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1da177e4 LT |
1 | /* |
2 | * Parallel port to Keyboard port adapter driver for Linux | |
3 | * | |
4 | * Copyright (c) 1999-2004 Vojtech Pavlik | |
5 | */ | |
6 | ||
7 | /* | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public License version 2 as published by | |
10 | * the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | /* | |
14 | * To connect an AT or XT keyboard to the parallel port, a fairly simple adapter | |
15 | * can be made: | |
16 | * | |
17 | * Parallel port Keyboard port | |
18 | * | |
19 | * +5V --------------------- +5V (4) | |
20 | * | |
21 | * ______ | |
22 | * +5V -------|______|--. | |
23 | * | | |
24 | * ACK (10) ------------| | |
25 | * |--- KBD CLOCK (5) | |
26 | * STROBE (1) ---|<|----' | |
27 | * | |
28 | * ______ | |
29 | * +5V -------|______|--. | |
30 | * | | |
31 | * BUSY (11) -----------| | |
32 | * |--- KBD DATA (1) | |
33 | * AUTOFD (14) --|<|----' | |
34 | * | |
35 | * GND (18-25) ------------- GND (3) | |
36 | * | |
37 | * The diodes can be fairly any type, and the resistors should be somewhere | |
38 | * around 5 kOhm, but the adapter will likely work without the resistors, | |
39 | * too. | |
40 | * | |
41 | * The +5V source can be taken either from USB, from mouse or keyboard ports, | |
42 | * or from a joystick port. Unfortunately, the parallel port of a PC doesn't | |
43 | * have a +5V pin, and feeding the keyboard from signal pins is out of question | |
44 | * with 300 mA power reqirement of a typical AT keyboard. | |
45 | */ | |
46 | ||
47 | #include <linux/module.h> | |
48 | #include <linux/parport.h> | |
5a0e3ad6 | 49 | #include <linux/slab.h> |
1da177e4 LT |
50 | #include <linux/init.h> |
51 | #include <linux/serio.h> | |
52 | ||
53 | MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); | |
54 | MODULE_DESCRIPTION("Parallel port to Keyboard port adapter driver"); | |
55 | MODULE_LICENSE("GPL"); | |
56 | ||
57 | static unsigned int parkbd_pp_no; | |
58 | module_param_named(port, parkbd_pp_no, int, 0); | |
59 | MODULE_PARM_DESC(port, "Parallel port the adapter is connected to (default is 0)"); | |
60 | ||
61 | static unsigned int parkbd_mode = SERIO_8042; | |
62 | module_param_named(mode, parkbd_mode, uint, 0); | |
63 | MODULE_PARM_DESC(mode, "Mode of operation: XT = 0/AT = 1 (default)"); | |
64 | ||
65 | #define PARKBD_CLOCK 0x01 /* Strobe & Ack */ | |
66 | #define PARKBD_DATA 0x02 /* AutoFd & Busy */ | |
67 | ||
68 | static int parkbd_buffer; | |
69 | static int parkbd_counter; | |
70 | static unsigned long parkbd_last; | |
71 | static int parkbd_writing; | |
72 | static unsigned long parkbd_start; | |
73 | ||
74 | static struct pardevice *parkbd_dev; | |
75 | static struct serio *parkbd_port; | |
76 | ||
77 | static int parkbd_readlines(void) | |
78 | { | |
79 | return (parport_read_status(parkbd_dev->port) >> 6) ^ 2; | |
80 | } | |
81 | ||
82 | static void parkbd_writelines(int data) | |
83 | { | |
84 | parport_write_control(parkbd_dev->port, (~data & 3) | 0x10); | |
85 | } | |
86 | ||
87 | static int parkbd_write(struct serio *port, unsigned char c) | |
88 | { | |
89 | unsigned char p; | |
90 | ||
91 | if (!parkbd_mode) return -1; | |
92 | ||
93 | p = c ^ (c >> 4); | |
94 | p = p ^ (p >> 2); | |
95 | p = p ^ (p >> 1); | |
96 | ||
97 | parkbd_counter = 0; | |
98 | parkbd_writing = 1; | |
99 | parkbd_buffer = c | (((int) (~p & 1)) << 8) | 0x600; | |
100 | ||
101 | parkbd_writelines(2); | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
5712cb3d | 106 | static void parkbd_interrupt(void *dev_id) |
1da177e4 LT |
107 | { |
108 | ||
109 | if (parkbd_writing) { | |
110 | ||
111 | if (parkbd_counter && ((parkbd_counter == 11) || time_after(jiffies, parkbd_last + HZ/100))) { | |
112 | parkbd_counter = 0; | |
113 | parkbd_buffer = 0; | |
114 | parkbd_writing = 0; | |
115 | parkbd_writelines(3); | |
116 | return; | |
117 | } | |
118 | ||
119 | parkbd_writelines(((parkbd_buffer >> parkbd_counter++) & 1) | 2); | |
120 | ||
121 | if (parkbd_counter == 11) { | |
122 | parkbd_counter = 0; | |
123 | parkbd_buffer = 0; | |
124 | parkbd_writing = 0; | |
125 | parkbd_writelines(3); | |
126 | } | |
127 | ||
128 | } else { | |
129 | ||
130 | if ((parkbd_counter == parkbd_mode + 10) || time_after(jiffies, parkbd_last + HZ/100)) { | |
131 | parkbd_counter = 0; | |
132 | parkbd_buffer = 0; | |
133 | } | |
134 | ||
135 | parkbd_buffer |= (parkbd_readlines() >> 1) << parkbd_counter++; | |
136 | ||
137 | if (parkbd_counter == parkbd_mode + 10) | |
7d12e780 | 138 | serio_interrupt(parkbd_port, (parkbd_buffer >> (2 - parkbd_mode)) & 0xff, 0); |
1da177e4 LT |
139 | } |
140 | ||
141 | parkbd_last = jiffies; | |
142 | } | |
143 | ||
144 | static int parkbd_getport(void) | |
145 | { | |
146 | struct parport *pp; | |
147 | ||
148 | pp = parport_find_number(parkbd_pp_no); | |
149 | ||
150 | if (pp == NULL) { | |
151 | printk(KERN_ERR "parkbd: no such parport\n"); | |
152 | return -ENODEV; | |
153 | } | |
154 | ||
155 | parkbd_dev = parport_register_device(pp, "parkbd", NULL, NULL, parkbd_interrupt, PARPORT_DEV_EXCL, NULL); | |
156 | parport_put_port(pp); | |
157 | ||
158 | if (!parkbd_dev) | |
159 | return -ENODEV; | |
160 | ||
161 | if (parport_claim(parkbd_dev)) { | |
162 | parport_unregister_device(parkbd_dev); | |
163 | return -EBUSY; | |
164 | } | |
165 | ||
166 | parkbd_start = jiffies; | |
167 | ||
168 | return 0; | |
169 | } | |
170 | ||
171 | static struct serio * __init parkbd_allocate_serio(void) | |
172 | { | |
173 | struct serio *serio; | |
174 | ||
b39787a9 | 175 | serio = kzalloc(sizeof(struct serio), GFP_KERNEL); |
1da177e4 | 176 | if (serio) { |
1da177e4 LT |
177 | serio->id.type = parkbd_mode; |
178 | serio->write = parkbd_write, | |
179 | strlcpy(serio->name, "PARKBD AT/XT keyboard adapter", sizeof(serio->name)); | |
180 | snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", parkbd_dev->port->name); | |
181 | } | |
182 | ||
183 | return serio; | |
184 | } | |
185 | ||
186 | static int __init parkbd_init(void) | |
187 | { | |
188 | int err; | |
189 | ||
190 | err = parkbd_getport(); | |
191 | if (err) | |
192 | return err; | |
193 | ||
194 | parkbd_port = parkbd_allocate_serio(); | |
195 | if (!parkbd_port) { | |
196 | parport_release(parkbd_dev); | |
197 | return -ENOMEM; | |
198 | } | |
199 | ||
200 | parkbd_writelines(3); | |
201 | ||
202 | serio_register_port(parkbd_port); | |
203 | ||
204 | printk(KERN_INFO "serio: PARKBD %s adapter on %s\n", | |
205 | parkbd_mode ? "AT" : "XT", parkbd_dev->port->name); | |
206 | ||
207 | return 0; | |
208 | } | |
209 | ||
210 | static void __exit parkbd_exit(void) | |
211 | { | |
212 | parport_release(parkbd_dev); | |
213 | serio_unregister_port(parkbd_port); | |
214 | parport_unregister_device(parkbd_dev); | |
215 | } | |
216 | ||
217 | module_init(parkbd_init); | |
218 | module_exit(parkbd_exit); |