arch/sh/boards/sh03/led.c

   1 /*
   2  * linux/arch/sh/boards/sh03/led.c
   3  *
   4  * Copyright (C) 2004  Saito.K Interface Corporation.
   5  *
   6  * This file contains Interface CTP/PCI-SH03 specific LED code.
   7  */
   8
   9 #include <linux/sched.h>
  10
  11 /* Cycle the LED's in the clasic Knightrider/Sun pattern */
  12 void heartbeat_sh03(void)
  13 {
  14         static unsigned int cnt = 0, period = 0;
  15         volatile unsigned char* p = (volatile unsigned char*)0xa0800000;
  16         static unsigned bit = 0, up = 1;
  17
  18         cnt += 1;
  19         if (cnt < period) {
  20                 return;
  21         }
  22
  23         cnt = 0;
  24
  25         /* Go through the points (roughly!):
  26          * f(0)=10, f(1)=16, f(2)=20, f(5)=35,f(inf)->110
  27          */
  28         period = 110 - ( (300<<FSHIFT)/
  29                          ((avenrun[0]/5) + (3<<FSHIFT)) );
  30
  31         if (up) {
  32                 if (bit == 7) {
  33                         bit--;
  34                         up=0;
  35                 } else {
  36                         bit ++;
  37                 }
  38         } else {
  39                 if (bit == 0) {
  40                         bit++;
  41                         up=1;
  42                 } else {
  43                         bit--;
  44                 }
  45         }
  46         *p = 1<<bit;
  47
  48 }