goto err_free_clk;
        }
 
-       r = request_mem_region(r->start, r->end - r->start + 1, pdev->name);
+       r = request_mem_region(r->start, resource_size(r), pdev->name);
        if (r == NULL) {
                dev_err(&pdev->dev, "failed to request memory resource\n");
                ret = -EBUSY;
                goto err_free_clk;
        }
 
-       pwm->mmio_base = ioremap(r->start, r->end - r->start + 1);
+       pwm->mmio_base = ioremap(r->start, resource_size(r));
        if (pwm->mmio_base == NULL) {
                dev_err(&pdev->dev, "failed to ioremap() registers\n");
                ret = -ENODEV;
        return 0;
 
 err_free_mem:
-       release_mem_region(r->start, r->end - r->start + 1);
+       release_mem_region(r->start, resource_size(r));
 err_free_clk:
        clk_put(pwm->clk);
 err_free:
        iounmap(pwm->mmio_base);
 
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       release_mem_region(r->start, r->end - r->start + 1);
+       release_mem_region(r->start, resource_size(r));
 
        clk_put(pwm->clk);