[PATCH] drivers/of: Improve documentation on match string

[Miquel Sabaté Solà]

The description of the function now explicitly states that it's
an *exact* match for the given string (i.e. not a submatch). It also
better states all the possible return values.

Moreover, this commit also makes sure that -ENODATA is returned if
prop->length is zero, just like it's done in other functions such as
'of_property_read_string'.

Signed-off-by: Miquel Sabaté Solà <mikisabate@xxxxxxxxx>
---
 drivers/of/property.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 164d77cb9445..1ff51d93178f 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -452,12 +452,17 @@ EXPORT_SYMBOL_GPL(of_property_read_string);

 /**
  * of_property_match_string() - Find string in a list and return index
- * @np: pointer to node containing string list property
+ * @np: pointer to the node containing the string list property
  * @propname: string list property name
- * @string: pointer to string to search for in string list
+ * @string: pointer to the string to search for in the string list
  *
- * This function searches a string list property and returns the index
- * of a specific string value.
+ * Search for an exact match of string in a device node property which is a
+ * list of strings.
+ *
+ * Return: the index of the first occurrence of the string on success, -EINVAL
+ * if the property does not exist, -ENODATA if the property does not have a
+ * value, and -EILSEQ if the string is not null-terminated within the length of
+ * the property data.
  */
 int of_property_match_string(const struct device_node *np, const char *propname,
 			     const char *string)
@@ -469,7 +474,7 @@ int of_property_match_string(const struct device_node *np, const char *propname,

 	if (!prop)
 		return -EINVAL;
-	if (!prop->value)
+	if (!prop->value || !prop->length)
 		return -ENODATA;

 	p = prop->value;
--
2.46.0