Double timer overflow interrupts

Hello,

I am using the GP timers on DM8168 to toggle a GPIO output in a given pattern (IR signal).

I have written a kernel module to do this, but have one remaining issue.

Sometimes the interrupt routine is being called TWICE per timer overflow interrupt.  I suspect this might be because the INT clear write has not happened by the time I exit the interrupt routine, thus it fires again immediately.

I have tried reading back the interrupt enable register in the IRQ, but this didn't help.

The hw pointer is declared using ioremap_nocache, so it shouldn't be cached. 

Any ideas?

BTW, the dmtimer routines do NOT work properly on dm8168.  Because of this, I am controlling the HW regs directly.

Code:

static irqreturn_t timer_irq_handler(int irq, void *dev_id)
{

        int ret;
        // reset the timer interrupt status
        //omap_dm_timer_write_status(timer_ptr, OMAP_TIMER_INT_OVERFLOW);
        //omap_dm_timer_read_status(timer_ptr); // YES, you really need to do this 'wasteful' read
        vsir_timer1[0x28>>2]=0x2;
        ret = vsir_timer1[0x28>>2];
        if (ret != 0){
                // repeat clear
                vsir_timer1[0x28>>2]=0x2;
        }
        //omap_writew(0x2, vsir_timer_base+0x28);
        //ret = omap_readw(vsir_timer_base+0x28);

        //printk("TIMER FIRED idx:%d cnt:%d",vsir_index,vsir_count);

        // set GPIO
        //    use set/clear registers
        //      GPIO0 set 0x48032194
        //      GPIO0 clear 0x48032190
        //    based on output variable
        if (((vsir_count%2)==0)&&((vsir_index%2)==0)){
                //gpio_set_value(outp,1);
                //writel(outp, vsir_gpio + 0x4);
                vsir_gpio[(0x194)>>2] = outp;
                //omap_writew(outp, GPIO_BASE);
        }else{
                //gpio_set_value(outp,0);
                vsir_gpio[(0x190)>>2] = outp;
                //omap_writew(outp, GPIO_BASE + 4);
        }
      // inc timer count
        vsir_count -= 1;
        if (vsir_count <=0){

                // get next sequence
                vsir_index++;
                if (vsir_index < time_max){
                        vsir_count = time_arr[vsir_index];
                }else if ((vsir_repeat>1)){
                        // restart
                        vsir_index=0;
                        vsir_count = time_arr[vsir_index];
                        if (vsir_repeat<999){vsir_repeat--;}
                }else{
                        vsir_stop_timers();
                }
        }

        // tell the kernel it's handled
        return IRQ_HANDLED;
}