diff --git a/tools/aconfig/src/codegen.rs b/tools/aconfig/src/codegen.rs
index 8ef0e0b..fea9961 100644
--- a/tools/aconfig/src/codegen.rs
+++ b/tools/aconfig/src/codegen.rs
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+use anyhow::{ensure, Result};
+
 pub fn is_valid_name_ident(s: &str) -> bool {
     // Identifiers must match [a-z][a-z0-9_]*
     let mut chars = s.chars();
@@ -30,6 +32,12 @@
     s.split('.').all(is_valid_name_ident)
 }
 
+pub fn create_device_config_ident(package: &str, flag_name: &str) -> Result<String> {
+    ensure!(is_valid_package_ident(package), "bad package");
+    ensure!(is_valid_package_ident(flag_name), "bad flag name");
+    Ok(format!("{}.{}", package, flag_name))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -62,4 +70,12 @@
         assert!(!is_valid_package_ident("."));
         assert!(!is_valid_package_ident("foo..bar"));
     }
+
+    #[test]
+    fn test_create_device_config_ident() {
+        assert_eq!(
+            "com.foo.bar.some_flag",
+            create_device_config_ident("com.foo.bar", "some_flag").unwrap()
+        );
+    }
 }