238 lines
7.4 KiB
C
238 lines
7.4 KiB
C
/****************************************************************************
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* drivers/analog/opamp.c
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*
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* Copyright (C) 2017 Gregory Nutt. All rights reserved.
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* Author: Mateusz Szafoni <raiden00@railab.me>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <semaphore.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/semaphore.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/analog/opamp.h>
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#include <nuttx/irq.h>
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int opamp_open(FAR struct file *filep);
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static int opamp_close(FAR struct file *filep);
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static int opamp_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations opamp_fops =
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{
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opamp_open, /* open */
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opamp_close, /* close */
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NULL, /* read */
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NULL, /* write */
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NULL, /* seek */
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opamp_ioctl /* ioctl */
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#ifndef CONFIG_DISABLE_POLL
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, NULL /* poll */
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#endif
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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, NULL /* unlink */
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#endif
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: opamp_open
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*
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* Description:
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* This function is called whenever the OPAMP device is opened.
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*
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****************************************************************************/
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static int opamp_open(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct opamp_dev_s *dev = inode->i_private;
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uint8_t tmp;
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int ret;
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/* If the port is the middle of closing, wait until the close is finished */
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ret = nxsem_wait(&dev->ad_closesem);
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if (ret >= 0)
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{
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/* Increment the count of references to the device. If this the first
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* time that the driver has been opened for this device, then initialize
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* the device.
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*/
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tmp = dev->ad_ocount + 1;
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if (tmp == 0)
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{
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/* More than 255 opens; uint8_t overflows to zero */
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ret = -EMFILE;
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}
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else
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{
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/* Check if this is the first time that the driver has been opened. */
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if (tmp == 1)
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{
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/* Yes.. perform one time hardware initialization. */
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irqstate_t flags = enter_critical_section();
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ret = dev->ad_ops->ao_setup(dev);
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if (ret == OK)
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{
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/* Save the new open count on success */
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dev->ad_ocount = tmp;
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}
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leave_critical_section(flags);
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}
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}
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nxsem_post(&dev->ad_closesem);
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}
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return ret;
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}
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/****************************************************************************
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* Name: opamp_close
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*
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* Description:
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* This routine is called when the OPAMP device is closed.
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* It waits for the last remaining data to be sent.
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*
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****************************************************************************/
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static int opamp_close(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct opamp_dev_s *dev = inode->i_private;
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irqstate_t flags;
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int ret;
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ret = nxsem_wait(&dev->ad_closesem);
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if (ret >= 0)
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{
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/* Decrement the references to the driver. If the reference count will
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* decrement to 0, then uninitialize the driver.
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*/
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if (dev->ad_ocount > 1)
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{
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dev->ad_ocount--;
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nxsem_post(&dev->ad_closesem);
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}
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else
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{
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/* There are no more references to the port */
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dev->ad_ocount = 0;
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/* Free the IRQ and disable the OPAMP device */
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flags = enter_critical_section(); /* Disable interrupts */
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dev->ad_ops->ao_shutdown(dev); /* Disable the OPAMP */
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leave_critical_section(flags);
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nxsem_post(&dev->ad_closesem);
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}
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}
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return ret;
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}
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/****************************************************************************
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* Name: opamp_ioctl
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****************************************************************************/
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static int opamp_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct opamp_dev_s *dev = inode->i_private;
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int ret;
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ret = dev->ad_ops->ao_ioctl(dev, cmd, arg);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: opamp_register
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****************************************************************************/
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int opamp_register(FAR const char *path, FAR struct opamp_dev_s *dev)
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{
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int ret;
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/* Initialize the OPAMP device structure */
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dev->ad_ocount = 0;
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/* Initialize semaphores */
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nxsem_init(&dev->ad_closesem, 0, 1);
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/* Register the OPAMP character driver */
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ret = register_driver(path, &opamp_fops, 0444, dev);
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if (ret < 0)
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{
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nxsem_destroy(&dev->ad_closesem);
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}
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return ret;
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}
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