arch/sh/boards/bigsur/led.c

   1 /*
   2  * linux/arch/sh/boards/bigsur/led.c
   3  *
   4  * By Dustin McIntire (dustin@sensoria.com) (c)2001
   5  * Derived from led_se.c and led.c, which bore the message:
   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 Big Sur specific LED code.
  12  */
  13
  14 #include <asm/io.h>
  15 #include <asm/bigsur/bigsur.h>
  16
  17 static void mach_led(int position, int value)
  18 {
  19         int word;
  20
  21         word = bigsur_inl(BIGSUR_CSLR);
  22         if (value) {
  23                 bigsur_outl(word & ~BIGSUR_LED, BIGSUR_CSLR);
  24         } else {
  25                 bigsur_outl(word | BIGSUR_LED, BIGSUR_CSLR);
  26         }
  27 }
  28
  29 #ifdef CONFIG_HEARTBEAT
  30
  31 #include <linux/sched.h>
  32
  33 /* Cycle the LED on/off */
  34 void heartbeat_bigsur(void)
  35 {
  36         static unsigned cnt = 0, period = 0, dist = 0;
  37
  38         if (cnt == 0 || cnt == dist)
  39                 mach_led( -1, 1);
  40         else if (cnt == 7 || cnt == dist+7)
  41                 mach_led( -1, 0);
  42
  43         if (++cnt > period) {
  44                 cnt = 0;
  45                 /* The hyperbolic function below modifies the heartbeat period
  46                  * length in dependency of the current (5min) load. It goes
  47                  * through the points f(0)=126, f(1)=86, f(5)=51,
  48                  * f(inf)->30. */
  49                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  50                 dist = period / 4;
  51         }
  52 }
  53 #endif /* CONFIG_HEARTBEAT */
  54