Hi Morimoto-san, (CC'ing Sakari) Thank you for the patch. On Fri, Aug 09, 2024 at 04:22:22AM +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 > for_each_of_graph_device_endpoint(). 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 {...}; > }; > ... > }; > > In the same time, same reason, we want to handle "ports" same as "port". > > node { > => ports@0 { > port@0 { > endpoint@0 {...}; > endpoint@1 {...}; > ... > }; > port@1 { > endpoint@0 {...}; > endpoint@1 {...}; > ... > }; > ... > }; > => ports@1 { > ... > }; > }; > > Add "ports" / "port" base functions. > For above case, we can use > > for_each_of_graph_ports(node, ports) { > for_each_of_graph_port(ports, port) { > ... > } > } > > This loop works in case of "node" doesn't have "ports" also. > > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx> > --- > drivers/of/property.c | 88 ++++++++++++++++++++++++++++++++++++++++ > include/linux/of_graph.h | 46 +++++++++++++++++++++ > 2 files changed, 134 insertions(+) > > diff --git a/drivers/of/property.c b/drivers/of/property.c > index 164d77cb9445..e4d5dfe70104 100644 > --- a/drivers/of/property.c > +++ b/drivers/of/property.c > @@ -625,6 +625,76 @@ 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) { > + prev = of_get_child_by_name(parent, "ports"); > + > + /* use parent as its ports of this device if it not exist */ > + if (!prev) > + prev = of_node_get(parent); > + > + return prev; > + } > + > + 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); Having multiple "ports" nodes in a device node is not something I've ever seen before. There may be use cases, but how widespread are they ? I would prefer handling this in driver code instead of creating a helper function if the use case is rare. > + > +/** > + * 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); This also makes me quite uncomfortable. Iterating over all ports of a device node that contains multiple "ports" children seems an ill-defined use case. > + > + 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_get_next_endpoint() - get next endpoint node > * @parent: pointer to the parent device node > @@ -823,6 +893,24 @@ unsigned int of_graph_get_endpoint_count(const struct device_node *np) > } > EXPORT_SYMBOL(of_graph_get_endpoint_count); > > +/** > + * of_graph_get_port_count() - get the number of port in a device node > + * @np: pointer to the parent device node > + * > + * Return: count of port of this device node > + */ > +unsigned int of_graph_get_port_count(struct device_node *np) > +{ > + struct device_node *port = NULL; > + int num = 0; As the counter can never be negative, you can make this an unsigned int. > + > + for_each_of_graph_port(np, port) > + num++; > + > + return num; > +} > +EXPORT_SYMBOL(of_graph_get_port_count); > + > /** > * of_graph_get_remote_node() - get remote parent device_node for given port/endpoint > * @node: pointer to parent device_node containing graph port/endpoint > diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h > index a4bea62bfa29..a6b91577700a 100644 > --- a/include/linux/of_graph.h > +++ b/include/linux/of_graph.h > @@ -37,14 +37,41 @@ struct of_endpoint { > for (child = of_graph_get_next_endpoint(parent, NULL); child != NULL; \ > child = of_graph_get_next_endpoint(parent, child)) > > +/** > + * for_each_of_graph_ports - iterate over every ports in a device node > + * @parent: parent device node containing ports > + * @child: loop variable pointing to the current ports node > + * > + * When breaking out of the loop, of_node_put(child) has to be called manually. > + */ > +#define for_each_of_graph_ports(parent, child) \ > + for (child = of_graph_get_next_ports(parent, NULL); child != NULL; \ > + child = of_graph_get_next_ports(parent, child)) > + > +/** > + * for_each_of_graph_port - iterate over every port in a device or ports node > + * @parent: parent device or ports node containing port > + * @child: loop variable pointing to the current port node > + * > + * When breaking out of the loop, of_node_put(child) has to be called manually. > + */ > +#define for_each_of_graph_port(parent, child) \ > + for (child = of_graph_get_next_port(parent, NULL); child != NULL; \ > + child = of_graph_get_next_port(parent, child)) I think I've proposed something similar a looooong time ago, and was told that iterating over ports is not something that drivers should do. The situation may have changed since though. Sakari, any opinion on this ? > + > #ifdef CONFIG_OF > bool of_graph_is_present(const struct device_node *node); > int of_graph_parse_endpoint(const struct device_node *node, > struct of_endpoint *endpoint); > unsigned int of_graph_get_endpoint_count(const struct device_node *np); > +unsigned int of_graph_get_port_count(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_ports(struct device_node *parent, > + struct device_node *ports); > +struct device_node *of_graph_get_next_port(struct device_node *parent, > + struct device_node *port); > struct device_node *of_graph_get_endpoint_by_regs( > const struct device_node *parent, int port_reg, int reg); > struct device_node *of_graph_get_remote_endpoint( > @@ -73,6 +100,11 @@ static inline unsigned int of_graph_get_endpoint_count(const struct device_node > return 0; > } > > +static inline unsigned int of_graph_get_port_count(struct device_node *np) > +{ > + return 0; > +} > + > static inline struct device_node *of_graph_get_port_by_id( > struct device_node *node, u32 id) > { > @@ -86,6 +118,20 @@ static inline struct device_node *of_graph_get_next_endpoint( > return NULL; > } > > +static inline struct device_node *of_graph_get_next_ports( > + struct device_node *parent, > + struct device_node *previous) > +{ > + return NULL; > +} > + > +static inline struct device_node *of_graph_get_next_port( > + struct device_node *parent, > + struct device_node *previous) > +{ > + return NULL; > +} > + > static inline struct device_node *of_graph_get_endpoint_by_regs( > const struct device_node *parent, int port_reg, int reg) > { -- Regards, Laurent Pinchart