question in request_threaded_irq

Hi, I have a question with respect to request_threaded_irq. Assume that one driver has registered and ISR on some particular irq number. Can i use the same irq number and register and isr in another driver. Because that is my requirement. when i try to do that is an error message with an error no as -19. err = request_threaded_irq(pdata->irq , NULL, testing_fucntion, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, "testing_function", dev); Can some one please help me whether it is possible. Regards, RB