/*
    comedi/drivers/mpc624.c
    Hardware driver for a Micro/sys inc. MPC-624 PC/104 board

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 2000 David A. Schleef <ds@schleef.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/
/*
Driver: mpc624
Description: Micro/sys MPC-624 PC/104 board
Devices: [Micro/sys] MPC-624 (mpc624)
Author: Stanislaw Raczynski <sraczynski@op.pl>
Updated: Thu, 15 Sep 2005 12:01:18 +0200
Status: working

    The Micro/sys MPC-624 board is based on the LTC2440 24-bit sigma-delta
    ADC chip.

    Subdevices supported by the driver:
    - Analog In:   supported
    - Digital I/O: not supported
    - LEDs:        not supported
    - EEPROM:      not supported

Configuration Options:
  [0] - I/O base address
  [1] - convertion rate
            Convertion rate  RMS noise  Effective Number Of Bits
         0      3.52kHz        23uV                17
         1      1.76kHz       3.5uV                20
         2       880Hz         2uV                21.3
         3       440Hz        1.4uV               21.8
         4       220Hz         1uV                22.4
         5       110Hz        750uV               22.9
         6       55Hz         510nV               23.4
         7      27.5Hz        375nV                24
         8      13.75Hz       250nV               24.4
         9      6.875Hz       200nV               24.6
   [2] - voltage range
         0      -1.01V .. +1.01V
         1      -10.1V .. +10.1V
*/

#include "../comedidev.h"

#include <linux/ioport.h>
#include <linux/delay.h>

// Consecutive I/O port addresses
#define MPC624_SIZE             16

// Offsets of different ports
#define MPC624_MASTER_CONTROL	0	// not used
#define MPC624_GNMUXCH          1	// Gain, Mux, Channel of ADC
#define MPC624_ADC              2	// read/write to/from ADC
#define MPC624_EE               3	// read/write to/from serial EEPROM via I2C
#define MPC624_LEDS             4	// write to LEDs
#define MPC624_DIO              5	// read/write to/from digital I/O ports
#define MPC624_IRQ_MASK         6	// IRQ masking enable/disable

// Register bits' names
#define MPC624_ADBUSY           (1<<5)
#define MPC624_ADSDO            (1<<4)
#define MPC624_ADFO             (1<<3)
#define MPC624_ADCS             (1<<2)
#define MPC624_ADSCK            (1<<1)
#define MPC624_ADSDI            (1<<0)

// SDI Speed/Resolution Programming bits
#define MPC624_OSR4             (1<<31)
#define MPC624_OSR3             (1<<30)
#define MPC624_OSR2             (1<<29)
#define MPC624_OSR1             (1<<28)
#define MPC624_OSR0             (1<<27)

// 32-bit output value bits' names
#define MPC624_EOC_BIT          (1<<31)
#define MPC624_DMY_BIT          (1<<30)
#define MPC624_SGN_BIT          (1<<29)

// Convertion speeds
/* OSR4 OSR3 OSR2 OSR1 OSR0  Convertion rate  RMS noise  ENOB^
 *  X    0    0    0    1        3.52kHz        23uV      17
 *  X    0    0    1    0        1.76kHz       3.5uV      20
 *  X    0    0    1    1         880Hz         2uV      21.3
 *  X    0    1    0    0         440Hz        1.4uV     21.8
 *  X    0    1    0    1         220Hz         1uV      22.4
 *  X    0    1    1    0         110Hz        750uV     22.9
 *  X    0    1    1    1          55Hz        510nV     23.4
 *  X    1    0    0    0         27.5Hz       375nV      24
 *  X    1    0    0    1        13.75Hz       250nV     24.4
 *  X    1    1    1    1        6.875Hz       200nV     24.6
 *
 * ^ - Effective Number Of Bits
 */

#define MPC624_SPEED_3_52_kHz   (MPC624_OSR4                                           | MPC624_OSR0)
#define MPC624_SPEED_1_76_kHz   (MPC624_OSR4                             | MPC624_OSR1              )
#define MPC624_SPEED_880_Hz     (MPC624_OSR4                             | MPC624_OSR1 | MPC624_OSR0)
#define MPC624_SPEED_440_Hz     (MPC624_OSR4               | MPC624_OSR2                            )
#define MPC624_SPEED_220_Hz     (MPC624_OSR4               | MPC624_OSR2               | MPC624_OSR0)
#define MPC624_SPEED_110_Hz     (MPC624_OSR4               | MPC624_OSR2 | MPC624_OSR1              )
#define MPC624_SPEED_55_Hz      (MPC624_OSR4               | MPC624_OSR2 | MPC624_OSR1 | MPC624_OSR0)
#define MPC624_SPEED_27_5_Hz    (MPC624_OSR4 | MPC624_OSR3                                          )
#define MPC624_SPEED_13_75_Hz   (MPC624_OSR4 | MPC624_OSR3                             | MPC624_OSR0)
#define MPC624_SPEED_6_875_Hz   (MPC624_OSR4 | MPC624_OSR3 | MPC624_OSR2 | MPC624_OSR1 | MPC624_OSR0)
//----------------------------------------------------------------------------
struct skel_private {

	unsigned long int ulConvertionRate;	// set by mpc624_attach() from driver's parameters
};


#define devpriv ((struct skel_private *)dev->private)
//----------------------------------------------------------------------------
static const struct comedi_lrange range_mpc624_bipolar1 = {
	1,
	{
//    BIP_RANGE(1.01) // this is correct,
			// but my MPC-624 actually seems to have a range of 2.02
			BIP_RANGE(2.02)
		}
};
static const struct comedi_lrange range_mpc624_bipolar10 = {
	1,
	{
//    BIP_RANGE(10.1) // this is correct,
			// but my MPC-624 actually seems to have a range of 20.2
			BIP_RANGE(20.2)
		}
};

//----------------------------------------------------------------------------
static int mpc624_attach(struct comedi_device * dev, struct comedi_devconfig * it);
static int mpc624_detach(struct comedi_device * dev);
//----------------------------------------------------------------------------
static struct comedi_driver driver_mpc624 = {
      driver_name:"mpc624",
      module:THIS_MODULE,
      attach:mpc624_attach,
      detach:mpc624_detach
};

//----------------------------------------------------------------------------
static int mpc624_ai_rinsn(struct comedi_device * dev, struct comedi_subdevice * s,
	struct comedi_insn * insn, unsigned int * data);
//----------------------------------------------------------------------------
static int mpc624_attach(struct comedi_device * dev, struct comedi_devconfig * it)
{
	struct comedi_subdevice *s;
	unsigned long iobase;

	iobase = it->options[0];
	rt_printk("comedi%d: mpc624 [0x%04lx, ", dev->minor, iobase);
	if (request_region(iobase, MPC624_SIZE, "mpc624") == NULL) {
		rt_printk("I/O port(s) in use\n");
		return -EIO;
	}

	dev->iobase = iobase;
	dev->board_name = "mpc624";

	// Private structure initialization
	if (alloc_private(dev, sizeof(struct skel_private)) < 0)
		return -ENOMEM;

	switch (it->options[1]) {
	case 0:
		devpriv->ulConvertionRate = MPC624_SPEED_3_52_kHz;
		rt_printk("3.52 kHz, ");
		break;
	case 1:
		devpriv->ulConvertionRate = MPC624_SPEED_1_76_kHz;
		rt_printk("1.76 kHz, ");
		break;
	case 2:
		devpriv->ulConvertionRate = MPC624_SPEED_880_Hz;
		rt_printk("880 Hz, ");
		break;
	case 3:
		devpriv->ulConvertionRate = MPC624_SPEED_440_Hz;
		rt_printk("440 Hz, ");
		break;
	case 4:
		devpriv->ulConvertionRate = MPC624_SPEED_220_Hz;
		rt_printk("220 Hz, ");
		break;
	case 5:
		devpriv->ulConvertionRate = MPC624_SPEED_110_Hz;
		rt_printk("110 Hz, ");
		break;
	case 6:
		devpriv->ulConvertionRate = MPC624_SPEED_55_Hz;
		rt_printk("55 Hz, ");
		break;
	case 7:
		devpriv->ulConvertionRate = MPC624_SPEED_27_5_Hz;
		rt_printk("27.5 Hz, ");
		break;
	case 8:
		devpriv->ulConvertionRate = MPC624_SPEED_13_75_Hz;
		rt_printk("13.75 Hz, ");
		break;
	case 9:
		devpriv->ulConvertionRate = MPC624_SPEED_6_875_Hz;
		rt_printk("6.875 Hz, ");
		break;
	default:
		rt_printk
			("illegal convertion rate setting! Valid numbers are 0..9. Using 9 => 6.875 Hz, ");
		devpriv->ulConvertionRate = MPC624_SPEED_3_52_kHz;
	}

	// Subdevices structures
	if (alloc_subdevices(dev, 1) < 0)
		return -ENOMEM;

	s = dev->subdevices + 0;
	s->type = COMEDI_SUBD_AI;
	s->subdev_flags = SDF_READABLE | SDF_DIFF;
	s->n_chan = 8;
	switch (it->options[1]) {
	default:
		s->maxdata = 0x3FFFFFFF;
		rt_printk("30 bit, ");
	}

	switch (it->options[1]) {
	case 0:
		s->range_table = &range_mpc624_bipolar1;
		rt_printk("1.01V]: ");
		break;
	default:
		s->range_table = &range_mpc624_bipolar10;
		rt_printk("10.1V]: ");
	}
	s->len_chanlist = 1;
	s->insn_read = mpc624_ai_rinsn;

	rt_printk("attached\n");

	return 1;
}

static int mpc624_detach(struct comedi_device * dev)
{
	rt_printk("comedi%d: mpc624: remove\n", dev->minor);

	if (dev->iobase)
		release_region(dev->iobase, MPC624_SIZE);

	return 0;
}

// Timeout 200ms
#define TIMEOUT 200

static int mpc624_ai_rinsn(struct comedi_device * dev, struct comedi_subdevice * s,
	struct comedi_insn * insn, unsigned int * data)
{
	int n, i;
	unsigned long int data_in, data_out;
	unsigned char ucPort;

	// WARNING: We always write 0 to GNSWA bit, so the channel range is +-/10.1Vdc
	outb(insn->chanspec, dev->iobase + MPC624_GNMUXCH);
//    rt_printk("Channel %d: \n", insn->chanspec);
	if (!insn->n) {
		rt_printk("MPC624: Warning, no data to aquire\n");
		return 0;
	}

	for (n = 0; n < insn->n; n++) {
		// Trigger the convertion
		outb(MPC624_ADSCK, dev->iobase + MPC624_ADC);
		comedi_udelay(1);
		outb(MPC624_ADCS | MPC624_ADSCK, dev->iobase + MPC624_ADC);
		comedi_udelay(1);
		outb(0, dev->iobase + MPC624_ADC);
		comedi_udelay(1);

		// Wait for the convertion to end
		for (i = 0; i < TIMEOUT; i++) {
			ucPort = inb(dev->iobase + MPC624_ADC);
			if (ucPort & MPC624_ADBUSY)
				comedi_udelay(1000);
			else
				break;
		}
		if (i == TIMEOUT) {
			rt_printk("MPC624: timeout (%dms)\n", TIMEOUT);
			data[n] = 0;
			return -ETIMEDOUT;
		}
		// Start reading data
		data_in = 0;
		data_out = devpriv->ulConvertionRate;
		comedi_udelay(1);
		for (i = 0; i < 32; i++) {
			// Set the clock low
			outb(0, dev->iobase + MPC624_ADC);
			comedi_udelay(1);

			if (data_out & (1 << 31))	// the next bit is a 1
			{
				// Set the ADSDI line (send to MPC624)
				outb(MPC624_ADSDI, dev->iobase + MPC624_ADC);
				comedi_udelay(1);
				// Set the clock high
				outb(MPC624_ADSCK | MPC624_ADSDI,
					dev->iobase + MPC624_ADC);
			} else	// the next bit is a 0
			{
				// Set the ADSDI line (send to MPC624)
				outb(0, dev->iobase + MPC624_ADC);
				comedi_udelay(1);
				// Set the clock high
				outb(MPC624_ADSCK, dev->iobase + MPC624_ADC);
			}
			// Read ADSDO on high clock (receive from MPC624)
			comedi_udelay(1);
			data_in <<= 1;
			data_in |=
				(inb(dev->iobase +
					MPC624_ADC) & MPC624_ADSDO) >> 4;
			comedi_udelay(1);

			data_out <<= 1;
		}

		// Received 32-bit long value consist of:
		//   31: EOC (End Of Transmission) bit - should be 0
		//   30: DMY (Dummy) bit               - should be 0
		//   29: SIG (Sign) bit                - 1 if the voltage is positive, 0 if negative
		//   28: MSB (Most Significant Bit)    - the first bit of convertion result
		//   ....
		//   05: LSB (Least Significant Bit)   - the last bit of convertion result
		//   04: sub-LSB                       - sub-LSBs are basically noise, but when
		//   03: sub-LSB                         averaged properly, they can increase convertion
		//   02: sub-LSB                         precision up to 29 bits; they can be discarded
		//   01: sub-LSB                         without loss of resolution.
		//   00: sub-LSB

		if (data_in & MPC624_EOC_BIT)
			rt_printk("MPC624: EOC bit is set (data_in=%lu)!",
				data_in);
		if (data_in & MPC624_DMY_BIT)
			rt_printk("MPC624: DMY bit is set (data_in=%lu)!",
				data_in);
		if (data_in & MPC624_SGN_BIT)	// check the sign bit
		{		// The voltage is positive
			data_in &= 0x3FFFFFFF;	// EOC and DMY should be 0, but we will mask them out just to be sure
			data[n] = data_in;	// comedi operates on unsigned numbers, so we don't clear the SGN bit
			// SGN bit is still set! It's correct, since we're converting to unsigned.
		} else {	// The voltage is negative
			// data_in contains a number in 30-bit two's complement code and we must deal with it
			data_in |= MPC624_SGN_BIT;
			data_in = ~data_in;
			data_in += 1;
			data_in &= ~(MPC624_EOC_BIT | MPC624_DMY_BIT);
			// clear EOC and DMY bits
			data_in = 0x20000000 - data_in;
			data[n] = data_in;
		}
	}

	// Return the number of samples read/written
	return n;
}

COMEDI_INITCLEANUP(driver_mpc624);