of: Add of_property_read_string_array()

of_property_read_string_array() is used to read a multistring device
tree property into an array of strings. This is taken from the kernel.
It is implemented around of_property_read_string_helper() which can be
used to implement of_property_count_strings() and
of_property_read_string_index() as well.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 70 insertions, 13 deletions

diff --git a/include/of.h b/include/of.h
index 98ddf795cb..f63a3efe13 100644
--- a/include/of.h
+++ b/include/of.h
@@ -197,14 +197,12 @@ extern int of_property_read_u64(const struct device_node *np,
 extern int of_property_read_string(struct device_node *np,
 				   const char *propname,
 				   const char **out_string);
-extern int of_property_read_string_index(struct device_node *np,
-					 const char *propname,
-					 int index, const char **output);
 extern int of_property_match_string(struct device_node *np,
 				    const char *propname,
 				    const char *string);
-extern int of_property_count_strings(struct device_node *np,
-				     const char *propname);
+extern int of_property_read_string_helper(const struct device_node *np,
+					      const char *propname,
+					      const char **out_strs, size_t sz, int index);
 
 extern const __be32 *of_prop_next_u32(struct property *prop,
 				const __be32 *cur, u32 *pu);
@@ -444,20 +442,15 @@ static inline int of_property_read_string(struct device_node *np,
 	return -ENOSYS;
 }
 
-static inline int of_property_read_string_index(struct device_node *np,
-			 const char *propname, int index, const char **output)
-{
-	return -ENOSYS;
-}
-
 static inline int of_property_match_string(struct device_node *np,
 				const char *propname, const char *string)
 {
 	return -ENOSYS;
 }
 
-static inline int of_property_count_strings(struct device_node *np,
-					const char *propname)
+static inline int of_property_read_string_helper(const struct device_node *np,
+						 const char *propname,
+						 const char **out_strs, size_t sz, int index)
 {
 	return -ENOSYS;
 }
@@ -753,6 +746,70 @@ static inline struct device_node *of_find_matching_node(
 	     child = of_get_next_available_child(parent, child))
 
 /**
+ * of_property_read_string_array() - Read an array of strings from a multiple
+ * strings property.
+ * @np:		device node from which the property value is to be read.
+ * @propname:	name of the property to be searched.
+ * @out_strs:	output array of string pointers.
+ * @sz:		number of array elements to read.
+ *
+ * Search for a property in a device tree node and retrieve a list of
+ * terminated string values (pointer to data, not a copy) in that property.
+ *
+ * If @out_strs is NULL, the number of strings in the property is returned.
+ */
+static inline int of_property_read_string_array(const struct device_node *np,
+						const char *propname, const char **out_strs,
+						size_t sz)
+{
+	return of_property_read_string_helper(np, propname, out_strs, sz, 0);
+}
+
+/**
+ * of_property_count_strings() - Find and return the number of strings from a
+ * multiple strings property.
+ * @np:		device node from which the property value is to be read.
+ * @propname:	name of the property to be searched.
+ *
+ * Search for a property in a device tree node and retrieve the number of null
+ * terminated string contain in it. Returns the number of strings on
+ * success, -EINVAL if the property does not exist, -ENODATA if property
+ * does not have a value, and -EILSEQ if the string is not null-terminated
+ * within the length of the property data.
+ */
+static inline int of_property_count_strings(const struct device_node *np,
+					    const char *propname)
+{
+	return of_property_read_string_helper(np, propname, NULL, 0, 0);
+}
+
+/**
+ * of_property_read_string_index() - Find and read a string from a multiple
+ * strings property.
+ * @np:		device node from which the property value is to be read.
+ * @propname:	name of the property to be searched.
+ * @index:	index of the string in the list of strings
+ * @out_string:	pointer to null terminated return string, modified only if
+ *		return value is 0.
+ *
+ * Search for a property in a device tree node and retrieve a null
+ * terminated string value (pointer to data, not a copy) in the list of strings
+ * contained in that property.
+ * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
+ * property does not have a value, and -EILSEQ if the string is not
+ * null-terminated within the length of the property data.
+ *
+ * The out_string pointer is modified only if a valid string can be decoded.
+ */
+static inline int of_property_read_string_index(const struct device_node *np,
+						const char *propname,
+						int index, const char **output)
+{
+	int rc = of_property_read_string_helper(np, propname, output, 1, index);
+	return rc < 0 ? rc : 0;
+}
+
+/**
  * of_property_read_bool - Findfrom a property
  * @np:		device node from which the property value is to be read.
  * @propname:	name of the property to be searched.