arch/sh/boards/se/73180/led.c

   1 /*
   2  * arch/sh/boards/se/73180/led.c
   3  *
   4  * Derived from arch/sh/boards/se/770x/led.c
   5  *
   6  * Copyright (C) 2000 Stuart Menefy <stuart.menefy@st.com>
   7  *
   8  * May be copied or modified under the terms of the GNU General Public
   9  * License.  See linux/COPYING for more information.
  10  *
  11  * This file contains Solution Engine specific LED code.
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/sched.h>
  16 #include <asm/mach/se73180.h>
  17
  18 static void
  19 mach_led(int position, int value)
  20 {
  21         volatile unsigned short *p = (volatile unsigned short *) PA_LED;
  22
  23         if (value) {
  24                 *p |= (1 << LED_SHIFT);
  25         } else {
  26                 *p &= ~(1 << LED_SHIFT);
  27         }
  28 }
  29
  30 /* Cycle the LED's in the clasic Knightrider/Sun pattern */
  31 void
  32 heartbeat_73180se(void)
  33 {
  34         static unsigned int cnt = 0, period = 0;
  35         volatile unsigned short *p = (volatile unsigned short *) PA_LED;
  36         static unsigned bit = 0, up = 1;
  37
  38         cnt += 1;
  39         if (cnt < period) {
  40                 return;
  41         }
  42
  43         cnt = 0;
  44
  45         /* Go through the points (roughly!):
  46          * f(0)=10, f(1)=16, f(2)=20, f(5)=35,f(inf)->110
  47          */
  48         period = 110 - ((300 << FSHIFT) / ((avenrun[0] / 5) + (3 << FSHIFT)));
  49
  50         if (up) {
  51                 if (bit == 7) {
  52                         bit--;
  53                         up = 0;
  54                 } else {
  55                         bit++;
  56                 }
  57         } else {
  58                 if (bit == 0) {
  59                         bit++;
  60                         up = 1;
  61                 } else {
  62                         bit--;
  63                 }
  64         }
  65         *p = 1 << (bit + LED_SHIFT);
  66
  67 }