Add loopback support to STM32 CAN driver; Add apps/examples/can loopback test

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4213 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -2287,6 +2287,6 @@
 	  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).
+	  check is incomplete).  Add loopback support to the driver.
 
 

Documentation/NuttxPortingGuide.html

@@ -4376,6 +4376,11 @@ build
   <li>
     <code>CONFIG_CAN_NPENDINGRTR</code>: The size of the list of pending RTR requests.  Default: 4
   </li>
+  <li>
+    <code>CONFIG_CAN_LOOPBACK</code>: A CAN driver may or may not support a loopback mode for testing.
+    If the driver does support loopback mode, the setting will enable it.
+    (If the driver does not, this setting will have no effect).
+  </li>
 </ul>
 
 <h3>SPI driver</h3>

arch/arm/src/common/up_internal.h

@@ -340,11 +340,6 @@ extern void up_usbuninitialize(void);
 # define up_usbuninitialize()
 #endif
 
-/* CAN **********************************************************************/
-
-struct can_dev_s;  /* Forward reference */
-extern FAR struct can_dev_s *up_caninitialize(int port);
-
 /****************************************************************************
  * Name: up_check_stack
  *
@@ -361,7 +356,6 @@ extern FAR struct can_dev_s *up_caninitialize(int port);
  *
  ****************************************************************************/
 
-
 #if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_STACK)
 extern size_t up_check_stack(void);
 extern size_t up_check_tcbstack(FAR _TCB);

arch/arm/src/lpc17xx/lpc17_can.c

@@ -354,7 +354,7 @@ static int can_interrupt(int irq, void *context)
  ****************************************************************************/
 
 /****************************************************************************
- * Name: up_caninitialize
+ * Name: lpc17_caninitialize
  *
  * Description:
  *   Initialize the selected can port
@@ -367,7 +367,7 @@ static int can_interrupt(int irq, void *context)
  *
  ****************************************************************************/
 
-FAR struct can_dev_s *up_caninitialize(int port)
+FAR struct can_dev_s *lpc17_caninitialize(int port)
 {
     uint32_t regval;
     irqstate_t flags;

arch/arm/src/lpc17xx/lpc17_internal.h

@@ -786,6 +786,25 @@ FAR struct adc_dev_s *stm32_adcinitialize(void);
 EXTERN FAR struct dac_dev_s *lpc17_dacinitialize(void);
 #endif
 
+/****************************************************************************
+ * Name: lpc17_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
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_CAN) && (defined(CONFIG_LPC17_CAN1) || defined(CONFIG_LPC17_CAN2))
+struct can_dev_s;
+EXTERN FAR struct can_dev_s *lpc17_caninitialize(int port);
+#endif
+
 #undef EXTERN
 #if defined(__cplusplus)
 }

arch/arm/src/stm32/stm32_can.c

@@ -60,34 +60,11 @@
 #include "stm32_internal.h"
 #include "stm32_can.h"
 
-#ifdef CONFIG_CAN
+#if defined(CONFIG_CAN) && (defined(CONFIG_STM32_CAN1) || defined(CONFIG_STM32_CAN2))
 
 /****************************************************************************
  * 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
-
 /* Delays *******************************************************************/
 /* Time out for INAK bit */
 
@@ -762,7 +739,7 @@ static int can_rx0interrupt(int irq, void *context)
 
   /* Provide the data to the upper half driver */
 
-  ret = can_receive(dev, (uint16_t)CAN_MSG(id, rtr, dlc), data);
+  ret = can_receive(dev, (uint16_t)CAN_HDR(id, rtr, dlc), data);
 
   /* Release the FIFO0 */
 
@@ -925,7 +902,7 @@ static int can_bittiming(struct stm32_can_s *priv)
   canvdbg("TS1: %d TS2: %d BRP: %d\n", ts1, ts2, brp);
 
  /* Configure bit timing.  This also does the the following, less obvious
-   * things:
+   * things.  Unless loopback mode is enabled, it:
    *
    * - Disables silent mode.
    * - Disables loopback mode.
@@ -936,6 +913,10 @@ static int can_bittiming(struct stm32_can_s *priv)
 
   tmp = ((brp - 1) << CAN_BTR_BRP_SHIFT) | ((ts1 - 1) << CAN_BTR_TS1_SHIFT) |
         ((ts2 - 1) << CAN_BTR_TS2_SHIFT) | ((1 - 1) << CAN_BTR_SJW_SHIFT);
+#ifdef CONFIG_CAN_LOOPBACK
+  tmp |= (CAN_BTR_LBKM | CAN_BTR_SILM);
+#endif
+
   can_putreg(priv, STM32_CAN_BTR_OFFSET, tmp);
   return OK;
 }
@@ -1126,7 +1107,7 @@ static int can_filterinit(struct stm32_can_s *priv)
  ****************************************************************************/
 
 /****************************************************************************
- * Name: up_caninitialize
+ * Name: stm32_caninitialize
  *
  * Description:
  *   Initialize the selected CAN port
@@ -1139,7 +1120,7 @@ static int can_filterinit(struct stm32_can_s *priv)
  *
  ****************************************************************************/
 
-FAR struct can_dev_s *up_caninitialize(int port)
+FAR struct can_dev_s *stm32_caninitialize(int port)
 {
   struct can_dev_s *dev = NULL;
 
@@ -1158,8 +1139,10 @@ FAR struct can_dev_s *up_caninitialize(int port)
        * file must have been disambiguated in the board.h file.
        */
 
+#ifndef CONFIG_CAN_LOOPBACK
       stm32_configgpio(GPIO_CAN1_RX);
       stm32_configgpio(GPIO_CAN1_TX);
+#endif
     }
   else
 #endif  
@@ -1174,19 +1157,20 @@ FAR struct can_dev_s *up_caninitialize(int port)
        * file must have been disambiguated in the board.h file.
        */
 
+#ifndef CONFIG_CAN_LOOPBACK
       stm32_configgpio(GPIO_CAN2_RX);
       stm32_configgpio(GPIO_CAN2_TX);
+#endif
     }
   else
 #endif  
     {
-      candbg("Unsupported port %d\n", priv->port);
+      candbg("Unsupported port %d\n", port);
       return NULL;
     }
 
   return dev;
 }
 
-#endif /* CONFIG_STM32_CAN1 || CONFIG_STM32_CAN2 */
+#endif /* CONFIG_CAN && (CONFIG_STM32_CAN1 || CONFIG_STM32_CAN2) */
-#endif /* CONFIG_CAN */
 

arch/arm/src/stm32/stm32_can.h

@@ -50,17 +50,73 @@
 /************************************************************************************
  * 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_CAN) && (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
 
 /************************************************************************************
  * Public Types
  ************************************************************************************/
 
+#ifndef __ASSEMBLY__
+
 /************************************************************************************
  * Public Data
  ************************************************************************************/
 
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
 /************************************************************************************
  * Public Functions
  ************************************************************************************/
 
+/****************************************************************************
+ * Name: stm32_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
+ *
+ ****************************************************************************/
+
+struct can_dev_s;
+EXTERN FAR struct can_dev_s *stm32_caninitialize(int port);
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __ASSEMBLY__ */
+#endif /* CONFIG_CAN && (CONFIG_STM32_CAN1 || CONFIG_STM32_CAN2) */
 #endif /* __ARCH_ARM_SRC_STM32_STM32_CAN_H */

configs/README.txt

@@ -641,6 +641,9 @@ defconfig -- This is a configuration file similar to the Linux
 		  Default: 8
 		CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 		  Default: 4
+		CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+		mode for testing. If the driver does support loopback mode, the setting
+		will enable it. (If the driver does not, this setting will have no effect).
 
 	SPI driver
 

configs/hymini-stm32v/README.txt

@@ -495,6 +495,8 @@ HY-Mini specific Configuration Options
 	  Default: 8
 	CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 	  Default: 4
+	CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+	  mode for testing. The STM32 CAN driver does support loopback mode.
 	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.
 

configs/stm3210e-eval/README.txt

@@ -583,6 +583,8 @@ STM3210E-EVAL-specific Configuration Options
 	  Default: 8
 	CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 	  Default: 4
+	CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+	  mode for testing. The STM32 CAN driver does support loopback mode.
 	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.
 

configs/stm3210e-eval/src/up_adc.c

@@ -124,6 +124,11 @@ int adc_devinit(void)
   /* Call stm32_adcinitialize() to get an instance of the ADC interface */
 
   adc = stm32_adcinitialize(1, g_chanlist, ADC_NCHANNELS);
+  if (adc == NULL)
+    {
+      adbg("ERROR: Failed to get ADC interface\n");
+      return;
+    }
 
   /* Register the ADC driver at "/dev/adc0" */
 
@@ -133,7 +138,7 @@ int adc_devinit(void)
       adbg("adc_register failed: %d\n", ret);
     }
 
-  return OK;
+  return ret;
 }
 
 #endif /* CONFIG_STM32_ADC || CONFIG_STM32_ADC2 || CONFIG_STM32_ADC3 */

configs/stm3240g-eval/README.txt

@@ -524,6 +524,8 @@ STM3240G-EVAL-specific Configuration Options
 	  Default: 8
 	CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 	  Default: 4
+	CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+	  mode for testing. The STM32 CAN driver does support loopback mode.
 	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.
 

configs/stm3240g-eval/dhcpd/defconfig

@@ -265,14 +265,17 @@ CONFIG_SSI_POLLWAIT=y
 #   Default: 8
 # CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 #   Default: 4
+# CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+#   mode for testing. The STM32 CAN driver does support loopback mode.
 # 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_CAN_LOOPBACK=n
-CONFIG_CAN2_BAUD=115200
+CONFIG_CAN1_BAUD=700000
+CONFIG_CAN2_BAUD=700000
 
 #
 # STM32F40xxx Ethernet device driver settings

configs/stm3240g-eval/nettest/defconfig

@@ -265,14 +265,17 @@ CONFIG_SSI_POLLWAIT=y
 #   Default: 8
 # CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 #   Default: 4
+# CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+#   mode for testing. The STM32 CAN driver does support loopback mode.
 # 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_CAN_LOOPBACK=n
-CONFIG_CAN2_BAUD=115200
+CONFIG_CAN1_BAUD=700000
+CONFIG_CAN2_BAUD=700000
 
 #
 # STM32F40xxx Ethernet device driver settings

configs/stm3240g-eval/nsh/appconfig

@@ -54,4 +54,7 @@ ifeq ($(CONFIG_PWM),y)
 CONFIGURED_APPS += examples/pwm
 endif
 
+ifeq ($(CONFIG_CAN),y)
+CONFIGURED_APPS += examples/can
+endif
 

configs/stm3240g-eval/nsh/defconfig

@@ -265,14 +265,17 @@ CONFIG_SSI_POLLWAIT=y
 #   Default: 8
 # CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 #   Default: 4
+# CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+#   mode for testing. The STM32 CAN driver does support loopback mode.
 # 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_CAN_LOOPBACK=n
-CONFIG_CAN2_BAUD=115200
+CONFIG_CAN1_BAUD=700000
+CONFIG_CAN2_BAUD=700000
 
 #
 # STM32F40xxx Ethernet device driver settings

configs/stm3240g-eval/ostest/defconfig

@@ -265,14 +265,17 @@ CONFIG_SSI_POLLWAIT=y
 #   Default: 8
 # CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
 #   Default: 4
+# CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
+#   mode for testing. The STM32 CAN driver does support loopback mode.
 # 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_CAN_LOOPBACK=n
-CONFIG_CAN2_BAUD=115200
+CONFIG_CAN1_BAUD=700000
+CONFIG_CAN2_BAUD=700000
 
 #
 # STM32F40xxx Ethernet device driver settings

configs/stm3240g-eval/src/Makefile

@@ -50,6 +50,10 @@ ifeq ($(CONFIG_PWM),y)
 CSRCS		+= up_pwm.c
 endif
 
+ifeq ($(CONFIG_CAN),y)
+CSRCS		+= up_can.c
+endif
+
 COBJS		= $(CSRCS:.c=$(OBJEXT))
 
 SRCS		= $(ASRCS) $(CSRCS)

configs/stm3240g-eval/src/stm3240g-internal.h

@@ -48,7 +48,7 @@
 /****************************************************************************************************
  * Definitions
  ****************************************************************************************************/
-
+/* Configuration ************************************************************************************/
 /* How many SPI modules does this chip support? */
 
 #if STM32_NSPI < 1
@@ -62,6 +62,36 @@
 #  undef CONFIG_STM32_SPI3
 #endif
 
+/* You can use either CAN1 or CAN2, but you can't use both because they share the same transceiver */
+
+#if defined(CONFIG_STM32_CAN1) && defined(CONFIG_STM32_CAN2)
+#  warning "The STM3250G-EVAL will only support one of CAN1 and CAN2"
+#endif
+
+/* You can't use CAN1 with FSMC:
+ *
+ *   PD0   = FSMC_D2 & CAN1_RX   
+ *   PD1   = FSMC_D3 & CAN1_TX  
+ */
+
+#ifndef CONFIG_CAN_LOOPBACK
+#  if defined(CONFIG_STM32_CAN1) && defined(CONFIG_STM32_FSMC)
+#    warning "The STM3250G-EVAL will only support one of CAN1 and FSMC"
+#  endif
+#endif
+
+/* The USB OTG HS ULPI bus is shared with CAN2 bus:
+ *
+ *   PB13  = ULPI_D6 & CAN2_TX
+ *   PB5   = ULPI_D7 & CAN2_RX
+ */
+
+#ifndef CONFIG_CAN_LOOPBACK
+#  if defined(CONFIG_STM32_CAN2) && defined(CONFIG_STM32_OTGHS)
+#    warning "The STM3250G-EVAL will only support one of CAN2 and USB OTG HS"
+#  endif
+#endif
+
 /* STM3240G-EVAL GPIOs ******************************************************************************/
 /* LEDs */
 

configs/stm3240g-eval/src/up_adc.c

@@ -91,21 +91,37 @@
  *
  ************************************************************************************/
 
-void adc_devinit(void)
+int adc_devinit(void)
 {
+  static bool initialized = false;
   struct adc_dev_s *adc;
   int ret;
 
-  /* Call stm32_adcinitialize() to get an instance of the ADC interface */
+  /* Check if we have already initialized */
+
+  if (!initialized)
+    {
+      /* Configure the pins as analog inputs for the selected channels */
 #warning "Missing Logic"
 
-  /* Register the ADC driver at "/dev/adc0" */
+      /* Call stm32_adcinitialize() to get an instance of the ADC interface */
+#warning "Missing Logic"
 
-  ret = adc_register("/dev/adc0", adc);
+      /* Register the ADC driver at "/dev/adc0" */
-  if (ret < 0)
+
-    {
+      ret = adc_register("/dev/adc0", adc);
-      adbg("adc_register failed: %d\n", ret);
+      if (ret < 0)
+        {
+          adbg("adc_register failed: %d\n", ret);
+          return ret;
+        }
+
+      /* Now we are initialized */
+
+      initialized = true;
     }
+
+  return OK;
 }
 
 #endif /* CONFIG_STM32_ADC || CONFIG_STM32_ADC2 || CONFIG_STM32_ADC3 */

configs/stm3240g-eval/src/up_can.c

@@ -0,0 +1,142 @@
+/************************************************************************************
+ * configs/stm3240g-eval/src/up_can.c
+ * arch/arm/src/board/up_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 <errno.h>
+#include <debug.h>
+
+#include <nuttx/can.h>
+#include <arch/board/board.h>
+
+#include "chip.h"
+#include "up_arch.h"
+
+#include "stm32.h"
+#include "stm32_can.h"
+#include "stm3240g-internal.h"
+
+#if defined(CONFIG_CAN) && (defined(CONFIG_STM32_CAN1) || defined(CONFIG_STM32_CAN2))
+
+/************************************************************************************
+ * Pre-processor Definitions
+ ************************************************************************************/
+/* Configuration ********************************************************************/
+
+#if defined(CONFIG_STM32_CAN1) && defined(CONFIG_STM32_CAN2)
+#  warning "Both CAN1 and CAN2 are enabled.  Assuming only CAN1."
+#  undef CONFIG_STM32_CAN2
+#endif
+
+#ifdef CONFIG_STM32_CAN1
+#  define CAN_PORT 1
+#else
+#  define CAN_PORT 2
+#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 Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Public Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Name: can_devinit
+ *
+ * Description:
+ *   All STM32 architectures must provide the following interface to work with
+ *   examples/can.
+ *
+ ************************************************************************************/
+
+int can_devinit(void)
+{
+  static bool initialized = false;
+  struct can_dev_s *can;
+  int ret;
+
+  /* Check if we have already initialized */
+
+  if (!initialized)
+    {
+      /* Call stm32_caninitialize() to get an instance of the CAN interface */
+
+      can = stm32_caninitialize(CAN_PORT);
+      if (can == NULL)
+        {
+          candbg("ERROR:  Failed to get CAN interface\n");
+          return -ENODEV;
+        }
+
+      /* Register the CAN driver at "/dev/can0" */
+
+      ret = can_register("/dev/can0", can);
+      if (ret < 0)
+        {
+          candbg("ERROR: can_register failed: %d\n", ret);
+          return ret;
+        }
+
+      /* Now we are initialized */
+
+      initialized = true;
+    }
+
+  return OK;
+}
+
+#endif /* CONFIG_STM32_CAN || CONFIG_STM32_CAN2 || CONFIG_STM32_CAN3 */

drivers/Makefile

@@ -65,12 +65,15 @@ include wireless/Make.defs
 
 ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
   CSRCS += dev_null.c dev_zero.c loop.c
+
 ifneq ($(CONFIG_DISABLE_MOUNTPOINT),y)
   CSRCS += ramdisk.c rwbuffer.c
 endif
-ifneq ($(CONFIG_CAN),y)
+
+ifeq ($(CONFIG_CAN),y)
   CSRCS += can.c
 endif
+
 ifeq ($(CONFIG_PWM),y)
   CSRCS += pwm.c
 endif

include/nuttx/can.h

@@ -88,14 +88,15 @@
 
 /* CAN message support */
 
-#define CAN_MAXDATALEN 8
+#define CAN_MAXDATALEN            8
+#define CAN_MAXMSGID              0x07ff
 
 #define CAN_ID(hdr)               ((uint16_t)(hdr) >> 5)
 #define CAN_RTR(hdr)              (((hdr) & 0x0010) != 0)
 #define CAN_DLC(hdr)              ((hdr) & 0x0f)
 #define CAN_MSGLEN(hdr)           (sizeof(struct can_msg_s) - (CAN_MAXDATALEN - CAN_DLC(hdr)))
 
-#define CAN_MSG(id, rtr, dlc)     ((uint16_t)id << 5 | (uint16_t)rtr << 4 | (uint16_t)dlc)
+#define CAN_HDR(id, rtr, dlc)     ((uint16_t)id << 5 | (uint16_t)rtr << 4 | (uint16_t)dlc)
 
 /* Built-in ioctl commands
  *