[PATCH RFC 01/15] of: property: add port base loop

From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
To: Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>
Cc: Linux-ALSA <alsa-devel@alsa-project.org>
Subject: [PATCH RFC 01/15] of: property: add port base loop
Date: 22 Jun 2021 10:14:13 +0900	[thread overview]
Message-ID: <87zgvi3dlm.wl-kuninori.morimoto.gx@renesas.com> (raw)
In-Reply-To: <871r8u4s6q.wl-kuninori.morimoto.gx@renesas.com>


From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

We have endpoint base functions
	- of_graph_get_next_endpoint()
	- of_graph_get_endpoint_count()
	- for_each_endpoint_of_node()

for_each_endpoint_of_node() loop finds endpoint.

	ports {
		port@0 {
(1)			endpoint {...};
		};
		port@1 {
(2)			endpoint {...};
		};
		...
	};

In above case, for_each_endpoint_of_node() loop
finds endpoint as (1) -> (2) -> ...
If we want to get port@0 -> port@1 -> ...
instead of endpoint, we need do like below

	for_each_endpoint_of_node(node, endpoint) {
		port = of_get_parent(endpoint);
		...
	}

But port might have multi endpoints.

	ports {
		port@0 {
(1)			endpoint@0 {...};
(2)			endpoint@1 {...};
		};
		port@1 {
(3)			endpoint {...};
		};
		...
	};

In such case, people want to have "port base" loop
instead of "endpoints base" loop.
This patch adds such functions/macros.

Link: https://lore.kernel.org/r/87pn29pc5w.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 drivers/of/property.c    | 69 ++++++++++++++++++++++++++++++++++------
 include/linux/of_graph.h | 14 ++++++++
 2 files changed, 73 insertions(+), 10 deletions(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 6c028632f425..bf3bdeeba2f9 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -650,15 +650,7 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 	 * parent port node.
 	 */
 	if (!prev) {
-		struct device_node *node;
-
-		node = of_get_child_by_name(parent, "ports");
-		if (node)
-			parent = node;
-
-		port = of_get_child_by_name(parent, "port");
-		of_node_put(node);
-
+		port = of_graph_get_next_port(parent, NULL);
 		if (!port) {
 			pr_err("graph: no port node found in %pOF\n", parent);
 			return NULL;
@@ -685,14 +677,59 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 		/* No more endpoints under this port, try the next one. */
 		prev = NULL;
 
+		port = of_graph_get_next_port(parent, port);
+		if (!port)
+			return NULL;
+	}
+}
+EXPORT_SYMBOL(of_graph_get_next_endpoint);
+
+/**
+ * of_graph_get_next_port() - get next port node
+ * @parent: pointer to the parent device node
+ * @prev: previous port node, or NULL to get first
+ *
+ * Return: An 'port' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is decremented.
+ */
+struct device_node *of_graph_get_next_port(const struct device_node *parent,
+					   struct device_node *prev)
+{
+	struct device_node *port = prev;
+
+	if (!parent)
+		return NULL;
+
+	/*
+	 * Start by locating the port node. If no previous endpoint is specified
+	 * search for the first port node, otherwise get the previous endpoint
+	 * parent port node.
+	 */
+	if (!port) {
+		struct device_node *node;
+
+		node = of_get_child_by_name(parent, "ports");
+		if (node)
+			parent = node;
+
+		port = of_get_child_by_name(parent, "port");
+		of_node_put(node);
+
+		if (!port) {
+			pr_err("graph: no port node found in %pOF\n", parent);
+			return NULL;
+		}
+	} else {
 		do {
 			port = of_get_next_child(parent, port);
 			if (!port)
 				return NULL;
 		} while (!of_node_name_eq(port, "port"));
 	}
+
+	return port;
 }
-EXPORT_SYMBOL(of_graph_get_next_endpoint);
+EXPORT_SYMBOL(of_graph_get_next_port);
 
 /**
  * of_graph_get_endpoint_by_regs() - get endpoint node of specific identifiers
@@ -819,6 +856,18 @@ int of_graph_get_endpoint_count(const struct device_node *np)
 }
 EXPORT_SYMBOL(of_graph_get_endpoint_count);
 
+int of_graph_get_port_count(const struct device_node *np)
+{
+	struct device_node *port;
+	int num = 0;
+
+	for_each_port_of_node(np, port)
+		num++;
+
+	return num;
+}
+EXPORT_SYMBOL(of_graph_get_port_count);
+
 /**
  * of_graph_get_remote_node() - get remote parent device_node for given port/endpoint
  * @node: pointer to parent device_node containing graph port/endpoint
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index 4d7756087b6b..8cd3bd674ebd 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -26,6 +26,17 @@ struct of_endpoint {
 	const struct device_node *local_node;
 };
 
+/**
+ * for_each_port_of_node - iterate over every port in a device node
+ * @parent: parent device node containing ports and port
+ * @child: loop variable pointing to the current port node
+ *
+ * When breaking out of the loop, of_node_put(child) has to be called manually.
+ */
+#define for_each_port_of_node(parent, child)			\
+	for (child = of_graph_get_next_port(parent, NULL); child != NULL; \
+	     child = of_graph_get_next_port(parent, child))
+
 /**
  * for_each_endpoint_of_node - iterate over every endpoint in a device node
  * @parent: parent device node containing ports and endpoints
@@ -41,8 +52,11 @@ struct of_endpoint {
 bool of_graph_is_present(const struct device_node *node);
 int of_graph_parse_endpoint(const struct device_node *node,
 				struct of_endpoint *endpoint);
+int of_graph_get_port_count(const struct device_node *np);
 int of_graph_get_endpoint_count(const struct device_node *np);
 struct device_node *of_graph_get_port_by_id(struct device_node *node, u32 id);
+struct device_node *of_graph_get_next_port(const struct device_node *parent,
+					   struct device_node *previous);
 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 					struct device_node *previous);
 struct device_node *of_graph_get_endpoint_by_regs(
-- 
2.25.1

