1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * comedi/drivers/8255.c
4 * Driver for 8255
5 *
6 * COMEDI - Linux Control and Measurement Device Interface
7 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
8 */
9
10 /*
11 * Driver: 8255
12 * Description: generic 8255 support
13 * Devices: [standard] 8255 (8255)
14 * Author: ds
15 * Status: works
16 * Updated: Fri, 7 Jun 2002 12:56:45 -0700
17 *
18 * The classic in digital I/O. The 8255 appears in Comedi as a single
19 * digital I/O subdevice with 24 channels. The channel 0 corresponds
20 * to the 8255's port A, bit 0; channel 23 corresponds to port C, bit
21 * 7. Direction configuration is done in blocks, with channels 0-7,
22 * 8-15, 16-19, and 20-23 making up the 4 blocks. The only 8255 mode
23 * supported is mode 0.
24 *
25 * You should enable compilation this driver if you plan to use a board
26 * that has an 8255 chip. For multifunction boards, the main driver will
27 * configure the 8255 subdevice automatically.
28 *
29 * This driver also works independently with ISA and PCI cards that
30 * directly map the 8255 registers to I/O ports, including cards with
31 * multiple 8255 chips. To configure the driver for such a card, the
32 * option list should be a list of the I/O port bases for each of the
33 * 8255 chips. For example,
34 *
35 * comedi_config /dev/comedi0 8255 0x200,0x204,0x208,0x20c
36 *
37 * Note that most PCI 8255 boards do NOT work with this driver, and
38 * need a separate driver as a wrapper. For those that do work, the
39 * I/O port base address can be found in the output of 'lspci -v'.
40 */
41
42 #include <linux/module.h>
43 #include "../comedidev.h"
44
45 #include "8255.h"
46
47 static int dev_8255_attach(struct comedi_device *dev,
48 struct comedi_devconfig *it)
49 {
50 struct comedi_subdevice *s;
51 unsigned long iobase;
52 int ret;
53 int i;
54
55 for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) {
56 iobase = it->options[i];
57 if (!iobase)
58 break;
59 }
60 if (i == 0) {
61 dev_warn(dev->class_dev, "no devices specified\n");
62 return -EINVAL;
63 }
64
65 ret = comedi_alloc_subdevices(dev, i);
66 if (ret)
67 return ret;
68
69 for (i = 0; i < dev->n_subdevices; i++) {
70 s = &dev->subdevices[i];
71 iobase = it->options[i];
72
73 /*
74 * __comedi_request_region() does not set dev->iobase.
75 *
76 * For 8255 devices that are manually attached using
77 * comedi_config, the 'iobase' is the actual I/O port
78 * base address of the chip.
79 */
80 ret = __comedi_request_region(dev, iobase, I8255_SIZE);
81 if (ret) {
82 s->type = COMEDI_SUBD_UNUSED;
83 } else {
84 ret = subdev_8255_init(dev, s, NULL, iobase);
85 if (ret) {
86 /*
87 * Release the I/O port region here, as the
88 * "detach" handler cannot find it.
89 */
90 release_region(iobase, I8255_SIZE);
91 s->type = COMEDI_SUBD_UNUSED;
92 return ret;
93 }
94 }
95 }
96
97 return 0;
98 }
99
100 static void dev_8255_detach(struct comedi_device *dev)
101 {
102 struct comedi_subdevice *s;
103 int i;
104
105 for (i = 0; i < dev->n_subdevices; i++) {
106 s = &dev->subdevices[i];
107 if (s->type != COMEDI_SUBD_UNUSED) {
108 unsigned long regbase = subdev_8255_regbase(s);
109
110 release_region(regbase, I8255_SIZE);
111 }
112 }
113 }
114
115 static struct comedi_driver dev_8255_driver = {
116 .driver_name = "8255",
117 .module = THIS_MODULE,
118 .attach = dev_8255_attach,
119 .detach = dev_8255_detach,
120 };
121 module_comedi_driver(dev_8255_driver);
122
123 MODULE_AUTHOR("Comedi http://www.comedi.org");
124 MODULE_DESCRIPTION("Comedi driver for standalone 8255 devices");
125 MODULE_LICENSE("GPL");