8255.c revision 7114a28011f9d5f3d981731ad341177c21f9d948 
1/*
2    comedi/drivers/8255.c
3    Driver for 8255
4
5    COMEDI - Linux Control and Measurement Device Interface
6    Copyright (C) 1998 David A. Schleef <ds@schleef.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/*
24Driver: 8255
25Description: generic 8255 support
26Devices: [standard] 8255 (8255)
27Author: ds
28Status: works
29Updated: Fri,  7 Jun 2002 12:56:45 -0700
30
31The classic in digital I/O.  The 8255 appears in Comedi as a single
32digital I/O subdevice with 24 channels.  The channel 0 corresponds
33to the 8255's port A, bit 0; channel 23 corresponds to port C, bit
347.  Direction configuration is done in blocks, with channels 0-7,
358-15, 16-19, and 20-23 making up the 4 blocks.  The only 8255 mode
36supported is mode 0.
37
38You should enable compilation this driver if you plan to use a board
39that has an 8255 chip.  For multifunction boards, the main driver will
40configure the 8255 subdevice automatically.
41
42This driver also works independently with ISA and PCI cards that
43directly map the 8255 registers to I/O ports, including cards with
44multiple 8255 chips.  To configure the driver for such a card, the
45option list should be a list of the I/O port bases for each of the
468255 chips.  For example,
47
48  comedi_config /dev/comedi0 8255 0x200,0x204,0x208,0x20c
49
50Note that most PCI 8255 boards do NOT work with this driver, and
51need a separate driver as a wrapper.  For those that do work, the
52I/O port base address can be found in the output of 'lspci -v'.
53
54*/
55
56/*
57   This file contains an exported subdevice for driving an 8255.
58
59   To use this subdevice as part of another driver, you need to
60   set up the subdevice in the attach function of the driver by
61   calling:
62
63     subdev_8255_init(device, subdevice, callback_function, arg)
64
65   device and subdevice are pointers to the device and subdevice
66   structures.  callback_function will be called to provide the
67   low-level input/output to the device, i.e., actual register
68   access.  callback_function will be called with the value of arg
69   as the last parameter.  If the 8255 device is mapped as 4
70   consecutive I/O ports, you can use NULL for callback_function
71   and the I/O port base for arg, and an internal function will
72   handle the register access.
73
74   In addition, if the main driver handles interrupts, you can
75   enable commands on the subdevice by calling subdev_8255_init_irq()
76   instead.  Then, when you get an interrupt that is likely to be
77   from the 8255, you should call subdev_8255_interrupt(), which
78   will copy the latched value to a Comedi buffer.
79 */
80
81#include "../comedidev.h"
82
83#include <linux/ioport.h>
84#include <linux/slab.h>
85#include "8255.h"
86
87#define _8255_SIZE 4
88
89#define _8255_DATA 0
90#define _8255_CR 3
91
92#define CR_C_LO_IO	0x01
93#define CR_B_IO		0x02
94#define CR_B_MODE	0x04
95#define CR_C_HI_IO	0x08
96#define CR_A_IO		0x10
97#define CR_A_MODE(a)	((a)<<5)
98#define CR_CW		0x80
99
100struct subdev_8255_struct {
101	unsigned long cb_arg;
102	int (*cb_func) (int, int, int, unsigned long);
103	int have_irq;
104};
105
106#define CALLBACK_ARG	(((struct subdev_8255_struct *)s->private)->cb_arg)
107#define CALLBACK_FUNC	(((struct subdev_8255_struct *)s->private)->cb_func)
108#define subdevpriv	((struct subdev_8255_struct *)s->private)
109
110static int dev_8255_attach(struct comedi_device *dev,
111			   struct comedi_devconfig *it);
112static int dev_8255_detach(struct comedi_device *dev);
113static struct comedi_driver driver_8255 = {
114	.driver_name = "8255",
115	.module = THIS_MODULE,
116	.attach = dev_8255_attach,
117	.detach = dev_8255_detach,
118};
119
120static int __init driver_8255_init_module(void)
121{
122	return comedi_driver_register(&driver_8255);
123}
124
125static void __exit driver_8255_cleanup_module(void)
126{
127	comedi_driver_unregister(&driver_8255);
128}
129
130module_init(driver_8255_init_module);
131module_exit(driver_8255_cleanup_module);
132
133static void do_config(struct comedi_device *dev, struct comedi_subdevice *s);
134
135void subdev_8255_interrupt(struct comedi_device *dev,
136			   struct comedi_subdevice *s)
137{
138	short d;
139
140	d = CALLBACK_FUNC(0, _8255_DATA, 0, CALLBACK_ARG);
141	d |= (CALLBACK_FUNC(0, _8255_DATA + 1, 0, CALLBACK_ARG) << 8);
142
143	comedi_buf_put(s->async, d);
144	s->async->events |= COMEDI_CB_EOS;
145
146	comedi_event(dev, s);
147}
148EXPORT_SYMBOL(subdev_8255_interrupt);
149
150static int subdev_8255_cb(int dir, int port, int data, unsigned long arg)
151{
152	unsigned long iobase = arg;
153
154	if (dir) {
155		outb(data, iobase + port);
156		return 0;
157	} else {
158		return inb(iobase + port);
159	}
160}
161
162static int subdev_8255_insn(struct comedi_device *dev,
163			    struct comedi_subdevice *s,
164			    struct comedi_insn *insn, unsigned int *data)
165{
166	if (data[0]) {
167		s->state &= ~data[0];
168		s->state |= (data[0] & data[1]);
169
170		if (data[0] & 0xff)
171			CALLBACK_FUNC(1, _8255_DATA, s->state & 0xff,
172				      CALLBACK_ARG);
173		if (data[0] & 0xff00)
174			CALLBACK_FUNC(1, _8255_DATA + 1, (s->state >> 8) & 0xff,
175				      CALLBACK_ARG);
176		if (data[0] & 0xff0000)
177			CALLBACK_FUNC(1, _8255_DATA + 2,
178				      (s->state >> 16) & 0xff, CALLBACK_ARG);
179	}
180
181	data[1] = CALLBACK_FUNC(0, _8255_DATA, 0, CALLBACK_ARG);
182	data[1] |= (CALLBACK_FUNC(0, _8255_DATA + 1, 0, CALLBACK_ARG) << 8);
183	data[1] |= (CALLBACK_FUNC(0, _8255_DATA + 2, 0, CALLBACK_ARG) << 16);
184
185	return 2;
186}
187
188static int subdev_8255_insn_config(struct comedi_device *dev,
189				   struct comedi_subdevice *s,
190				   struct comedi_insn *insn, unsigned int *data)
191{
192	unsigned int mask;
193	unsigned int bits;
194
195	mask = 1 << CR_CHAN(insn->chanspec);
196	if (mask & 0x0000ff)
197		bits = 0x0000ff;
198	else if (mask & 0x00ff00)
199		bits = 0x00ff00;
200	else if (mask & 0x0f0000)
201		bits = 0x0f0000;
202	else
203		bits = 0xf00000;
204
205	switch (data[0]) {
206	case INSN_CONFIG_DIO_INPUT:
207		s->io_bits &= ~bits;
208		break;
209	case INSN_CONFIG_DIO_OUTPUT:
210		s->io_bits |= bits;
211		break;
212	case INSN_CONFIG_DIO_QUERY:
213		data[1] = (s->io_bits & bits) ? COMEDI_OUTPUT : COMEDI_INPUT;
214		return insn->n;
215		break;
216	default:
217		return -EINVAL;
218	}
219
220	do_config(dev, s);
221
222	return 1;
223}
224
225static void do_config(struct comedi_device *dev, struct comedi_subdevice *s)
226{
227	int config;
228
229	config = CR_CW;
230	/* 1 in io_bits indicates output, 1 in config indicates input */
231	if (!(s->io_bits & 0x0000ff))
232		config |= CR_A_IO;
233	if (!(s->io_bits & 0x00ff00))
234		config |= CR_B_IO;
235	if (!(s->io_bits & 0x0f0000))
236		config |= CR_C_LO_IO;
237	if (!(s->io_bits & 0xf00000))
238		config |= CR_C_HI_IO;
239	CALLBACK_FUNC(1, _8255_CR, config, CALLBACK_ARG);
240}
241
242static int subdev_8255_cmdtest(struct comedi_device *dev,
243			       struct comedi_subdevice *s,
244			       struct comedi_cmd *cmd)
245{
246	int err = 0;
247	unsigned int tmp;
248
249	/* step 1 */
250
251	tmp = cmd->start_src;
252	cmd->start_src &= TRIG_NOW;
253	if (!cmd->start_src || tmp != cmd->start_src)
254		err++;
255
256	tmp = cmd->scan_begin_src;
257	cmd->scan_begin_src &= TRIG_EXT;
258	if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src)
259		err++;
260
261	tmp = cmd->convert_src;
262	cmd->convert_src &= TRIG_FOLLOW;
263	if (!cmd->convert_src || tmp != cmd->convert_src)
264		err++;
265
266	tmp = cmd->scan_end_src;
267	cmd->scan_end_src &= TRIG_COUNT;
268	if (!cmd->scan_end_src || tmp != cmd->scan_end_src)
269		err++;
270
271	tmp = cmd->stop_src;
272	cmd->stop_src &= TRIG_NONE;
273	if (!cmd->stop_src || tmp != cmd->stop_src)
274		err++;
275
276	if (err)
277		return 1;
278
279	/* step 2 */
280
281	if (err)
282		return 2;
283
284	/* step 3 */
285
286	if (cmd->start_arg != 0) {
287		cmd->start_arg = 0;
288		err++;
289	}
290	if (cmd->scan_begin_arg != 0) {
291		cmd->scan_begin_arg = 0;
292		err++;
293	}
294	if (cmd->convert_arg != 0) {
295		cmd->convert_arg = 0;
296		err++;
297	}
298	if (cmd->scan_end_arg != 1) {
299		cmd->scan_end_arg = 1;
300		err++;
301	}
302	if (cmd->stop_arg != 0) {
303		cmd->stop_arg = 0;
304		err++;
305	}
306
307	if (err)
308		return 3;
309
310	/* step 4 */
311
312	if (err)
313		return 4;
314
315	return 0;
316}
317
318static int subdev_8255_cmd(struct comedi_device *dev,
319			   struct comedi_subdevice *s)
320{
321	/* FIXME */
322
323	return 0;
324}
325
326static int subdev_8255_cancel(struct comedi_device *dev,
327			      struct comedi_subdevice *s)
328{
329	/* FIXME */
330
331	return 0;
332}
333
334int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
335		     int (*cb) (int, int, int, unsigned long),
336		     unsigned long arg)
337{
338	s->type = COMEDI_SUBD_DIO;
339	s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
340	s->n_chan = 24;
341	s->range_table = &range_digital;
342	s->maxdata = 1;
343
344	s->private = kmalloc(sizeof(struct subdev_8255_struct), GFP_KERNEL);
345	if (!s->private)
346		return -ENOMEM;
347
348	CALLBACK_ARG = arg;
349	if (cb == NULL)
350		CALLBACK_FUNC = subdev_8255_cb;
351	else
352		CALLBACK_FUNC = cb;
353	s->insn_bits = subdev_8255_insn;
354	s->insn_config = subdev_8255_insn_config;
355
356	s->state = 0;
357	s->io_bits = 0;
358	do_config(dev, s);
359
360	return 0;
361}
362EXPORT_SYMBOL(subdev_8255_init);
363
364int subdev_8255_init_irq(struct comedi_device *dev, struct comedi_subdevice *s,
365			 int (*cb) (int, int, int, unsigned long),
366			 unsigned long arg)
367{
368	int ret;
369
370	ret = subdev_8255_init(dev, s, cb, arg);
371	if (ret < 0)
372		return ret;
373
374	s->do_cmdtest = subdev_8255_cmdtest;
375	s->do_cmd = subdev_8255_cmd;
376	s->cancel = subdev_8255_cancel;
377
378	subdevpriv->have_irq = 1;
379
380	return 0;
381}
382EXPORT_SYMBOL(subdev_8255_init_irq);
383
384void subdev_8255_cleanup(struct comedi_device *dev, struct comedi_subdevice *s)
385{
386	if (s->private) {
387		/* this test does nothing, so comment it out
388		 * if (subdevpriv->have_irq) {
389		 * }
390		 */
391
392		kfree(s->private);
393	}
394}
395EXPORT_SYMBOL(subdev_8255_cleanup);
396
397/*
398
399   Start of the 8255 standalone device
400
401 */
402
403static int dev_8255_attach(struct comedi_device *dev,
404			   struct comedi_devconfig *it)
405{
406	int ret;
407	unsigned long iobase;
408	int i;
409
410	dev->board_name = "8255";
411
412	for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) {
413		iobase = it->options[i];
414		if (!iobase)
415			break;
416	}
417	if (i == 0) {
418		printk(KERN_WARNING
419		       "comedi%d: 8255: no devices specified\n", dev->minor);
420		return -EINVAL;
421	}
422
423	ret = alloc_subdevices(dev, i);
424	if (ret < 0) {
425		/* FIXME this printk call should give a proper message, the
426		 * below line just maintains previous functionality */
427		printk("comedi%d: 8255:", dev->minor);
428		return ret;
429	}
430
431	printk(KERN_INFO "comedi%d: 8255:", dev->minor);
432
433	for (i = 0; i < dev->n_subdevices; i++) {
434		iobase = it->options[i];
435
436		printk(" 0x%04lx", iobase);
437		if (!request_region(iobase, _8255_SIZE, "8255")) {
438			printk(" (I/O port conflict)");
439
440			dev->subdevices[i].type = COMEDI_SUBD_UNUSED;
441		} else {
442			subdev_8255_init(dev, dev->subdevices + i, NULL,
443					 iobase);
444		}
445	}
446
447	printk("\n");
448
449	return 0;
450}
451
452static int dev_8255_detach(struct comedi_device *dev)
453{
454	int i;
455	unsigned long iobase;
456	struct comedi_subdevice *s;
457
458	printk(KERN_INFO "comedi%d: 8255: remove\n", dev->minor);
459
460	for (i = 0; i < dev->n_subdevices; i++) {
461		s = dev->subdevices + i;
462		if (s->type != COMEDI_SUBD_UNUSED) {
463			iobase = CALLBACK_ARG;
464			release_region(iobase, _8255_SIZE);
465		}
466		subdev_8255_cleanup(dev, s);
467	}
468
469	return 0;
470}
471
472MODULE_AUTHOR("Comedi http://www.comedi.org");
473MODULE_DESCRIPTION("Comedi low-level driver");
474MODULE_LICENSE("GPL");
475