drivers/char/scan_keyb.c

   1 /*
   2  *      $Id: scan_keyb.c,v 1.2 2000/07/04 06:24:42 yaegashi Exp $
   3  *      Copyright (C) 2000 YAEGASHI Takeshi
   4  *      Generic scan keyboard driver
   5  */
   6
   7 #include <linux/spinlock.h>
   8 #include <linux/sched.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/tty.h>
  11 #include <linux/mm.h>
  12 #include <linux/signal.h>
  13 #include <linux/init.h>
  14 #include <linux/kbd_ll.h>
  15 #include <linux/delay.h>
  16 #include <linux/random.h>
  17 #include <linux/poll.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/slab.h>
  20 #include <linux/kbd_kern.h>
  21 #include <linux/timer.h>
  22
  23 #define SCANHZ  (HZ/20)
  24
  25 struct scan_keyboard {
  26         struct scan_keyboard *next;
  27         int (*scan)(unsigned char *buffer);
  28         const unsigned char *table;
  29         unsigned char *s0, *s1;
  30         int length;
  31 };
  32
  33 static int scan_jiffies=0;
  34 static struct scan_keyboard *keyboards=NULL;
  35 struct timer_list scan_timer;
  36
  37 static void check_kbd(const unsigned char *table,
  38                       unsigned char *new, unsigned char *old, int length)
  39 {
  40         int need_tasklet_schedule=0;
  41         unsigned int xor, bit;
  42
  43         while(length-->0) {
  44                 if((xor=*new^*old)==0) {
  45                         table+=8;
  46                 }
  47                 else {
  48                         for(bit=0x01; bit<0x100; bit<<=1) {
  49                                 if(xor&bit) {
  50                                         handle_scancode(*table, !(*new&bit));
  51                                         need_tasklet_schedule=1;
  52 #if 0
  53                                         printk("0x%x %s\n", *table, (*new&bit)?"released":"pressed");
  54 #endif
  55                                 }
  56                                 table++;
  57                         }
  58                 }
  59                 new++; old++;
  60         }
  61
  62         if(need_tasklet_schedule)
  63                 tasklet_schedule(&keyboard_tasklet);
  64 }
  65
  66
  67 static void scan_kbd(unsigned long dummy)
  68 {
  69         struct scan_keyboard *kbd;
  70
  71         scan_jiffies++;
  72
  73         for(kbd=keyboards; kbd!=NULL; kbd=kbd->next) {
  74                 if(scan_jiffies&1) {
  75                         if(!kbd->scan(kbd->s0))
  76                                 check_kbd(kbd->table,
  77                                           kbd->s0, kbd->s1, kbd->length);
  78                         else
  79                                 memcpy(kbd->s0, kbd->s1, kbd->length);
  80                 }
  81                 else {
  82                         if(!kbd->scan(kbd->s1))
  83                                 check_kbd(kbd->table,
  84                                           kbd->s1, kbd->s0, kbd->length);
  85                         else
  86                                 memcpy(kbd->s1, kbd->s0, kbd->length);
  87                 }
  88
  89         }
  90
  91         init_timer(&scan_timer);
  92         scan_timer.expires = jiffies + SCANHZ;
  93         scan_timer.data = 0;
  94         scan_timer.function = scan_kbd;
  95         add_timer(&scan_timer);
  96 }
  97
  98
  99 int register_scan_keyboard(int (*scan)(unsigned char *buffer),
 100                            const unsigned char *table,
 101                            int length)
 102 {
 103         struct scan_keyboard *kbd;
 104
 105         kbd = kmalloc(sizeof(struct scan_keyboard), GFP_KERNEL);
 106         if (kbd == NULL)
 107                 goto error_out;
 108
 109         kbd->scan=scan;
 110         kbd->table=table;
 111         kbd->length=length;
 112
 113         kbd->s0 = kmalloc(length, GFP_KERNEL);
 114         if (kbd->s0 == NULL)
 115                 goto error_free_kbd;
 116
 117         kbd->s1 = kmalloc(length, GFP_KERNEL);
 118         if (kbd->s1 == NULL)
 119                 goto error_free_s0;
 120
 121         memset(kbd->s0, -1, kbd->length);
 122         memset(kbd->s1, -1, kbd->length);
 123
 124         kbd->next=keyboards;
 125         keyboards=kbd;
 126
 127         return 0;
 128
 129  error_free_s0:
 130         kfree(kbd->s0);
 131
 132  error_free_kbd:
 133         kfree(kbd);
 134
 135  error_out:
 136         return -ENOMEM;
 137 }
 138
 139
 140 void __init scan_kbd_init(void)
 141 {
 142         init_timer(&scan_timer);
 143         scan_timer.expires = jiffies + SCANHZ;
 144         scan_timer.data = 0;
 145         scan_timer.function = scan_kbd;
 146         add_timer(&scan_timer);
 147
 148         printk(KERN_INFO "Generic scan keyboard driver initialized\n");
 149 }