drivers/staging/comedi/drivers/pcmda12.c

   1 /*
   2     comedi/drivers/pcmda12.c
   3     Driver for Winsystems PC-104 based PCM-D/A-12 8-channel AO board.
   4
   5     COMEDI - Linux Control and Measurement Device Interface
   6     Copyright (C) 2006 Calin A. Culianu <calin@ajvar.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 Driver: pcmda12
  24 Description: A driver for the Winsystems PCM-D/A-12
  25 Devices: [Winsystems] PCM-D/A-12 (pcmda12)
  26 Author: Calin Culianu <calin@ajvar.org>
  27 Updated: Fri, 13 Jan 2006 12:01:01 -0500
  28 Status: works
  29
  30 A driver for the relatively straightforward-to-program PCM-D/A-12.
  31 This board doesn't support commands, and the only way to set its
  32 analog output range is to jumper the board.  As such,
  33 comedi_data_write() ignores the range value specified.
  34
  35 The board uses 16 consecutive I/O addresses starting at the I/O port
  36 base address.  Each address corresponds to the LSB then MSB of a
  37 particular channel from 0-7.
  38
  39 Note that the board is not ISA-PNP capable and thus
  40 needs the I/O port comedi_config parameter.
  41
  42 Note that passing a nonzero value as the second config option will
  43 enable "simultaneous xfer" mode for this board, in which AO writes
  44 will not take effect until a subsequent read of any AO channel.  This
  45 is so that one can speed up programming by preloading all AO registers
  46 with values before simultaneously setting them to take effect with one
  47 read command.
  48
  49 Configuration Options:
  50   [0] - I/O port base address
  51   [1] - Do Simultaneous Xfer (see description)
  52 */
  53
  54 #include "../comedidev.h"
  55
  56 #include <linux/pci.h>          /* for PCI devices */
  57
  58 #define SDEV_NO ((int)(s - dev->subdevices))
  59 #define CHANS 8
  60 #define IOSIZE 16
  61 #define LSB(x) ((unsigned char)((x) & 0xff))
  62 #define MSB(x) ((unsigned char)((((unsigned short)(x))>>8) & 0xff))
  63 #define LSB_PORT(chan) (dev->iobase + (chan)*2)
  64 #define MSB_PORT(chan) (LSB_PORT(chan)+1)
  65 #define BITS 12
  66
  67 /*
  68  * Bords
  69  */
  70 struct pcmda12_board {
  71         const char *name;
  72 };
  73
  74 /* note these have no effect and are merely here for reference..
  75    these are configured by jumpering the board! */
  76 static const struct comedi_lrange pcmda12_ranges = {
  77         3,
  78         {
  79          UNI_RANGE(5), UNI_RANGE(10), BIP_RANGE(5)
  80          }
  81 };
  82
  83 struct pcmda12_private {
  84
  85         unsigned int ao_readback[CHANS];
  86         int simultaneous_xfer_mode;
  87 };
  88
  89 #define devpriv ((struct pcmda12_private *)(dev->private))
  90
  91 static void zero_chans(struct comedi_device *dev)
  92 {                               /* sets up an
  93                                    ASIC chip to defaults */
  94         int i;
  95         for (i = 0; i < CHANS; ++i) {
  96 /*      /\* do this as one instruction?? *\/ */
  97 /*      outw(0, LSB_PORT(chan)); */
  98                 outb(0, LSB_PORT(i));
  99                 outb(0, MSB_PORT(i));
 100         }
 101         inb(LSB_PORT(0));       /* update chans. */
 102 }
 103
 104 static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
 105                     struct comedi_insn *insn, unsigned int *data)
 106 {
 107         int i;
 108         int chan = CR_CHAN(insn->chanspec);
 109
 110         /* Writing a list of values to an AO channel is probably not
 111          * very useful, but that's how the interface is defined. */
 112         for (i = 0; i < insn->n; ++i) {
 113
 114 /*      /\* do this as one instruction?? *\/ */
 115 /*      outw(data[i], LSB_PORT(chan)); */
 116
 117                 /* Need to do this as two instructions due to 8-bit bus?? */
 118                 /*  first, load the low byte */
 119                 outb(LSB(data[i]), LSB_PORT(chan));
 120                 /*  next, write the high byte */
 121                 outb(MSB(data[i]), MSB_PORT(chan));
 122
 123                 /* save shadow register */
 124                 devpriv->ao_readback[chan] = data[i];
 125
 126                 if (!devpriv->simultaneous_xfer_mode)
 127                         inb(LSB_PORT(chan));
 128         }
 129
 130         /* return the number of samples written */
 131         return i;
 132 }
 133
 134 /* AO subdevices should have a read insn as well as a write insn.
 135
 136    Usually this means copying a value stored in devpriv->ao_readback.
 137    However, since this driver supports simultaneous xfer then sometimes
 138    this function actually accomplishes work.
 139
 140    Simultaneaous xfer mode is accomplished by loading ALL the values
 141    you want for AO in all the channels, then READing off one of the AO
 142    registers to initiate the instantaneous simultaneous update of all
 143    DAC outputs, which makes all AO channels update simultaneously.
 144    This is useful for some control applications, I would imagine.
 145 */
 146 static int ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
 147                     struct comedi_insn *insn, unsigned int *data)
 148 {
 149         int i;
 150         int chan = CR_CHAN(insn->chanspec);
 151
 152         for (i = 0; i < insn->n; i++) {
 153                 if (devpriv->simultaneous_xfer_mode)
 154                         inb(LSB_PORT(chan));
 155                 /* read back shadow register */
 156                 data[i] = devpriv->ao_readback[chan];
 157         }
 158
 159         return i;
 160 }
 161
 162 static int pcmda12_attach(struct comedi_device *dev,
 163                           struct comedi_devconfig *it)
 164 {
 165         const struct pcmda12_board *board = comedi_board(dev);
 166         struct comedi_subdevice *s;
 167         unsigned long iobase;
 168         int ret;
 169
 170         iobase = it->options[0];
 171         printk(KERN_INFO
 172                "comedi%d: %s: io: %lx %s ", dev->minor, dev->driver->driver_name,
 173                iobase, it->options[1] ? "simultaneous xfer mode enabled" : "");
 174
 175         if (!request_region(iobase, IOSIZE, dev->driver->driver_name)) {
 176                 printk("I/O port conflict\n");
 177                 return -EIO;
 178         }
 179         dev->iobase = iobase;
 180
 181         dev->board_name = board->name;
 182
 183 /*
 184  * Allocate the private structure area.  alloc_private() is a
 185  * convenient macro defined in comedidev.h.
 186  */
 187         if (alloc_private(dev, sizeof(struct pcmda12_private)) < 0) {
 188                 printk(KERN_ERR "cannot allocate private data structure\n");
 189                 return -ENOMEM;
 190         }
 191
 192         devpriv->simultaneous_xfer_mode = it->options[1];
 193
 194         ret = comedi_alloc_subdevices(dev, 1);
 195         if (ret)
 196                 return ret;
 197
 198         s = dev->subdevices;
 199         s->private = NULL;
 200         s->maxdata = (0x1 << BITS) - 1;
 201         s->range_table = &pcmda12_ranges;
 202         s->type = COMEDI_SUBD_AO;
 203         s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
 204         s->n_chan = CHANS;
 205         s->insn_write = &ao_winsn;
 206         s->insn_read = &ao_rinsn;
 207
 208         zero_chans(dev);        /* clear out all the registers, basically */
 209
 210         printk(KERN_INFO "attached\n");
 211
 212         return 1;
 213 }
 214
 215 static void pcmda12_detach(struct comedi_device *dev)
 216 {
 217         if (dev->iobase)
 218                 release_region(dev->iobase, IOSIZE);
 219 }
 220
 221 static const struct pcmda12_board pcmda12_boards[] = {
 222         {
 223                 .name   = "pcmda12",
 224         },
 225 };
 226
 227 static struct comedi_driver pcmda12_driver = {
 228         .driver_name    = "pcmda12",
 229         .module         = THIS_MODULE,
 230         .attach         = pcmda12_attach,
 231         .detach         = pcmda12_detach,
 232         .board_name     = &pcmda12_boards[0].name,
 233         .offset         = sizeof(struct pcmda12_board),
 234         .num_names      = ARRAY_SIZE(pcmda12_boards),
 235 };
 236 module_comedi_driver(pcmda12_driver);
 237
 238 MODULE_AUTHOR("Comedi http://www.comedi.org");
 239 MODULE_DESCRIPTION("Comedi low-level driver");
 240 MODULE_LICENSE("GPL");