of: add optional options parameter to of_find_node_by_path()

Update of_find_node_by_path():
1) Rename function to of_find_node_opts_by_path(), adding an optional
   pointer argument. Provide a static inline wrapper version of
   of_find_node_by_path() which calls the new function with NULL as
   the optional argument.
2) Ignore any part of the path beyond and including the ':' separator.
3) Set the new provided pointer argument to the beginning of the string
   following the ':' separator.
4: Add tests.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

3 files changed, 59 insertions, 5 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 99bc95e83d09..bdf051d0a7e6 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -714,10 +714,15 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
 {
         struct device_node *child;
         int len = strchrnul(path, '/') - path;
+        int term;
 
         if (!len)
                 return NULL;
 
+        term = strchrnul(path, ':') - path;
+        if (term < len)
+                len = term;
+
         __for_each_child_of_node(parent, child) {
                 const char *name = strrchr(child->full_name, '/');
                 if (WARN(!name, "malformed device_node %s\n", child->full_name))
@@ -730,11 +735,14 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
 }
 
 /**
- *      of_find_node_by_path - Find a node matching a full OF path
+ *      of_find_node_opts_by_path - Find a node matching a full OF path
  *      @path: Either the full path to match, or if the path does not
  *             start with '/', the name of a property of the /aliases
  *             node (an alias).  In the case of an alias, the node
  *             matching the alias' value will be returned.
+ *      @opts: Address of a pointer into which to store the start of
+ *             an options string appended to the end of the path with
+ *             a ':' separator.
  *
  *      Valid paths:
  *              /foo/bar        Full path
@@ -744,11 +752,15 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
  *      Returns a node pointer with refcount incremented, use
  *      of_node_put() on it when done.
  */
-struct device_node *of_find_node_by_path(const char *path)
+struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
 {
         struct device_node *np = NULL;
         struct property *pp;
         unsigned long flags;
+        const char *separator = strchr(path, ':');
+
+        if (opts)
+                *opts = separator ? separator + 1 : NULL;
 
         if (strcmp(path, "/") == 0)
                 return of_node_get(of_root);
@@ -756,7 +768,7 @@ struct device_node *of_find_node_by_path(const char *path)
         /* The path could begin with an alias */
         if (*path != '/') {
                 char *p = strchrnul(path, '/');
-                int len = p - path;
+                int len = separator ? separator - path : p - path;
 
                 /* of_aliases must not be NULL */
                 if (!of_aliases)
@@ -785,7 +797,7 @@ struct device_node *of_find_node_by_path(const char *path)
         raw_spin_unlock_irqrestore(&devtree_lock, flags);
         return np;
 }
-EXPORT_SYMBOL(of_find_node_by_path);
+EXPORT_SYMBOL(of_find_node_opts_by_path);
 
 /**
  *      of_find_node_by_name - Find a node by its "name" property
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 7a7ae07d592f..1807a0458648 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -47,6 +47,7 @@ static bool selftest_live_tree;
 static void __init of_selftest_find_node_by_name(void)
 {
         struct device_node *np;
+        const char *options;
 
         np = of_find_node_by_path("/testcase-data");
         selftest(np && !strcmp("/testcase-data", np->full_name),
@@ -87,6 +88,35 @@ static void __init of_selftest_find_node_by_name(void)
         np = of_find_node_by_path("testcase-alias/missing-path");
         selftest(!np, "non-existent alias with relative path returned node %s\n", np->full_name);
         of_node_put(np);
+
+        np = of_find_node_opts_by_path("/testcase-data:testoption", &options);
+        selftest(np && !strcmp("testoption", options),
+                 "option path test failed\n");
+        of_node_put(np);
+
+        np = of_find_node_opts_by_path("/testcase-data:testoption", NULL);
+        selftest(np, "NULL option path test failed\n");
+        of_node_put(np);
+
+        np = of_find_node_opts_by_path("testcase-alias:testaliasoption",
+                                       &options);
+        selftest(np && !strcmp("testaliasoption", options),
+                 "option alias path test failed\n");
+        of_node_put(np);
+
+        np = of_find_node_opts_by_path("testcase-alias:testaliasoption", NULL);
+        selftest(np, "NULL option alias path test failed\n");
+        of_node_put(np);
+
+        options = "testoption";
+        np = of_find_node_opts_by_path("testcase-alias", &options);
+        selftest(np && !options, "option clearing test failed\n");
+        of_node_put(np);
+
+        options = "testoption";
+        np = of_find_node_opts_by_path("/", &options);
+        selftest(np && !options, "option clearing root node test failed\n");
+        of_node_put(np);
 }
 
 static void __init of_selftest_dynamic(void)
diff --git a/include/linux/of.h b/include/linux/of.h
index aa01cf5852f8..8b021db3e16e 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -236,7 +236,13 @@ extern struct device_node *of_find_matching_node_and_match(
         const struct of_device_id *matches,
         const struct of_device_id **match);
 
-extern struct device_node *of_find_node_by_path(const char *path);
+extern struct device_node *of_find_node_opts_by_path(const char *path,
+        const char **opts);
+static inline struct device_node *of_find_node_by_path(const char *path)
+{
+        return of_find_node_opts_by_path(path, NULL);
+}
+
 extern struct device_node *of_find_node_by_phandle(phandle handle);
 extern struct device_node *of_get_parent(const struct device_node *node);
 extern struct device_node *of_get_next_parent(struct device_node *node);
@@ -383,6 +389,12 @@ static inline struct device_node *of_find_node_by_path(const char *path)
         return NULL;
 }
 
+static inline struct device_node *of_find_node_opts_by_path(const char *path,
+        const char **opts)
+{
+        return NULL;
+}
+
 static inline struct device_node *of_get_parent(const struct device_node *node)
 {
         return NULL;