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- /****************************************************************************
- * drivers/analog/opamp.c
- *
- * Copyright (C) 2017 Gregory Nutt. All rights reserved.
- * Author: Mateusz Szafoni <raiden00@railab.me>
- *
- * 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 <sys/types.h>
- #include <stdint.h>
- #include <unistd.h>
- #include <semaphore.h>
- #include <fcntl.h>
- #include <errno.h>
- #include <debug.h>
- #include <nuttx/arch.h>
- #include <nuttx/semaphore.h>
- #include <nuttx/fs/fs.h>
- #include <nuttx/analog/opamp.h>
- #include <nuttx/irq.h>
- /****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
- static int opamp_open(FAR struct file *filep);
- static int opamp_close(FAR struct file *filep);
- static int opamp_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- static const struct file_operations opamp_fops =
- {
- opamp_open, /* open */
- opamp_close, /* close */
- NULL, /* read */
- NULL, /* write */
- NULL, /* seek */
- opamp_ioctl, /* ioctl */
- NULL /* poll */
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- , NULL /* unlink */
- #endif
- };
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: opamp_open
- *
- * Description:
- * This function is called whenever the OPAMP device is opened.
- *
- ****************************************************************************/
- static int opamp_open(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct opamp_dev_s *dev = inode->i_private;
- uint8_t tmp;
- int ret;
- /* If the port is the middle of closing, wait until the close is finished */
- ret = nxsem_wait(&dev->ad_closesem);
- if (ret >= 0)
- {
- /* 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 = dev->ad_ocount + 1;
- if (tmp == 0)
- {
- /* More than 255 opens; uint8_t overflows to zero */
- ret = -EMFILE;
- }
- else
- {
- /* Check if this is the first time that the driver has been opened. */
- if (tmp == 1)
- {
- /* Yes.. perform one time hardware initialization. */
- irqstate_t flags = enter_critical_section();
- ret = dev->ad_ops->ao_setup(dev);
- if (ret == OK)
- {
- /* Save the new open count on success */
- dev->ad_ocount = tmp;
- }
- leave_critical_section(flags);
- }
- }
- nxsem_post(&dev->ad_closesem);
- }
- return ret;
- }
- /****************************************************************************
- * Name: opamp_close
- *
- * Description:
- * This routine is called when the OPAMP device is closed.
- * It waits for the last remaining data to be sent.
- *
- ****************************************************************************/
- static int opamp_close(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct opamp_dev_s *dev = inode->i_private;
- irqstate_t flags;
- int ret;
- ret = nxsem_wait(&dev->ad_closesem);
- if (ret >= 0)
- {
- /* Decrement the references to the driver. If the reference count will
- * decrement to 0, then uninitialize the driver.
- */
- if (dev->ad_ocount > 1)
- {
- dev->ad_ocount--;
- nxsem_post(&dev->ad_closesem);
- }
- else
- {
- /* There are no more references to the port */
- dev->ad_ocount = 0;
- /* Free the IRQ and disable the OPAMP device */
- flags = enter_critical_section(); /* Disable interrupts */
- dev->ad_ops->ao_shutdown(dev); /* Disable the OPAMP */
- leave_critical_section(flags);
- nxsem_post(&dev->ad_closesem);
- }
- }
- return ret;
- }
- /****************************************************************************
- * Name: opamp_ioctl
- ****************************************************************************/
- static int opamp_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct opamp_dev_s *dev = inode->i_private;
- int ret;
- ret = dev->ad_ops->ao_ioctl(dev, cmd, arg);
- return ret;
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: opamp_register
- ****************************************************************************/
- int opamp_register(FAR const char *path, FAR struct opamp_dev_s *dev)
- {
- int ret;
- /* Initialize the OPAMP device structure */
- dev->ad_ocount = 0;
- /* Initialize semaphores */
- nxsem_init(&dev->ad_closesem, 0, 1);
- /* Register the OPAMP character driver */
- ret = register_driver(path, &opamp_fops, 0444, dev);
- if (ret < 0)
- {
- nxsem_destroy(&dev->ad_closesem);
- }
- return ret;
- }
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