arch/sh/boards/se/7343/led.c

   1 /*
   2  * arch/sh/boards/se/7343/led.c
   3  *
   4  */
   5 #include <linux/sched.h>
   6 #include <asm/mach/se7343.h>
   7
   8 /* Cycle the LED's in the clasic Knightrider/Sun pattern */
   9 void heartbeat_7343se(void)
  10 {
  11         static unsigned int cnt = 0, period = 0;
  12         volatile unsigned short *p = (volatile unsigned short *) PA_LED;
  13         static unsigned bit = 0, up = 1;
  14
  15         cnt += 1;
  16         if (cnt < period) {
  17                 return;
  18         }
  19
  20         cnt = 0;
  21
  22         /* Go through the points (roughly!):
  23          * f(0)=10, f(1)=16, f(2)=20, f(5)=35,f(inf)->110
  24          */
  25         period = 110 - ((300 << FSHIFT) / ((avenrun[0] / 5) + (3 << FSHIFT)));
  26
  27         if (up) {
  28                 if (bit == 7) {
  29                         bit--;
  30                         up = 0;
  31                 } else {
  32                         bit++;
  33                 }
  34         } else {
  35                 if (bit == 0) {
  36                         bit++;
  37                         up = 1;
  38                 } else {
  39                         bit--;
  40                 }
  41         }
  42         *p = 1 << (bit + LED_SHIFT);
  43
  44 }