We already have of_graph_get_next_endpoint(), but it is not
intuitive to use.
(X) node {
(Y) ports {
port@0 { endpoint { remote-endpoint = ...; };};
(A1) port@1 { endpoint { remote-endpoint = ...; };
(A2) endpoint { remote-endpoint = ...; };};
(B) port@2 { endpoint { remote-endpoint = ...; };};
};
};
For example, if I want to handle port@1's 2 endpoints (= A1, A2),
I want to use like below
A1 = of_graph_get_next_endpoint(port1, NULL);
A2 = of_graph_get_next_endpoint(port1, A1);
But 1st one will be error, because of_graph_get_next_endpoint()
requested "parent" means "node" (X) or "ports" (Y), not "port".
Below are OK
/* These will be node/ports/port@0/endpoint */
of_graph_get_next_endpoint(node, NULL);
of_graph_get_next_endpoint(ports, NULL);
In other words, we can't handle A1/A2 directly via
of_graph_get_next_endpoint() so far.
There is another non intuitive behavior on of_graph_get_next_endpoint().
In case of if I could get A1 pointer for some way, and if I want to
handle port@1 things, I would like use it like below
/*
* "ep" is now A1, and handle port1 things here,
* but we don't know how many endpoints port1 has.
*
* Because "ep" is non NULL, we can use port1
* as of_graph_get_next_endpoint(port1, xxx)
*/
do {
/* do something for port1 specific things here */
} while (ep = of_graph_get_next_endpoint(port1, ep))
But it also not worked as I expected.
I expect it will be A1 -> A2 -> NULL,
but it will be A1 -> A2 -> B, because
of_graph_get_next_endpoint() will fetch "endpoint" beyond the "port".
It is not useful on generic driver like Generic Sound Card.
It uses of_get_next_child() instead for now, but it is not intuitive.
And it doesn't check node name (= "endpoint").
To handle endpoint more intuitive, create of_graph_get_next_port_endpoint()
of_graph_get_next_port_endpoint(port1, NULL); // A1
of_graph_get_next_port_endpoint(port1, A1); // A2
of_graph_get_next_port_endpoint(port1, A2); // NULL
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
---
drivers/of/property.c | 22 ++++++++++++++++++++++
include/linux/of_graph.h | 20 ++++++++++++++++++++
2 files changed, 42 insertions(+)
diff --git a/drivers/of/property.c b/drivers/of/property.c
index e4d5dfe70104..dace154baaab 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -695,6 +695,28 @@ struct device_node *of_graph_get_next_port(struct device_node *parent,
}
EXPORT_SYMBOL(of_graph_get_next_port);
+/**
+ * of_graph_get_next_port_endpoint() - get next endpoint node in port.
+ * If it reached to end of the port, it will return NULL.
+ * @port: pointer to the target port node
+ * @prev: previous endpoint node, or NULL to get first
+ *
+ * Return: An 'endpoint' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is decremented.
+ */
+struct device_node *of_graph_get_next_port_endpoint(const struct device_node *port,
+ struct device_node *prev)
+{
+ do {
+ prev = of_get_next_child(port, prev);
+ if (!prev)
+ break;
+ } while (!of_node_name_eq(prev, "endpoint"));
+
+ return prev;
+}
+EXPORT_SYMBOL(of_graph_get_next_port_endpoint);
+
/**
* of_graph_get_next_endpoint() - get next endpoint node
* @parent: pointer to the parent device node
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index a6b91577700a..967ee14a1ff3 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -59,6 +59,17 @@ struct of_endpoint {
for (child = of_graph_get_next_port(parent, NULL); child != NULL; \
child = of_graph_get_next_port(parent, child))
+/**
+ * for_each_of_graph_port_endpoint - iterate over every endpoint in a port node
+ * @parent: parent port node
+ * @child: loop variable pointing to the current endpoint node
+ *
+ * When breaking out of the loop, of_node_put(child) has to be called manually.
+ */
+#define for_each_of_graph_port_endpoint(parent, child) \
+ for (child = of_graph_get_next_port_endpoint(parent, NULL); child != NULL; \
+ child = of_graph_get_next_port_endpoint(parent, child))
+
#ifdef CONFIG_OF
bool of_graph_is_present(const struct device_node *node);
int of_graph_parse_endpoint(const struct device_node *node,
@@ -72,6 +83,8 @@ struct device_node *of_graph_get_next_ports(struct device_node *parent,
struct device_node *ports);
struct device_node *of_graph_get_next_port(struct device_node *parent,
struct device_node *port);
+struct device_node *of_graph_get_next_port_endpoint(const struct device_node *port,
+ struct device_node *prev);
struct device_node *of_graph_get_endpoint_by_regs(
const struct device_node *parent, int port_reg, int reg);
struct device_node *of_graph_get_remote_endpoint(
@@ -132,6 +145,13 @@ static inline struct device_node *of_graph_get_next_port(
return NULL;
}
+static inline struct device_node *of_graph_get_next_port_endpoint(
+ const struct device_node *parent,
+ struct device_node *previous)
+{
+ return NULL;
+}
+
static inline struct device_node *of_graph_get_endpoint_by_regs(
const struct device_node *parent, int port_reg, int reg)
{
--
2.43.0
