drm/imx/dcss: request memory region

The driver's memory regions are currently just ioremap()ed, but not
reserved through a request. That's not a bug, but having the request is
a little more robust.

Implement the region-request through the corresponding managed
devres-function.
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
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/20240124111904.18261-3-pstanner@redhat.com

drivers/gpu/drm/imx/dcss/dcss-dev.c

@@ -170,6 +170,7 @@ 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) {
@@ -183,6 +184,12 @@ 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")) {
+		dev_err(dev, "cannot request memory region\n");
+		return ERR_PTR(-EBUSY);
+	}
+
 	dcss = kzalloc(sizeof(*dcss), GFP_KERNEL);
 	if (!dcss)
 		return ERR_PTR(-ENOMEM);