arch/sh/boards/harp/led.c

   1 /*
   2  * linux/arch/sh/stboards/led.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 ST40STB1 HARP and compatible code.
  10  */
  11
  12 #include <asm/io.h>
  13 #include <asm/harp/harp.h>
  14
  15 /* Harp: Flash LD10 (front pannel) connected to EPLD (IC8) */
  16 /* Overdrive: Flash LD1 (front panel) connected to EPLD (IC4) */
  17 /* Works for HARP and overdrive */
  18 static void mach_led(int position, int value)
  19 {
  20         if (value) {
  21                 ctrl_outl(EPLD_LED_ON, EPLD_LED);
  22         } else {
  23                 ctrl_outl(EPLD_LED_OFF, EPLD_LED);
  24         }
  25 }
  26
  27 #ifdef CONFIG_HEARTBEAT
  28
  29 #include <linux/sched.h>
  30
  31 /* acts like an actual heart beat -- ie thump-thump-pause... */
  32 void heartbeat_harp(void)
  33 {
  34         static unsigned cnt = 0, period = 0, dist = 0;
  35
  36         if (cnt == 0 || cnt == dist)
  37                 mach_led( -1, 1);
  38         else if (cnt == 7 || cnt == dist+7)
  39                 mach_led( -1, 0);
  40
  41         if (++cnt > period) {
  42                 cnt = 0;
  43                 /* The hyperbolic function below modifies the heartbeat period
  44                  * length in dependency of the current (5min) load. It goes
  45                  * through the points f(0)=126, f(1)=86, f(5)=51,
  46                  * f(inf)->30. */
  47                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  48                 dist = period / 4;
  49         }
  50 }
  51 #endif