[PATCH v2 01/16] device property: Add fwnode_graph_get_port_by_id()

[Chen-Yu Tsai <wenst@chromium.org>]

In some cases the driver needs a reference to the port firmware node.
Once such case is the upcoming USB power sequencing integration. The
USB hub port is tied to the corresponding port firmware node if it
exists.

Provide a helper for this.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 drivers/base/property.c  | 22 ++++++++++++++++++++++
 include/linux/property.h |  1 +
 2 files changed, 23 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 9387bb83eb54..a2afd854a604 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -1346,6 +1346,28 @@ int fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL(fwnode_graph_parse_endpoint);
 
+/**
+ * fwnode_graph_get_port_by_id - get the port matching a given id
+ * @fwnode: parent fwnode_handle containing the graph
+ * @id: id of the port
+ *
+ * Return: A 'port' firmware node pointer with refcount incremented.
+ *
+ * The caller is responsible for calling fwnode_handle_put() on the returned
+ * fwnode pointer.
+ */
+struct fwnode_handle *fwnode_graph_get_port_by_id(struct fwnode_handle *fwnode, u32 id)
+{
+	struct fwnode_handle *ep;
+
+	ep = fwnode_graph_get_endpoint_by_id(fwnode, id, 0, FWNODE_GRAPH_ENDPOINT_NEXT);
+	if (!ep)
+		return NULL;
+
+	return fwnode_get_next_parent(ep);
+}
+EXPORT_SYMBOL_GPL(fwnode_graph_get_port_by_id);
+
 const void *device_get_match_data(const struct device *dev)
 {
 	return fwnode_call_ptr_op(dev_fwnode(dev), device_get_match_data, dev);
diff --git a/include/linux/property.h b/include/linux/property.h
index e30ef23a9af3..11f3b54c7de0 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -499,6 +499,7 @@ int fwnode_get_phy_mode(const struct fwnode_handle *fwnode);
 
 void __iomem *fwnode_iomap(struct fwnode_handle *fwnode, int index);
 
+struct fwnode_handle *fwnode_graph_get_port_by_id(struct fwnode_handle *fwnode, u32 id);
 struct fwnode_handle *fwnode_graph_get_next_endpoint(
 	const struct fwnode_handle *fwnode, struct fwnode_handle *prev);
 struct fwnode_handle *
-- 
2.54.0.1099.g489fc7bff1-goog