request_threaded_irq() is used in the driver why not request_irq()? What are the differences between two?

Question

I posted this is the thread which discussed about request_threaded_irq but I did not get any reply. So I am posting it freshly.

I am working on a touchscreen driver for

Answer 1

Another important aspect: "If you want to set up a threaded irq handler for your device then you need to supply handler and thread_fn. handler is still called in hard interrupt context and has to check whether the interrupt originates from the device. If yes it needs to disable the interrupt on the device and return IRQ_WAKE_THREAD which will wake up the handler thread and run thread_fn."

Source: https://www.kernel.org/doc/htmldocs/genericirq.html