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 /* note these have no effect and are merely here for reference..
  68    these are configured by jumpering the board! */
  69 static const struct comedi_lrange pcmda12_ranges = {
  70         3,
  71         {
  72          UNI_RANGE(5), UNI_RANGE(10), BIP_RANGE(5)
  73          }
  74 };
  75
  76 struct pcmda12_private {
  77
  78         unsigned int ao_readback[CHANS];
  79         int simultaneous_xfer_mode;
  80 };
  81
  82 static void zero_chans(struct comedi_device *dev)
  83 {                               /* sets up an
  84                                    ASIC chip to defaults */
  85         int i;
  86         for (i = 0; i < CHANS; ++i) {
  87 /*      /\* do this as one instruction?? *\/ */
  88 /*      outw(0, LSB_PORT(chan)); */
  89                 outb(0, LSB_PORT(i));
  90                 outb(0, MSB_PORT(i));
  91         }
  92         inb(LSB_PORT(0));       /* update chans. */
  93 }
  94
  95 static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
  96                     struct comedi_insn *insn, unsigned int *data)
  97 {
  98         struct pcmda12_private *devpriv = dev->private;
  99         int i;
 100         int chan = CR_CHAN(insn->chanspec);
 101
 102         /* Writing a list of values to an AO channel is probably not
 103          * very useful, but that's how the interface is defined. */
 104         for (i = 0; i < insn->n; ++i) {
 105
 106 /*      /\* do this as one instruction?? *\/ */
 107 /*      outw(data[i], LSB_PORT(chan)); */
 108
 109                 /* Need to do this as two instructions due to 8-bit bus?? */
 110                 /*  first, load the low byte */
 111                 outb(LSB(data[i]), LSB_PORT(chan));
 112                 /*  next, write the high byte */
 113                 outb(MSB(data[i]), MSB_PORT(chan));
 114
 115                 /* save shadow register */
 116                 devpriv->ao_readback[chan] = data[i];
 117
 118                 if (!devpriv->simultaneous_xfer_mode)
 119                         inb(LSB_PORT(chan));
 120         }
 121
 122         /* return the number of samples written */
 123         return i;
 124 }
 125
 126 /* AO subdevices should have a read insn as well as a write insn.
 127
 128    Usually this means copying a value stored in devpriv->ao_readback.
 129    However, since this driver supports simultaneous xfer then sometimes
 130    this function actually accomplishes work.
 131
 132    Simultaneaous xfer mode is accomplished by loading ALL the values
 133    you want for AO in all the channels, then READing off one of the AO
 134    registers to initiate the instantaneous simultaneous update of all
 135    DAC outputs, which makes all AO channels update simultaneously.
 136    This is useful for some control applications, I would imagine.
 137 */
 138 static int ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
 139                     struct comedi_insn *insn, unsigned int *data)
 140 {
 141         struct pcmda12_private *devpriv = dev->private;
 142         int i;
 143         int chan = CR_CHAN(insn->chanspec);
 144
 145         for (i = 0; i < insn->n; i++) {
 146                 if (devpriv->simultaneous_xfer_mode)
 147                         inb(LSB_PORT(chan));
 148                 /* read back shadow register */
 149                 data[i] = devpriv->ao_readback[chan];
 150         }
 151
 152         return i;
 153 }
 154
 155 static int pcmda12_attach(struct comedi_device *dev,
 156                           struct comedi_devconfig *it)
 157 {
 158         struct pcmda12_private *devpriv;
 159         struct comedi_subdevice *s;
 160         unsigned long iobase;
 161         int ret;
 162
 163         iobase = it->options[0];
 164         printk(KERN_INFO
 165                "comedi%d: %s: io: %lx %s ", dev->minor, dev->driver->driver_name,
 166                iobase, it->options[1] ? "simultaneous xfer mode enabled" : "");
 167
 168         if (!request_region(iobase, IOSIZE, dev->driver->driver_name)) {
 169                 printk("I/O port conflict\n");
 170                 return -EIO;
 171         }
 172         dev->iobase = iobase;
 173
 174         dev->board_name = dev->driver->driver_name;
 175
 176         devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
 177         if (!devpriv)
 178                 return -ENOMEM;
 179         dev->private = devpriv;
 180
 181         devpriv->simultaneous_xfer_mode = it->options[1];
 182
 183         ret = comedi_alloc_subdevices(dev, 1);
 184         if (ret)
 185                 return ret;
 186
 187         s = &dev->subdevices[0];
 188         s->private = NULL;
 189         s->maxdata = (0x1 << BITS) - 1;
 190         s->range_table = &pcmda12_ranges;
 191         s->type = COMEDI_SUBD_AO;
 192         s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
 193         s->n_chan = CHANS;
 194         s->insn_write = &ao_winsn;
 195         s->insn_read = &ao_rinsn;
 196
 197         zero_chans(dev);        /* clear out all the registers, basically */
 198
 199         printk(KERN_INFO "attached\n");
 200
 201         return 1;
 202 }
 203
 204 static void pcmda12_detach(struct comedi_device *dev)
 205 {
 206         if (dev->iobase)
 207                 release_region(dev->iobase, IOSIZE);
 208 }
 209
 210 static struct comedi_driver pcmda12_driver = {
 211         .driver_name    = "pcmda12",
 212         .module         = THIS_MODULE,
 213         .attach         = pcmda12_attach,
 214         .detach         = pcmda12_detach,
 215 };
 216 module_comedi_driver(pcmda12_driver);
 217
 218 MODULE_AUTHOR("Comedi http://www.comedi.org");
 219 MODULE_DESCRIPTION("Comedi low-level driver");
 220 MODULE_LICENSE("GPL");