diff --git a/api/mraa/i2c.h b/api/mraa/i2c.h
index 5de3319..34c7395 100644
--- a/api/mraa/i2c.h
+++ b/api/mraa/i2c.h
@@ -69,7 +69,7 @@ mraa_i2c_context mraa_i2c_init(int bus);
 mraa_i2c_context mraa_i2c_init_raw(unsigned int bus);
 
 /**
- * Sets the frequency of the i2c context
+ * Sets the frequency of the i2c context. Most platforms do not support this.
  *
  * @param dev The i2c context
  * @param hz The bus frequency in hertz
diff --git a/src/i2c/i2c.c b/src/i2c/i2c.c
index a4aa9e0..54c2cf7 100644
--- a/src/i2c/i2c.c
+++ b/src/i2c/i2c.c
@@ -81,7 +81,7 @@ mraa_i2c_frequency(mraa_i2c_context dev, int hz)
 {
     dev->hz = hz;
 
-    return MRAA_SUCCESS;
+    return MRAA_ERROR_FEATURE_NOT_SUPPORTED;
 }
 
 int