arch/sh/boards/se/770x/led.c

   1 /*
   2  * linux/arch/sh/kernel/led_se.c
   3  *
   4  * Copyright (C) 2000 Stuart Menefy <stuart.menefy@st.com>
   5  *
   6  * May be copied or modified under the terms of the GNU General Public
   7  * License.  See linux/COPYING for more information.
   8  *
   9  * This file contains Solution Engine specific LED code.
  10  */
  11
  12 #include <linux/sched.h>
  13 #include <asm/se.h>
  14
  15 /* Cycle the LED's in the clasic Knightrider/Sun pattern */
  16 void heartbeat_se(void)
  17 {
  18         static unsigned int cnt = 0, period = 0;
  19         volatile unsigned short* p = (volatile unsigned short*)PA_LED;
  20         static unsigned bit = 0, up = 1;
  21
  22         cnt += 1;
  23         if (cnt < period) {
  24                 return;
  25         }
  26
  27         cnt = 0;
  28
  29         /* Go through the points (roughly!):
  30          * f(0)=10, f(1)=16, f(2)=20, f(5)=35,f(inf)->110
  31          */
  32         period = 110 - ( (300<<FSHIFT)/
  33                          ((avenrun[0]/5) + (3<<FSHIFT)) );
  34
  35         if (up) {
  36                 if (bit == 7) {
  37                         bit--;
  38                         up=0;
  39                 } else {
  40                         bit ++;
  41                 }
  42         } else {
  43                 if (bit == 0) {
  44                         bit++;
  45                         up=1;
  46                 } else {
  47                         bit--;
  48                 }
  49         }
  50         *p = 1<<(bit+8);
  51
  52 }