[PATCH 3.2 129/164] of: Add of_property_match_string() to find index into a string list

[Ben Hutchings]

3.2.70-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Grant Likely <grant.likely@xxxxxxxxxxxx>

commit 7aff0fe33033fc75b61446ba29d38b1b1354af9f upstream.

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@xxxxxxxxxxxx>
[jt: dropped changes to files not existing in the 3.2 tree]
Signed-off-by: Jonathan Toppins <jtoppins@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Andy Gospodarek <gospo@xxxxxxxxxxxxxxxxxxx>
Acked-by: Curt Brune <curt@xxxxxxxxxxxxxxxxxxx>
Acked-by: Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/of/base.c  | 36 ++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  3 +++
 2 files changed, 39 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 37639a6..21935580 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -761,6 +761,42 @@ int of_property_read_string_index(struct device_node *np, const char *propname,
 }
 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
diff --git a/include/linux/of.h b/include/linux/of.h
index 9bf9611..7e8f2c6 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -211,6 +211,9 @@ extern int of_property_read_string(struct device_node *np,
 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_device_is_compatible(const struct device_node *device,

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