From 19d31412f7bc9bf9572ff2f3043bbe92b67b898f Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Sat, 29 Nov 2014 07:08:30 -0600
Subject: [PATCH] Update/correct some comments

---
 drivers/input/Kconfig           |  5 +++--
 drivers/input/ajoystick.c       | 11 +++++++++++
 drivers/input/djoystick.c       | 11 +++++++++++
 include/nuttx/input/ajoystick.h |  9 ++++++---
 4 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
index 12717e2f65..2a58768f47 100644
--- a/drivers/input/Kconfig
+++ b/drivers/input/Kconfig
@@ -347,8 +347,9 @@ config AJOYSTICK
 	---help---
 		Enable standard analog joystick upper half driver.  An analog
 		joystick refers to a joystick that provides position data as an
-		integer value that might have been obtained through DACs.
-		Discrete button inputs are also supported.
+		integer value that might have been obtained through Analog-
+		to-Digital Conversion (ADC).  The analog positional data may also
+		be accompanied by discrete button data.
 
 if AJOYSTICK
 
diff --git a/drivers/input/ajoystick.c b/drivers/input/ajoystick.c
index 4ab7e6dd63..1054b8ca37 100644
--- a/drivers/input/ajoystick.c
+++ b/drivers/input/ajoystick.c
@@ -33,6 +33,17 @@
  *
  ****************************************************************************/
 
+/* This file provides a driver for a standard analog joystick device.  An
+ * analog joystick refers to a joystick that provides X/Y positional data as
+ * integer values such as might be provides by Analog-to-Digital Conversion
+ * (ADC).  The analog positional data may also be accompanied by discrete
+ * button data.
+ *
+ * The analog joystick driver exports a standard character driver
+ * interface. By convention, the analog joystick is registered as an input
+ * device at /dev/ajoyN where N uniquely identifies the driver instance.
+ */
+
 /****************************************************************************
  * Included Files
  ****************************************************************************/
diff --git a/drivers/input/djoystick.c b/drivers/input/djoystick.c
index 80e704851f..0e746634f2 100644
--- a/drivers/input/djoystick.c
+++ b/drivers/input/djoystick.c
@@ -33,6 +33,17 @@
  *
  ****************************************************************************/
 
+/* This file provides a driver for a standard discrete joystick device.  A
+ * discrete joystick refers to a joystick that could be implemented entirely
+ * with GPIO input pins.  So up, down, left, and right are all discrete
+ * values like buttons (as opposed to integer values like you might obtain
+ * from an analog joystick).
+ *
+ * The discrete joystick driver exports a standard character driver
+ * interface. By convention, the discrete joystick is registered as an input
+ * device at /dev/djoyN where N uniquely identifies the driver instance.
+ */
+
 /****************************************************************************
  * Included Files
  ****************************************************************************/
diff --git a/include/nuttx/input/ajoystick.h b/include/nuttx/input/ajoystick.h
index 3537f15f1a..12f8ae4067 100644
--- a/include/nuttx/input/ajoystick.h
+++ b/include/nuttx/input/ajoystick.h
@@ -35,8 +35,9 @@
 
 /* This header file provides definition for a standard analog joystick
  * interface.  An analog joystick refers to a joystick that provides X/Y
- * positional data as integer values such as might be provides by DACs.
- * The analog positional data may be accompanied by discrete button data.
+ * positional data as integer values such as might be provides by Analog-
+ * to-Digital Conversion (ADC).  The analog positional data may also be
+ * accompanied by discrete button data.
  *
  * The analog joystick driver exports a standard character driver
  * interface. By convention, the analog joystick is registered as an input
@@ -109,7 +110,9 @@
  *
  * 1) The read() method will always return a single value of size
  *    struct ajoy_sample_s represent the current joystick positional and the
- *    state of all joystick buttons. read() never blocks.
+ *    state of all joystick buttons. read() never blocks.  X an Y position
+ *    data is raw converted data.  Zeroing and scaling must be performed by
+ *    the application.
  * 2) The poll() method can be used to notify a client if there is a change
  *    in any of the joystick button inputs.  This feature, of course,
  *    depends upon interrupt GPIO support from the platform.  NOTE: that