diff --git a/sys/compat/linuxkpi/common/include/linux/platform_device.h b/sys/compat/linuxkpi/common/include/linux/platform_device.h
--- a/sys/compat/linuxkpi/common/include/linux/platform_device.h
+++ b/sys/compat/linuxkpi/common/include/linux/platform_device.h
@@ -42,6 +42,8 @@
 	struct device_driver		driver;
 };
 
+#define	dev_is_platform(dev)	(false)
+#define	to_platform_device(dev)	(NULL)
 
 static __inline int
 platform_driver_register(struct platform_driver *pdrv)
@@ -76,4 +78,12 @@
 	return;
 }
 
+static __inline void
+platform_device_unregister(struct platform_device *pdev)
+{
+
+	pr_debug("%s: TODO\n", __func__);
+	return;
+}
+
 #endif	/* _LINUXKPI_LINUX_PLATFORM_DEVICE_H */