From b0bf66456c2f6340eade34204137b09c24d1428e Mon Sep 17 00:00:00 2001
From: patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>
Date: Wed, 21 Dec 2011 15:50:06 +0000
Subject: [PATCH] Add the beginning of an STM32 CAN driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4209 42af7a65-404d-4744-a932-0658087f49c3
---
 ChangeLog                               |   2 +
 Documentation/NuttxPortingGuide.html    |  60 +-
 arch/arm/src/lpc17xx/Make.defs          |  13 +-
 arch/arm/src/stm32/Make.defs            |   6 +-
 arch/arm/src/stm32/stm32_can.c          | 761 ++++++++++++++++++++++++
 arch/arm/src/stm32/stm32_pwm.c          |   2 +-
 configs/README.txt                      |   9 +
 configs/hymini-stm32v/README.txt        |  14 +-
 configs/stm3210e-eval/README.txt        |  11 +
 configs/stm3240g-eval/README.txt        |  11 +
 configs/stm3240g-eval/dhcpd/defconfig   |  18 +
 configs/stm3240g-eval/nettest/defconfig |  18 +
 configs/stm3240g-eval/nsh/defconfig     |  18 +
 configs/stm3240g-eval/ostest/defconfig  |  18 +
 drivers/Makefile                        |   7 +-
 drivers/can.c                           |  29 +-
 include/nuttx/can.h                     |  23 +-
 17 files changed, 986 insertions(+), 34 deletions(-)
 create mode 100755 arch/arm/src/stm32/stm32_can.c

diff --git a/ChangeLog b/ChangeLog
index 061be118e3a..288bf202911 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2286,5 +2286,7 @@
 	* drivers/mtd/mp25x.c:  Add ability to use different SPI modes and different
 	  manufacturers codes.  Fix a error in the wait for not busy (submitted by
 	  Mohammad Elwakeel.
+	* arch/arm/src/stm32/stm32_can.c.  Add a low-level STM32 CAN driver. (Initial
+	  check is incomplete).
 
 
diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index 293b7d683cf..f68dc3d7963 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -12,7 +12,7 @@
       <h1><big><font color="#3c34ec">
         <i>NuttX RTOS Porting Guide</i>
       </font></big></h1>
-      <p>Last Updated: December 19, 2011</p>
+      <p>Last Updated: December 21, 2011</p>
     </td>
   </tr>
 </table>
@@ -127,7 +127,8 @@
        <a href="#usbhostdrivers">6.3.9 USB Host-Side Drivers</a><br>
        <a href="#usbdevdrivers">6.3.10 USB Device-Side Drivers</a><br>
        <a href="#analogdrivers">6.3.11 Analog (ADC/DAC) Drivers</a><br>
-       <a href="#pwmdrivers">6.3.12 PWM Drivers</a>
+       <a href="#pwmdrivers">6.3.12 PWM Drivers</a><br>
+       <a href="#candrivers">6.3.13 CAN Drivers</a>
     </ul>
     <a href="#pwrmgmt">6.4 Power Management</a>
     <ul>
@@ -3212,23 +3213,55 @@ extern void up_ledoff(int led);
     A &quot;lower half&quot;, platform-specific driver that implements the low-level timer controls to implement the PWM functionality.
   </li>
 </ol>
-
+<p>
+  Files supporting PWM can be found in the following locations:
+</p>
 <ul>
-  <li>
+  <li><b>Interface Definition</b>.
     The header file for the NuttX PWM driver reside at <code>include/nuttx/pwm.h</code>.
     This header file includes both the application level interface to the PWM driver as well as the interface between the &quot;upper half&quot; and &quot;lower half&quot; drivers.
     The PWM module uses a standard character driver framework.
     However, since the PWM driver is a devices control interface and not a data transfer interface,
     the majority of the functionality available to the application is implemented in driver ioctl calls.
   </li>
-  <li>
+  <li><b>&quot;Upper Half&quot; Driver</b>.
     The generic, &quot;upper half&quot; PWM driver resides at <code>drivers/pwm.c</code>.
   </li>
-  <li>
-    Platform-specific PWM drivers reside in <code>arch/</code><i>&lt;architecture&gt;</i><code>/src/</code><i>&lt;chip&gt;</i> directory for the specific processor <i>&lt;architecture&gt;</i> and for the specific <i>&lt;chip&gt;</i> analog peripheral devices.
+  <li><b>&quot;Lower Half&quot; Drivers</b>.
+    Platform-specific PWM drivers reside in <code>arch/</code><i>&lt;architecture&gt;</i><code>/src/</code><i>&lt;chip&gt;</i> directory for the specific processor <i>&lt;architecture&gt;</i> and for the specific <i>&lt;chip&gt;</i> PWM peripheral devices.
   </li>
 </ul>
 
+<h3><a name="candrivers">6.3.13 CAN Drivers</a></h3>
+<p>
+  NuttX supports only a very low-level CAN driver.
+  This driver supports only the data exchange and does not include any high-level CAN protocol.
+  The NuttX CAN driver is split into two parts:
+</p>
+<ol>
+  <li>
+    An &quot;upper half&quot;, generic driver that provides the comman CAN interface to application level code, and
+  </li>
+  <li>
+    A &quot;lower half&quot;, platform-specific driver that implements the low-level timer controls to implement the CAN functionality.
+  </li>
+</ol>
+<p>
+  Files supporting CAN can be found in the following locations:
+</p>
+<ul>
+  <li><b>Interface Definition</b>.
+    The header file for the NuttX CAN driver reside at <code>include/nuttx/can.h</code>.
+    This header file includes both the application level interface to the CAN driver as well as the interface between the &quot;upper half&quot; and &quot;lower half&quot; drivers.
+    The CAN module uses a standard character driver framework.
+  </li>
+  <li><b>&quot;Upper Half&quot; Driver</b>.
+    The generic, &quot;upper half&quot; CAN driver resides at <code>drivers/can.c</code>.
+  </li>
+  <li><b>&quot;Lower Half&quot; Drivers</b>.
+    Platform-specific CAN drivers reside in <code>arch/</code><i>&lt;architecture&gt;</i><code>/src/</code><i>&lt;chip&gt;</i> directory for the specific processor <i>&lt;architecture&gt;</i> and for the specific <i>&lt;chip&gt;</i> CAN peripheral devices.
+  </li>
+</ul>
 
 <h2><a name="pwrmgmt">6.4 Power Management</a></h2>
 
@@ -4332,6 +4365,19 @@ build
   </li>
 </ul>
 
+<h3>CAN driver</h3>
+<ul>
+  <li>
+    <code>CONFIG_CAN</code>: Enables CAN support
+  </li>
+  <li>
+    <code>CONFIG_CAN_FIFOSIZE</code>: The size of the circular buffer of CAN messages. Default: 8
+  </li>
+  <li>
+    <code>CONFIG_CAN_NPENDINGRTR</code>: The size of the list of pending RTR requests.  Default: 4
+  </li>
+</ul>
+
 <h3>SPI driver</h3>
 <ul>
   <li>
diff --git a/arch/arm/src/lpc17xx/Make.defs b/arch/arm/src/lpc17xx/Make.defs
index 34591e53195..56aef87fd0b 100755
--- a/arch/arm/src/lpc17xx/Make.defs
+++ b/arch/arm/src/lpc17xx/Make.defs
@@ -2,7 +2,7 @@
 # arch/arm/src/lpc17xx/Make.defs
 #
 #   Copyright (C) 2010-2011 Gregory Nutt. All rights reserved.
-#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -57,10 +57,9 @@ endif
 # Required LPC17xx files
 
 CHIP_ASRCS	=
-CHIP_CSRCS	= lpc17_allocateheap.c lpc17_can.c lpc17_clockconfig.c \
-		  lpc17_clrpend.c lpc17_gpio.c lpc17_i2c.c lpc17_idle.c lpc17_irq.c \
-		  lpc17_lowputc.c lpc17_serial.c lpc17_spi.c lpc17_ssp.c lpc17_start.c \
-		  lpc17_timerisr.c
+CHIP_CSRCS	= lpc17_allocateheap.c lpc17_clockconfig.c lpc17_clrpend.c \
+		  lpc17_gpio.c lpc17_i2c.c lpc17_idle.c lpc17_irq.c lpc17_lowputc.c \
+		  lpc17_serial.c lpc17_spi.c lpc17_ssp.c lpc17_start.c lpc17_timerisr.c
 
 # Configuration-dependent LPC17xx files
 
@@ -90,6 +89,10 @@ CHIP_CSRCS	+= lpc17_ethernet.c
 endif
 endif
 
+ifeq ($(CONFIG_CAN),y)
+CHIP_CSRCS	+= lpc17_can.c
+endif
+
 ifeq ($(CONFIG_LPC17_ADC),y)
 CHIP_CSRCS	+= lpc17_adc.c
 endif
diff --git a/arch/arm/src/stm32/Make.defs b/arch/arm/src/stm32/Make.defs
index d877516ab80..0d046ebc381 100644
--- a/arch/arm/src/stm32/Make.defs
+++ b/arch/arm/src/stm32/Make.defs
@@ -2,7 +2,7 @@
 # arch/arm/src/stm32/Make.defs
 #
 #   Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
-#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -87,6 +87,10 @@ ifeq ($(CONFIG_PWM),y)
 CHIP_CSRCS	+= stm32_pwm.c
 endif
 
+ifeq ($(CONFIG_CAN),y)
+CHIP_CSRCS	+= stm32_can.c
+endif
+
 ifeq ($(CONFIG_DEBUG),y)
 CHIP_CSRCS	+= stm32_dumpgpio.c
 endif
diff --git a/arch/arm/src/stm32/stm32_can.c b/arch/arm/src/stm32/stm32_can.c
new file mode 100755
index 00000000000..404bf4a1a63
--- /dev/null
+++ b/arch/arm/src/stm32/stm32_can.c
@@ -0,0 +1,761 @@
+/************************************************************************************
+ * arch/arm/src/stm32/stm32_can.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <semaphore.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <arch/board/board.h>
+#include <nuttx/arch.h>
+#include <nuttx/can.h>
+
+#include "up_internal.h"
+#include "up_arch.h"
+
+#include "os_internal.h"
+
+#include "chip.h"
+#include "stm32_internal.h"
+#include "stm32_can.h"
+
+#ifdef CONFIG_CAN
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+/* Configuration ************************************************************/
+/* Up to 2 CAN interfaces are supported */
+
+#if STM32_NCAN < 2
+#  undef CONFIG_STM32_CAN2
+#endif
+
+#if STM32_NCAN < 1
+#  undef CONFIG_STM32_CAN1
+#endif
+
+#if defined(CONFIG_STM32_CAN1) || defined(CONFIG_STM32_CAN2)
+
+/* CAN BAUD */
+
+#if defined(CONFIG_STM32_CAN1) && !defined(CONFIG_CAN1_BAUD)
+#  error "CONFIG_CAN1_BAUD is not defined"
+#endif
+
+#if defined(CONFIG_STM32_CAN2) && !defined(CONFIG_CAN2_BAUD)
+#  error "CONFIG_CAN2_BAUD is not defined"
+#endif
+
+/* Debug ********************************************************************/
+/* Non-standard debug that may be enabled just for testing CAN */
+
+#ifdef CONFIG_DEBUG_CAN
+#  define candbg    dbg
+#  define canvdbg   vdbg
+#  define canlldbg  lldbg
+#  define canllvdbg llvdbg
+#else
+#  define candbg(x...)
+#  define canvdbg(x...)
+#  define canlldbg(x...)
+#  define canllvdbg(x...)
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct stm32_can_s
+{
+  uint8_t  port;   /* CAN port number (1 or 2) */
+  uint8_t  cantx;  /* CAN TX IRQ number */
+  uint8_t  canrx0; /* CAN RX FIFO 0 IRQ number */
+  uint8_t  canrx1; /* CAN RX FIFO 1 IRQ number */
+  uint8_t  cansce; /* CAN RX0 Status change error (SCE) IRQ number */
+  uint32_t baud;   /* Configured baud */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/* CAN driver methods */
+
+static void can_reset(FAR struct can_dev_s *dev);
+static int  can_setup(FAR struct can_dev_s *dev);
+static void can_shutdown(FAR struct can_dev_s *dev);
+static void can_rxint(FAR struct can_dev_s *dev, bool enable);
+static void can_txint(FAR struct can_dev_s *dev, bool enable);
+static int  can_ioctl(FAR struct can_dev_s *dev, int cmd, unsigned long arg);
+static int  can_remoterequest(FAR struct can_dev_s *dev, uint16_t id);
+static int  can_send(FAR struct can_dev_s *dev, FAR struct can_msg_s *msg);
+static bool can_txempty(FAR struct can_dev_s *dev);
+
+/* CAN interrupt handling */
+
+static int  can_txinterrupt(int irq, void *context);
+static int  can_rx0interrupt(int irq, void *context);
+static int  can_rx1interrupt(int irq, void *context);
+static int  can_sceinterrupt(int irq, void *context);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct can_ops_s g_canops =
+{
+  .co_reset         = can_reset,
+  .co_setup         = can_setup,
+  .co_shutdown      = can_shutdown,
+  .co_rxint         = can_rxint,
+  .co_txint         = can_txint,
+  .co_ioctl         = can_ioctl,
+  .co_remoterequest = can_remoterequest,
+  .co_send          = can_send,
+  .co_txempty       = can_txempty,
+};
+
+#ifdef CONFIG_STM32_CAN1
+static struct stm32_can_s g_can1priv =
+{
+  .port             = 1,
+#if defined(CONFIG_STM32_STM32F10XX) && !defined(CONFIG_STM32_CONNECTIVITY_LINE)
+  .cantx            = STM32_IRQ_USBHPCANTX,
+  .canrx0           = STM32_IRQ_USBLPCANRX0,
+#else
+  .cantx            = STM32_IRQ_CAN1TX,
+  .canrx0           = STM32_IRQ_CAN1RX0,
+#endif
+  .canrx1           = STM32_IRQ_CAN1RX1,
+  .cansce           = STM32_IRQ_CAN1SCE,
+  .baud             = CONFIG_CAN1_BAUD,
+};
+
+static struct can_dev_s g_can1dev =
+{
+  .cd_ops           = &g_canops,
+  .cd_priv          = &g_can1priv,
+};
+#endif
+
+#ifdef CONFIG_STM32_CAN2
+static struct stm32_can_s g_can2priv =
+{
+  .port             = 2,
+  .cantx            = STM32_IRQ_CAN2TX,
+  .canrx0           = STM32_IRQ_CAN2RX0,
+  .canrx1           = STM32_IRQ_CAN2RX1,
+  .cansce           = STM32_IRQ_CAN2SCE,
+  .baud             = CONFIG_CAN2_BAUD,
+};
+
+static struct can_dev_s g_can2dev =
+{
+  .cd_ops           = &g_canops,
+  .cd_priv          = &g_can2priv,
+};
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: can_reset
+ *
+ * Description:
+ *   Reset the CAN device.  Called early to initialize the hardware. This
+ *   function is called, before can_setup() and on error conditions.
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *  None
+ *
+ ****************************************************************************/
+
+static void can_reset(FAR struct can_dev_s *dev)
+{
+  FAR struct stm32_can_s *priv = dev->cd_priv;
+  irqstate_t flags;
+
+  /* Disable interrupts momentary to stop any ongoing CAN event processing */
+
+  flags = irqsave();
+
+#ifdef CONFIG_STM32_CAN1  
+  if (priv->port == 1)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+#ifdef CONFIG_STM32_CAN2 
+  if (priv->port == 2)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+    {
+      candbg("Unsupport port %d\n", priv->port);
+    }
+  irqrestore(flags);
+}
+
+/****************************************************************************
+ * Name: can_setup
+ *
+ * Description:
+ *   Configure the CAN. This method is called the first time that the CAN
+ *   device is opened.  This will occur when the port is first opened.
+ *   This setup includes configuring and attaching CAN interrupts.
+ *   All CAN interrupts are disabled upon return.
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int can_setup(FAR struct can_dev_s *dev)
+{
+  FAR struct stm32_can_s *priv = dev->cd_priv;
+  int ret;
+
+  /* Attach all CAN interrupts */
+
+  ret = irq_attach(priv->cantx, can_txinterrupt);
+  if (ret < 0)
+    {
+      candbg("Failed to attach CAN%d TX IRQ (%d)", priv->port, priv->cantx);
+      return ret;
+    }
+
+  ret = irq_attach(priv->canrx0, can_rx0interrupt);
+  if (ret < 0)
+    {
+      candbg("Failed to attach CAN%d RX0 IRQ (%d)", priv->port, priv->canrx0);
+      return ret;
+    }
+
+  ret = irq_attach(priv->canrx1, can_rx1interrupt);
+  if (ret < 0)
+    {
+      candbg("Failed to attach CAN%d RX1 IRQ (%d)", priv->port, priv->canrx1);
+      return ret;
+    }
+
+  ret = irq_attach(priv->cansce, can_sceinterrupt);
+  if (ret < 0)
+    {
+      candbg("Failed to attach CAN%d SCE IRQ (%d)", priv->port, priv->cansce);
+      return ret;
+    }
+
+  /* Enable all interrupts at the NVIC.  Interrupts are still disabled in
+   * the CAN module.  Since we coming out of reset here, there should be
+   */
+
+  up_enable_irq(priv->cantx);
+  up_enable_irq(priv->canrx0);
+  up_enable_irq(priv->canrx1);
+  up_enable_irq(priv->cansce);
+  return OK;
+}
+
+/****************************************************************************
+ * Name: can_shutdown
+ *
+ * Description:
+ *   Disable the CAN.  This method is called when the CAN device is closed.
+ *   This method reverses the operation the setup method.
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static void can_shutdown(FAR struct can_dev_s *dev)
+{
+  FAR struct stm32_can_s *priv = dev->cd_priv;
+
+  /* Disable all interrupts */
+
+  up_disable_irq(priv->cantx);
+  up_disable_irq(priv->canrx0);
+  up_disable_irq(priv->canrx1);
+  up_disable_irq(priv->cansce);
+
+  /* Detach all interrupts */
+
+  irq_detach(priv->cantx);
+  irq_detach(priv->canrx0);
+  irq_detach(priv->canrx1);
+  irq_detach(priv->cansce);
+
+  /* And reset the hardware */
+
+  can_reset(dev);
+}
+
+/****************************************************************************
+ * Name: can_rxint
+ *
+ * Description:
+ *   Call to enable or disable RX interrupts.
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static void can_rxint(FAR struct can_dev_s *dev, bool enable)
+{
+  FAR struct stm32_can_s *priv = dev->cd_priv;
+
+#ifdef CONFIG_STM32_CAN1  
+  if (priv->port == 1)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+#ifdef CONFIG_STM32_CAN2 
+  if (priv->port == 2)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+    {
+      candbg("Unsupport port %d\n", priv->port);
+    }
+}
+
+/****************************************************************************
+ * Name: can_txint
+ *
+ * Description:
+ *   Call to enable or disable TX interrupts.
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static void can_txint(FAR struct can_dev_s *dev, bool enable)
+{
+  FAR struct stm32_can_s *priv = dev->cd_priv;
+
+#ifdef CONFIG_STM32_CAN1  
+  if (priv->port == 1)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+#ifdef CONFIG_STM32_CAN2 
+  if (priv->port == 2)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+    {
+      candbg("Unsupport port %d\n", priv->port);
+    }
+}
+
+/****************************************************************************
+ * Name: can_ioctl
+ *
+ * Description:
+ *   All ioctl calls will be routed through this method
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int can_ioctl(FAR struct can_dev_s *dev, int cmd, unsigned long arg)
+{
+  /* No CAN ioctls are supported */
+
+  return -ENOTTY;
+}
+
+/****************************************************************************
+ * Name: can_remoterequest
+ *
+ * Description:
+ *   Send a remote request
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int  can_remoterequest(FAR struct can_dev_s *dev, uint16_t id)
+{
+#warning "Missing logic"
+  return -ENOSYS;
+}
+
+/****************************************************************************
+ * Name: can_send
+ *
+ * Description:
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int  can_send(FAR struct can_dev_s *dev, FAR struct can_msg_s *msg)
+{
+  FAR struct stm32_can_s *priv = dev->cd_priv;
+
+#ifdef CONFIG_STM32_CAN1  
+  if (priv->port == 1)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+#ifdef CONFIG_STM32_CAN2 
+  if (priv->port == 2)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+    {
+      candbg("Unsupport port %d\n", priv->port);
+      return -EINVAL;
+    }
+
+#warning "Missing logic"
+  return OK;
+}
+
+/****************************************************************************
+ * Name: can_txempty
+ *
+ * Description:
+ *   Return true if all message have been sent.  If for example, the CAN
+ *   hardware implements FIFOs, then this would mean the transmit FIFO is
+ *   empty.  This method is called when the driver needs to make sure that
+ *   all characters are "drained" from the TX hardware before calling
+ *   co_shutdown().
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static bool can_txempty(FAR struct can_dev_s *dev)
+{
+  FAR struct stm32_can_s *priv = dev->cd_priv;
+
+#ifdef CONFIG_STM32_CAN1  
+  if (priv->port == 1)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+#ifdef CONFIG_STM32_CAN2 
+  if (priv->port == 2)
+    {
+#warning "Missing logic"
+    }
+  else
+#endif
+    {
+      candbg("Unsupport port %d\n", priv->port);
+      return true;
+    }
+
+#warning "Missing logic"
+  return true;
+}
+
+/****************************************************************************
+ * Name: can_txinterrupt
+ *
+ * Description:
+ *   CAN TX interrupt handler
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int can_txinterrupt(int irq, void *context)
+{
+  FAR struct stm32_can_s *priv;
+
+#if defined(CONFIG_STM32_CAN1) && defined(CONFIG_STM32_CAN2)
+  if (g_can1priv.cantx == irq)
+    {
+      priv = &g_can1priv;
+    }
+  else if (g_can2priv.cantx == irq)
+    {
+      priv = &g_can2priv;
+    }
+  else
+    {
+      PANIC(OSERR_UNEXPECTEDISR);
+    }
+#elif defined(CONFIG_STM32_CAN1)
+  priv = &g_can1priv;
+#else /* defined(CONFIG_STM32_CAN2) */
+  priv = &g_can2priv;
+#endif
+
+#warning "Missing logic"
+    return OK;
+}
+
+/****************************************************************************
+ * Name: can_rx0interrupt
+ *
+ * Description:
+ *   CAN RX FIFO 0 interrupt handler
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int can_rx0interrupt(int irq, void *context)
+{
+  FAR struct stm32_can_s *priv;
+
+#if defined(CONFIG_STM32_CAN1) && defined(CONFIG_STM32_CAN2)
+  if (g_can1priv.canrx0 == irq)
+    {
+      priv = &g_can1priv;
+    }
+  else if (g_can2priv.canrx0 == irq)
+    {
+      priv = &g_can2priv;
+    }
+  else
+    {
+      PANIC(OSERR_UNEXPECTEDISR);
+    }
+#elif defined(CONFIG_STM32_CAN1)
+  priv = &g_can1priv;
+#else /* defined(CONFIG_STM32_CAN2) */
+  priv = &g_can2priv;
+#endif
+
+#warning "Missing logic"
+    return OK;
+}
+
+/****************************************************************************
+ * Name: can_rx1interrupt
+ *
+ * Description:
+ *   CAN FIFO 1 interrupt handler
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int can_rx1interrupt(int irq, void *context)
+{
+  FAR struct stm32_can_s *priv;
+
+#if defined(CONFIG_STM32_CAN1) && defined(CONFIG_STM32_CAN2)
+  if (g_can1priv.canrx1 == irq)
+    {
+      priv = &g_can1priv;
+    }
+  else if (g_can2priv.canrx1 == irq)
+    {
+      priv = &g_can2priv;
+    }
+  else
+    {
+      PANIC(OSERR_UNEXPECTEDISR);
+    }
+#elif defined(CONFIG_STM32_CAN1)
+  priv = &g_can1priv;
+#else /* defined(CONFIG_STM32_CAN2) */
+  priv = &g_can2priv;
+#endif
+
+#warning "Missing logic"
+    return OK;
+}
+
+/****************************************************************************
+ * Name: can_sceinterrupt
+ *
+ * Description:
+ *   CAN Status Change Error (SCE) interrupt handler
+ *
+ * Input Parameters:
+ *   dev - An instance of the "upper half" can driver state structure.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+static int can_sceinterrupt(int irq, void *context)
+{
+  FAR struct stm32_can_s *priv;
+
+#if defined(CONFIG_STM32_CAN1) && defined(CONFIG_STM32_CAN2)
+  if (g_can1priv.cansce == irq)
+    {
+      priv = &g_can1priv;
+    }
+  else if (g_can2priv.cansce == irq)
+    {
+      priv = &g_can2priv;
+    }
+  else
+    {
+      PANIC(OSERR_UNEXPECTEDISR);
+    }
+#elif defined(CONFIG_STM32_CAN1)
+  priv = &g_can1priv;
+#else /* defined(CONFIG_STM32_CAN2) */
+  priv = &g_can2priv;
+#endif
+
+#warning "Missing logic"
+    return OK;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_caninitialize
+ *
+ * Description:
+ *   Initialize the selected CAN port
+ *
+ * Input Parameter:
+ *   Port number (for hardware that has mutiple CAN interfaces)
+ *
+ * Returned Value:
+ *   Valid CAN device structure reference on succcess; a NULL on failure
+ *
+ ****************************************************************************/
+
+FAR struct can_dev_s *up_caninitialize(int port)
+{
+  struct can_dev_s *dev = NULL;
+
+#ifdef CONFIG_STM32_CAN1  
+  if( port == 1 )
+    {
+      dev = &g_can1dev;
+    }
+  else
+#endif  
+#ifdef CONFIG_STM32_CAN2  
+  if ( port ==2 )
+    {
+      dev = &g_can2dev;
+    }
+  else
+#endif  
+    {
+      candbg("Unsupport port %d\n", priv->port);
+      return NULL;
+    }
+
+#warning "Missing logic"
+  return dev;
+}
+
+#endif /* CONFIG_STM32_CAN1 || CONFIG_STM32_CAN2 */
+#endif /* CONFIG_CAN */
+
diff --git a/arch/arm/src/stm32/stm32_pwm.c b/arch/arm/src/stm32/stm32_pwm.c
index 99d2e310ce1..fb3323d7eaf 100644
--- a/arch/arm/src/stm32/stm32_pwm.c
+++ b/arch/arm/src/stm32/stm32_pwm.c
@@ -2,7 +2,7 @@
  * arch/arm/src/stm32/stm32_pwm.c
  *
  *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
diff --git a/configs/README.txt b/configs/README.txt
index a85348babe0..90302fff64e 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -633,6 +633,15 @@ defconfig -- This is a configuration file similar to the Linux
 		CONFIG_RTC_ALARM - Enable if the RTC hardware supports setting of an
 		  alarm.  A callback function will be executed when the alarm goes off
 
+	CAN driver
+
+		CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+		  CONFIG_STM32_CAN2 must also be defined)
+		CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+		  Default: 8
+		CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+		  Default: 4
+
 	SPI driver
 
 		CONFIG_SPI_OWNBUS - Set if there is only one active device
diff --git a/configs/hymini-stm32v/README.txt b/configs/hymini-stm32v/README.txt
index 016604d8872..ccb3850e2ed 100755
--- a/configs/hymini-stm32v/README.txt
+++ b/configs/hymini-stm32v/README.txt
@@ -486,8 +486,18 @@ HY-Mini specific Configuration Options
 	  4-bit transfer mode.
     CONFIG_MMCSD_HAVECARDDETECT - Select if SDIO driver card detection
       is 100% accurate  (it is on the  HY-MiniSTM32V)
-    
-    
+
+  HY-MiniSTM32V CAN Configuration
+
+	CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+	  CONFIG_STM32_CAN2 must also be defined)
+	CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+	  Default: 8
+	CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+	  Default: 4
+	CONFIG_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1 is defined.
+	CONFIG_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2 is defined.
+
   HY-MiniSTM32V LCD Hardware Configuration  (SSD1289 controler)
 
     CONFIG_NX_LCDDRIVER - To be defined to include LCD driver
diff --git a/configs/stm3210e-eval/README.txt b/configs/stm3210e-eval/README.txt
index f8868373fa1..e5f2541d8e2 100755
--- a/configs/stm3210e-eval/README.txt
+++ b/configs/stm3210e-eval/README.txt
@@ -575,6 +575,17 @@ STM3210E-EVAL-specific Configuration Options
 	CONFIG_SDIO_WIDTH_D1_ONLY - Select 1-bit transfer mode.  Default:
 	  4-bit transfer mode.
 
+  STM3210E-EVAL CAN Configuration
+
+	CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+	  CONFIG_STM32_CAN2 must also be defined)
+	CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+	  Default: 8
+	CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+	  Default: 4
+	CONFIG_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1 is defined.
+	CONFIG_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2 is defined.
+
   STM3210E-EVAL LCD Hardware Configuration
 
     CONFIG_LCD_LANDSCAPE - Define for 320x240 display "landscape"
diff --git a/configs/stm3240g-eval/README.txt b/configs/stm3240g-eval/README.txt
index a7e49a73a37..8813ac821f6 100755
--- a/configs/stm3240g-eval/README.txt
+++ b/configs/stm3240g-eval/README.txt
@@ -481,6 +481,17 @@ STM3240G-EVAL-specific Configuration Options
 	CONFIG_STM32_ETH_PTP - Precision Time Protocol (PTP).  Not supported
 	  but some hooks are indicated with this condition.
 
+  STM3240G-EVAL CAN Configuration
+
+	CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+	  CONFIG_STM32_CAN2 must also be defined)
+	CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+	  Default: 8
+	CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+	  Default: 4
+	CONFIG_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1 is defined.
+	CONFIG_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2 is defined.
+
   STM3240G-EVAL LCD Hardware Configuration
 
 Configurations
diff --git a/configs/stm3240g-eval/dhcpd/defconfig b/configs/stm3240g-eval/dhcpd/defconfig
index 3675f5b8524..a0ba27c0b98 100755
--- a/configs/stm3240g-eval/dhcpd/defconfig
+++ b/configs/stm3240g-eval/dhcpd/defconfig
@@ -256,6 +256,24 @@ CONFIG_SSI1_DISABLE=y
 CONFIG_SSI_POLLWAIT=y
 #CONFIG_SSI_TXLIMIT=4
 
+#
+# STM32F40xxx specific CAN device driver settings
+#
+# CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+#   CONFIG_STM32_CAN2 must also be defined)
+# CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+#   Default: 8
+# CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+#   Default: 4
+# CONFIG_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1 is defined.
+# CONFIG_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2 is defined.
+#
+CONFIG_CAN=n
+#CONFIG_CAN_FIFOSIZE
+#CONFIG_CAN_NPENDINGRTR
+CONFIG_CAN1_BAUD=115200
+CONFIG_CAN2_BAUD=115200
+
 #
 # STM32F40xxx Ethernet device driver settings
 #
diff --git a/configs/stm3240g-eval/nettest/defconfig b/configs/stm3240g-eval/nettest/defconfig
index 6884ad3d7e6..afcd39512c1 100755
--- a/configs/stm3240g-eval/nettest/defconfig
+++ b/configs/stm3240g-eval/nettest/defconfig
@@ -256,6 +256,24 @@ CONFIG_SSI1_DISABLE=y
 CONFIG_SSI_POLLWAIT=y
 #CONFIG_SSI_TXLIMIT=4
 
+#
+# STM32F40xxx specific CAN device driver settings
+#
+# CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+#   CONFIG_STM32_CAN2 must also be defined)
+# CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+#   Default: 8
+# CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+#   Default: 4
+# CONFIG_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1 is defined.
+# CONFIG_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2 is defined.
+#
+CONFIG_CAN=n
+#CONFIG_CAN_FIFOSIZE
+#CONFIG_CAN_NPENDINGRTR
+CONFIG_CAN1_BAUD=115200
+CONFIG_CAN2_BAUD=115200
+
 #
 # STM32F40xxx Ethernet device driver settings
 #
diff --git a/configs/stm3240g-eval/nsh/defconfig b/configs/stm3240g-eval/nsh/defconfig
index 8acd5de7c34..72ab549efab 100755
--- a/configs/stm3240g-eval/nsh/defconfig
+++ b/configs/stm3240g-eval/nsh/defconfig
@@ -256,6 +256,24 @@ CONFIG_SSI1_DISABLE=y
 CONFIG_SSI_POLLWAIT=y
 #CONFIG_SSI_TXLIMIT=4
 
+#
+# STM32F40xxx specific CAN device driver settings
+#
+# CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+#   CONFIG_STM32_CAN2 must also be defined)
+# CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+#   Default: 8
+# CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+#   Default: 4
+# CONFIG_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1 is defined.
+# CONFIG_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2 is defined.
+#
+CONFIG_CAN=n
+#CONFIG_CAN_FIFOSIZE
+#CONFIG_CAN_NPENDINGRTR
+CONFIG_CAN1_BAUD=115200
+CONFIG_CAN2_BAUD=115200
+
 #
 # STM32F40xxx Ethernet device driver settings
 #
diff --git a/configs/stm3240g-eval/ostest/defconfig b/configs/stm3240g-eval/ostest/defconfig
index 2b51d88c7db..e0b696dfee1 100755
--- a/configs/stm3240g-eval/ostest/defconfig
+++ b/configs/stm3240g-eval/ostest/defconfig
@@ -256,6 +256,24 @@ CONFIG_SSI1_DISABLE=y
 CONFIG_SSI_POLLWAIT=y
 #CONFIG_SSI_TXLIMIT=4
 
+#
+# STM32F40xxx specific CAN device driver settings
+#
+# CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
+#   CONFIG_STM32_CAN2 must also be defined)
+# CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
+#   Default: 8
+# CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
+#   Default: 4
+# CONFIG_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1 is defined.
+# CONFIG_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2 is defined.
+#
+CONFIG_CAN=n
+#CONFIG_CAN_FIFOSIZE
+#CONFIG_CAN_NPENDINGRTR
+CONFIG_CAN1_BAUD=115200
+CONFIG_CAN2_BAUD=115200
+
 #
 # STM32F40xxx Ethernet device driver settings
 #
diff --git a/drivers/Makefile b/drivers/Makefile
index b76a04a8cdf..a6fcbe1f04f 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -2,7 +2,7 @@
 # drivers/Makefile
 #
 #   Copyright (C) 2007-2011 Gregory Nutt. All rights reserved.
-#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -64,10 +64,13 @@ include usbhost/Make.defs
 include wireless/Make.defs
 
 ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
-  CSRCS += dev_null.c dev_zero.c loop.c  can.c
+  CSRCS += dev_null.c dev_zero.c loop.c
 ifneq ($(CONFIG_DISABLE_MOUNTPOINT),y)
   CSRCS += ramdisk.c rwbuffer.c
 endif
+ifneq ($(CONFIG_CAN),y)
+  CSRCS += can.c
+endif
 ifeq ($(CONFIG_PWM),y)
   CSRCS += pwm.c
 endif
diff --git a/drivers/can.c b/drivers/can.c
index fc70678a7d1..532eef59206 100644
--- a/drivers/can.c
+++ b/drivers/can.c
@@ -1,8 +1,8 @@
 /****************************************************************************
  * drivers/can.c
  *
- *   Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Copyright (C) 2008-2009, 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -33,10 +33,6 @@
  *
  ****************************************************************************/
 
-/****************************************************************************
- * Compilation Switches
- ****************************************************************************/
-
 /****************************************************************************
  * Included Files
  ****************************************************************************/
@@ -60,9 +56,27 @@
 
 #include <arch/irq.h>
 
+#ifdef CONFIG_CAN
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
+/* Debug ********************************************************************/
+/* Non-standard debug that may be enabled just for testing CAN */
+
+#ifdef CONFIG_DEBUG_CAN
+#  define candbg    dbg
+#  define canvdbg   vdbg
+#  define canlldbg  lldbg
+#  define canllvdbg llvdbg
+#else
+#  define candbg(x...)
+#  define canvdbg(x...)
+#  define canlldbg(x...)
+#  define canllvdbg(x...)
+#endif
+
+/* Timing Definitions *******************************************************/
 
 #define HALF_SECOND_MSEC 500
 #define HALF_SECOND_USEC 500000L
@@ -619,7 +633,7 @@ int can_register(FAR const char *path, FAR struct can_dev_s *dev)
 
   /* Register the CAN device */
 
-  dbg("Registering %s\n", path);
+  canvdbg("Registering %s\n", path);
   return register_driver(path, &g_canops, 0666, dev);
 }
 
@@ -768,3 +782,4 @@ int can_txdone(FAR struct can_dev_s *dev)
   return ret;
 }
 
+#endif /* CONFIG_CAN */
diff --git a/include/nuttx/can.h b/include/nuttx/can.h
index 8b438ffdaec..f87c2eac476 100644
--- a/include/nuttx/can.h
+++ b/include/nuttx/can.h
@@ -1,8 +1,8 @@
 /************************************************************************************
  * include/nuttx/can.h
  *
- *   Copyright (C) 2008, 2009 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Copyright (C) 2008, 2009, 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -33,8 +33,8 @@
  *
  ************************************************************************************/
 
-#ifndef __NUTTX_CAN_H
-#define __NUTTX_CAN_H
+#ifndef _INCLUDE_NUTTX_CAN_H
+#define _INCLUDE_NUTTX_CAN_H
 
 /************************************************************************************
  * Included Files
@@ -46,14 +46,18 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <semaphore.h>
+
 #include <nuttx/fs.h>
 
+#ifdef CONFIG_CAN
+
 /************************************************************************************
  * Pre-processor Definitions
  ************************************************************************************/
 
-/* Default configuration settings that may be overridden in the board configuration.
- * file.  The configured size is limited to 255 to fit into a uint8_t.
+/* Default configuration settings that may be overridden in the NuttX configuration
+ * file or in the board configuration file.  The configured size is limited to 255
+ * to fit into a uint8_t.
  */
 
 #if !defined(CONFIG_CAN_FIFOSIZE)
@@ -165,8 +169,8 @@ struct can_ops_s
 
   /* Configure the CAN. This method is called the first time that the CAN
    * device is opened.  This will occur when the port is first opened. 
-   * This setup includes configuring and attaching CAN interrupts.  Interrupts
-   * are all disabled upon return.
+   * This setup includes configuring and attaching CAN interrupts.  All CAN
+   * interrupts are disabled upon return.
    */
 
   CODE int (*co_setup)(FAR struct can_dev_s *dev);
@@ -305,4 +309,5 @@ EXTERN int can_txdone(FAR struct can_dev_s *dev);
 }
 #endif
 
-#endif /* __NUTTX_CAN_H */
+#endif /* CONFIG_CAN */
+#endif /* _INCLUDE_NUTTX_CAN_H */