arch/arm/mach-ks8695/time.c

   1 /*
   2  *  linux/arch/arm/mach-ks8695/time.c
   3  *
   4  *  Copyright (C) 2002 Micrel Inc.
   5  *  Copyright (C) 2006 Greg Ungerer <gerg@snapgear.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/init.h>
  25 #include <linux/time.h>
  26 #include <linux/irq.h>
  27 #include <asm/system.h>
  28 #include <asm/hardware.h>
  29 #include <asm/irq.h>
  30 #include <asm/io.h>
  31 #include <asm/mach/time.h>
  32
  33
  34 /*
  35  * Cannout read back time on KS8695.
  36  */
  37 static unsigned long ks8695_gettimeoffset(void)
  38 {
  39         return 0;
  40 }
  41
  42 static irqreturn_t ks8695_timer_interrupt(int irq, void *dev_id)
  43 {
  44         write_seqlock(&xtime_lock);
  45         __raw_writel(KS8695_INTMASK_TIMERINT1, KS8695_REG(KS8695_INT_STATUS));
  46         timer_tick();
  47         write_sequnlock(&xtime_lock);
  48         return IRQ_HANDLED;
  49 }
  50
  51 static struct irqaction ks8695_timer_irq = {
  52         .name    = "KS8695 Timer Tick",
  53         .flags   = IRQF_DISABLED | IRQF_TIMER,
  54         .handler = ks8695_timer_interrupt,
  55 };
  56
  57 /*
  58  * Set up timer interrupt, and return the current time in seconds.
  59  */
  60 static void __init ks8695_timer_init(void)
  61 {
  62         unsigned long tmout = CLOCK_TICK_RATE / HZ / 2;
  63
  64         /* Initialise to a known state (all timers off) */
  65         __raw_writel(0, KS8695_REG(KS8695_TIMER_CTRL));
  66
  67         /* enable timer 1 as HZ clock */
  68         __raw_writel(tmout, KS8695_REG(KS8695_TIMER1));
  69         __raw_writel(tmout, KS8695_REG(KS8695_TIMER1_PCOUNT));
  70         __raw_writel(0x02, KS8695_REG(KS8695_TIMER_CTRL));
  71
  72         setup_irq(KS8695_INT_TIMERINT1, &ks8695_timer_irq);
  73 }
  74
  75 struct sys_timer ks8695_timer = {
  76         .init   = ks8695_timer_init,
  77         .offset = ks8695_gettimeoffset,
  78 };
  79