/************************************************************************************
 * arch/drivers/analog/ads1255.c
 *
 *   Copyright (C) 2011 Li Zhuoyi. All rights reserved.
 *   Author: Li Zhuoyi <lzyy.cn@gmail.com>
 *   History: 0.1 2011-08-05 initial version
 *            0.2 2011-08-25 fix bug in g_adcdev (cd_ops -> ad_ops,cd_priv -> ad_priv)
 *
 * This file is a part of NuttX:
 *
 *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
 *
 * 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.
 *
 ************************************************************************************/

#include <nuttx/config.h>

#include <stdio.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <semaphore.h>
#include <errno.h>
#include <debug.h>

#include <arch/board/board.h>
#include <nuttx/arch.h>
#include <nuttx/spi/spi.h>
#include <nuttx/analog/adc.h>

#if defined(CONFIG_ADC_ADS1255)

#define ADS125X_BUFON   0x02
#define ADS125X_BUFOFF  0x00

#define ADS125X_PGA1    0x00
#define ADS125X_PGA2    0x01
#define ADS125X_PGA4    0x02
#define ADS125X_PGA8    0x03
#define ADS125X_PGA16   0x04
#define ADS125X_PGA32   0x05
#define ADS125X_PGA64   0x06

#define ADS125X_RDATA     0x01    /* Read Data */
#define ADS125X_RDATAC    0x03    /* Read Data Continuously */
#define ADS125X_SDATAC    0x0F    /* Stop Read Data Continuously */
#define ADS125X_RREG      0x10    /* Read from REG */
#define ADS125X_WREG      0x50    /* Write to REG */
#define ADS125X_SELFCAL   0xF0    /* Offset and Gain Self-Calibration */
#define ADS125X_SELFOCAL  0xF1    /* Offset Self-Calibration */
#define ADS125X_SELFGCAL  0xF2    /* Gain Self-Calibration */
#define ADS125X_SYSOCAL   0xF3    /* System Offset Calibration */
#define ADS125X_SYSGCAL   0xF4    /* System Gain Calibration */
#define ADS125X_SYNC      0xFC    /* Synchronize the A/D Conversion */
#define ADS125X_STANDBY   0xFD    /* Begin Standby Mode */
#define ADS125X_RESET     0xFE    /* Reset to Power-Up Values */
#define ADS125X_WAKEUP    0xFF    /* Completes SYNC and Exits Standby Mode */

#ifndef CONFIG_ADS1255_FREQUENCY
#  define CONFIG_ADS1255_FREQUENCY  1000000
#endif
#ifndef CONFIG_ADS1255_MUX
#  define CONFIG_ADS1255_MUX      0x01
#endif
#ifndef CONFIG_ADS1255_CHMODE
#  define CONFIG_ADS1255_CHMODE   0x00
#endif
#ifndef CONFIG_ADS1255_BUFON
#  define CONFIG_ADS1255_BUFON    1
#endif
#ifndef CONFIG_ADS1255_PGA
#  define CONFIG_ADS1255_PGA      ADS125X_PGA2
#endif
#ifndef CONFIG_ADS1255_SPS
#  define CONFIG_ADS1255_SPS      50
#endif

/****************************************************************************
 * ad_private Types
 ****************************************************************************/

struct up_dev_s
{
  uint8_t channel;
  uint32_t sps;
  uint8_t pga;
  uint8_t buf;
  const uint8_t *mux;
  int irq;
  int devno;
  FAR struct spi_dev_s *spi;      /* Cached SPI device reference */
};

/****************************************************************************
 * ad_private Function Prototypes
 ****************************************************************************/

/* ADC methods */

static void adc_reset(FAR struct adc_dev_s *dev);
static int  adc_setup(FAR struct adc_dev_s *dev);
static void adc_shutdown(FAR struct adc_dev_s *dev);
static void adc_rxint(FAR struct adc_dev_s *dev, bool enable);
static int  adc_ioctl(FAR struct adc_dev_s *dev, int cmd, unsigned long arg);
static int  adc_interrupt(int irq, void *context);

/****************************************************************************
 * ad_private Data
 ****************************************************************************/

static const struct adc_ops_s g_adcops =
{
  .ao_reset = adc_reset,        /* ao_reset */
  .ao_setup = adc_setup,        /* ao_setup */
  .ao_shutdown = adc_shutdown,  /* ao_shutdown */
  .ao_rxint = adc_rxint,        /* ao_rxint */
  .ao_ioctl = adc_ioctl         /* ao_read */
};

static struct up_dev_s g_adcpriv =
{
  .mux  = (const uint8_t [])
  {
    CONFIG_ADS1255_MUX,0
  },
  .sps  = CONFIG_ADS1255_SPS,
  .channel = 0,
  .irq  = CONFIG_ADS1255_IRQ,
};

static struct adc_dev_s g_adcdev =
{
  .ad_ops = &g_adcops,
  .ad_priv= &g_adcpriv,
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

static uint8_t getspsreg(uint16_t sps)
{
  static const unsigned short sps_tab[]=
  {
      3,     7,     12,    20,    27,    40,    55,    80,
    300,   750,   1500,  3000,  5000, 10000, 20000, 65535,
  };
  static const unsigned char sps_reg[]=
  {
    0x03,  0x13,  0x23,  0x33,  0x43,  0x53,  0x63,  0x72,
    0x82,  0x92,  0xa1,  0xb0,  0xc0,  0xd0,  0xe0,  0xf0,
  };
  int i;

  for (i = 0; i < 16; i++)
    {
      if (sps < sps_tab[i])
        {
          return sps_reg[i];
        }
    }

  return sps_reg[15];
}

/****************************************************************************
 * ad_private Functions
 ****************************************************************************/
/* Reset the ADC device.  Called early to initialize the hardware. This
 * is called, before ao_setup() and on error conditions.
 */

static void adc_reset(FAR struct adc_dev_s *dev)
{
  FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->ad_priv;
  FAR struct spi_dev_s *spi = priv->spi;

  SPI_SETMODE(spi, SPIDEV_MODE1);
  SPI_SETBITS(spi, 8);
  SPI_SETFREQUENCY(spi, CONFIG_ADS1255_FREQUENCY);
  usleep(1000);
  SPI_SELECT(spi, priv->devno, true);
  SPI_SEND(spi,ADS125X_WREG+0x03);    /* WRITE SPS REG */
  SPI_SEND(spi,0x00);                 /* count=1 */
  SPI_SEND(spi,0x63);
  SPI_SELECT(spi, priv->devno, false);
}

/* Configure the ADC. This method is called the first time that the ADC
 * device is opened.  This will occur when the port is first opened.
 * This setup includes configuring and attaching ADC interrupts.  Interrupts
 * are all disabled upon return.
 */

static int  adc_setup(FAR struct adc_dev_s *dev)
{
  FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->ad_priv;
  FAR struct spi_dev_s *spi = priv->spi;
  int ret = irq_attach(priv->irq, adc_interrupt);

  if (ret == OK)
    {
      SPI_SELECT(spi, priv->devno, true);
      SPI_SEND(spi,ADS125X_WREG);         /* WRITE REG from 0 */
      SPI_SEND(spi,0x03);                 /* count=4+1 */
      if (priv->buf)
        {
          SPI_SEND(spi,ADS125X_BUFON);    /* REG0 STATUS BUFFER ON */
        }
      else
        {
          SPI_SEND(spi,ADS125X_BUFOFF);
        }

      SPI_SEND(spi,priv->mux[0]);
      SPI_SEND(spi,priv->pga);            /* REG2 ADCON PGA=2 */
      SPI_SEND(spi,getspsreg(priv->sps));
      usleep(1000);
      SPI_SEND(spi,ADS125X_SELFCAL);
      SPI_SELECT(spi, priv->devno, false);
      up_enable_irq(priv->irq);
    }

  return ret;
}

/* Disable the ADC.  This method is called when the ADC device is closed.
 * This method reverses the operation the setup method.
 */

static void adc_shutdown(FAR struct adc_dev_s *dev)
{
  FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->ad_priv;
  up_disable_irq(priv->irq);
  irq_detach(priv->irq);
}

/* Call to enable or disable RX interrupts */

static void adc_rxint(FAR struct adc_dev_s *dev, bool enable)
{
  FAR struct up_dev_s *priv = (FAR struct up_dev_s *)dev->ad_priv;
  if (enable)
    {
      up_enable_irq(priv->irq);
    }
  else
    {
      up_disable_irq(priv->irq);
    }
}

/* All ioctl calls will be routed through this method */

static int  adc_ioctl(FAR struct adc_dev_s *dev, int cmd, unsigned long arg)
{
  dbg("Fix me:Not Implemented\n");
  return 0;
}

static int adc_interrupt(int irq, void *context)
{
  FAR struct up_dev_s *priv = (FAR struct up_dev_s *)g_adcdev.ad_priv;
  FAR struct spi_dev_s *spi = priv->spi;
  unsigned char buf[4];
  unsigned char ch;

  SPI_SELECT(spi, priv->devno, true);
  SPI_SEND(spi,ADS125X_RDATA);
  up_udelay(10);
  buf[3]=SPI_SEND(spi,0xff);
  buf[2]=SPI_SEND(spi,0xff);
  buf[1]=SPI_SEND(spi,0xff);
  buf[0]=0;

  priv->channel++;
  ch = priv->mux[priv->channel];
  if ( ch == 0 )
    {
      priv->channel=0;
      ch = priv->mux[0];
    }

  SPI_SEND(spi,ADS125X_WREG+0x01);
  SPI_SEND(spi,0x00);
  SPI_SEND(spi,ch);
  SPI_SEND(spi,ADS125X_SYNC);
  up_udelay(2);
  SPI_SEND(spi,ADS125X_WAKEUP);
  SPI_SELECT(spi, priv->devno, false);

  adc_receive(&g_adcdev,priv->channel,*(int32_t *)buf);
  return OK;
}

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

/****************************************************************************
 * Name: up_ads1255initialize
 *
 * Description:
 *   Initialize the selected adc port
 *
 * Input Parameter:
 *   Port number (for hardware that has multiple adc interfaces)
 *
 * Returned Value:
 *   Valid can device structure reference on success; a NULL on failure
 *
 ****************************************************************************/

FAR struct adc_dev_s *up_ads1255initialize(FAR struct spi_dev_s *spi,
                                           unsigned int devno)
{
  FAR struct up_dev_s *priv = (FAR struct up_dev_s *)g_adcdev.ad_priv;

  /* Driver state data */

  priv->spi      = spi;
  priv->devno    = devno;
  return &g_adcdev;
}
#endif
