Hi Michal,
On Fri, 18 Jan 2019 at 08:13, Michal Simek michal.simek@xilinx.com wrote:
The same functionality was added to Linux for i2c bus registration with this commit message:
" 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: Wolfram Sang wsa+renesas@sang-engineering.com Acked-by: Rob Herring robh@kernel.org Signed-off-by: Wolfram Sang wsa@the-dreams.de "
Add it also to U-Boot for DM I2C support.
Signed-off-by: Michal Simek michal.simek@xilinx.com
drivers/core/of_access.c | 18 ++++++++++++++++++ include/dm/of_access.h | 9 +++++++++ 2 files changed, 27 insertions(+)
diff --git a/drivers/core/of_access.c b/drivers/core/of_access.c index 14c020a687b7..7c2df2354109 100644 --- a/drivers/core/of_access.c +++ b/drivers/core/of_access.c @@ -812,6 +812,24 @@ int of_alias_get_id(const struct device_node *np, const char *stem) return id; }
+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;+}
struct device_node *of_get_stdout(void) { return of_stdout; diff --git a/include/dm/of_access.h b/include/dm/of_access.h index 5ed1a0cdb427..5cbfd220bfd4 100644 --- a/include/dm/of_access.h +++ b/include/dm/of_access.h @@ -425,6 +425,15 @@ int of_alias_scan(void); int of_alias_get_id(const struct device_node *np, const char *stem);
/**
- 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.
@return
- */
+int of_alias_get_highest_id(const char *stem);
+/**
- of_get_stdout() - Get node to use for stdout
- @return node referred to by stdout-path alias, or NULL if none
-- 1.9.1
Can we place have a test that calls this for a few values?
Also see uclass_find_next_free_req_seq() and uclass_resolve_seq() which is what U-Boot does today. It is first in, first served. This is supposed to mean that devices without an alias don't get a req_seq value, meaning that the seq value is set to the next available value.
I suspect it is OK to change the behaviour though. It might affect some boards which rely on not having aliases but still getting bus numbers.
Regards, Simon