Hi Dmitry

On Sat, Apr 18, 2020 at 08:06:58PM +0300, Dmitry Osipenko wrote:
> In some case, like a DRM display code for example, it's useful to silently
> check whether port node exists at all in a device-tree before proceeding
> with parsing the graph.
> 
> This patch adds of_graph_get_local_port() which returns pointer to a local
> port node, or NULL if graph isn't specified in a device-tree for a given
> device node.
> 
> Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
Nice little helper function.
Reviewed-by: Sam Ravnborg <s...@ravnborg.org>

Rob - OK to commit to drm-misc-next?

        Sam

> ---
>  drivers/of/property.c    | 32 +++++++++++++++++++++++---------
>  include/linux/of_graph.h |  7 +++++++
>  2 files changed, 30 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 252e4f600155..5dbeccaabb86 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -608,15 +608,7 @@ struct device_node *of_graph_get_next_endpoint(const 
> struct device_node *parent,
>        * parent port node.
>        */
>       if (!prev) {
> -             struct device_node *node;
> -
> -             node = of_get_child_by_name(parent, "ports");
> -             if (node)
> -                     parent = node;
> -
> -             port = of_get_child_by_name(parent, "port");
> -             of_node_put(node);
> -
> +             port = of_graph_get_local_port(parent);
>               if (!port) {
>                       pr_err("graph: no port node found in %pOF\n", parent);
>                       return NULL;
> @@ -765,6 +757,28 @@ struct device_node *of_graph_get_remote_port(const 
> struct device_node *node)
>  }
>  EXPORT_SYMBOL(of_graph_get_remote_port);
>  
> +/**
> + * of_graph_get_local_port() - get local port node
> + * @node: pointer to a local endpoint device_node
> + *
> + * Return: First local port node associated with local endpoint node linked
> + *      to @node. Use of_node_put() on it when done.
> + */
> +struct device_node *of_graph_get_local_port(const struct device_node *node)
> +{
> +     struct device_node *ports, *port;
> +
> +     ports = of_get_child_by_name(node, "ports");
> +     if (ports)
> +             node = ports;
> +
> +     port = of_get_child_by_name(node, "port");
> +     of_node_put(ports);
> +
> +     return port;
> +}
> +EXPORT_SYMBOL(of_graph_get_local_port);
> +
>  int of_graph_get_endpoint_count(const struct device_node *np)
>  {
>       struct device_node *endpoint;
> diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
> index 01038a6aade0..1fdeb72c7765 100644
> --- a/include/linux/of_graph.h
> +++ b/include/linux/of_graph.h
> @@ -54,6 +54,7 @@ struct device_node *of_graph_get_remote_port_parent(
>  struct device_node *of_graph_get_remote_port(const struct device_node *node);
>  struct device_node *of_graph_get_remote_node(const struct device_node *node,
>                                            u32 port, u32 endpoint);
> +struct device_node *of_graph_get_local_port(const struct device_node *node);
>  #else
>  
>  static inline int of_graph_parse_endpoint(const struct device_node *node,
> @@ -116,6 +117,12 @@ static inline struct device_node 
> *of_graph_get_remote_node(
>       return NULL;
>  }
>  
> +static inline struct device_node *of_graph_get_local_port(
> +                                     const struct device_node *node)
> +{
> +     return NULL;
> +}
> +
>  #endif /* CONFIG_OF */
>  
>  #endif /* __LINUX_OF_GRAPH_H */
> -- 
> 2.26.0
> 
> _______________________________________________
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> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
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