[PATCH v3 1/5] of: add of_property_write_string_array()

[Fabian Pflug <f.pflug@pengutronix.de>]

Helper function to write an array of string into a property.

Signed-off-by: Fabian Pflug <f.pflug@pengutronix.de>
---
 drivers/of/base.c             | 43 +++++++++++++++++++++++++++++++++++++++++++
 include/of.h                  |  3 +++
 test/self/of_manipulation.c   | 14 +++++++++++++-
 test/self/of_manipulation.dts |  5 +++++
 4 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 460b5e2f4b..376a2ac6a8 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1570,6 +1570,49 @@ int of_property_write_u64_array(struct device_node *np,
 	return 0;
 }
 
+/**
+ * of_property_write_string_array - Write strings to a property. If
+ * the property does not exist, it will be created and appended to the given
+ * device node.
+ *
+ * @np:		device node to which the property value is to be written.
+ * @propname:	name of the property to be written.
+ * @values:	pointer to array elements to write.
+ * @sz:		number of array elements to write.
+ *
+ * Search for a property in a device node and write a string to
+ * it. If the property does not exist, it will be created and appended to
+ * the device node. Returns 0 on success, -ENOMEM if the property or array
+ * of elements cannot be created, -EINVAL if no strings specified.
+ */
+int of_property_write_string_array(struct device_node *np,
+				   const char *propname, const char **values,
+				   size_t sz)
+{
+	char *buf = NULL, *next;
+	size_t len = 0;
+	int ret = 0, i;
+
+	for (i = 0; i < sz; i++)
+		len += strlen(values[i]) + 1;
+
+	if (!len)
+		return -EINVAL;
+
+	buf = malloc(len);
+	if (!buf)
+		return -ENOMEM;
+
+	next = buf;
+
+	for (i = 0; i < sz; i++)
+		next = stpcpy(next, values[i]) + 1;
+
+	ret = of_set_property(np, propname, buf, len, 1);
+	free(buf);
+	return ret;
+}
+
 /**
  * of_property_write_strings - Write strings to a property. If
  * the property does not exist, it will be created and appended to the given
diff --git a/include/of.h b/include/of.h
index ba8d1e358d..34439ee763 100644
--- a/include/of.h
+++ b/include/of.h
@@ -310,6 +310,9 @@ extern int of_property_write_string(struct device_node *np, const char *propname
 				    const char *value);
 extern int of_property_write_strings(struct device_node *np, const char *propname,
 				    ...) __attribute__((__sentinel__));
+int of_property_write_string_array(struct device_node *np,
+				   const char *propname, const char **values,
+				   size_t sz);
 int of_property_sprintf(struct device_node *np, const char *propname, const char *fmt, ...)
 	__printf(3, 4);
 
diff --git a/test/self/of_manipulation.c b/test/self/of_manipulation.c
index 8d645b1137..faf948a17b 100644
--- a/test/self/of_manipulation.c
+++ b/test/self/of_manipulation.c
@@ -71,13 +71,19 @@ static void test_of_basics(struct device_node *root)
 
 static void test_of_property_strings(struct device_node *root)
 {
-	struct device_node *np1, *np2, *np3, *np4;
+	struct device_node *np1, *np2, *np3, *np4, *np5;
 	char properties[] = "ayy\0bee\0sea";
+	static const char * const prop_array[] = {
+		"ayy",
+		"bee\0\0\0",
+		"sea\0",
+	};
 
 	np1 = of_new_node(root, "np1");
 	np2 = of_new_node(root, "np2");
 	np3 = of_new_node(root, "np3");
 	np4 = of_new_node(root, "np4");
+	np5 = of_new_node(root, "np5");
 
 	of_property_sprintf(np1, "property-single", "%c%c%c", 'a', 'y', 'y');
 
@@ -108,6 +114,12 @@ static void test_of_property_strings(struct device_node *root)
 	of_prepend_property(np4, "property-multi", "ayy", 4);
 
 	assert_equal(np3, np4);
+
+	of_property_write_string_array(np5, "property-single", prop_array, 1);
+
+	of_property_write_string_array(np5, "property-multi", prop_array, 3);
+
+	assert_equal(np4, np5);
 }
 
 static void __init test_of_manipulation(void)
diff --git a/test/self/of_manipulation.dts b/test/self/of_manipulation.dts
index 2cc6773fa9..7a1fb1217d 100644
--- a/test/self/of_manipulation.dts
+++ b/test/self/of_manipulation.dts
@@ -34,4 +34,9 @@ np4 {
 		property-single = "ayy";
 		property-multi = "ayy", "bee", "sea";
 	};
+
+	np5 {
+		property-single = "ayy";
+		property-multi = "ayy", "bee", "sea";
+	};
 };

-- 
2.47.3