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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);
- static void adc_notify(FAR struct adc_dev_s *dev);
- static int adc_poll(FAR struct file *filep, struct pollfd *fds, bool setup);
- /****************************************************************************
- * 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 */
- adc_poll /* poll */
- #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
- , NULL /* unlink */
- #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;
- /* 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)
- {
- /* 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);
- }
- }
- nxsem_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;
- 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 ADC device */
- flags = enter_critical_section(); /* Disable interrupts */
- dev->ad_ops->ao_shutdown(dev); /* Disable the ADC */
- leave_critical_section(flags);
- nxsem_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 = nxsem_wait(&dev->ad_recv.af_sem);
- dev->ad_nrxwaiters--;
- if (ret < 0)
- {
- 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;
- adc_notify(dev);
- errcode = OK;
- }
- return errcode;
- }
- /****************************************************************************
- * Name: adc_pollnotify
- ****************************************************************************/
- static void adc_pollnotify(FAR struct adc_dev_s *dev, uint32_t type)
- {
- int i;
- for (i = 0; i < CONFIG_ADC_NPOLLWAITERS; i++)
- {
- struct pollfd *fds = dev->fds[i];
- if (fds)
- {
- fds->revents |= type;
- nxsem_post(fds->sem);
- }
- }
- }
- /****************************************************************************
- * Name: adc_notify
- ****************************************************************************/
- static void adc_notify(FAR struct adc_dev_s *dev)
- {
- FAR struct adc_fifo_s *fifo = &dev->ad_recv;
- /* If there are threads waiting for read data, then signal one of them
- * that the read data is available.
- */
- if (dev->ad_nrxwaiters > 0)
- {
- nxsem_post(&fifo->af_sem);
- }
- /* If there are threads waiting on poll() for data to become available,
- * then wake them up now.
- */
- adc_pollnotify(dev, POLLIN);
- }
- /************************************************************************************
- * Name: adc_poll
- ************************************************************************************/
- static int adc_poll(FAR struct file *filep, struct pollfd *fds, bool setup)
- {
- FAR struct inode *inode = filep->f_inode;
- FAR struct adc_dev_s *dev = inode->i_private;
- irqstate_t flags;
- int ret = 0;
- int i;
- /* Interrupts must be disabled while accessing the list of poll structures
- * and ad_recv FIFO.
- */
- flags = enter_critical_section();
- if (setup)
- {
- /* Ignore waits that do not include POLLIN */
- if ((fds->events & POLLIN) == 0)
- {
- ret = -EDEADLK;
- goto return_with_irqdisabled;
- }
- /* This is a request to set up the poll. Find an available
- * slot for the poll structure reference
- */
- for (i = 0; i < CONFIG_ADC_NPOLLWAITERS; i++)
- {
- /* Find an available slot */
- if (!dev->fds[i])
- {
- /* Bind the poll structure and this slot */
- dev->fds[i] = fds;
- fds->priv = &dev->fds[i];
- break;
- }
- }
- if (i >= CONFIG_ADC_NPOLLWAITERS)
- {
- fds->priv = NULL;
- ret = -EBUSY;
- goto return_with_irqdisabled;
- }
- /* Should we immediately notify on any of the requested events? */
- if (dev->ad_recv.af_head != dev->ad_recv.af_tail)
- {
- adc_pollnotify(dev, POLLIN);
- }
- }
- else if (fds->priv)
- {
- /* This is a request to tear down the poll. */
- struct pollfd **slot = (struct pollfd **)fds->priv;
- /* Remove all memory of the poll setup */
- *slot = NULL;
- fds->priv = NULL;
- }
- return_with_irqdisabled:
- leave_critical_section(flags);
- return ret;
- }
- /****************************************************************************
- * 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 */
- nxsem_init(&dev->ad_recv.af_sem, 0, 0);
- nxsem_init(&dev->ad_closesem, 0, 1);
- /* The receive semaphore is used for signaling and, hence, should not have
- * priority inheritance enabled.
- */
- nxsem_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)
- {
- nxsem_destroy(&dev->ad_recv.af_sem);
- nxsem_destroy(&dev->ad_closesem);
- }
- return ret;
- }
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