diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 1f3d89c3194a..c89687a10835 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -515,7 +515,7 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
+	ioarea = request_mem_region(mem->start, resource_size(mem),
 				    pdev->name);
 	if (!ioarea) {
 		dev_err(&pdev->dev, "I2C region already claimed\n");
@@ -578,7 +578,7 @@ err_free_mem:
 	put_device(&pdev->dev);
 	kfree(dev);
 err_release_region:
-	release_mem_region(mem->start, (mem->end - mem->start) + 1);
+	release_mem_region(mem->start, resource_size(mem));
 
 	return r;
 }
@@ -601,7 +601,7 @@ static int davinci_i2c_remove(struct platform_device *pdev)
 	kfree(dev);
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	release_mem_region(mem->start, (mem->end - mem->start) + 1);
+	release_mem_region(mem->start, resource_size(mem));
 	return 0;
 }
 
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index ad8d2010c921..fdd83277c8a8 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -806,7 +806,7 @@ omap_i2c_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
+	ioarea = request_mem_region(mem->start, resource_size(mem),
 			pdev->name);
 	if (!ioarea) {
 		dev_err(&pdev->dev, "I2C region already claimed\n");
@@ -905,7 +905,7 @@ err_free_mem:
 	platform_set_drvdata(pdev, NULL);
 	kfree(dev);
 err_release_region:
-	release_mem_region(mem->start, (mem->end - mem->start) + 1);
+	release_mem_region(mem->start, resource_size(mem));
 
 	return r;
 }
@@ -925,7 +925,7 @@ omap_i2c_remove(struct platform_device *pdev)
 	iounmap(dev->base);
 	kfree(dev);
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	release_mem_region(mem->start, (mem->end - mem->start) + 1);
+	release_mem_region(mem->start, resource_size(mem));
 	return 0;
 }
 
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 1c01083b01b5..4f3d99cd1692 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -563,7 +563,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
 		goto err_irq;
 	}
 
-	size = (res->end - res->start) + 1;
+	size = resource_size(res);
 
 	pd->reg = ioremap(res->start, size);
 	if (pd->reg == NULL) {
diff --git a/drivers/i2c/busses/i2c-simtec.c b/drivers/i2c/busses/i2c-simtec.c
index 042fda295f3a..6407f47bda82 100644
--- a/drivers/i2c/busses/i2c-simtec.c
+++ b/drivers/i2c/busses/i2c-simtec.c
@@ -92,7 +92,7 @@ static int simtec_i2c_probe(struct platform_device *dev)
 		goto err;
 	}
 
-	size = (res->end-res->start)+1;
+	size = resource_size(res);
 
 	pd->ioarea = request_mem_region(res->start, size, dev->name);
 	if (pd->ioarea == NULL) {