Commit 351d224f authored by Wolfram Sang's avatar Wolfram Sang Committed by Wolfram Sang
Browse files

of: base: add function to get highest id of an alias stem 



I2C supports adding adapters using either a dynamic or fixed id. The
latter is provided by aliases in the DT case. To prevent id collisions
of those two types, install this function which gives us the highest
fixed id, so we can then let the dynamically created ones come after
this highest number.

Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent b20d3864

drivers/of/base.c

+26 −0
Original line number Diff line number Diff line
@@ -1958,6 +1958,32 @@ int of_alias_get_id(struct device_node *np, const char *stem) 
}

EXPORT_SYMBOL_GPL(of_alias_get_id);



/**

 * of_alias_get_highest_id - Get highest alias id for the given stem

 * @stem:	Alias stem to be examined

 *

 * The function travels the lookup table to get the highest alias id for the

 * given alias stem.  It returns the alias id if found.

 */

int of_alias_get_highest_id(const char *stem)

{

	struct alias_prop *app;

	int id = -ENODEV;



	mutex_lock(&of_mutex);

	list_for_each_entry(app, &aliases_lookup, link) {

		if (strcmp(app->stem, stem) != 0)

			continue;



		if (app->id > id)

			id = app->id;

	}

	mutex_unlock(&of_mutex);



	return id;

}

EXPORT_SYMBOL_GPL(of_alias_get_highest_id);



const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,

			       u32 *pu)

{

include/linux/of.h

+6 −0
Original line number Diff line number Diff line
@@ -332,6 +332,7 @@ extern int of_count_phandle_with_args(const struct device_node *np, 


extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));

extern int of_alias_get_id(struct device_node *np, const char *stem);

extern int of_alias_get_highest_id(const char *stem);



extern int of_machine_is_compatible(const char *compat);
@@ -594,6 +595,11 @@ static inline int of_alias_get_id(struct device_node *np, const char *stem) 
	return -ENOSYS;

}



static inline int of_alias_get_highest_id(const char *stem)

{

	return -ENOSYS;

}



static inline int of_machine_is_compatible(const char *compat)

{

	return 0;

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