boards/stm32f4discovery: add setup of pwm capture device

drivers/timers/capture.c: add support of pwm capture driver

boards/arm/stm32/stm32f4discovery/include/board.h

@@ -314,6 +314,15 @@
 
 #define GPIO_TIM4_CH2OUT  GPIO_TIM4_CH2OUT_2
 
+/* Capture
+ *
+ * The STM32F4 Discovery has no real on-board pwm capture devices, but the
+ * board can be configured to capture pwm using TIM3 CH2 PB5.
+ */
+
+#define GPIO_TIM3_CH2IN  GPIO_TIM3_CH2IN_2
+#define GPIO_TIM3_CH1IN  GPIO_TIM3_CH2IN_2
+
 /* RGB LED
  *
  * R = TIM1 CH1 on PE9 | G = TIM2 CH2 on PA1 | B = TIM3 CH3 on PB0

boards/arm/stm32/stm32f4discovery/src/Make.defs

@@ -92,6 +92,10 @@ ifeq ($(CONFIG_PWM),y)
 CSRCS += stm32_pwm.c
 endif
 
+ifeq ($(CONFIG_CAPTURE),y)
+CSRCS += stm32_capture.c
+endif
+
 ifeq ($(CONFIG_BOARDCTL),y)
 CSRCS += stm32_appinit.c
 ifeq ($(CONFIG_BOARDCTL_RESET),y)

boards/arm/stm32/stm32f4discovery/src/stm32_bringup.c

@@ -347,6 +347,17 @@ int stm32_bringup(void)
     }
 #endif
 
+#ifdef CONFIG_CAPTURE
+  /* Initialize Capture and register the Capture driver. */
+
+  ret = stm32_capture_setup("/dev/capture0");
+  if (ret < 0)
+    {
+      syslog(LOG_ERR, "ERROR: stm32_capture_setup failed: %d\n", ret);
+      return ret;
+    }
+#endif
+
 #ifdef CONFIG_STM32_CAN_CHARDRIVER
   /* Initialize CAN and register the CAN driver. */
 

boards/arm/stm32/stm32f4discovery/src/stm32_capture.c

@@ -0,0 +1,109 @@
+/****************************************************************************
+ * boards/arm/stm32/stm32f4discovery/src/stm32_capture.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <errno.h>
+#include <debug.h>
+#include <nuttx/timers/capture.h>
+#include <arch/board/board.h>
+
+#include "chip.h"
+
+#include "stm32.h"
+#include "stm32_capture.h"
+#include "arm_internal.h"
+
+#include "stm32f4discovery.h"
+
+#if defined(CONFIG_CAPTURE)
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Capture
+ *
+ * The stm32f4discovery has no real on-board pwm capture devices, but the
+ * board can be configured to capture pwm using TIM3 CH2 PB5.
+ */
+
+#define HAVE_CAPTURE 1
+
+#ifndef CONFIG_CAPTURE
+#  undef HAVE_CAPTURE
+#endif
+
+#ifndef CONFIG_STM32_TIM3
+#  undef HAVE_CAPTURE
+#endif
+
+#ifndef CONFIG_STM32_TIM3_CAP
+#  undef HAVE_CAPTURE
+#endif
+
+#if !defined(CONFIG_STM32_TIM3_CHANNEL) || CONFIG_STM32_TIM3_CHANNEL != STM32F4DISCOVERY_CAPTURECHANNEL
+#  undef HAVE_CAPTURE
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: stm32_capture_setup
+ *
+ * Description:
+ *   Initialize and register the pwm capture driver.
+ *
+ * Input parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/capture0"
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int stm32_capture_setup(FAR const char *devpath)
+{
+#ifdef HAVE_CAPTURE
+  struct cap_lowerhalf_s *capture;
+  int ret;
+
+  capture = stm32_cap_initialize(STM32F4DISCOVERY_CAPTURETIMER);
+
+  /* Then register the pwm capture sensor */
+
+  ret = cap_register(devpath, capture);
+  if (ret < 0)
+    {
+      mtrerr("ERROR: Error registering capture\n");
+    }
+
+  return ret;
+#else
+  return -ENODEV;
+#endif
+}
+
+#endif /* CONFIG_CAPTURE */

boards/arm/stm32/stm32f4discovery/src/stm32f4discovery.h

@@ -243,6 +243,15 @@
 #define STM32F4DISCOVERY_PWMTIMER   4
 #define STM32F4DISCOVERY_PWMCHANNEL 2
 
+/* Capture
+ *
+ * The STM32F4 Discovery has no real on-board pwm capture devices, but the
+ * board can be configured to capture pwm using TIM3 CH2 PB5.
+ */
+
+#define STM32F4DISCOVERY_CAPTURETIMER   3
+#define STM32F4DISCOVERY_CAPTURECHANNEL 2
+
 /* SPI chip selects */
 
 #define GPIO_CS_MEMS      (GPIO_OUTPUT|GPIO_PUSHPULL|GPIO_SPEED_50MHz|\
@@ -555,6 +564,18 @@ int stm32_usbhost_initialize(void);
 int stm32_pwm_setup(void);
 #endif
 
+/****************************************************************************
+ * Name: stm32_capture_setup
+ *
+ * Description:
+ *  Initialize pwm capture support
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_CAPTURE
+int stm32_capture_setup(FAR const char *devpath);
+#endif
+
 /****************************************************************************
  * Name: stm32_can_setup
  *

drivers/timers/capture.c

@@ -358,7 +358,6 @@ int cap_register(FAR const char *devpath, FAR struct cap_lowerhalf_s *lower)
            kmm_zalloc(sizeof(struct cap_upperhalf_s));
   if (!upper)
     {
-      snprintf("ERROR: Allocation failed\n");
       return -ENOMEM;
     }