On 29/01/2024 02:54, Kuninori Morimoto wrote:
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
of_graph_get_next_endpoint(node, NULL); // node/ports/port@0/endpoint
of_graph_get_next_endpoint(ports, NULL); // node/ports/port@0/endpoint
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
/*
* "endpoint" is now A1, and handle port1 things here,
* but we don't know how many endpoints port1 has.
*
* Because "endpoint" is non NULL, we can use port1
* as of_graph_get_next_endpoint(port1, xxx)
*/
do {
/* do something for port1 specific things here */
} while (endpoint = of_graph_get_next_endpoint(port1, endpoint))
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 not check node name (= "endpoint").
To handle endpoint more intuitive, create of_graph_get_next_endpoint_raw()
of_graph_get_next_endpoint_raw(port1, NULL); // A1
of_graph_get_next_endpoint_raw(port1, A1); // A2
of_graph_get_next_endpoint_raw(port1, A2); // NULL
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
---
drivers/of/property.c | 26 +++++++++++++++++++++++++-
include/linux/of_graph.h | 2 ++
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/of/property.c b/drivers/of/property.c
index 14ffd199c9b1..37dbb1b0e742 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -667,6 +667,30 @@ struct device_node *of_graph_get_next_port(const struct device_node *parent,
}
EXPORT_SYMBOL(of_graph_get_next_port);
+/**
+ * of_graph_get_next_endpoint_raw() - get next endpoint node
How about "of_graph_get_next_port_endpoint()"?
+ * @port: pointer to the target port node
+ * @endpoint: current endpoint node, or NULL to get first
+ *
+ * Return: An 'endpoint' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is decremented.
+ */
It might be good to highlight here the difference to the
of_graph_get_next_endpoint().
+struct device_node *of_graph_get_next_endpoint_raw(const struct device_node *port,
+ struct device_node *endpoint)
+{
+ if (!port)
+ return NULL;
+
+ do {
+ endpoint = of_get_next_child(port, endpoint);
+ if (!endpoint)
+ break;
+ } while (!of_node_name_eq(endpoint, "endpoint"));
+
+ return endpoint;
+}
+EXPORT_SYMBOL(of_graph_get_next_endpoint_raw);
+
/**
* of_graph_get_next_endpoint() - get next endpoint node
* @parent: pointer to the parent device node
@@ -708,7 +732,7 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
* getting the next child. If the previous endpoint is NULL this
* will return the first child.
*/
- endpoint = of_get_next_child(port, prev);
+ endpoint = of_graph_get_next_endpoint_raw(port, prev);
if (endpoint) {
of_node_put(port);
return endpoint;
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index fff598640e93..427905a6e8c3 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -57,6 +57,8 @@ int of_graph_get_port_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_endpoint(const struct device_node *parent,
struct device_node *previous);
+struct device_node *of_graph_get_next_endpoint_raw(const struct device_node *port,
+ struct device_node *prev);
struct device_node *of_graph_get_next_port(const struct device_node *parent,
struct device_node *previous);
struct device_node *of_graph_get_endpoint_by_regs(
