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@xxxxxxxxxxx> > --- > 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); > +