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- /****************************************************************************
- * drivers/analog/comp.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 <poll.h>
- #include <nuttx/arch.h>
- #include <nuttx/semaphore.h>
- #include <nuttx/fs/fs.h>
- #include <nuttx/analog/comp.h>
- #include <nuttx/irq.h>
- /****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
- static int comp_open(FAR struct file *filep);
- static int comp_close(FAR struct file *filep);
- static ssize_t comp_read(FAR struct file *filep, FAR char *buffer,
- size_t buflen);
- static int comp_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
- static int comp_poll(FAR struct file *filep, FAR struct pollfd *fds,
- bool setup);
- static int comp_notify(FAR struct comp_dev_s *dev, uint8_t val);
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- static const struct file_operations comp_fops =
- {
- comp_open, /* open */
- comp_close, /* close */
- comp_read, /* read */
- NULL, /* write */
- NULL, /* seek */
- comp_ioctl, /* ioctl */
- comp_poll /* poll */
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- , NULL /* unlink */
- #endif
- };
- static const struct comp_callback_s g_comp_callback =
- {
- comp_notify /* au_notify */
- };
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: comp_pollnotify
- *
- * Description:
- * This function is called to notificy any waiters of poll-reated events.
- *
- ****************************************************************************/
- static void comp_pollnotify(FAR struct comp_dev_s *dev,
- pollevent_t eventset)
- {
- int i;
- if (eventset & POLLERR)
- {
- eventset &= ~(POLLOUT | POLLIN);
- }
- for (i = 0; i < CONFIG_DEV_COMP_NPOLLWAITERS; i++)
- {
- FAR struct pollfd *fds = dev->d_fds[i];
- if (fds)
- {
- fds->revents |= eventset & (fds->events | POLLERR | POLLHUP);
- if ((fds->revents & (POLLOUT | POLLHUP)) == (POLLOUT | POLLHUP))
- {
- /* POLLOUT and POLLHUP are mutually exclusive. */
- fds->revents &= ~POLLOUT;
- }
- if (fds->revents != 0)
- {
- ainfo("Report events: %02x\n", fds->revents);
- nxsem_post(fds->sem);
- }
- }
- }
- }
- /****************************************************************************
- * Name: comp_semtake
- ****************************************************************************/
- static void comp_semtake(FAR sem_t *sem)
- {
- int ret;
- do
- {
- /* Take the semaphore (perhaps waiting) */
- ret = nxsem_wait(sem);
- /* The only case that an error should occur here is if the wait was
- * awakened by a signal.
- */
- DEBUGASSERT(ret == OK || ret == -EINTR);
- }
- while (ret == -EINTR);
- }
- /****************************************************************************
- * Name: comp_poll
- ****************************************************************************/
- static int comp_poll(FAR struct file *filep, FAR struct pollfd *fds,
- bool setup)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct comp_dev_s *dev = inode->i_private;
- int ret = OK;
- int i;
- DEBUGASSERT(dev && fds);
- /* Are we setting up the poll? Or tearing it down? */
- comp_semtake(&dev->ad_sem);
- if (setup)
- {
- /* This is a request to set up the poll. Find an available
- * slot for the poll structure reference
- */
- for (i = 0; i < CONFIG_DEV_COMP_NPOLLWAITERS; i++)
- {
- /* Find an available slot */
- if (!dev->d_fds[i])
- {
- /* Bind the poll structure and this slot */
- dev->d_fds[i] = fds;
- fds->priv = &dev->d_fds[i];
- break;
- }
- }
- if (i >= CONFIG_DEV_COMP_NPOLLWAITERS)
- {
- fds->priv = NULL;
- ret = -EBUSY;
- goto errout;
- }
- }
- else
- {
- /* This is a request to tear down the poll. */
- FAR struct pollfd **slot = (FAR struct pollfd **)fds->priv;
- #ifdef CONFIG_DEBUG_FEATURES
- if (!slot)
- {
- ret = -EIO;
- goto errout;
- }
- #endif
- /* Remove all memory of the poll setup */
- *slot = NULL;
- fds->priv = NULL;
- }
- errout:
- nxsem_post(&dev->ad_sem);
- return ret;
- }
- /****************************************************************************
- * Name: comp_notify
- *
- * Description:
- * This function is called from the lower half driver to notify
- * the change of the comparator output.
- *
- ****************************************************************************/
- static int comp_notify(FAR struct comp_dev_s *dev, uint8_t val)
- {
- /* TODO: store values in FIFO? */
- dev->val = val;
- comp_pollnotify(dev, POLLIN);
- nxsem_post(&dev->ad_readsem);
- return 0;
- }
- /****************************************************************************
- * Name: comp_open
- *
- * Description:
- * This function is called whenever the COMP device is opened.
- *
- ****************************************************************************/
- static int comp_open(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct comp_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_sem);
- 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_sem);
- }
- return ret;
- }
- /****************************************************************************
- * Name: comp_close
- *
- * Description:
- * This routine is called when the COMP device is closed.
- * It waits for the last remaining data to be sent.
- *
- ****************************************************************************/
- static int comp_close(FAR struct file *filep)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct comp_dev_s *dev = inode->i_private;
- irqstate_t flags;
- int ret;
- ret = nxsem_wait(&dev->ad_sem);
- 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_sem);
- }
- else
- {
- /* There are no more references to the port */
- dev->ad_ocount = 0;
- /* Free the IRQ and disable the COMP device */
- flags = enter_critical_section(); /* Disable interrupts */
- dev->ad_ops->ao_shutdown(dev); /* Disable the COMP */
- leave_critical_section(flags);
- nxsem_post(&dev->ad_sem);
- }
- }
- return ret;
- }
- /****************************************************************************
- * Name: comp_read
- ****************************************************************************/
- static ssize_t comp_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct comp_dev_s *dev = inode->i_private;
- int ret;
- /* If non-blocking read, read the value immediately and return. */
- if (filep->f_oflags & O_NONBLOCK)
- {
- ret = dev->ad_ops->ao_read(dev);
- buffer[0] = (uint8_t)ret;
- return 1;
- }
- ret = nxsem_wait(&dev->ad_readsem);
- if (ret < 0)
- {
- aerr("nxsem_wait() failed: %d\n", ret);
- return ret;
- }
- buffer[0] = dev->val;
- return 1;
- }
- /****************************************************************************
- * Name: comp_ioctl
- ****************************************************************************/
- static int comp_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct comp_dev_s *dev = inode->i_private;
- int ret;
- ret = dev->ad_ops->ao_ioctl(dev, cmd, arg);
- return ret;
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: comp_register
- ****************************************************************************/
- int comp_register(FAR const char *path, FAR struct comp_dev_s *dev)
- {
- int ret;
- /* Initialize the COMP device structure */
- dev->ad_ocount = 0;
- /* Initialize semaphores */
- nxsem_init(&dev->ad_sem, 0, 1);
- (void)nxsem_setprotocol(&dev->ad_sem, SEM_PRIO_NONE);
- nxsem_init(&dev->ad_readsem, 0, 0);
- (void)nxsem_setprotocol(&dev->ad_readsem, SEM_PRIO_NONE);
- /* Bind the upper-half callbacks to the lower half COMP driver */
- DEBUGASSERT(dev->ad_ops != NULL);
- if (dev->ad_ops->ao_bind != NULL)
- {
- ret = dev->ad_ops->ao_bind(dev, &g_comp_callback);
- if (ret < 0)
- {
- aerr("ERROR: Failed to bind callbacks: %d\n", ret);
- return ret;
- }
- }
- /* Register the COMP character driver */
- ret = register_driver(path, &comp_fops, 0444, dev);
- if (ret < 0)
- {
- nxsem_destroy(&dev->ad_sem);
- }
- return ret;
- }
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