linux/drivers/comedi/drivers/mpc624.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * mpc624.c
   4 * Hardware driver for a Micro/sys inc. MPC-624 PC/104 board
   5 *
   6 * COMEDI - Linux Control and Measurement Device Interface
   7 * Copyright (C) 2000 David A. Schleef <ds@schleef.org>
   8 */
   9
  10/*
  11 * Driver: mpc624
  12 * Description: Micro/sys MPC-624 PC/104 board
  13 * Devices: [Micro/sys] MPC-624 (mpc624)
  14 * Author: Stanislaw Raczynski <sraczynski@op.pl>
  15 * Updated: Thu, 15 Sep 2005 12:01:18 +0200
  16 * Status: working
  17 *
  18 * The Micro/sys MPC-624 board is based on the LTC2440 24-bit sigma-delta
  19 * ADC chip.
  20 *
  21 * Subdevices supported by the driver:
  22 * - Analog In:   supported
  23 * - Digital I/O: not supported
  24 * - LEDs:        not supported
  25 * - EEPROM:      not supported
  26 *
  27 * Configuration Options:
  28 *   [0] - I/O base address
  29 *   [1] - conversion rate
  30 *         Conversion rate   RMS noise  Effective Number Of Bits
  31 *         0    3.52kHz         23uV            17
  32 *         1    1.76kHz         3.5uV           20
  33 *         2    880Hz           2uV             21.3
  34 *         3    440Hz           1.4uV           21.8
  35 *         4    220Hz           1uV             22.4
  36 *         5    110Hz           750uV           22.9
  37 *         6    55Hz            510nV           23.4
  38 *         7    27.5Hz          375nV           24
  39 *         8    13.75Hz         250nV           24.4
  40 *         9    6.875Hz         200nV           24.6
  41 *   [2] - voltage range
  42 *         0    -1.01V .. +1.01V
  43 *         1    -10.1V .. +10.1V
  44 */
  45
  46#include <linux/module.h>
  47#include "../comedidev.h"
  48
  49#include <linux/delay.h>
  50
  51/* Offsets of different ports */
  52#define MPC624_MASTER_CONTROL   0 /* not used */
  53#define MPC624_GNMUXCH          1 /* Gain, Mux, Channel of ADC */
  54#define MPC624_ADC              2 /* read/write to/from ADC */
  55#define MPC624_EE               3 /* read/write to/from serial EEPROM via I2C */
  56#define MPC624_LEDS             4 /* write to LEDs */
  57#define MPC624_DIO              5 /* read/write to/from digital I/O ports */
  58#define MPC624_IRQ_MASK         6 /* IRQ masking enable/disable */
  59
  60/* Register bits' names */
  61#define MPC624_ADBUSY           BIT(5)
  62#define MPC624_ADSDO            BIT(4)
  63#define MPC624_ADFO             BIT(3)
  64#define MPC624_ADCS             BIT(2)
  65#define MPC624_ADSCK            BIT(1)
  66#define MPC624_ADSDI            BIT(0)
  67
  68/* 32-bit output value bits' names */
  69#define MPC624_EOC_BIT          BIT(31)
  70#define MPC624_DMY_BIT          BIT(30)
  71#define MPC624_SGN_BIT          BIT(29)
  72
  73/* SDI Speed/Resolution Programming bits */
  74#define MPC624_OSR(x)           (((x) & 0x1f) << 27)
  75#define MPC624_SPEED_3_52_KHZ   MPC624_OSR(0x11)
  76#define MPC624_SPEED_1_76_KHZ   MPC624_OSR(0x12)
  77#define MPC624_SPEED_880_HZ     MPC624_OSR(0x13)
  78#define MPC624_SPEED_440_HZ     MPC624_OSR(0x14)
  79#define MPC624_SPEED_220_HZ     MPC624_OSR(0x15)
  80#define MPC624_SPEED_110_HZ     MPC624_OSR(0x16)
  81#define MPC624_SPEED_55_HZ      MPC624_OSR(0x17)
  82#define MPC624_SPEED_27_5_HZ    MPC624_OSR(0x18)
  83#define MPC624_SPEED_13_75_HZ   MPC624_OSR(0x19)
  84#define MPC624_SPEED_6_875_HZ   MPC624_OSR(0x1f)
  85
  86struct mpc624_private {
  87        unsigned int ai_speed;
  88};
  89
  90/* -------------------------------------------------------------------------- */
  91static const struct comedi_lrange range_mpc624_bipolar1 = {
  92        1,
  93        {
  94/* BIP_RANGE(1.01)  this is correct, */
  95         /*  but my MPC-624 actually seems to have a range of 2.02 */
  96         BIP_RANGE(2.02)
  97        }
  98};
  99
 100static const struct comedi_lrange range_mpc624_bipolar10 = {
 101        1,
 102        {
 103/* BIP_RANGE(10.1)   this is correct, */
 104         /*  but my MPC-624 actually seems to have a range of 20.2 */
 105         BIP_RANGE(20.2)
 106        }
 107};
 108
 109static unsigned int mpc624_ai_get_sample(struct comedi_device *dev,
 110                                         struct comedi_subdevice *s)
 111{
 112        struct mpc624_private *devpriv = dev->private;
 113        unsigned int data_out = devpriv->ai_speed;
 114        unsigned int data_in = 0;
 115        unsigned int bit;
 116        int i;
 117
 118        /* Start reading data */
 119        udelay(1);
 120        for (i = 0; i < 32; i++) {
 121                /* Set the clock low */
 122                outb(0, dev->iobase + MPC624_ADC);
 123                udelay(1);
 124
 125                /* Set the ADSDI line for the next bit (send to MPC624) */
 126                bit = (data_out & BIT(31)) ? MPC624_ADSDI : 0;
 127                outb(bit, dev->iobase + MPC624_ADC);
 128                udelay(1);
 129
 130                /* Set the clock high */
 131                outb(MPC624_ADSCK | bit, dev->iobase + MPC624_ADC);
 132                udelay(1);
 133
 134                /* Read ADSDO on high clock (receive from MPC624) */
 135                data_in <<= 1;
 136                data_in |= (inb(dev->iobase + MPC624_ADC) & MPC624_ADSDO) >> 4;
 137                udelay(1);
 138
 139                data_out <<= 1;
 140        }
 141
 142        /*
 143         * Received 32-bit long value consist of:
 144         *      31: EOC - (End Of Transmission) bit - should be 0
 145         *      30: DMY - (Dummy) bit - should be 0
 146         *      29: SIG - (Sign) bit - 1 if positive, 0 if negative
 147         *      28: MSB - (Most Significant Bit) - the first bit of the
 148         *                                         conversion result
 149         *      ....
 150         *      05: LSB - (Least Significant Bit)- the last bit of the
 151         *                                         conversion result
 152         *      04-00: sub-LSB - sub-LSBs are basically noise, but when
 153         *                       averaged properly, they can increase
 154         *                       conversion precision up to 29 bits;
 155         *                       they can be discarded without loss of
 156         *                       resolution.
 157         */
 158        if (data_in & MPC624_EOC_BIT)
 159                dev_dbg(dev->class_dev, "EOC bit is set!");
 160        if (data_in & MPC624_DMY_BIT)
 161                dev_dbg(dev->class_dev, "DMY bit is set!");
 162
 163        if (data_in & MPC624_SGN_BIT) {
 164                /*
 165                 * Voltage is positive
 166                 *
 167                 * comedi operates on unsigned numbers, so mask off EOC
 168                 * and DMY and don't clear the SGN bit
 169                 */
 170                data_in &= 0x3fffffff;
 171        } else {
 172                /*
 173                 * The voltage is negative
 174                 *
 175                 * data_in contains a number in 30-bit two's complement
 176                 * code and we must deal with it
 177                 */
 178                data_in |= MPC624_SGN_BIT;
 179                data_in = ~data_in;
 180                data_in += 1;
 181                /* clear EOC and DMY bits */
 182                data_in &= ~(MPC624_EOC_BIT | MPC624_DMY_BIT);
 183                data_in = 0x20000000 - data_in;
 184        }
 185        return data_in;
 186}
 187
 188static int mpc624_ai_eoc(struct comedi_device *dev,
 189                         struct comedi_subdevice *s,
 190                         struct comedi_insn *insn,
 191                         unsigned long context)
 192{
 193        unsigned char status;
 194
 195        status = inb(dev->iobase + MPC624_ADC);
 196        if ((status & MPC624_ADBUSY) == 0)
 197                return 0;
 198        return -EBUSY;
 199}
 200
 201static int mpc624_ai_insn_read(struct comedi_device *dev,
 202                               struct comedi_subdevice *s,
 203                               struct comedi_insn *insn,
 204                               unsigned int *data)
 205{
 206        int ret;
 207        int i;
 208
 209        /*
 210         *  WARNING:
 211         *  We always write 0 to GNSWA bit, so the channel range is +-/10.1Vdc
 212         */
 213        outb(insn->chanspec, dev->iobase + MPC624_GNMUXCH);
 214
 215        for (i = 0; i < insn->n; i++) {
 216                /*  Trigger the conversion */
 217                outb(MPC624_ADSCK, dev->iobase + MPC624_ADC);
 218                udelay(1);
 219                outb(MPC624_ADCS | MPC624_ADSCK, dev->iobase + MPC624_ADC);
 220                udelay(1);
 221                outb(0, dev->iobase + MPC624_ADC);
 222                udelay(1);
 223
 224                /*  Wait for the conversion to end */
 225                ret = comedi_timeout(dev, s, insn, mpc624_ai_eoc, 0);
 226                if (ret)
 227                        return ret;
 228
 229                data[i] = mpc624_ai_get_sample(dev, s);
 230        }
 231
 232        return insn->n;
 233}
 234
 235static int mpc624_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 236{
 237        struct mpc624_private *devpriv;
 238        struct comedi_subdevice *s;
 239        int ret;
 240
 241        ret = comedi_request_region(dev, it->options[0], 0x10);
 242        if (ret)
 243                return ret;
 244
 245        devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
 246        if (!devpriv)
 247                return -ENOMEM;
 248
 249        switch (it->options[1]) {
 250        case 0:
 251                devpriv->ai_speed = MPC624_SPEED_3_52_KHZ;
 252                break;
 253        case 1:
 254                devpriv->ai_speed = MPC624_SPEED_1_76_KHZ;
 255                break;
 256        case 2:
 257                devpriv->ai_speed = MPC624_SPEED_880_HZ;
 258                break;
 259        case 3:
 260                devpriv->ai_speed = MPC624_SPEED_440_HZ;
 261                break;
 262        case 4:
 263                devpriv->ai_speed = MPC624_SPEED_220_HZ;
 264                break;
 265        case 5:
 266                devpriv->ai_speed = MPC624_SPEED_110_HZ;
 267                break;
 268        case 6:
 269                devpriv->ai_speed = MPC624_SPEED_55_HZ;
 270                break;
 271        case 7:
 272                devpriv->ai_speed = MPC624_SPEED_27_5_HZ;
 273                break;
 274        case 8:
 275                devpriv->ai_speed = MPC624_SPEED_13_75_HZ;
 276                break;
 277        case 9:
 278                devpriv->ai_speed = MPC624_SPEED_6_875_HZ;
 279                break;
 280        default:
 281                devpriv->ai_speed = MPC624_SPEED_3_52_KHZ;
 282        }
 283
 284        ret = comedi_alloc_subdevices(dev, 1);
 285        if (ret)
 286                return ret;
 287
 288        /* Analog Input subdevice */
 289        s = &dev->subdevices[0];
 290        s->type         = COMEDI_SUBD_AI;
 291        s->subdev_flags = SDF_READABLE | SDF_DIFF;
 292        s->n_chan       = 4;
 293        s->maxdata      = 0x3fffffff;
 294        s->range_table  = (it->options[1] == 0) ? &range_mpc624_bipolar1
 295                                                : &range_mpc624_bipolar10;
 296        s->insn_read    = mpc624_ai_insn_read;
 297
 298        return 0;
 299}
 300
 301static struct comedi_driver mpc624_driver = {
 302        .driver_name    = "mpc624",
 303        .module         = THIS_MODULE,
 304        .attach         = mpc624_attach,
 305        .detach         = comedi_legacy_detach,
 306};
 307module_comedi_driver(mpc624_driver);
 308
 309MODULE_AUTHOR("Comedi https://www.comedi.org");
 310MODULE_DESCRIPTION("Comedi driver for Micro/sys MPC-624 PC/104 board");
 311MODULE_LICENSE("GPL");
 312
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