drm/imx/dcss: fix resource size calculation

The resource is inclusive of the ->start and ->end addresses so this
calculation is not correct.  It should be "res->end - res->start + 1".
Use the resource_size() to do the calculation.

Fixes: 90393c9b5408 ("drm/imx/dcss: request memory region")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4914592b-4256-4c9c-bc1d-6dec1e473831@moroto.mountain

diff --git a/drivers/gpu/drm/imx/dcss/dcss-dev.c b/drivers/gpu/drm/imx/dcss/dcss-dev.c
index 597e9b7bd4bfa4faf3864322af318835e95d0f80..7fd0c4c14205dca533552f8d7551656888ca311a 100644 (file)
--- a/drivers/gpu/drm/imx/dcss/dcss-dev.c
+++ b/drivers/gpu/drm/imx/dcss/dcss-dev.c
@@ -167,7 +167,6 @@ struct dcss_dev *dcss_dev_create(struct device *dev, bool hdmi_output)
        struct resource *res;
        struct dcss_dev *dcss;
        const struct dcss_type_data *devtype;
-       resource_size_t res_len;
 
        devtype = of_device_get_match_data(dev);
        if (!devtype) {
@@ -181,8 +180,7 @@ struct dcss_dev *dcss_dev_create(struct device *dev, bool hdmi_output)
                return ERR_PTR(-EINVAL);
        }
 
-       res_len = res->end - res->start;
-       if (!devm_request_mem_region(dev, res->start, res_len, "dcss")) {
+       if (!devm_request_mem_region(dev, res->start, resource_size(res), "dcss")) {
                dev_err(dev, "cannot request memory region\n");
                return ERR_PTR(-EBUSY);
        }