/****************************************************************************
 * drivers/analog/adc.c
 *
 *   Copyright (C) 2011 Li Zhuoyi. All rights reserved.
 *   Author: Li Zhuoyi <lzyy.cn@gmail.com>
 *   History: 0.1 2011-08-04 initial version
 *
 * Derived from drivers/can.c
 *
 *   Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * 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.h>
#include <nuttx/arch.h>
#include <nuttx/analog/adc.h>

#include <arch/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 *, FAR char *, size_t);
static ssize_t adc_write(FAR struct file *filep, FAR const char *buffer, size_t buflen);
static int     adc_ioctl(FAR struct file *filep,int cmd,unsigned long arg);

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const struct file_operations adc_fops =
{
    adc_open,     /* open */
    adc_close,    /* close */
    adc_read,     /* read */
    adc_write,    /* write */
    0,            /* seek */
    adc_ioctl     /* ioctl */
#ifndef CONFIG_DISABLE_POLL
    , 0           /* poll */
#endif
};

/****************************************************************************
 * 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 = irqsave();
                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 CAN RX interrupt */

                    dev->ad_ops->ao_rxint(dev, true);

                    /* Save the new open count on success */

                    dev->ad_ocount = tmp;
                }
                irqrestore(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 = irqsave();       /* Disable interrupts */
            dev->ad_ops->ao_shutdown(dev);       /* Disable the ADC */
            irqrestore(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;

    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 = irqsave();
        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 (ret + msglen > buflen)
            {
                break;
            }

            /* Copy the message to the user buffer */

            if (msglen==1)
            {
                buffer[nread]=msg->am_data>>24;                //Only one channel,read highest 8bits
            }
            else if (msglen==2)
            {
                *(int16_t *)&buffer[nread]=msg->am_data>>16;   //Only one channel,read highest 16bits
            }
            else if (msglen==3)
            {
                buffer[nread]=msg->am_channel;
                *(int16_t *)&buffer[nread+1]=msg->am_data>>16; //read channel highest 16bits
            }
            else if (msglen==4)
            {
                *(int32_t *)&buffer[nread]=msg->am_data;       //read channel highest 24bits
                buffer[nread]=msg->am_channel;
            }
            else
            {
                *(int32_t *)&buffer[nread+1]=msg->am_data;     //read all
                buffer[nread]=msg->am_channel;
            }
            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:
        irqrestore(flags);
    }
    return ret;
}

/************************************************************************************
 * Name: adc_write
 ************************************************************************************/

static ssize_t adc_write(FAR struct file *filep, FAR const char *buffer, size_t buflen)
{
    return 0;
}

/************************************************************************************
 * 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   = OK;

    ret = dev->ad_ops->ao_ioctl(dev, cmd, arg);
    return ret;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

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                    err = -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 CAN message 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);
        err = OK;
    }
    return err;
}

int adc_register(FAR const char *path, FAR struct adc_dev_s *dev)
{
    /* Initialize the ADC device structure */

    dev->ad_ocount = 0;

    sem_init(&dev->ad_recv.af_sem, 0, 0);
    sem_init(&dev->ad_closesem, 0, 1);

    dev->ad_ops->ao_reset(dev);

    return register_driver(path, &adc_fops, 0444, dev);
}