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, unsigned int *data)
131 struct subdev_8255_private *spriv = s->private;
132 unsigned long iobase = spriv->iobase;
146 spriv->io(1, _8255_DATA, v & 0xff, iobase);
148 spriv->io(1, _8255_DATA + 1, (v >> 8) & 0xff, iobase);
150 spriv->io(1, _8255_DATA + 2, (v >> 16) & 0xff, iobase);
155 v = spriv->io(0, _8255_DATA, 0, iobase);
156 v |= (spriv->io(0, _8255_DATA + 1, 0, iobase) << 8);
157 v |= (spriv->io(0, _8255_DATA + 2, 0, iobase) << 16);
164 static void subdev_8255_do_config(struct comedi_device *dev,
165 struct comedi_subdevice *s)
167 struct subdev_8255_private *spriv = s->private;
168 unsigned long iobase = spriv->iobase;
172 /* 1 in io_bits indicates output, 1 in config indicates input */
173 if (!(s->io_bits & 0x0000ff))
175 if (!(s->io_bits & 0x00ff00))
177 if (!(s->io_bits & 0x0f0000))
178 config |= CR_C_LO_IO;
179 if (!(s->io_bits & 0xf00000))
180 config |= CR_C_HI_IO;
182 spriv->io(1, _8255_CR, config, iobase);
185 static int subdev_8255_insn_config(struct comedi_device *dev,
186 struct comedi_subdevice *s,
187 struct comedi_insn *insn,
190 unsigned int chan = CR_CHAN(insn->chanspec);
203 ret = comedi_dio_insn_config(dev, s, insn, data, mask);
207 subdev_8255_do_config(dev, s);
212 static int subdev_8255_cmdtest(struct comedi_device *dev,
213 struct comedi_subdevice *s,
214 struct comedi_cmd *cmd)
218 /* Step 1 : check if triggers are trivially valid */
220 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
221 err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_EXT);
222 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_FOLLOW);
223 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
224 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_NONE);
229 /* Step 2a : make sure trigger sources are unique */
230 /* Step 2b : and mutually compatible */
235 /* Step 3: check if arguments are trivially valid */
237 err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
238 err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
239 err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
240 err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
241 err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
254 static int subdev_8255_cmd(struct comedi_device *dev,
255 struct comedi_subdevice *s)
262 static int subdev_8255_cancel(struct comedi_device *dev,
263 struct comedi_subdevice *s)
270 int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
271 int (*io) (int, int, int, unsigned long),
272 unsigned long iobase)
274 struct subdev_8255_private *spriv;
276 spriv = comedi_alloc_spriv(s, sizeof(*spriv));
280 spriv->iobase = iobase;
281 spriv->io = io ? io : subdev_8255_io;
283 s->type = COMEDI_SUBD_DIO;
284 s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
286 s->range_table = &range_digital;
288 s->insn_bits = subdev_8255_insn;
289 s->insn_config = subdev_8255_insn_config;
294 subdev_8255_do_config(dev, s);
298 EXPORT_SYMBOL_GPL(subdev_8255_init);
300 int subdev_8255_init_irq(struct comedi_device *dev, struct comedi_subdevice *s,
301 int (*io) (int, int, int, unsigned long),
302 unsigned long iobase)
306 ret = subdev_8255_init(dev, s, io, iobase);
310 s->do_cmdtest = subdev_8255_cmdtest;
311 s->do_cmd = subdev_8255_cmd;
312 s->cancel = subdev_8255_cancel;
316 EXPORT_SYMBOL_GPL(subdev_8255_init_irq);
320 Start of the 8255 standalone device
324 static int dev_8255_attach(struct comedi_device *dev,
325 struct comedi_devconfig *it)
327 struct comedi_subdevice *s;
329 unsigned long iobase;
332 for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) {
333 iobase = it->options[i];
338 dev_warn(dev->class_dev, "no devices specified\n");
342 ret = comedi_alloc_subdevices(dev, i);
346 for (i = 0; i < dev->n_subdevices; i++) {
347 s = &dev->subdevices[i];
348 iobase = it->options[i];
350 ret = __comedi_request_region(dev, iobase, _8255_SIZE);
352 s->type = COMEDI_SUBD_UNUSED;
354 ret = subdev_8255_init(dev, s, NULL, iobase);
363 static void dev_8255_detach(struct comedi_device *dev)
365 struct comedi_subdevice *s;
366 struct subdev_8255_private *spriv;
369 for (i = 0; i < dev->n_subdevices; i++) {
370 s = &dev->subdevices[i];
371 if (s->type != COMEDI_SUBD_UNUSED) {
373 release_region(spriv->iobase, _8255_SIZE);
378 static struct comedi_driver dev_8255_driver = {
379 .driver_name = "8255",
380 .module = THIS_MODULE,
381 .attach = dev_8255_attach,
382 .detach = dev_8255_detach,
384 module_comedi_driver(dev_8255_driver);
386 MODULE_AUTHOR("Comedi http://www.comedi.org");
387 MODULE_DESCRIPTION("Comedi low-level driver");
388 MODULE_LICENSE("GPL");