Re: [PATCH 13/22] OF: base: import parent/child functions from Linux OF API

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, Jun 18, 2013 at 07:29:58PM +0200, Sebastian Hesselbarth wrote:
> This imports of_get_parent, of_get_next_child, of_get_next_available_child,
> and of_get_child_by_name and corresponding helpers from Linux OF API.
> 
> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
> ---
> Cc: barebox@lists.infradead.org
> ---
>  drivers/of/base.c |   78 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/of.h      |   49 +++++++++++++++++++++++++++++++++
>  2 files changed, 127 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 148f832..17364ea 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -862,6 +862,84 @@ int of_device_is_available(const struct device_node *device)
>  }
>  EXPORT_SYMBOL(of_device_is_available);
>  
> +/**
> + *	of_get_parent - Get a node's parent if any
> + *	@node:	Node to get parent
> + *
> + *	Returns a pointer to the parent node or NULL if already at root.
> + */
> +struct device_node *of_get_parent(const struct device_node *node)
> +{
> +	if (!node)
> +		return NULL;
> +
> +	return (node == root_node) ? NULL : node->parent;
> +}
> +EXPORT_SYMBOL(of_get_parent);
> +
> +/**
> + *	of_get_next_child - Iterate a node childs
> + *	@node:	parent node
> + *	@prev:	previous child of the parent node, or NULL to get first
> + *
> + *	Returns a pointer to the next child or NULL.
> + */
> +struct device_node *of_get_next_child(const struct device_node *node,
> +	struct device_node *prev)
> +{
> +	if (!node)
> +		return NULL;
> +
> +	if (!prev)
> +		return list_prepare_entry(prev, &node->children, parent_list);
> +
> +	list_for_each_entry_continue(prev, &node->children, parent_list)
> +		return prev;
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL(of_get_next_child);
> +
> +/**
> + *	of_get_next_available_child - Find the next available child node
> + *	@node:	parent node
> + *	@prev:	previous child of the parent node, or NULL to get first
> + *
> + *      This function is like of_get_next_child(), except that it
> + *      automatically skips any disabled nodes (i.e. status = "disabled").
> + */
> +struct device_node *of_get_next_available_child(const struct device_node *node,
> +	struct device_node *prev)
> +{
> +	for_each_child_of_node(node, prev)
> +		if (of_device_is_available(prev))
> +			return prev;
> +	return NULL;
> +}
> +EXPORT_SYMBOL(of_get_next_available_child);
> +
> +/**
> + *	of_get_child_by_name - Find the child node by name for a 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 or NULL.
> + */
> +struct device_node *of_get_child_by_name(const struct device_node *node,
> +				const char *name)
> +{
> +	struct device_node *child;
> +
> +	for_each_child_of_node(node, child)
> +		if (child->name && (of_node_cmp(child->name, name) == 0))
> +			return child;
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL(of_get_child_by_name);
> +
>  void of_print_nodes(struct device_node *node, int indent)
>  {
>  	struct device_node *n;
> diff --git a/include/of.h b/include/of.h
> index 208b00b..c69b9ad 100644
> --- a/include/of.h
> +++ b/include/of.h
> @@ -195,6 +195,14 @@ extern struct device_node *of_find_node_with_property(
>  	struct device_node *from, const char *prop_name);
>  extern int of_device_is_available(const struct device_node *device);
>  
> +extern struct device_node *of_get_parent(const struct device_node *node);
> +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_by_name(const struct device_node *node,
> +					const char *name);
> +
>  extern void of_alias_scan(void);
>  extern int of_alias_get_id(struct device_node *np, const char *stem);
>  extern const char *of_alias_get(struct device_node *np);
> @@ -239,6 +247,29 @@ static inline struct device_node *of_get_root_node(void)
>  	return NULL;
>  }
>  
> +static inline struct device_node *of_get_parent(const struct device_node *node)
> +{
> +	return NULL;
> +}
> +
> +static inline struct device_node *of_get_next_child(
> +		const struct device_node *node, struct device_node *prev)
> +{
> +	return NULL;
> +}
> +
> +static inline struct device_node *of_get_next_available_child(
> +		const struct device_node *node, struct device_node *prev)
> +{
> +	return NULL;
> +}
> +
> +static inline struct device_node *of_get_child_by_name(
> +			const struct device_node *node, const char *name)
> +{
> +	return NULL;
> +}
> +
>  static inline struct property *of_find_property(const struct device_node *np,
>  						const char *name,
>  						int *lenp)
> @@ -321,4 +352,22 @@ static inline struct device_node *of_find_matching_node(
>  	for (dn = of_find_node_with_property(NULL, prop_name); dn; \
>  	     dn = of_find_node_with_property(dn, prop_name))
>  
> +#define for_each_child_of_node(parent, child) \
> +	for (child = of_get_next_child(parent, NULL); child != NULL; \
> +	     child = of_get_next_child(parent, child))

Why don't we just rename the original list iteration #define?

I think we shouldn't generate worse code just for the sake of being in
sync with Linux.

I wonder why the Linux implementation doesn't use the Linux list
implementation...

Sascha

-- 
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