arch/sh/boards/renesas/rts7751r2d/led.c

   1 /*
   2  * linux/arch/sh/boards/renesas/rts7751r2d/led.c
   3  *
   4  * Copyright (C) Atom Create Engineering Co., Ltd.
   5  *
   6  * May be copied or modified under the terms of GNU General Public
   7  * License.  See linux/COPYING for more information.
   8  *
   9  * This file contains Renesas Technology Sales RTS7751R2D specific LED code.
  10  */
  11 #include <linux/io.h>
  12 #include <linux/sched.h>
  13 #include <asm/rts7751r2d.h>
  14
  15 /* Cycle the LED's in the clasic Knightriger/Sun pattern */
  16 void heartbeat_rts7751r2d(void)
  17 {
  18         static unsigned int cnt = 0, period = 0;
  19         volatile unsigned short *p = (volatile unsigned short *)PA_OUTPORT;
  20         static unsigned bit = 0, up = 1;
  21
  22         cnt += 1;
  23         if (cnt < period)
  24                 return;
  25
  26         cnt = 0;
  27
  28         /* Go through the points (roughly!):
  29          * f(0)=10, f(1)=16, f(2)=20, f(5)=35, f(int)->110
  30          */
  31         period = 110 - ((300 << FSHIFT)/((avenrun[0]/5) + (3<<FSHIFT)));
  32
  33         *p = 1 << bit;
  34         if (up)
  35                 if (bit == 7) {
  36                         bit--;
  37                         up = 0;
  38                 } else
  39                         bit++;
  40         else if (bit == 0)
  41                 up = 1;
  42         else
  43                 bit--;
  44 }