device property: Add helpers to count items in an array

The usual pattern to allocate the necessary space for an array of properties is
to count them first by calling:

  count = device_property_read_uXX_array(dev, propname, NULL, 0);
  if (count < 0)
	return count;

Introduce helpers device_property_count_uXX() to count items by supplying hard
coded last two parameters to device_property_readXX_array().

Signed-off-by: Andy Shevchenko <[email protected]>
Acked-by: Sakari Ailus <[email protected]>
Reviewed-by: Heikki Krogerus <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

Author: andy-shev

include/linux/property.h

@@ -148,6 +148,26 @@ static inline int device_property_read_u64(struct device *dev,
 	return device_property_read_u64_array(dev, propname, val, 1);
 }
 
+static inline int device_property_count_u8(struct device *dev, const char *propname)
+{
+	return device_property_read_u8_array(dev, propname, NULL, 0);
+}
+
+static inline int device_property_count_u16(struct device *dev, const char *propname)
+{
+	return device_property_read_u16_array(dev, propname, NULL, 0);
+}
+
+static inline int device_property_count_u32(struct device *dev, const char *propname)
+{
+	return device_property_read_u32_array(dev, propname, NULL, 0);
+}
+
+static inline int device_property_count_u64(struct device *dev, const char *propname)
+{
+	return device_property_read_u64_array(dev, propname, NULL, 0);
+}
+
 static inline bool fwnode_property_read_bool(const struct fwnode_handle *fwnode,
 					     const char *propname)
 {
@@ -178,6 +198,30 @@ static inline int fwnode_property_read_u64(const struct fwnode_handle *fwnode,
 	return fwnode_property_read_u64_array(fwnode, propname, val, 1);
 }
 
+static inline int fwnode_property_count_u8(const struct fwnode_handle *fwnode,
+					   const char *propname)
+{
+	return fwnode_property_read_u8_array(fwnode, propname, NULL, 0);
+}
+
+static inline int fwnode_property_count_u16(const struct fwnode_handle *fwnode,
+					    const char *propname)
+{
+	return fwnode_property_read_u16_array(fwnode, propname, NULL, 0);
+}
+
+static inline int fwnode_property_count_u32(const struct fwnode_handle *fwnode,
+					    const char *propname)
+{
+	return fwnode_property_read_u32_array(fwnode, propname, NULL, 0);
+}
+
+static inline int fwnode_property_count_u64(const struct fwnode_handle *fwnode,
+					    const char *propname)
+{
+	return fwnode_property_read_u64_array(fwnode, propname, NULL, 0);
+}
+
 /**
  * struct property_entry - "Built-in" device property representation.
  * @name: Name of the property.