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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> | |
49 | #include <linux/init.h> | |
50 | #include <linux/serio.h> | |
51 | ||
52 | MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); | |
53 | MODULE_DESCRIPTION("Parallel port to Keyboard port adapter driver"); | |
54 | MODULE_LICENSE("GPL"); | |
55 | ||
56 | static unsigned int parkbd_pp_no; | |
57 | module_param_named(port, parkbd_pp_no, int, 0); | |
58 | MODULE_PARM_DESC(port, "Parallel port the adapter is connected to (default is 0)"); | |
59 | ||
60 | static unsigned int parkbd_mode = SERIO_8042; | |
61 | module_param_named(mode, parkbd_mode, uint, 0); | |
62 | MODULE_PARM_DESC(mode, "Mode of operation: XT = 0/AT = 1 (default)"); | |
63 | ||
64 | #define PARKBD_CLOCK 0x01 /* Strobe & Ack */ | |
65 | #define PARKBD_DATA 0x02 /* AutoFd & Busy */ | |
66 | ||
67 | static int parkbd_buffer; | |
68 | static int parkbd_counter; | |
69 | static unsigned long parkbd_last; | |
70 | static int parkbd_writing; | |
71 | static unsigned long parkbd_start; | |
72 | ||
73 | static struct pardevice *parkbd_dev; | |
74 | static struct serio *parkbd_port; | |
75 | ||
76 | static int parkbd_readlines(void) | |
77 | { | |
78 | return (parport_read_status(parkbd_dev->port) >> 6) ^ 2; | |
79 | } | |
80 | ||
81 | static void parkbd_writelines(int data) | |
82 | { | |
83 | parport_write_control(parkbd_dev->port, (~data & 3) | 0x10); | |
84 | } | |
85 | ||
86 | static int parkbd_write(struct serio *port, unsigned char c) | |
87 | { | |
88 | unsigned char p; | |
89 | ||
90 | if (!parkbd_mode) return -1; | |
91 | ||
92 | p = c ^ (c >> 4); | |
93 | p = p ^ (p >> 2); | |
94 | p = p ^ (p >> 1); | |
95 | ||
96 | parkbd_counter = 0; | |
97 | parkbd_writing = 1; | |
98 | parkbd_buffer = c | (((int) (~p & 1)) << 8) | 0x600; | |
99 | ||
100 | parkbd_writelines(2); | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
5712cb3d | 105 | static void parkbd_interrupt(void *dev_id) |
1da177e4 LT |
106 | { |
107 | ||
108 | if (parkbd_writing) { | |
109 | ||
110 | if (parkbd_counter && ((parkbd_counter == 11) || time_after(jiffies, parkbd_last + HZ/100))) { | |
111 | parkbd_counter = 0; | |
112 | parkbd_buffer = 0; | |
113 | parkbd_writing = 0; | |
114 | parkbd_writelines(3); | |
115 | return; | |
116 | } | |
117 | ||
118 | parkbd_writelines(((parkbd_buffer >> parkbd_counter++) & 1) | 2); | |
119 | ||
120 | if (parkbd_counter == 11) { | |
121 | parkbd_counter = 0; | |
122 | parkbd_buffer = 0; | |
123 | parkbd_writing = 0; | |
124 | parkbd_writelines(3); | |
125 | } | |
126 | ||
127 | } else { | |
128 | ||
129 | if ((parkbd_counter == parkbd_mode + 10) || time_after(jiffies, parkbd_last + HZ/100)) { | |
130 | parkbd_counter = 0; | |
131 | parkbd_buffer = 0; | |
132 | } | |
133 | ||
134 | parkbd_buffer |= (parkbd_readlines() >> 1) << parkbd_counter++; | |
135 | ||
136 | if (parkbd_counter == parkbd_mode + 10) | |
7d12e780 | 137 | serio_interrupt(parkbd_port, (parkbd_buffer >> (2 - parkbd_mode)) & 0xff, 0); |
1da177e4 LT |
138 | } |
139 | ||
140 | parkbd_last = jiffies; | |
141 | } | |
142 | ||
143 | static int parkbd_getport(void) | |
144 | { | |
145 | struct parport *pp; | |
146 | ||
147 | pp = parport_find_number(parkbd_pp_no); | |
148 | ||
149 | if (pp == NULL) { | |
150 | printk(KERN_ERR "parkbd: no such parport\n"); | |
151 | return -ENODEV; | |
152 | } | |
153 | ||
154 | parkbd_dev = parport_register_device(pp, "parkbd", NULL, NULL, parkbd_interrupt, PARPORT_DEV_EXCL, NULL); | |
155 | parport_put_port(pp); | |
156 | ||
157 | if (!parkbd_dev) | |
158 | return -ENODEV; | |
159 | ||
160 | if (parport_claim(parkbd_dev)) { | |
161 | parport_unregister_device(parkbd_dev); | |
162 | return -EBUSY; | |
163 | } | |
164 | ||
165 | parkbd_start = jiffies; | |
166 | ||
167 | return 0; | |
168 | } | |
169 | ||
170 | static struct serio * __init parkbd_allocate_serio(void) | |
171 | { | |
172 | struct serio *serio; | |
173 | ||
b39787a9 | 174 | serio = kzalloc(sizeof(struct serio), GFP_KERNEL); |
1da177e4 | 175 | if (serio) { |
1da177e4 LT |
176 | serio->id.type = parkbd_mode; |
177 | serio->write = parkbd_write, | |
178 | strlcpy(serio->name, "PARKBD AT/XT keyboard adapter", sizeof(serio->name)); | |
179 | snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", parkbd_dev->port->name); | |
180 | } | |
181 | ||
182 | return serio; | |
183 | } | |
184 | ||
185 | static int __init parkbd_init(void) | |
186 | { | |
187 | int err; | |
188 | ||
189 | err = parkbd_getport(); | |
190 | if (err) | |
191 | return err; | |
192 | ||
193 | parkbd_port = parkbd_allocate_serio(); | |
194 | if (!parkbd_port) { | |
195 | parport_release(parkbd_dev); | |
196 | return -ENOMEM; | |
197 | } | |
198 | ||
199 | parkbd_writelines(3); | |
200 | ||
201 | serio_register_port(parkbd_port); | |
202 | ||
203 | printk(KERN_INFO "serio: PARKBD %s adapter on %s\n", | |
204 | parkbd_mode ? "AT" : "XT", parkbd_dev->port->name); | |
205 | ||
206 | return 0; | |
207 | } | |
208 | ||
209 | static void __exit parkbd_exit(void) | |
210 | { | |
211 | parport_release(parkbd_dev); | |
212 | serio_unregister_port(parkbd_port); | |
213 | parport_unregister_device(parkbd_dev); | |
214 | } | |
215 | ||
216 | module_init(parkbd_init); | |
217 | module_exit(parkbd_exit); |