[U-Boot] [PATCH v2 1/7] dm: core: Add of_alias_get_highest_id()

[Michal Simek]

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 at sang-engineering.com>
Acked-by: Rob Herring <robh at kernel.org>
Signed-off-by: Wolfram Sang <wsa at the-dreams.de>
"

Add it also to U-Boot for DM I2C support.

Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---

Changes in v2:
- Update kernel-doc binding
- Return -1 in case of error. -1 means that the next free alias is 0.

 drivers/core/of_access.c | 18 ++++++++++++++++++
 include/dm/of_access.h   | 10 ++++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/core/of_access.c b/drivers/core/of_access.c
index 14c020a687b7..945b81448cce 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 = -1;
+
+	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..13fedb7cf5e6 100644
--- a/include/dm/of_access.h
+++ b/include/dm/of_access.h
@@ -425,6 +425,16 @@ 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.
+ * @return alias ID, if found, else -1
+ */
+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