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nuttx/drivers/analog/adc.c

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/****************************************************************************
* drivers/analog/adc.c
*
* Copyright (C) 2008-2009, 2016-2017 Gregory Nutt. All rights reserved.
* Copyright (C) 2011 Li Zhuoyi. All rights reserved.
* Author: Li Zhuoyi <lzyy.cn@gmail.com>
* Gregory Nutt <gnutt@nuttx.org>
*
* Derived from drivers/can.c
*
* Copyright (C) 2008-2009 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <string.h>
#include <semaphore.h>
#include <fcntl.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/fs/fs.h>
#include <nuttx/arch.h>
#include <nuttx/semaphore.h>
#include <nuttx/analog/adc.h>
#include <nuttx/random.h>
#include <nuttx/irq.h>
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int adc_open(FAR struct file *filep);
static int adc_close(FAR struct file *filep);
static ssize_t adc_read(FAR struct file *fielp, FAR char *buffer,
size_t buflen);
static int adc_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
static int adc_receive(FAR struct adc_dev_s *dev, uint8_t ch,
int32_t data);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_adc_fops =
{
adc_open, /* open */
adc_close, /* close */
adc_read, /* read */
0, /* write */
0, /* seek */
adc_ioctl /* ioctl */
#ifndef CONFIG_DISABLE_POLL
, 0 /* poll */
#endif
};
static const struct adc_callback_s g_adc_callback =
{
adc_receive /* au_receive */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/************************************************************************************
* Name: adc_open
*
* Description:
* This function is called whenever the ADC device is opened.
*
************************************************************************************/
static int adc_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct adc_dev_s *dev = inode->i_private;
uint8_t tmp;
int ret = OK;
/* If the port is the middle of closing, wait until the close is finished */
if (sem_wait(&dev->ad_closesem) != OK)
{
ret = -errno;
}
else
{
/* 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)
{
/* Mark the FIFOs empty */
dev->ad_recv.af_head = 0;
dev->ad_recv.af_tail = 0;
/* Finally, Enable the ADC RX interrupt */
dev->ad_ops->ao_rxint(dev, true);
/* Save the new open count on success */
dev->ad_ocount = tmp;
}
leave_critical_section(flags);
}
}
sem_post(&dev->ad_closesem);
}
return ret;
}
/************************************************************************************
* Name: adc_close
*
* Description:
* This routine is called when the ADC device is closed.
* It waits for the last remaining data to be sent.
*
************************************************************************************/
static int adc_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct adc_dev_s *dev = inode->i_private;
irqstate_t flags;
int ret = OK;
if (sem_wait(&dev->ad_closesem) != OK)
{
ret = -errno;
}
else
{
/* 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--;
sem_post(&dev->ad_closesem);
}
else
{
/* There are no more references to the port */
dev->ad_ocount = 0;
/* Free the IRQ and disable the ADC device */
flags = enter_critical_section(); /* Disable interrupts */
dev->ad_ops->ao_shutdown(dev); /* Disable the ADC */
leave_critical_section(flags);
sem_post(&dev->ad_closesem);
}
}
return ret;
}
/****************************************************************************
* Name: adc_read
****************************************************************************/
static ssize_t adc_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct adc_dev_s *dev = inode->i_private;
size_t nread;
irqstate_t flags;
int ret = 0;
int msglen;
ainfo("buflen: %d\n", (int)buflen);
/* Determine size of the messages to return.
*
* REVISIT: What if buflen is 8 does that mean 4 messages of size 2? Or
* 2 messages of size 4? What if buflen is 12. Does that mean 3 at size
* 4? Or 4 at size 3? The form of the return data should probably really
* be specified via IOCTL.
*/
if (buflen % 5 == 0)
{
msglen = 5;
}
else if (buflen % 4 == 0)
{
msglen = 4;
}
else if (buflen % 3 == 0)
{
msglen = 3;
}
else if (buflen % 2 == 0)
{
msglen = 2;
}
else if (buflen == 1)
{
msglen = 1;
}
else
{
msglen = 5;
}
if (buflen >= msglen)
{
/* Interrupts must be disabled while accessing the ad_recv FIFO */
flags = enter_critical_section();
while (dev->ad_recv.af_head == dev->ad_recv.af_tail)
{
/* The receive FIFO is empty -- was non-blocking mode selected? */
if (filep->f_oflags & O_NONBLOCK)
{
ret = -EAGAIN;
goto return_with_irqdisabled;
}
/* Wait for a message to be received */
dev->ad_nrxwaiters++;
ret = sem_wait(&dev->ad_recv.af_sem);
dev->ad_nrxwaiters--;
if (ret < 0)
{
ret = -errno;
goto return_with_irqdisabled;
}
}
/* The ad_recv FIFO is not empty. Copy all buffered data that will fit
* in the user buffer.
*/
nread = 0;
do
{
FAR struct adc_msg_s *msg = &dev->ad_recv.af_buffer[dev->ad_recv.af_head];
/* Will the next message in the FIFO fit into the user buffer? */
if (nread + msglen > buflen)
{
/* No.. break out of the loop now with nread equal to the actual
* number of bytes transferred.
*/
break;
}
/* Feed ADC data to entropy pool */
add_sensor_randomness(msg->am_data);
/* Copy the message to the user buffer */
if (msglen == 1)
{
/* Only one channel, return MS 8-bits of the sample*/
buffer[nread] = msg->am_data >> 24;
}
else if (msglen == 2)
{
/* Only one channel, return only the MS 16-bits of the sample.*/
int16_t data16 = msg->am_data >> 16;
memcpy(&buffer[nread], &data16, 2);
}
else if (msglen == 3)
{
int16_t data16;
/* Return the channel and the MS 16-bits of the sample. */
buffer[nread] = msg->am_channel;
data16 = msg->am_data >> 16;
memcpy(&buffer[nread + 1], &data16, 2);
}
else if (msglen == 4)
{
int32_t data24;
#ifdef CONFIG_ENDIAN_BIG
/* In the big endian case, we simply copy the MS three bytes
* which are indices: 0-2.
*/
data24 = msg->am_data;
#else
/* In the little endian case, indices 0-2 correspond to the
* the three LS bytes.
*/
data24 = msg->am_data >> 8;
#endif
/* Return the channel and the most significant 24-bits */
buffer[nread] = msg->am_channel;
memcpy(&buffer[nread + 1], &data24, 3);
}
else
{
/* Return the channel and all four bytes of the sample */
buffer[nread] = msg->am_channel;
memcpy(&buffer[nread + 1], &msg->am_data, 4);
}
nread += msglen;
/* Increment the head of the circular message buffer */
if (++dev->ad_recv.af_head >= CONFIG_ADC_FIFOSIZE)
{
dev->ad_recv.af_head = 0;
}
}
while (dev->ad_recv.af_head != dev->ad_recv.af_tail);
/* All on the messages have bee transferred. Return the number of bytes
* that were read.
*/
ret = nread;
return_with_irqdisabled:
leave_critical_section(flags);
}
ainfo("Returning: %d\n", ret);
return ret;
}
/************************************************************************************
* Name: adc_ioctl
************************************************************************************/
static int adc_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct adc_dev_s *dev = inode->i_private;
int ret;
ret = dev->ad_ops->ao_ioctl(dev, cmd, arg);
return ret;
}
/****************************************************************************
* Name: adc_receive
****************************************************************************/
static int adc_receive(FAR struct adc_dev_s *dev, uint8_t ch, int32_t data)
{
FAR struct adc_fifo_s *fifo = &dev->ad_recv;
int nexttail;
int errcode = -ENOMEM;
/* Check if adding this new message would over-run the drivers ability to enqueue
* read data.
*/
nexttail = fifo->af_tail + 1;
if (nexttail >= CONFIG_ADC_FIFOSIZE)
{
nexttail = 0;
}
/* Refuse the new data if the FIFO is full */
if (nexttail != fifo->af_head)
{
/* Add the new, decoded ADC sample at the tail of the FIFO */
fifo->af_buffer[fifo->af_tail].am_channel = ch;
fifo->af_buffer[fifo->af_tail].am_data = data;
/* Increment the tail of the circular buffer */
fifo->af_tail = nexttail;
if (dev->ad_nrxwaiters > 0)
{
sem_post(&fifo->af_sem);
}
errcode = OK;
}
return errcode;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: adc_register
****************************************************************************/
int adc_register(FAR const char *path, FAR struct adc_dev_s *dev)
{
int ret;
DEBUGASSERT(path != NULL && dev != NULL);
/* Bind the upper-half callbacks to the lower half ADC driver */
DEBUGASSERT(dev->ad_ops != NULL && dev->ad_ops->ao_bind != NULL);
ret = dev->ad_ops->ao_bind(dev, &g_adc_callback);
if (ret < 0)
{
aerr("ERROR: Failed to bind callbacks: %d\n", ret);
return ret;
}
/* Initialize the ADC device structure */
dev->ad_ocount = 0;
/* Initialize semaphores */
sem_init(&dev->ad_recv.af_sem, 0, 0);
sem_init(&dev->ad_closesem, 0, 1);
/* The receive semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
sem_setprotocol(&dev->ad_recv.af_sem, SEM_PRIO_NONE);
/* Reset the ADC hardware */
DEBUGASSERT(dev->ad_ops->ao_reset != NULL);
dev->ad_ops->ao_reset(dev);
/* Register the ADC character driver */
ret = register_driver(path, &g_adc_fops, 0444, dev);
if (ret < 0)
{
sem_destroy(&dev->ad_recv.af_sem);
sem_destroy(&dev->ad_closesem);
}
return ret;
}
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