx4008_wdt.c b/drivers/watchdog/pnx4008_wdt.c
index 4d227b15..430a584 100644
--- a/drivers/watchdog/pnx4008_wdt.c
+++ b/drivers/watchdog/pnx4008_wdt.c
@@ -264,7 +264,7 @@
 		return -ENOENT;
 	}
 
-	size = res->end - res->start + 1;
+	size = resource_size(res);
 	wdt_mem = request_mem_region(res->start, size, pdev->name);
 
 	if (wdt_mem == NULL) {
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 85b93e1..8760a26 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -421,7 +421,7 @@
 		return -ENOENT;
 	}
 
-	size = (res->end - res->start) + 1;
+	size = resource_size(res);
 	wdt_mem = request_mem_region(res->start, size, pdev->name);
 	if (wdt_mem == NULL) {
 		dev_err(dev, "failed to get memory region\n");
diff --git a/drivers/watchdog/txx9wdt.c b/drivers/watchdog/txx9wdt.c
index 6adab77..d635566 100644
--- a/drivers/watchdog/txx9wdt.c
+++ b/drivers/watchdog/txx9wdt.c
@@ -214,12 +214,10 @@
 	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	if (!res)
 		goto exit_busy;
-	if (!devm_request_mem_region(&dev->dev,
-				     res->start, res->end - res->start + 1,
+	if (!devm_request_mem_region(&dev->dev, res->start, resource_size(res),
 				     "txx9wdt"))
 		goto exit_busy;
-	txx9wdt_reg = devm_ioremap(&dev->dev,
-				   res->start, res->end - res->start + 1);
+	txx9wdt_reg = devm_ioremap(&dev->dev, res->start, resource_size(res));
 	if (!txx9wdt_reg)
 		goto exit_busy;