/****************************************************************************
* 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;
}