of: Add of_property_match_string() to find index into a string list
Add a helper function for finding the index of a string in a string
list property. This helper is useful for bindings that use a separate
*-name property for attaching names to tuples in another property such
as 'reg' or 'gpios'.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 133908a..13ba728 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -761,6 +761,42 @@
}
EXPORT_SYMBOL_GPL(of_property_read_string_index);
+/**
+ * of_property_match_string() - Find string in a list and return index
+ * @np: pointer to node containing string list property
+ * @propname: string list property name
+ * @string: pointer to string to search for in string list
+ *
+ * This function searches a string list property and returns the index
+ * of a specific string value.
+ */
+int of_property_match_string(struct device_node *np, const char *propname,
+ const char *string)
+{
+ struct property *prop = of_find_property(np, propname, NULL);
+ size_t l;
+ int i;
+ const char *p, *end;
+
+ if (!prop)
+ return -EINVAL;
+ if (!prop->value)
+ return -ENODATA;
+
+ p = prop->value;
+ end = p + prop->length;
+
+ for (i = 0; p < end; i++, p += l) {
+ l = strlen(p) + 1;
+ if (p + l > end)
+ return -EILSEQ;
+ pr_debug("comparing %s with %s\n", string, p);
+ if (strcmp(string, p) == 0)
+ return i; /* Found it; return index */
+ }
+ return -ENODATA;
+}
+EXPORT_SYMBOL_GPL(of_property_match_string);
/**
* of_property_count_strings - Find and return the number of strings from a