DM355 TIMER IRQ

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DM355 TIMER IRQ

Digant
Hello everyone,

I m using MV 4 and DM355 EVM.

I want to use timers and generate 1MHZ frequncy from GPIO pins.Using timer
IRQS.

*1-how to use high resoltion timers and its IRQ form kernel space driver ??*

**I have tried but some how the APIs in

/arch/arm/mach-davinci/time.c

#1. *scedule_hr_timer_int*

#2.*get_arch_cycles*

I am getting  warning at compile time : scedule_hr_timer_int is *undefined*!!!

though I have added *</asm/arch/hrtime.h>  *in my kernel driver code

I have also enabled HIGH_RES_TIMERS in my configurations.

It is getting initialised whie bootup I have also checked it using printks.

2- Is there any other way to use timers apart form High resolution timers
???

I just want timer interrupt at 1 Mhz from kernel space.

Please help.

thank you
-Digant Desai
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DM355 TIMER IRQ

Nick Thompson
On 12/11/09 08:00, Digant wrote:
> I want to use timers and generate 1MHZ frequncy from GPIO pins.Using timer
> IRQS.

Are you sure you want to? You're going to need an interrupt every 500ns to
do that. Your ARM is not going to be able to do much else, even if you can
get interrupts going that quickly.

Does your hardware have a timer that is running that fast? If not, HR timers
will not be able to help you.

Interrupt latencies will lead to inaccurate frequency control and mark-space
ratio control in any case.

What about a PWM or something similar?

Nick.