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

drivers/timers/Kconfig

@@ -53,6 +53,13 @@ config PWM_NCHANNELS
 endif # PWM_MULTICHAN
 endif # PWM
 
+config CAPTURE
+	bool "Capture Driver Support"
+	default n
+	---help---
+		This selection enables building of the "upper-half" Capture driver.
+		See include/nuttx/timers/capture.h for further Capture driver information.
+
 config TIMER
 	bool "Timer Support"
 	default n

drivers/timers/Make.defs

@@ -104,6 +104,12 @@ ifeq ($(CONFIG_PWM),y)
   TMRVPATH = :timers
 endif
 
+ifeq ($(CONFIG_CAPTURE),y)
+  CSRCS += capture.c
+  TMRDEPPATH = --dep-path timers
+  TMRVPATH = :timers
+endif
+
 # Include timer build support (if any were selected)
 
 DEPPATH += $(TMRDEPPATH)

drivers/timers/capture.c

@@ -0,0 +1,377 @@
+/****************************************************************************
+ * drivers/timers/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 <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/arch.h>
+#include <nuttx/semaphore.h>
+#include <nuttx/timers/capture.h>
+
+#include <arch/irq.h>
+
+#ifdef CONFIG_CAPTURE
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Debug ********************************************************************/
+
+/****************************************************************************
+ * Private Type Definitions
+ ****************************************************************************/
+
+/* This structure describes the state of the upper half driver */
+
+struct cap_upperhalf_s
+{
+  uint8_t                    crefs;    /* The number of times the device has been opened */
+  sem_t                      exclsem;  /* Supports mutual exclusion */
+  FAR struct cap_lowerhalf_s *lower;   /* lower-half state */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int     cap_open(FAR struct file *filep);
+static int     cap_close(FAR struct file *filep);
+static ssize_t cap_read(FAR struct file *filep, FAR char *buffer,
+                       size_t buflen);
+static ssize_t cap_write(FAR struct file *filep, FAR const char *buffer,
+                        size_t buflen);
+static int cap_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct file_operations g_capops =
+{
+  cap_open,  /* open */
+  cap_close, /* close */
+  cap_read,  /* read */
+  cap_write, /* write */
+  NULL,      /* seek */
+  cap_ioctl, /* ioctl */
+  NULL,      /* poll */
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+  NULL       /* unlink */
+#endif
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cap_open
+ *
+ * Description:
+ *   This function is called whenever the PWM Capture device is opened.
+ *
+ ****************************************************************************/
+
+static int cap_open(FAR struct file *filep)
+{
+  FAR struct inode           *inode = filep->f_inode;
+  FAR struct cap_upperhalf_s *upper = inode->i_private;
+  uint8_t                     tmp;
+  int                         ret;
+
+  /* Get exclusive access to the device structures */
+
+  ret = nxsem_wait(&upper->exclsem);
+  if (ret < 0)
+    {
+      goto errout;
+    }
+
+  /* Increment the count of references to the device.  If this is the first
+   * time that the driver has been opened for this device, then initialize
+   * the device.
+   */
+
+  tmp = upper->crefs + 1;
+  if (tmp == 0)
+    {
+      /* More than 255 opens; uint8_t overflows to zero */
+
+      ret = -EMFILE;
+      goto errout_with_sem;
+    }
+
+  /* Check if this is the first time that the driver has been opened. */
+
+  if (tmp == 1)
+    {
+      FAR struct cap_lowerhalf_s *lower = upper->lower;
+
+      /* Yes.. perform one time hardware initialization. */
+
+      DEBUGASSERT(lower->ops->start != NULL);
+
+      ret = lower->ops->start(lower);
+      if (ret < 0)
+        {
+          goto errout_with_sem;
+        }
+    }
+
+  /* Save the new open count on success */
+
+  upper->crefs = tmp;
+  ret = OK;
+
+errout_with_sem:
+  nxsem_post(&upper->exclsem);
+
+errout:
+  return ret;
+}
+
+/****************************************************************************
+ * Name: cap_close
+ *
+ * Description:
+ *   This function is called when the PWM Capture device is closed.
+ *
+ ****************************************************************************/
+
+static int cap_close(FAR struct file *filep)
+{
+  FAR struct inode           *inode = filep->f_inode;
+  FAR struct cap_upperhalf_s *upper = inode->i_private;
+  int                         ret;
+
+  /* Get exclusive access to the device structures */
+
+  ret = nxsem_wait(&upper->exclsem);
+  if (ret < 0)
+    {
+      goto errout;
+    }
+
+  /* Decrement the references to the driver.  If the reference count will
+   * decrement to 0, then uninitialize the driver.
+   */
+
+  if (upper->crefs > 1)
+    {
+      upper->crefs--;
+    }
+  else
+    {
+      FAR struct cap_lowerhalf_s *lower = upper->lower;
+
+      /* There are no more references to the port */
+
+      upper->crefs = 0;
+
+      /* Disable the PWM Capture device */
+
+      DEBUGASSERT(lower->ops->stop != NULL);
+
+      lower->ops->stop(lower);
+    }
+
+  nxsem_post(&upper->exclsem);
+  ret = OK;
+
+errout:
+  return ret;
+}
+
+/****************************************************************************
+ * Name: cap_read
+ *
+ * Description:
+ *   A dummy read method.  This is provided only to satisfy the VFS layer.
+ *
+ ****************************************************************************/
+
+static ssize_t cap_read(FAR struct file *filep,
+                       FAR char *buffer,
+                       size_t buflen)
+{
+  /* Return zero -- usually meaning end-of-file */
+
+  return 0;
+}
+
+/****************************************************************************
+ * Name: cap_write
+ *
+ * Description:
+ *   A dummy write method.  This is provided only to satisfy the VFS layer.
+ *
+ ****************************************************************************/
+
+static ssize_t cap_write(FAR struct file *filep,
+                        FAR const char *buffer,
+                        size_t buflen)
+{
+  /* Return a failure */
+
+  return -EPERM;
+}
+
+/****************************************************************************
+ * Name: cap_ioctl
+ *
+ * Description:
+ *   The standard ioctl method.
+ *   This is where ALL of the PWM Capture work is done.
+ *
+ ****************************************************************************/
+
+static int cap_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
+{
+  FAR struct inode          *inode = filep->f_inode;
+  FAR struct cap_upperhalf_s *upper;
+  FAR struct cap_lowerhalf_s *lower;
+  int                        ret;
+
+  snprintf("cmd: %d arg: %ld\n", cmd, arg);
+  upper = inode->i_private;
+  DEBUGASSERT(upper != NULL);
+  lower = upper->lower;
+  DEBUGASSERT(lower != NULL);
+
+  /* Get exclusive access to the device structures */
+
+  ret = nxsem_wait(&upper->exclsem);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Handle built-in ioctl commands */
+
+  switch (cmd)
+    {
+      /* CAPIOC_DUTYCYCLE - Get the pwm duty from the capture.
+       * Argument: int8_t pointer to the location to return the duty.
+       */
+
+      case CAPIOC_DUTYCYCLE:
+        {
+          FAR uint8_t *ptr = (FAR uint8_t *)((uintptr_t)arg);
+          DEBUGASSERT(lower->ops->getduty != NULL && ptr);
+          ret = lower->ops->getduty(lower, ptr);
+        }
+        break;
+
+      /* CAPIOC_FREQUENCE - Get the pulse frequence from the capture.
+       * Argument: int32_t pointer to the location to return the frequence.
+       */
+
+      case CAPIOC_FREQUENCE:
+        {
+          FAR uint32_t *ptr = (FAR uint32_t *)((uintptr_t)arg);
+          DEBUGASSERT(lower->ops->getfreq != NULL && ptr);
+          ret = lower->ops->getfreq(lower, ptr);
+        }
+        break;
+
+      /* Any unrecognized IOCTL commands might be platform-specific ioctl
+       * commands
+       */
+
+      default:
+        {
+          snprintf("Forwarding unrecognized cmd: %d arg: %ld\n", cmd, arg);
+        }
+        break;
+    }
+
+  nxsem_post(&upper->exclsem);
+  return ret;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cap_register
+ *
+ * Description:
+ *   Register the PWM Capture lower half device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/cap0"
+ *   lower - An instance of the lower half interface
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.  The following
+ *   possible error values may be returned (most are returned by
+ *   register_driver()):
+ *
+ *   EINVAL - 'path' is invalid for this operation
+ *   EEXIST - An inode already exists at 'path'
+ *   ENOMEM - Failed to allocate in-memory resources for the operation
+ *
+ ****************************************************************************/
+
+int cap_register(FAR const char *devpath, FAR struct cap_lowerhalf_s *lower)
+{
+  FAR struct cap_upperhalf_s *upper;
+
+  /* Allocate the upper-half data structure */
+
+  upper = (FAR struct cap_upperhalf_s *)
+           kmm_zalloc(sizeof(struct cap_upperhalf_s));
+  if (!upper)
+    {
+      snprintf("ERROR: Allocation failed\n");
+      return -ENOMEM;
+    }
+
+  /* Initialize the PWM Capture device structure
+   * (it was already zeroed by kmm_zalloc())
+   */
+
+  nxsem_init(&upper->exclsem, 0, 1);
+  upper->lower = lower;
+
+  /* Register the PWM Capture device */
+
+  return register_driver(devpath, &g_capops, 0666, upper);
+}
+
+#endif /* CONFIG_CAPTURE */

include/nuttx/fs/ioctl.h

@@ -56,7 +56,7 @@
 #define _AUDIOIOCBASE   (0x1000) /* Audio ioctl commands */
 #define _LCDIOCBASE     (0x1100) /* LCD character driver ioctl commands */
 #define _SLCDIOCBASE    (0x1200) /* Segment LCD ioctl commands */
-                                 /* 0x1300: Not used */
+#define _CAPIOCBASE     (0x1300) /* Capture ioctl commands */
 #define _WLCIOCBASE     (0x1400) /* Wireless modules ioctl character driver commands */
 #define _CFGDIOCBASE    (0x1500) /* Config Data device (app config) ioctl commands */
 #define _TCIOCBASE      (0x1600) /* Timer ioctl commands */
@@ -325,6 +325,11 @@
 #define _PWMIOCVALID(c)   (_IOC_TYPE(c)==_PWMIOCBASE)
 #define _PWMIOC(nr)       _IOC(_PWMIOCBASE,nr)
 
+/* NuttX Capture ioctl definitions (see nuttx/timers/capture.h) *************/
+
+#define _CAPIOCVALID(c)   (_IOC_TYPE(c)==_CAPIOCBASE)
+#define _CAPIOC(nr)       _IOC(_CAPIOCBASE,nr)
+
 /* NuttX USB CDC/ACM serial driver ioctl definitions ************************/
 
 /* (see nuttx/usb/cdcacm.h) */

include/nuttx/timers/capture.h

@@ -0,0 +1,128 @@
+/****************************************************************************
+ * include/nuttx/timers/capture.h
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_TIMERS_CAPTURE_H
+#define __INCLUDE_NUTTX_TIMERS_CAPTURE_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/fs/ioctl.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* IOCTL Commands ***********************************************************/
+
+#define CAPIOC_DUTYCYCLE _CAPIOC(1)
+#define CAPIOC_FREQUENCE _CAPIOC(2)
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* This structure provides the "lower-half" driver operations available to
+ * the "upper-half" driver.
+ */
+
+struct cap_lowerhalf_s;
+struct cap_ops_s
+{
+  /* Required methods *******************************************************/
+
+  /* Start the capture, resetting the configure of timers */
+
+  CODE int (*start)(FAR struct cap_lowerhalf_s *lower);
+
+  /* Stop the capture */
+
+  CODE int (*stop)(FAR struct cap_lowerhalf_s *lower);
+
+  /* Get the result pwm capture duty value */
+
+  CODE int (*getduty)(FAR struct cap_lowerhalf_s *lower,
+                      FAR uint8_t *duty);
+
+  /* Get the result pwm capture frequence value */
+
+  CODE int (*getfreq)(FAR struct cap_lowerhalf_s *lower,
+                      FAR uint32_t *freq);
+};
+
+/* This structure provides the publicly visible representation of the
+ * "lower-half" driver state structure.  "lower half" drivers will have an
+ * internal structure definition that will be cast-compatible with this
+ * structure definitions.
+ */
+
+struct cap_lowerhalf_s
+{
+  FAR const struct cap_ops_s *ops;
+};
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cap_register
+ *
+ * Description:
+ *   Register the pulse capture lower half device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/cap0"
+ *   lower - An instance of the lower half interface
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.  The following
+ *   possible error values may be returned (most are returned by
+ *   register_driver()):
+ *
+ *   EINVAL - 'path' is invalid for this operation
+ *   EEXIST - An inode already exists at 'path'
+ *   ENOMEM - Failed to allocate in-memory resources for the operation
+ *
+ ****************************************************************************/
+
+int cap_register(FAR const char *devpath,
+                 FAR struct cap_lowerhalf_s *lower);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __INCLUDE_NUTTX_TIMERS_CAPTURE_H */