5 COMEDI - Linux Control and Measurement Device Interface
6 Copyright (C) 1998 David A. Schleef <ds@schleef.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.
20 Description: generic 8255 support
21 Devices: [standard] 8255 (8255)
24 Updated: Fri, 7 Jun 2002 12:56:45 -0700
26 The classic in digital I/O. The 8255 appears in Comedi as a single
27 digital I/O subdevice with 24 channels. The channel 0 corresponds
28 to the 8255's port A, bit 0; channel 23 corresponds to port C, bit
29 7. Direction configuration is done in blocks, with channels 0-7,
30 8-15, 16-19, and 20-23 making up the 4 blocks. The only 8255 mode
33 You should enable compilation this driver if you plan to use a board
34 that has an 8255 chip. For multifunction boards, the main driver will
35 configure the 8255 subdevice automatically.
37 This driver also works independently with ISA and PCI cards that
38 directly map the 8255 registers to I/O ports, including cards with
39 multiple 8255 chips. To configure the driver for such a card, the
40 option list should be a list of the I/O port bases for each of the
41 8255 chips. For example,
43 comedi_config /dev/comedi0 8255 0x200,0x204,0x208,0x20c
45 Note that most PCI 8255 boards do NOT work with this driver, and
46 need a separate driver as a wrapper. For those that do work, the
47 I/O port base address can be found in the output of 'lspci -v'.
52 This file contains an exported subdevice for driving an 8255.
54 To use this subdevice as part of another driver, you need to
55 set up the subdevice in the attach function of the driver by
58 subdev_8255_init(device, subdevice, io_function, iobase)
60 device and subdevice are pointers to the device and subdevice
61 structures. io_function will be called to provide the
62 low-level input/output to the device, i.e., actual register
63 access. io_function will be called with the value of iobase
64 as the last parameter. If the 8255 device is mapped as 4
65 consecutive I/O ports, you can use NULL for io_function
66 and the I/O port base for iobase, and an internal function will
67 handle the register access.
69 In addition, if the main driver handles interrupts, you can
70 enable commands on the subdevice by calling subdev_8255_init_irq()
71 instead. Then, when you get an interrupt that is likely to be
72 from the 8255, you should call subdev_8255_interrupt(), which
73 will copy the latched value to a Comedi buffer.
76 #include <linux/module.h>
77 #include "../comedidev.h"
79 #include "comedi_fc.h"
87 #define CR_C_LO_IO 0x01
89 #define CR_B_MODE 0x04
90 #define CR_C_HI_IO 0x08
92 #define CR_A_MODE(a) ((a)<<5)
95 struct subdev_8255_private {
97 int (*io) (int, int, int, unsigned long);
100 static int subdev_8255_io(int dir, int port, int data, unsigned long iobase)
103 outb(data, iobase + port);
106 return inb(iobase + port);
110 void subdev_8255_interrupt(struct comedi_device *dev,
111 struct comedi_subdevice *s)
113 struct subdev_8255_private *spriv = s->private;
114 unsigned long iobase = spriv->iobase;
117 d = spriv->io(0, _8255_DATA, 0, iobase);
118 d |= (spriv->io(0, _8255_DATA + 1, 0, iobase) << 8);
120 comedi_buf_put(s->async, d);
121 s->async->events |= COMEDI_CB_EOS;
123 comedi_event(dev, s);
125 EXPORT_SYMBOL_GPL(subdev_8255_interrupt);
127 static int subdev_8255_insn(struct comedi_device *dev,
128 struct comedi_subdevice *s,
129 struct comedi_insn *insn,
132 struct subdev_8255_private *spriv = s->private;
133 unsigned long iobase = spriv->iobase;
137 mask = comedi_dio_update_state(s, data);
140 spriv->io(1, _8255_DATA, s->state & 0xff, iobase);
142 spriv->io(1, _8255_DATA + 1, (s->state >> 8) & 0xff,
145 spriv->io(1, _8255_DATA + 2, (s->state >> 16) & 0xff,
149 v = spriv->io(0, _8255_DATA, 0, iobase);
150 v |= (spriv->io(0, _8255_DATA + 1, 0, iobase) << 8);
151 v |= (spriv->io(0, _8255_DATA + 2, 0, iobase) << 16);
158 static void subdev_8255_do_config(struct comedi_device *dev,
159 struct comedi_subdevice *s)
161 struct subdev_8255_private *spriv = s->private;
162 unsigned long iobase = spriv->iobase;
166 /* 1 in io_bits indicates output, 1 in config indicates input */
167 if (!(s->io_bits & 0x0000ff))
169 if (!(s->io_bits & 0x00ff00))
171 if (!(s->io_bits & 0x0f0000))
172 config |= CR_C_LO_IO;
173 if (!(s->io_bits & 0xf00000))
174 config |= CR_C_HI_IO;
176 spriv->io(1, _8255_CR, config, iobase);
179 static int subdev_8255_insn_config(struct comedi_device *dev,
180 struct comedi_subdevice *s,
181 struct comedi_insn *insn,
184 unsigned int chan = CR_CHAN(insn->chanspec);
197 ret = comedi_dio_insn_config(dev, s, insn, data, mask);
201 subdev_8255_do_config(dev, s);
206 static int subdev_8255_cmdtest(struct comedi_device *dev,
207 struct comedi_subdevice *s,
208 struct comedi_cmd *cmd)
212 /* Step 1 : check if triggers are trivially valid */
214 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
215 err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_EXT);
216 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_FOLLOW);
217 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
218 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_NONE);
223 /* Step 2a : make sure trigger sources are unique */
224 /* Step 2b : and mutually compatible */
229 /* Step 3: check if arguments are trivially valid */
231 err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
232 err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
233 err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
234 err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
235 err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
248 static int subdev_8255_cmd(struct comedi_device *dev,
249 struct comedi_subdevice *s)
256 static int subdev_8255_cancel(struct comedi_device *dev,
257 struct comedi_subdevice *s)
264 int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
265 int (*io) (int, int, int, unsigned long),
266 unsigned long iobase)
268 struct subdev_8255_private *spriv;
270 spriv = comedi_alloc_spriv(s, sizeof(*spriv));
274 spriv->iobase = iobase;
275 spriv->io = io ? io : subdev_8255_io;
277 s->type = COMEDI_SUBD_DIO;
278 s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
280 s->range_table = &range_digital;
282 s->insn_bits = subdev_8255_insn;
283 s->insn_config = subdev_8255_insn_config;
285 subdev_8255_do_config(dev, s);
289 EXPORT_SYMBOL_GPL(subdev_8255_init);
291 int subdev_8255_init_irq(struct comedi_device *dev, struct comedi_subdevice *s,
292 int (*io) (int, int, int, unsigned long),
293 unsigned long iobase)
297 ret = subdev_8255_init(dev, s, io, iobase);
301 s->do_cmdtest = subdev_8255_cmdtest;
302 s->do_cmd = subdev_8255_cmd;
303 s->cancel = subdev_8255_cancel;
307 EXPORT_SYMBOL_GPL(subdev_8255_init_irq);
311 Start of the 8255 standalone device
315 static int dev_8255_attach(struct comedi_device *dev,
316 struct comedi_devconfig *it)
318 struct comedi_subdevice *s;
320 unsigned long iobase;
323 for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) {
324 iobase = it->options[i];
329 dev_warn(dev->class_dev, "no devices specified\n");
333 ret = comedi_alloc_subdevices(dev, i);
337 for (i = 0; i < dev->n_subdevices; i++) {
338 s = &dev->subdevices[i];
339 iobase = it->options[i];
341 ret = __comedi_request_region(dev, iobase, _8255_SIZE);
343 s->type = COMEDI_SUBD_UNUSED;
345 ret = subdev_8255_init(dev, s, NULL, iobase);
354 static void dev_8255_detach(struct comedi_device *dev)
356 struct comedi_subdevice *s;
357 struct subdev_8255_private *spriv;
360 for (i = 0; i < dev->n_subdevices; i++) {
361 s = &dev->subdevices[i];
362 if (s->type != COMEDI_SUBD_UNUSED) {
364 release_region(spriv->iobase, _8255_SIZE);
369 static struct comedi_driver dev_8255_driver = {
370 .driver_name = "8255",
371 .module = THIS_MODULE,
372 .attach = dev_8255_attach,
373 .detach = dev_8255_detach,
375 module_comedi_driver(dev_8255_driver);
377 MODULE_AUTHOR("Comedi http://www.comedi.org");
378 MODULE_DESCRIPTION("Comedi low-level driver");
379 MODULE_LICENSE("GPL");