diff --git a/drivers/analog/Kconfig b/drivers/analog/Kconfig
index 5c68f518e7e..20d99f8acb4 100644
--- a/drivers/analog/Kconfig
+++ b/drivers/analog/Kconfig
@@ -11,6 +11,16 @@ config ADC
 		not only Analog-to-Digital Converters (ADC) but also amplifiers and
 		analog multiplexers.
 
+		This selection enables:
+
+			- The upper half, device-independent ADC character driver, and
+			- Selection of common lower half ADC drivers.
+
+		MCU-specific, lower half drivers may be selected independently of
+		CONFIG_ADC.  However, if CONFIG_ADC is selected, then it is assume
+		that lower half ADC drivers will be used only with the commoun ADC
+		upper half driver.
+
 if ADC
 
 config ADC_FIFOSIZE
diff --git a/include/nuttx/analog/adc.h b/include/nuttx/analog/adc.h
index f08687a5a42..0044c03364d 100644
--- a/include/nuttx/analog/adc.h
+++ b/include/nuttx/analog/adc.h
@@ -1,10 +1,10 @@
 /************************************************************************************
  * include/nuttx/analog/adc.h
  *
+ *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
  *   Copyright (C) 2011 Li Zhuoyi. All rights reserved.
  *   Author: Li Zhuoyi <lzyy.cn@gmail.com>
- *   History: 0.1 2011-08-04 initial version
- *            0.2 remove ao_read
+ *           Gregory Nutt <gnutt@nuttx.org>
  *
  * Derived from include/nuttx/can.h
  *
@@ -186,11 +186,7 @@ struct adc_dev_s
 };
 
 /************************************************************************************
- * Public Data
- ************************************************************************************/
-
-/************************************************************************************
- * Public Functions
+ * Public Function Prototypes
  ************************************************************************************/
 
 #if defined(__cplusplus)
@@ -201,6 +197,7 @@ extern "C"
 /************************************************************************************
  * "Upper-Half" ADC Driver Interfaces
  ************************************************************************************/
+
 /************************************************************************************
  * Name: adc_register
  *
@@ -228,6 +225,7 @@ int adc_register(FAR const char *path, FAR struct adc_dev_s *dev);
 /************************************************************************************
  * Platform-Independent "Lower Half" ADC Driver Interfaces
  ************************************************************************************/
+
 /************************************************************************************
  * Name: up_ads1255initialize
  *
@@ -236,7 +234,8 @@ int adc_register(FAR const char *path, FAR struct adc_dev_s *dev);
  *
  ************************************************************************************/
 
-FAR struct adc_dev_s *up_ads1255initialize(FAR struct spi_dev_s *spi, unsigned int devno);
+FAR struct adc_dev_s *up_ads1255initialize(FAR struct spi_dev_s *spi,
+                                           unsigned int devno);
 
 #if defined(__cplusplus)
 }
diff --git a/include/nuttx/i2c/i2c_master.h b/include/nuttx/i2c/i2c_master.h
index 1938bcbfa10..c3684398ee6 100644
--- a/include/nuttx/i2c/i2c_master.h
+++ b/include/nuttx/i2c/i2c_master.h
@@ -155,10 +155,10 @@ struct i2c_master_s;
 struct i2c_msg_s;
 struct i2c_ops_s
 {
-  int (*transfer)(FAR struct i2c_master_s *dev, FAR struct i2c_msg_s *msgs,
-                  int count);
+  CODE int (*transfer)(FAR struct i2c_master_s *dev,
+                       FAR struct i2c_msg_s *msgs, int count);
 #ifdef CONFIG_I2C_RESET
-  int (*reset)(FAR struct i2c_master_s *dev);
+  CODE int (*reset)(FAR struct i2c_master_s *dev);
 #endif
 };