hardware: add hardware_device_api_version() macro

Change-Id: I79c4d65f6bab227364d5f271df9bd7bc565857c2
Signed-off-by: Dima Zavin <dima@android.com>
diff --git a/include/hardware/hardware.h b/include/hardware/hardware.h
index 67ba9f1..b106e2b 100644
--- a/include/hardware/hardware.h
+++ b/include/hardware/hardware.h
@@ -51,12 +51,17 @@
 #define HARDWARE_HAL_API_VERSION HARDWARE_MAKE_API_VERSION(1, 0)
 
 /*
- * Helper macro for module implementors.
+ * Helper macros for module implementors.
  *
  * Use this macro to set the hw_module_t.module_api_version field.
  */
 #define HARDWARE_MODULE_API_VERSION(maj,min) HARDWARE_MAKE_API_VERSION(maj,min)
 
+/*
+ * Use this macro to set the hw_device_t.version field
+ */
+#define HARDWARE_DEVICE_API_VERSION(maj,min) HARDWARE_MAKE_API_VERSION(maj,min)
+
 struct hw_module_t;
 struct hw_module_methods_t;
 struct hw_device_t;