coresight: stm: Rearrange probing the stimulus area

As we are about to refactor the platform specific handling
re-arrange some of the DT specific property handling.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-stm.c

@@ -683,14 +683,15 @@ static const struct attribute_group *coresight_stm_groups[] = {
 	NULL,
 };
 
-static int stm_get_resource_byname(struct device_node *np,
-				   char *ch_base, struct resource *res)
+#ifdef CONFIG_OF
+static int of_stm_get_stimulus_area(struct device *dev, struct resource *res)
 {
 	const char *name = NULL;
 	int index = 0, found = 0;
+	struct device_node *np = dev->of_node;
 
 	while (!of_property_read_string_index(np, "reg-names", index, &name)) {
-		if (strcmp(ch_base, name)) {
+		if (strcmp("stm-stimulus-base", name)) {
 			index++;
 			continue;
 		}
@@ -705,6 +706,20 @@ static int stm_get_resource_byname(struct device_node *np,
 
 	return of_address_to_resource(np, index, res);
 }
+#else
+static inline int of_stm_get_stimulus_area(struct device *dev,
+					   struct resource *res)
+{
+	return -ENOENT;
+}
+#endif
+
+static int stm_get_stimulus_area(struct device *dev, struct resource *res)
+{
+	if (is_of_node(dev_fwnode(dev)))
+		return of_stm_get_stimulus_area(dev, res);
+	return -ENOENT;
+}
 
 static u32 stm_fundamental_data_size(struct stm_drvdata *drvdata)
 {
@@ -819,7 +834,7 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id)
 		return PTR_ERR(base);
 	drvdata->base = base;
 
-	ret = stm_get_resource_byname(np, "stm-stimulus-base", &ch_res);
+	ret = stm_get_stimulus_area(dev, &ch_res);
 	if (ret)
 		return ret;
 	drvdata->chs.phys = ch_res.start;