Handle binary or unicode with JSONField

docs/api-guide/fields.md

@@ -461,7 +461,7 @@ You can also use the declarative style, as with `ListField`. For example:
 
 ## JSONField
 
-A field class that validates that the incoming data structure consists of valid JSON primitives. In its alternate binary mode, it will represent and validate JSON encoded strings.
+A field class that validates that the incoming data structure consists of valid JSON primitives. In its alternate binary mode, it will represent and validate JSON-encoded binary strings.
 
 **Signature**: `JSONField(binary)`
 

rest_framework/fields.py

@@ -1535,6 +1535,8 @@ class JSONField(Field):
     def to_internal_value(self, data):
         try:
             if self.binary:
+                if isinstance(data, six.binary_type):
+                    data = data.decode('utf-8')
                 return json.loads(data)
             else:
                 json.dumps(data)