diff --git a/io/i2c/devfs.go b/io/i2c/devfs.go
index 2ddd8d6..849f220 100644
--- a/io/i2c/devfs.go
+++ b/io/i2c/devfs.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build linux
+
 package i2c
 
 import (
diff --git a/io/i2c/example/displayip/main.go b/io/i2c/example/displayip/main.go
index e182726..657c4cf 100644
--- a/io/i2c/example/displayip/main.go
+++ b/io/i2c/example/displayip/main.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build linux
+
 // Package main contains a program that displays the IPv4 address
 // of the machine on an a Grove-LCD RGB backlight.
 package main
diff --git a/io/i2c/example_test.go b/io/i2c/example_test.go
index 28e5316..ac24ebc 100644
--- a/io/i2c/example_test.go
+++ b/io/i2c/example_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build linux
+
 package i2c_test
 
 import (
diff --git a/io/spi/devfs.go b/io/spi/devfs.go
index 7d62cc4..b40a8ae 100644
--- a/io/spi/devfs.go
+++ b/io/spi/devfs.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build linux
+
 package spi
 
 import (
diff --git a/io/spi/example_test.go b/io/spi/example_test.go
index ce3aadb..96157f9 100644
--- a/io/spi/example_test.go
+++ b/io/spi/example_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build linux
+
 package spi_test
 
 import "golang.org/x/exp/io/spi"