1 files changed, 396 insertions, 0 deletions
diff --git a/nuttx/drivers/sensors/qencoder.c b/nuttx/drivers/sensors/qencoder.c
new file mode 100644
index 000000000..edbe8255c
--- /dev/null
+++ b/nuttx/drivers/sensors/qencoder.c
@@ -0,0 +1,396 @@
+/****************************************************************************
+ * drivers/sensors/qencoder.c
+ *
+ *   Copyright (C) 2012 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Compilation Switches
+ ****************************************************************************/
+
+/****************************************************************************
+ * 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 <semaphore.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/fs.h>
+#include <nuttx/arch.h>
+#include <nuttx/sensors/qencoder.h>
+
+#include <arch/irq.h>
+
+#ifdef CONFIG_QENCODER
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+/* Debug ********************************************************************/
+/* Non-standard debug that may be enabled just for testing PWM */
+
+#ifdef CONFIG_DEBUG_QENCODER
+#  define qedbg    dbg
+#  define qevdbg   vdbg
+#  define qelldbg  lldbg
+#  define qellvdbg llvdbg
+#else
+#  define qedbg(x...)
+#  define qevdbg(x...)
+#  define qelldbg(x...)
+#  define qellvdbg(x...)
+#endif
+
+/****************************************************************************
+ * Private Type Definitions
+ ****************************************************************************/
+
+/* This structure describes the state of the upper half drivere */
+
+struct qe_upperhalf_s
+{
+  uint8_t                    crefs;    /* The number of times the device has been opened */
+  sem_t                      exclsem;  /* Supports mutual exclusion */
+  FAR struct qe_lowerhalf_s *lower;    /* lower-half state */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int     qe_open(FAR struct file *filep);
+static int     qe_close(FAR struct file *filep);
+static ssize_t qe_read(FAR struct file *filep, FAR char *buffer, size_t buflen);
+static ssize_t qe_write(FAR struct file *filep, FAR const char *buffer, size_t buflen);
+static int     qe_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct file_operations g_qeops =
+{
+  qe_open,  /* open */
+  qe_close, /* close */
+  qe_read,  /* read */
+  qe_write, /* write */
+  0,         /* seek */
+  qe_ioctl  /* ioctl */
+#ifndef CONFIG_DISABLE_POLL
+  , 0        /* poll */
+#endif
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/************************************************************************************
+ * Name: qe_open
+ *
+ * Description:
+ *   This function is called whenever the PWM device is opened.
+ *
+ ************************************************************************************/
+
+static int qe_open(FAR struct file *filep)
+{
+  FAR struct inode           *inode = filep->f_inode;
+  FAR struct qe_upperhalf_s *upper = inode->i_private;
+  uint8_t                     tmp;
+  int                         ret;
+
+  qevdbg("crefs: %d\n", upper->crefs);
+
+  /* Get exclusive access to the device structures */
+
+  ret = sem_wait(&upper->exclsem);
+  if (ret < 0)
+    {
+      ret = -errno;
+      goto errout;
+    }
+
+  /* Increment the count of references to the device.  If this 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 qe_lowerhalf_s *lower = upper->lower;
+
+      /* Yes.. perform one time hardware initialization. */
+
+      DEBUGASSERT(lower->ops->setup != NULL);
+      qevdbg("calling setup\n");
+
+      ret = lower->ops->setup(lower);
+      if (ret < 0)
+        {
+          goto errout_with_sem;
+        }
+    }
+
+  /* Save the new open count on success */
+
+  upper->crefs = tmp;
+  ret = OK;
+
+errout_with_sem:
+  sem_post(&upper->exclsem);
+  
+errout:
+  return ret;
+}
+
+/************************************************************************************
+ * Name: qe_close
+ *
+ * Description:
+ *   This function is called when the PWM device is closed.
+ *
+ ************************************************************************************/
+
+static int qe_close(FAR struct file *filep)
+{
+  FAR struct inode           *inode = filep->f_inode;
+  FAR struct qe_upperhalf_s *upper = inode->i_private;
+  int                         ret;
+
+  qevdbg("crefs: %d\n", upper->crefs);
+
+  /* Get exclusive access to the device structures */
+
+  ret = sem_wait(&upper->exclsem);
+  if (ret < 0)
+    {
+      ret = -errno;
+      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 qe_lowerhalf_s *lower = upper->lower;
+
+      /* There are no more references to the port */
+
+      upper->crefs = 0;
+
+      /* Disable the PWM device */
+
+      DEBUGASSERT(lower->ops->shutdown != NULL);
+      qevdbg("calling shutdown: %d\n");
+
+      lower->ops->shutdown(lower);
+    }
+  ret = OK;
+
+//errout_with_sem:
+  sem_post(&upper->exclsem);
+  
+errout:
+  return ret;
+}
+
+/************************************************************************************
+ * Name: qe_read
+ *
+ * Description:
+ *   A dummy read method.  This is provided only to satsify the VFS layer.
+ *
+ ************************************************************************************/
+
+static ssize_t qe_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
+{
+  /* Return zero -- usually meaning end-of-file */
+
+  return 0;
+}
+
+/************************************************************************************
+ * Name: qe_write
+ *
+ * Description:
+ *   A dummy write method.  This is provided only to satsify the VFS layer.
+ *
+ ************************************************************************************/
+
+static ssize_t qe_write(FAR struct file *filep, FAR const char *buffer, size_t buflen)
+{
+  /* Return a failure */
+
+  return -EPERM;
+}
+
+/************************************************************************************
+ * Name: qe_ioctl
+ *
+ * Description:
+ *   The standard ioctl method.  This is where ALL of the PWM work is done.
+ *   
+ ************************************************************************************/
+
+static int qe_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
+{
+  FAR struct inode          *inode = filep->f_inode;
+  FAR struct qe_upperhalf_s *upper = inode->i_private;
+  FAR struct qe_lowerhalf_s *lower = upper->lower;
+  int                        ret;
+
+  qevdbg("cmd: %d arg: %ld\n", cmd, arg);
+  DEBUGASSERT(upper && lower);
+
+  /* Get exclusive access to the device structures */
+
+  ret = sem_wait(&upper->exclsem);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Handle built-in ioctl commands */
+
+  switch (cmd)
+    {
+      /* QEIOC_POSITION - Get the current position from the encoder.
+       *   Argument: int32_t pointer to the location to return the position.
+       */
+
+      case QEIOC_POSITION:
+        {
+          FAR int32_t *ptr = (FAR int32_t *)((uintptr_t)arg);
+          DEBUGASSERT(lower->ops->position != NULL && ptr);
+          ret = lower->ops->position(lower, ptr);
+        }
+        break;
+
+      /* QEIOC_RESET - Reset the position to zero.
+       *   Argument: None
+       */
+
+      case QEIOC_RESET:
+        {
+          DEBUGASSERT(lower->ops->reset != NULL);
+          ret = lower->ops->reset(lower);
+        }
+        break;
+
+      /* Any unrecognized IOCTL commands might be platform-specific ioctl commands */
+
+      default:
+        {
+          qevdbg("Forwarding unrecognized cmd: %d arg: %ld\n", cmd, arg);
+          DEBUGASSERT(lower->ops->ioctl != NULL);
+          ret = lower->ops->ioctl(lower, cmd, arg);
+        }
+        break;
+    }
+
+  sem_post(&upper->exclsem);
+  return ret;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: qe_register
+ *
+ * Description:
+ *   Register the Quadrature Encoder lower half device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/qe0"
+ *   lower - An instance of the lower half interface
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int qe_register(FAR const char *devpath, FAR struct qe_lowerhalf_s *lower)
+{
+  FAR struct qe_upperhalf_s *upper;
+
+  /* Allocate the upper-half data structure */
+
+  upper = (FAR struct qe_upperhalf_s *)zalloc(sizeof(struct qe_upperhalf_s));
+  if (!upper)
+    {
+      qedbg("Allocation failed\n");
+      return -ENOMEM;
+    }
+
+  /* Initialize the PWM device structure (it was already zeroed by zalloc()) */
+
+  sem_init(&upper->exclsem, 0, 1);
+  upper->lower = lower;
+
+  /* Register the PWM device */
+
+  qevdbg("Registering %s\n", devpath);
+  return register_driver(devpath, &g_qeops, 0666, upper);
+}
+
+#endif /* CONFIG_QENCODER */