2 comedi/drivers/pcmda12.c
3 Driver for Winsystems PC-104 based PCM-D/A-12 8-channel AO board.
5 COMEDI - Linux Control and Measurement Device Interface
6 Copyright (C) 2006 Calin A. Culianu <calin@ajvar.org>
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.
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.
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.
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
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.
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.
39 Note that the board is not ISA-PNP capable and thus
40 needs the I/O port comedi_config parameter.
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
49 Configuration Options:
50 [0] - I/O port base address
51 [1] - Do Simultaneous Xfer (see description)
54 #include "../comedidev.h"
58 #define LSB(x) ((unsigned char)((x) & 0xff))
59 #define MSB(x) ((unsigned char)((((unsigned short)(x))>>8) & 0xff))
60 #define LSB_PORT(chan) (dev->iobase + (chan)*2)
61 #define MSB_PORT(chan) (LSB_PORT(chan)+1)
64 /* note these have no effect and are merely here for reference..
65 these are configured by jumpering the board! */
66 static const struct comedi_lrange pcmda12_ranges = {
69 UNI_RANGE(5), UNI_RANGE(10), BIP_RANGE(5)
73 struct pcmda12_private {
75 unsigned int ao_readback[CHANS];
76 int simultaneous_xfer_mode;
79 static void zero_chans(struct comedi_device *dev)
81 ASIC chip to defaults */
83 for (i = 0; i < CHANS; ++i) {
84 /* /\* do this as one instruction?? *\/ */
85 /* outw(0, LSB_PORT(chan)); */
89 inb(LSB_PORT(0)); /* update chans. */
92 static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
93 struct comedi_insn *insn, unsigned int *data)
95 struct pcmda12_private *devpriv = dev->private;
97 int chan = CR_CHAN(insn->chanspec);
99 /* Writing a list of values to an AO channel is probably not
100 * very useful, but that's how the interface is defined. */
101 for (i = 0; i < insn->n; ++i) {
103 /* /\* do this as one instruction?? *\/ */
104 /* outw(data[i], LSB_PORT(chan)); */
106 /* Need to do this as two instructions due to 8-bit bus?? */
107 /* first, load the low byte */
108 outb(LSB(data[i]), LSB_PORT(chan));
109 /* next, write the high byte */
110 outb(MSB(data[i]), MSB_PORT(chan));
112 /* save shadow register */
113 devpriv->ao_readback[chan] = data[i];
115 if (!devpriv->simultaneous_xfer_mode)
119 /* return the number of samples written */
123 /* AO subdevices should have a read insn as well as a write insn.
125 Usually this means copying a value stored in devpriv->ao_readback.
126 However, since this driver supports simultaneous xfer then sometimes
127 this function actually accomplishes work.
129 Simultaneaous xfer mode is accomplished by loading ALL the values
130 you want for AO in all the channels, then READing off one of the AO
131 registers to initiate the instantaneous simultaneous update of all
132 DAC outputs, which makes all AO channels update simultaneously.
133 This is useful for some control applications, I would imagine.
135 static int ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
136 struct comedi_insn *insn, unsigned int *data)
138 struct pcmda12_private *devpriv = dev->private;
140 int chan = CR_CHAN(insn->chanspec);
142 for (i = 0; i < insn->n; i++) {
143 if (devpriv->simultaneous_xfer_mode)
145 /* read back shadow register */
146 data[i] = devpriv->ao_readback[chan];
152 static int pcmda12_attach(struct comedi_device *dev,
153 struct comedi_devconfig *it)
155 struct pcmda12_private *devpriv;
156 struct comedi_subdevice *s;
157 unsigned long iobase;
160 iobase = it->options[0];
162 "comedi%d: %s: io: %lx %s ", dev->minor, dev->driver->driver_name,
163 iobase, it->options[1] ? "simultaneous xfer mode enabled" : "");
165 if (!request_region(iobase, IOSIZE, dev->driver->driver_name)) {
166 printk("I/O port conflict\n");
169 dev->iobase = iobase;
171 dev->board_name = dev->driver->driver_name;
173 devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
176 dev->private = devpriv;
178 devpriv->simultaneous_xfer_mode = it->options[1];
180 ret = comedi_alloc_subdevices(dev, 1);
184 s = &dev->subdevices[0];
186 s->maxdata = (0x1 << BITS) - 1;
187 s->range_table = &pcmda12_ranges;
188 s->type = COMEDI_SUBD_AO;
189 s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
191 s->insn_write = &ao_winsn;
192 s->insn_read = &ao_rinsn;
194 zero_chans(dev); /* clear out all the registers, basically */
196 printk(KERN_INFO "attached\n");
201 static void pcmda12_detach(struct comedi_device *dev)
204 release_region(dev->iobase, IOSIZE);
207 static struct comedi_driver pcmda12_driver = {
208 .driver_name = "pcmda12",
209 .module = THIS_MODULE,
210 .attach = pcmda12_attach,
211 .detach = pcmda12_detach,
213 module_comedi_driver(pcmda12_driver);
215 MODULE_AUTHOR("Comedi http://www.comedi.org");
216 MODULE_DESCRIPTION("Comedi low-level driver");
217 MODULE_LICENSE("GPL");