[PATCH 3.6.0-rc5] dt: introduce of_get_child to get child node by name.
Rob Herring
robherring2 at gmail.com
Fri Sep 14 06:32:03 EST 2012
On 09/13/2012 06:10 AM, Srinivas KANDAGATLA wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla at st.com>
>
> This patch introduces of_get_child function to get a child node by its
> name in a given parent node.
>
> Without this patch each driver code has to iterate the parent and do
> a string compare, However having of_get_child libary function would
> avoid code duplication, errors and is more convenient.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at st.com>
> ---
> drivers/of/base.c | 27 +++++++++++++++++++++++++++
> include/linux/of.h | 2 ++
> 2 files changed, 29 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index d4a1c9a..d4b6840 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -391,6 +391,33 @@ struct device_node *of_get_next_available_child(const struct device_node *node,
> EXPORT_SYMBOL(of_get_next_available_child);
>
> /**
> + * of_get_child - Find the child node by name for given parent
> + * @node: parent node
> + * @name: child name to look for.
> + *
> + * This function looks for child node for given matching name
> + *
> + * Returns a node pointer if found, with refcount incremented, use
> + * of_node_put() on it when done.
> + * else returns NULL.
> + */
> +
> +struct device_node *of_get_child(const struct device_node *node,
of_get_child_by_name would be more consistent naming with other apis.
> + const char *name)
> +{
> + struct device_node *child;
> +
> + read_lock(&devtree_lock);
I don't think you need the lock here. The for_each takes the lock while
finding the node.
> + for_each_child_of_node(node, child)
> + if (child->name && (of_node_cmp(child->name, name) == 0)
> + && of_node_get(child))
> + break;
> + read_unlock(&devtree_lock);
> + return child;
> +}
> +EXPORT_SYMBOL(of_get_child);
> +
> +/**
> * of_find_node_by_path - Find a node matching a full OF path
> * @path: The full path to match
> *
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 1b11632..510e1fe 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -192,6 +192,8 @@ extern struct device_node *of_get_next_child(const struct device_node *node,
> struct device_node *prev);
> extern struct device_node *of_get_next_available_child(
> const struct device_node *node, struct device_node *prev);
> +extern struct device_node *of_get_child(const struct device_node *node,
> + const char *name);
>
> #define for_each_child_of_node(parent, child) \
> for (child = of_get_next_child(parent, NULL); child != NULL; \
>
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