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/config.h>
  10 #include <linux/sched.h>
  11
  12 /* Cycle the LED's in the clasic Knightrider/Sun pattern */
  13 void heartbeat_sh03(void)
  14 {
  15         static unsigned int cnt = 0, period = 0;
  16         volatile unsigned char* p = (volatile unsigned char*)0xa0800000;
  17         static unsigned bit = 0, up = 1;
  18
  19         cnt += 1;
  20         if (cnt < period) {
  21                 return;
  22         }
  23
  24         cnt = 0;
  25
  26         /* Go through the points (roughly!):
  27          * f(0)=10, f(1)=16, f(2)=20, f(5)=35,f(inf)->110
  28          */
  29         period = 110 - ( (300<<FSHIFT)/
  30                          ((avenrun[0]/5) + (3<<FSHIFT)) );
  31
  32         if (up) {
  33                 if (bit == 7) {
  34                         bit--;
  35                         up=0;
  36                 } else {
  37                         bit ++;
  38                 }
  39         } else {
  40                 if (bit == 0) {
  41                         bit++;
  42                         up=1;
  43                 } else {
  44                         bit--;
  45                 }
  46         }
  47         *p = 1<<bit;
  48
  49 }