interconnect: Add of_icc_get_by_index() helper function

This is the same as the traditional of_icc_get() function, but the
difference is that it takes index as an argument, instead of name.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20200512125327.1868-4-georgi.djakov@linaro.org
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

drivers/interconnect/core.c

@@ -351,9 +351,9 @@ static struct icc_node *of_icc_get_from_provider(struct of_phandle_args *spec)
 }
 
 /**
- * of_icc_get() - get a path handle from a DT node based on name
+ * of_icc_get_by_index() - get a path handle from a DT node based on index
  * @dev: device pointer for the consumer device
- * @name: interconnect path name
+ * @idx: interconnect path index
  *
  * This function will search for a path between two endpoints and return an
  * icc_path handle on success. Use icc_put() to release constraints when they
@@ -365,13 +365,12 @@ static struct icc_node *of_icc_get_from_provider(struct of_phandle_args *spec)
  * Return: icc_path pointer on success or ERR_PTR() on error. NULL is returned
  * when the API is disabled or the "interconnects" DT property is missing.
  */
-struct icc_path *of_icc_get(struct device *dev, const char *name)
+struct icc_path *of_icc_get_by_index(struct device *dev, int idx)
 {
-	struct icc_path *path = ERR_PTR(-EPROBE_DEFER);
+	struct icc_path *path;
 	struct icc_node *src_node, *dst_node;
-	struct device_node *np = NULL;
+	struct device_node *np;
 	struct of_phandle_args src_args, dst_args;
-	int idx = 0;
 	int ret;
 
 	if (!dev || !dev->of_node)
@@ -391,12 +390,6 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 	 * lets support only global ids and extend this in the future if needed
 	 * without breaking DT compatibility.
 	 */
-	if (name) {
-		idx = of_property_match_string(np, "interconnect-names", name);
-		if (idx < 0)
-			return ERR_PTR(idx);
-	}
-
 	ret = of_parse_phandle_with_args(np, "interconnects",
 					 "#interconnect-cells", idx * 2,
 					 &src_args);
@@ -439,12 +432,8 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 		return path;
 	}
 
-	if (name)
+	path->name = kasprintf(GFP_KERNEL, "%s-%s",
-		path->name = kstrdup_const(name, GFP_KERNEL);
+			       src_node->name, dst_node->name);
-	else
-		path->name = kasprintf(GFP_KERNEL, "%s-%s",
-				       src_node->name, dst_node->name);
-
 	if (!path->name) {
 		kfree(path);
 		return ERR_PTR(-ENOMEM);
@@ -452,6 +441,53 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 
 	return path;
 }
+EXPORT_SYMBOL_GPL(of_icc_get_by_index);
+
+/**
+ * of_icc_get() - get a path handle from a DT node based on name
+ * @dev: device pointer for the consumer device
+ * @name: interconnect path name
+ *
+ * This function will search for a path between two endpoints and return an
+ * icc_path handle on success. Use icc_put() to release constraints when they
+ * are not needed anymore.
+ * If the interconnect API is disabled, NULL is returned and the consumer
+ * drivers will still build. Drivers are free to handle this specifically,
+ * but they don't have to.
+ *
+ * Return: icc_path pointer on success or ERR_PTR() on error. NULL is returned
+ * when the API is disabled or the "interconnects" DT property is missing.
+ */
+struct icc_path *of_icc_get(struct device *dev, const char *name)
+{
+	struct device_node *np;
+	int idx = 0;
+
+	if (!dev || !dev->of_node)
+		return ERR_PTR(-ENODEV);
+
+	np = dev->of_node;
+
+	/*
+	 * When the consumer DT node do not have "interconnects" property
+	 * return a NULL path to skip setting constraints.
+	 */
+	if (!of_find_property(np, "interconnects", NULL))
+		return NULL;
+
+	/*
+	 * We use a combination of phandle and specifier for endpoint. For now
+	 * lets support only global ids and extend this in the future if needed
+	 * without breaking DT compatibility.
+	 */
+	if (name) {
+		idx = of_property_match_string(np, "interconnect-names", name);
+		if (idx < 0)
+			return ERR_PTR(idx);
+	}
+
+	return of_icc_get_by_index(dev, idx);
+}
 EXPORT_SYMBOL_GPL(of_icc_get);
 
 /**

include/linux/interconnect.h

@@ -28,6 +28,7 @@ struct device;
 struct icc_path *icc_get(struct device *dev, const int src_id,
 			 const int dst_id);
 struct icc_path *of_icc_get(struct device *dev, const char *name);
+struct icc_path *of_icc_get_by_index(struct device *dev, int idx);
 void icc_put(struct icc_path *path);
 int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw);
 void icc_set_tag(struct icc_path *path, u32 tag);
@@ -46,6 +47,11 @@ static inline struct icc_path *of_icc_get(struct device *dev,
 	return NULL;
 }
 
+static inline struct icc_path *of_icc_get_by_index(struct device *dev, int idx)
+{
+	return NULL;
+}
+
 static inline void icc_put(struct icc_path *path)
 {
 }