On Wed, Aug 28, 2024 at 05:11:37AM +0000, Kuninori Morimoto wrote:
> We have endpoint base functions
> - of_graph_get_next_device_endpoint()
> - of_graph_get_device_endpoint_count()
> - for_each_of_graph_device_endpoint()
>
> Here, for_each_of_graph_device_endpoint() loop finds each endpoints
>
> ports {
> port@0 {
> (1) endpoint {...};
> };
> port@1 {
> (2) endpoint {...};
> };
> ...
> };
>
> In above case, it 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" via existing
> for_each_of_graph_device_endpoint(). Getting "port" via of_get_parent()
> from "endpoint" doesn't work. see below.
>
> ports {
> port@0 {
> (1) endpoint@0 {...};
> (2) endpoint@1 {...};
> };
> port@1 {
> (3) endpoint {...};
> };
> ...
> };
>
> In other case, we want to handle "ports" same as "port" for some reasons.
>
> node {
> => ports@0 {
> port@0 { ... };
> port@1 { ... };
> ...
> };
> => ports@1 {
> ...
> };
> };
>
> Add "ports" / "port" base functions.
>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
> ---
> drivers/of/property.c | 108 +++++++++++++++++++++++++++++++++++++++
> include/linux/of_graph.h | 49 ++++++++++++++++++
> 2 files changed, 157 insertions(+)
>
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 164d77cb94458..d99b34dd2d5b4 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -625,6 +625,97 @@ 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_ports() - get next ports node.
> + * @parent: pointer to the parent device node
> + * @prev: previous ports node, or NULL to get first
> + *
> + * If "parent" node doesn't have "ports" node, it returns "parent" node itself as "ports" node.
> + *
> + * Return: A 'ports' node pointer with refcount incremented. Refcount
> + * of the passed @prev node is decremented.
> + */
> +struct device_node *of_graph_get_next_ports(struct device_node *parent,
> + struct device_node *prev)
> +{
> + if (!parent)
> + return NULL;
> +
> + if (!prev) {
> + /*
> + * Find "ports" node from parent
> + *
> + * parent {
> + * => ports {
> + * port {...};
> + * };
> + * };
> + */
> + prev = of_get_child_by_name(parent, "ports");
> +
> + /*
> + * Use parent as its ports if it not exist
> + *
> + * => parent {
> + * port {...};
> + * };
> + */
> + if (!prev) {
> + /* check whether "parent" has "port" node */
> + struct device_node *port __free(device_node) = of_get_child_by_name(parent, "port");
> +
> + if (port)
> + prev = of_node_get(parent);
> + }
> +
> + return prev;
> + }
> +
> + /* Find next ports */
> + do {
> + prev = of_get_next_child(parent, prev);
> + if (!prev)
> + break;
> + } while (!of_node_name_eq(prev, "ports"));
> +
> + return prev;
> +}
> +EXPORT_SYMBOL(of_graph_get_next_ports);
> +
> +/**
> + * of_graph_get_next_port() - get next port node.
> + * @parent: pointer to the parent device node, or parent ports node
> + * @prev: previous port node, or NULL to get first
> + *
> + * Parent device node can be used as @parent whether device node has ports node or not.
> + * It will work same as ports@0 node.
> + *
> + * Return: A 'port' node pointer with refcount incremented. Refcount
> + * of the passed @prev node is decremented.
> + */
> +struct device_node *of_graph_get_next_port(struct device_node *parent,
> + struct device_node *prev)
> +{
> + if (!parent)
> + return NULL;
> +
> + if (!prev) {
> + struct device_node *ports __free(device_node) =
> + of_graph_get_next_ports(parent, NULL);
> +
> + return of_get_child_by_name(ports, "port");
> + }
> +
> + do {
> + prev = of_get_next_child(parent, prev);
> + if (!prev)
> + break;
> + } while (!of_node_name_eq(prev, "port"));
> +
> + return prev;
> +}
> +EXPORT_SYMBOL(of_graph_get_next_port);
of_graph_is_present should be reimplemented using this function. So
should part of of_graph_get_next_endpoint().
Rob
