[PATCH] of: implement of_property_present helper

[Ahmad Fatoum]

We have various code using of_find_property(np, propname, NULL) to
detect whether propname exists and some more that uses
of_property_read_bool on non-boolean properties.

There's work underway in Linux to switch a lot of these instances to
of_property_present[1]. Let's prepare for porting Linux code that
uses the property by adding it.

[1]: https://lore.kernel.org/linux-devicetree/?q=of_property_present

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 include/of.h | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/include/of.h b/include/of.h
index 3fb6ecec8dfe..22358f5579ec 100644
--- a/include/of.h
+++ b/include/of.h
@@ -1038,8 +1038,10 @@ static inline int of_property_read_string_index(const struct device_node *np,
  * @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 node.
- * Returns true if the property exist false otherwise.
+ * Search for a boolean property in a device node. Usage on non-boolean
+ * property types is deprecated.
+
+ * Return: true if the property exist false otherwise.
  */
 static inline bool of_property_read_bool(const struct device_node *np,
 					 const char *propname)
@@ -1049,6 +1051,20 @@ static inline bool of_property_read_bool(const struct device_node *np,
 	return prop ? true : false;
 }
 
+/**
+ * of_property_present - Test if a property is present in a node
+ * @np:		device node to search for the property.
+ * @propname:	name of the property to be searched.
+ *
+ * Test for a property present in a device node.
+ *
+ * Return: true if the property exists false otherwise.
+ */
+static inline bool of_property_present(const struct device_node *np, const char *propname)
+{
+	return of_property_read_bool(np, propname);
+}
+
 static inline int of_property_read_u8(const struct device_node *np,
 				       const char *propname,
 				       u8 *out_value)
-- 
2.39.2