On Mon, Jan 29, 2024 at 12:54:44AM +0000, Kuninori Morimoto wrote:
We have endpoint base functions
- of_graph_get_next_endpoint()
- of_graph_get_endpoint_count()
- for_each_endpoint_of_node()
Here, for_each_endpoint_of_node() loop finds each endpoints
ports { port@0 { (1) endpoint {...}; }; port@1 { (2) endpoint {...}; }; ... };
In above case, for_each_endpoint_of_node() loop finds endpoint as (1) -> (2) -> ...
Basically, user/driver knows which port is used for what, but not in all cases. For example on flexible/generic driver case, how many ports are used is not fixed.
For example Sound Generic Card driver which is used from many venders can't know how many ports are used. Because the driver is very flexible/generic, it is impossible to know how many ports are used, it depends on each vender SoC and/or its used board.
And more, the port can have multi endpoints. For example Generic Sound Card case, it supports many type of connection between CPU / Codec, and some of them uses multi endpoint in one port. Then, Generic Sound Card want to handle each connection via "port" instead of "endpoint". But, it is very difficult to handle each "port" by for_each_endpoint_of_node(). Getting "port" by using of_get_parent() from "endpoint" doesn't work. see below.
ports { port@0 { (1) endpoint@0 {...}; (2) endpoint@1 {...}; }; port@1 { (3) endpoint {...}; }; ... };
Add "port" base functions.
Signed-off-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com
drivers/of/property.c | 48 ++++++++++++++++++++++++++++++++++++++++ include/linux/of_graph.h | 21 ++++++++++++++++++ 2 files changed, 69 insertions(+)
diff --git a/drivers/of/property.c b/drivers/of/property.c index afdaefbd03f6..9e670e99dbbb 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -631,6 +631,42 @@ struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id) } EXPORT_SYMBOL(of_graph_get_port_by_id);
+/**
- of_graph_get_next_port() - get next port node
- @parent: pointer to the parent device node
- @port: current 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 *port)+{
- if (!parent)
return NULL;- if (!port) {
struct device_node *node;node = of_get_child_by_name(parent, "ports");if (node) {parent = node;of_node_put(node);
The original code had this right, but here you have it wrong.
You are releasing ports here, but then using it...
}return of_get_child_by_name(parent, "port");
...here. You have to get the child before you can put the parent.
- }
- do {
port = of_get_next_child(parent, port);if (!port)break;- } while (!of_node_name_eq(port, "port"));
- return port;
+} +EXPORT_SYMBOL(of_graph_get_next_port);