include/asm-arm/arch-ks8695/fast_timer.h

   1 #ifndef __ASM_ARM_MACH_FAST_TIMER_H
   2 #define __ASM_ARM_MACH_FAST_TIMER_H
   3
   4 #include <linux/sched.h>
   5 #include <linux/timex.h>
   6 #include <linux/interrupt.h>
   7 #include <asm/hardware.h>
   8 #include <asm/irq.h>
   9 #include <asm/io.h>
  10
  11 static irqreturn_t fast_timer_interrupt(int irq, void *dev_id)
  12 {
  13         __raw_writel(KS8695_INTMASK_TIMERINT0, KS8695_REG(KS8695_INT_STATUS));
  14         do_fast_timer();
  15         return IRQ_HANDLED;
  16 }
  17
  18 static void fast_timer_set(void)
  19 {
  20         unsigned long interval, data, pulse, ctrl;
  21
  22         /* Setup TIMER0 as fast clock */
  23         interval = (CLOCK_TICK_RATE/1000000) * fast_timer_rate;
  24         data = interval >> 1;
  25         pulse = interval - data;
  26         __raw_writel(data, KS8695_REG(KS8695_TIMER0));
  27         __raw_writel(pulse, KS8695_REG(KS8695_TIMER0_PCOUNT));
  28         ctrl = __raw_readl(KS8695_REG(KS8695_TIMER_CTRL)) | 0x01;
  29         __raw_writel(ctrl, KS8695_REG(KS8695_TIMER_CTRL));
  30 }
  31
  32 static int __init fast_timer_setup(void)
  33 {
  34         /* Connect the interrupt handler and enable the interrupt */
  35         if (request_irq(KS8695_INT_TIMERINT0, fast_timer_interrupt,
  36                                 SA_INTERRUPT, "fast timer", NULL))
  37                 return -EBUSY;
  38
  39         fast_timer_rate = 2000;
  40         fast_timer_set();
  41
  42         printk("fast timer: %d Hz, IRQ %d\n", fast_timer_rate,
  43                         KS8695_INT_TIMERINT0);
  44         return 0;
  45 }
  46
  47 static void __exit fast_timer_cleanup(void)
  48 {
  49         unsigned long ctrl;
  50
  51         ctrl = __raw_readl(KS8695_REG(KS8695_TIMER_CTRL)) & 0x02;
  52         __raw_writel(ctrl, KS8695_REG(KS8695_TIMER_CTRL));
  53         free_irq(KS8695_INT_TIMERINT0, NULL);
  54 }
  55
  56 #endif