arch/sh/boards/bigsur/led.c

   1 /*
   2  * linux/arch/sh/kernel/led_bigsur.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 <linux/config.h>
  15 #include <asm/io.h>
  16 #include <asm/bigsur/bigsur.h>
  17
  18 static void mach_led(int position, int value)
  19 {
  20         int word;
  21
  22         word = bigsur_inl(BIGSUR_CSLR);
  23         if (value) {
  24                 bigsur_outl(word & ~BIGSUR_LED, BIGSUR_CSLR);
  25         } else {
  26                 bigsur_outl(word | BIGSUR_LED, BIGSUR_CSLR);
  27         }
  28 }
  29
  30 #ifdef CONFIG_HEARTBEAT
  31
  32 #include <linux/sched.h>
  33
  34 /* Cycle the LED on/off */
  35 void heartbeat_bigsur(void)
  36 {
  37         static unsigned cnt = 0, period = 0, dist = 0;
  38
  39         if (cnt == 0 || cnt == dist)
  40                 mach_led( -1, 1);
  41         else if (cnt == 7 || cnt == dist+7)
  42                 mach_led( -1, 0);
  43
  44         if (++cnt > period) {
  45                 cnt = 0;
  46                 /* The hyperbolic function below modifies the heartbeat period
  47                  * length in dependency of the current (5min) load. It goes
  48                  * through the points f(0)=126, f(1)=86, f(5)=51,
  49                  * f(inf)->30. */
  50                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  51                 dist = period / 4;
  52         }
  53 }
  54 #endif /* CONFIG_HEARTBEAT */
  55