On Mon, Jan 29, 2024 at 02:29:22PM +0200, Tomi Valkeinen wrote:
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@renesas.com
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()"?
We may want to also rename the existing of_graph_get_next_endpoint() function to of_graph_next_dev_endpoint() then. It would be a tree-wide patch, which is always annoying to get reviewed and merged, so if Rob would prefer avoiding the rename, I'm fine with that.
- @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().
Yes, and the documentation of of_graph_get_next_endpoint() shoul also be improved.
+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);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);