aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/char/scan_keyb.c
blob: 2b5bb4f5754dc8828389bfef2b298335fc418ac1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
/*
 *	$Id: scan_keyb.c,v 1.2 2000/07/04 06:24:42 yaegashi Exp $ 
 *	Copyright (C) 2000 YAEGASHI Takeshi
 *	Generic scan keyboard driver
 */

#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/mm.h>
#include <linux/signal.h>
#include <linux/init.h>
#include <linux/kbd_ll.h>
#include <linux/delay.h>
#include <linux/random.h>
#include <linux/poll.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/kbd_kern.h>
#include <linux/timer.h>

#define SCANHZ	(HZ/20)

struct scan_keyboard {
	struct scan_keyboard *next;
	int (*scan)(unsigned char *buffer);
	const unsigned char *table;
	unsigned char *s0, *s1;
	int length;
};

static int scan_jiffies=0;
static struct scan_keyboard *keyboards=NULL;
struct timer_list scan_timer;

static void check_kbd(const unsigned char *table,
		      unsigned char *new, unsigned char *old, int length)
{
	int need_tasklet_schedule=0;
	unsigned int xor, bit;
	
	while(length-->0) {
		if((xor=*new^*old)==0) {
			table+=8;
		}
		else {
			for(bit=0x01; bit<0x100; bit<<=1) {
				if(xor&bit) {
					handle_scancode(*table, !(*new&bit));
					need_tasklet_schedule=1;
#if 0
					printk("0x%x %s\n", *table, (*new&bit)?"released":"pressed");
#endif
				}
				table++;
			}
		}
		new++; old++;
	}

	if(need_tasklet_schedule)
		tasklet_schedule(&keyboard_tasklet);
}


static void scan_kbd(unsigned long dummy)
{
	struct scan_keyboard *kbd;

	scan_jiffies++;

	for(kbd=keyboards; kbd!=NULL; kbd=kbd->next) {
		if(scan_jiffies&1) {
			if(!kbd->scan(kbd->s0))
				check_kbd(kbd->table,
					  kbd->s0, kbd->s1, kbd->length);
			else
				memcpy(kbd->s0, kbd->s1, kbd->length);
		}
		else {
			if(!kbd->scan(kbd->s1))
				check_kbd(kbd->table,
					  kbd->s1, kbd->s0, kbd->length);
			else
				memcpy(kbd->s1, kbd->s0, kbd->length);
		}
		
	}

	init_timer(&scan_timer);
	scan_timer.expires = jiffies + SCANHZ;
	scan_timer.data = 0;
	scan_timer.function = scan_kbd;
	add_timer(&scan_timer);
}


int register_scan_keyboard(int (*scan)(unsigned char *buffer),
			   const unsigned char *table,
			   int length)
{
	struct scan_keyboard *kbd;

	kbd = kmalloc(sizeof(struct scan_keyboard), GFP_KERNEL);
	if (kbd == NULL)
		goto error_out;

	kbd->scan=scan;
	kbd->table=table;
	kbd->length=length;

	kbd->s0 = kmalloc(length, GFP_KERNEL);
	if (kbd->s0 == NULL)
		goto error_free_kbd;

	kbd->s1 = kmalloc(length, GFP_KERNEL);
	if (kbd->s1 == NULL)
		goto error_free_s0;

	memset(kbd->s0, -1, kbd->length);
	memset(kbd->s1, -1, kbd->length);
	
	kbd->next=keyboards;
	keyboards=kbd;

	return 0;

 error_free_s0:
	kfree(kbd->s0);

 error_free_kbd:
	kfree(kbd);

 error_out:
	return -ENOMEM;
}
			      
			      
void __init scan_kbd_init(void)
{
	init_timer(&scan_timer);
	scan_timer.expires = jiffies + SCANHZ;
	scan_timer.data = 0;
	scan_timer.function = scan_kbd;
	add_timer(&scan_timer);

	printk(KERN_INFO "Generic scan keyboard driver initialized\n");
}