Got it! We have added a device driver for cpld and added interrupt handling in it. Now it works.
Registered irq request in init function
struct device_node *node = of_find_node_by_name(NULL, "board-control");
irqNum = of_irq_to_resource(node, 0, &resource);
result = request_irq(irqNum, (irq_handler_t) irq5_handler, IRQF_TRIGGER_RISING, "irq0_handler", NULL);
In interrupt handler function irq5_handler ISR added.
static irq_handler_t irq5_handler(unsigned int irq, void *dev_id, struct pt_regs *regs) {
// ISR here
}