drivers/staging/comedi/drivers/pcmad.c

   1 /*
   2     comedi/drivers/pcmad.c
   3     Hardware driver for Winsystems PCM-A/D12 and PCM-A/D16
   4
   5     COMEDI - Linux Control and Measurement Device Interface
   6     Copyright (C) 2000,2001 David A. Schleef <ds@schleef.org>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22 */
  23 /*
  24 Driver: pcmad
  25 Description: Winsystems PCM-A/D12, PCM-A/D16
  26 Author: ds
  27 Devices: [Winsystems] PCM-A/D12 (pcmad12), PCM-A/D16 (pcmad16)
  28 Status: untested
  29
  30 This driver was written on a bet that I couldn't write a driver
  31 in less than 2 hours.  I won the bet, but never got paid.  =(
  32
  33 Configuration options:
  34   [0] - I/O port base
  35   [1] - unused
  36   [2] - Analog input reference
  37         0 = single ended
  38         1 = differential
  39   [3] - Analog input encoding (must match jumpers)
  40         0 = straight binary
  41         1 = two's complement
  42 */
  43
  44 #include <linux/interrupt.h>
  45 #include "../comedidev.h"
  46
  47 #include <linux/ioport.h>
  48
  49 #define PCMAD_SIZE              4
  50
  51 #define PCMAD_STATUS            0
  52 #define PCMAD_LSB               1
  53 #define PCMAD_MSB               2
  54 #define PCMAD_CONVERT           1
  55
  56 struct pcmad_board_struct {
  57         const char *name;
  58         int n_ai_bits;
  59 };
  60
  61 struct pcmad_priv_struct {
  62         int differential;
  63         int twos_comp;
  64 };
  65
  66 #define TIMEOUT 100
  67
  68 static int pcmad_ai_insn_read(struct comedi_device *dev,
  69                               struct comedi_subdevice *s,
  70                               struct comedi_insn *insn, unsigned int *data)
  71 {
  72         const struct pcmad_board_struct *board = comedi_board(dev);
  73         struct pcmad_priv_struct *devpriv = dev->private;
  74         int i;
  75         int chan;
  76         int n;
  77
  78         chan = CR_CHAN(insn->chanspec);
  79
  80         for (n = 0; n < insn->n; n++) {
  81                 outb(chan, dev->iobase + PCMAD_CONVERT);
  82
  83                 for (i = 0; i < TIMEOUT; i++) {
  84                         if ((inb(dev->iobase + PCMAD_STATUS) & 0x3) == 0x3)
  85                                 break;
  86                 }
  87                 data[n] = inb(dev->iobase + PCMAD_LSB);
  88                 data[n] |= (inb(dev->iobase + PCMAD_MSB) << 8);
  89
  90                 if (devpriv->twos_comp)
  91                         data[n] ^= (1 << (board->n_ai_bits - 1));
  92         }
  93
  94         return n;
  95 }
  96
  97 /*
  98  * options:
  99  * 0    i/o base
 100  * 1    unused
 101  * 2    0=single ended 1=differential
 102  * 3    0=straight binary 1=two's comp
 103  */
 104 static int pcmad_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 105 {
 106         const struct pcmad_board_struct *board = comedi_board(dev);
 107         struct pcmad_priv_struct *devpriv;
 108         int ret;
 109         struct comedi_subdevice *s;
 110         unsigned long iobase;
 111
 112         iobase = it->options[0];
 113         printk(KERN_INFO "comedi%d: pcmad: 0x%04lx ", dev->minor, iobase);
 114         if (!request_region(iobase, PCMAD_SIZE, "pcmad")) {
 115                 printk(KERN_CONT "I/O port conflict\n");
 116                 return -EIO;
 117         }
 118         printk(KERN_CONT "\n");
 119         dev->iobase = iobase;
 120
 121         ret = comedi_alloc_subdevices(dev, 1);
 122         if (ret)
 123                 return ret;
 124
 125         devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
 126         if (!devpriv)
 127                 return -ENOMEM;
 128         dev->private = devpriv;
 129
 130         dev->board_name = board->name;
 131
 132         s = &dev->subdevices[0];
 133         s->type = COMEDI_SUBD_AI;
 134         s->subdev_flags = SDF_READABLE | AREF_GROUND;
 135         s->n_chan = 16;         /* XXX */
 136         s->len_chanlist = 1;
 137         s->insn_read = pcmad_ai_insn_read;
 138         s->maxdata = (1 << board->n_ai_bits) - 1;
 139         s->range_table = &range_unknown;
 140
 141         return 0;
 142 }
 143
 144 static void pcmad_detach(struct comedi_device *dev)
 145 {
 146         if (dev->irq)
 147                 free_irq(dev->irq, dev);
 148         if (dev->iobase)
 149                 release_region(dev->iobase, PCMAD_SIZE);
 150 }
 151
 152 static const struct pcmad_board_struct pcmad_boards[] = {
 153         {
 154                 .name           = "pcmad12",
 155                 .n_ai_bits      = 12,
 156         }, {
 157                 .name           = "pcmad16",
 158                 .n_ai_bits      = 16,
 159         },
 160 };
 161 static struct comedi_driver pcmad_driver = {
 162         .driver_name    = "pcmad",
 163         .module         = THIS_MODULE,
 164         .attach         = pcmad_attach,
 165         .detach         = pcmad_detach,
 166         .board_name     = &pcmad_boards[0].name,
 167         .num_names      = ARRAY_SIZE(pcmad_boards),
 168         .offset         = sizeof(pcmad_boards[0]),
 169 };
 170 module_comedi_driver(pcmad_driver);
 171
 172 MODULE_AUTHOR("Comedi http://www.comedi.org");
 173 MODULE_DESCRIPTION("Comedi low-level driver");
 174 MODULE_LICENSE("GPL");