[PATCH 01/14] of: Create of_property_match()

[Viresh Kumar]

Create a new routine of_property_match() that will match a property between two
nodes. If they are exactly same, it returns 1 else 0. If the property isn't
available in any of the nodes or the API isn't implemented, proper error codes
would be returned.

The first user of this routine would be cpufreq-cpu0 driver, which requires to
match "clock" property between CPU nodes to identify which CPUs share clock
line. And hence this routine.

Cc: Rob Herring <rob.herring@xxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
 drivers/of/base.c  | 29 +++++++++++++++++++++++++++++
 include/linux/of.h | 10 ++++++++++
 2 files changed, 39 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index b986480..a036c91 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1490,6 +1490,35 @@ int of_property_count_strings(struct device_node *np, const char *propname)
 }
 EXPORT_SYMBOL_GPL(of_property_count_strings);
 
+/**
+ * of_property_match - Match 'prop' property between two nodes
+ * @np1, np2: Nodes to match for property
+ * @prop_name: property to match
+ *
+ * Returns 1 on match, 0 on no match, and error for missing property.
+ */
+int of_property_match(const struct device_node *np1,
+		      const struct device_node *np2, const char *prop_name)
+{
+	const __be32 *prop1, *prop2;
+	int size1, size2;
+
+	/* Retrieve property from both nodes */
+	prop1 = of_get_property(np1, prop_name, &size1);
+	if (!prop1)
+		return -ENOENT;
+
+	prop2 = of_get_property(np2, prop_name, &size2);
+	if (!prop2)
+		return -ENOENT;
+
+	if (size1 != size2)
+		return 0;
+
+	return !memcmp(prop1, prop2, size1);
+}
+EXPORT_SYMBOL_GPL(of_property_match);
+
 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
 {
 	int i;
diff --git a/include/linux/of.h b/include/linux/of.h
index 196b34c..4e9cf5a 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -275,6 +275,9 @@ extern int of_property_match_string(struct device_node *np,
 				    const char *string);
 extern int of_property_count_strings(struct device_node *np,
 				     const char *propname);
+extern int of_property_match(const struct device_node *np1,
+			     const struct device_node *np2,
+			     const char *prop_name);
 extern int of_device_is_compatible(const struct device_node *device,
 				   const char *);
 extern int of_device_is_available(const struct device_node *device);
@@ -498,6 +501,13 @@ static inline int of_property_count_strings(struct device_node *np,
 	return -ENOSYS;
 }
 
+static inline int of_property_match(const struct device_node *np1,
+				    const struct device_node *np2,
+				    const char *prop_name)
+{
+	return -ENOSYS;
+}
+
 static inline const void *of_get_property(const struct device_node *node,
 				const char *name,
 				int *lenp)
-- 
2.0.0.rc2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/