arch/sh/boards/se/7300/led.c

   1 /*
   2  * linux/arch/sh/boards/se/7300/led.c
   3  *
   4  * Derived from linux/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/se7300.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 << 8);
  25         } else {
  26                 *p &= ~(1 << 8);
  27         }
  28 }
  29
  30
  31 /* Cycle the LED's in the clasic Knightrider/Sun pattern */
  32 void
  33 heartbeat_7300se(void)
  34 {
  35         static unsigned int cnt = 0, period = 0;
  36         volatile unsigned short *p = (volatile unsigned short *) PA_LED;
  37         static unsigned bit = 0, up = 1;
  38
  39         cnt += 1;
  40         if (cnt < period) {
  41                 return;
  42         }
  43
  44         cnt = 0;
  45
  46         /* Go through the points (roughly!):
  47          * f(0)=10, f(1)=16, f(2)=20, f(5)=35,f(inf)->110
  48          */
  49         period = 110 - ((300 << FSHIFT) / ((avenrun[0] / 5) + (3 << FSHIFT)));
  50
  51         if (up) {
  52                 if (bit == 7) {
  53                         bit--;
  54                         up = 0;
  55                 } else {
  56                         bit++;
  57                 }
  58         } else {
  59                 if (bit == 0) {
  60                         bit++;
  61                         up = 1;
  62                 } else {
  63                         bit--;
  64                 }
  65         }
  66         *p = 1 << (bit + 8);
  67
  68 }
  69