Merge tag 'staging-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh...

[pandora-kernel.git] / drivers / of / base.c

diff --git a/drivers/of/base.c b/drivers/of/base.c
index fd4b9c2..5f81bfe 100644 (file)
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -904,6 +904,38 @@ struct device_node *of_find_node_by_phandle(phandle handle)
 }
 EXPORT_SYMBOL(of_find_node_by_phandle);
 
+/**
+ * of_property_count_elems_of_size - Count the number of elements in a property
+ *
+ * @np:                device node from which the property value is to be read.
+ * @propname:  name of the property to be searched.
+ * @elem_size: size of the individual element
+ *
+ * Search for a property in a device node and count the number of elements of
+ * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
+ * property does not exist or its length does not match a multiple of elem_size
+ * and -ENODATA if the property does not have a value.
+ */
+int of_property_count_elems_of_size(const struct device_node *np,
+                               const char *propname, int elem_size)
+{
+       struct property *prop = of_find_property(np, propname, NULL);
+
+       if (!prop)
+               return -EINVAL;
+       if (!prop->value)
+               return -ENODATA;
+
+       if (prop->length % elem_size != 0) {
+               pr_err("size of %s in node %s is not a multiple of %d\n",
+                      propname, np->full_name, elem_size);
+               return -EINVAL;
+       }
+
+       return prop->length / elem_size;
+}
+EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);
+
 /**
  * of_find_property_value_of_size
  *