#!/bin/sh

echo "$1" > /sys/class/gpio/export
echo "low" > /sys/class/gpio/gpio$1/direction

cat /proc/interrupts | grep "IRQ_PIN"

for N in $(seq 1 $2)
do
echo "1" > /sys/class/gpio/gpio$1/value
echo "0" > /sys/class/gpio/gpio$1/value
done

echo "pulse count: $N"

cat /proc/interrupts | grep "IRQ_PIN"

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include "pinctrl.h"

#define PINID_GPMI_CE1N MXS_PIN_ENCODE(2, 27)
#define IRQ_PIN PINID_GPMI_CE1N

static irqreturn_t tstdrv_interrupt(int irq, void *dev_id)
{
return IRQ_HANDLED;
}

static int irq_init(void)
{
int ret;

ret = gpio_request(MXS_PIN_TO_GPIO(IRQ_PIN), "IRQ_PIN");
if (ret < 0) {
printk("TSTDRV: can't get GPIO pin: %d\n", IRQ_PIN);
return ret;
}
printk("GPIO pin: %d\n", MXS_PIN_TO_GPIO(IRQ_PIN));

gpio_direction_input(MXS_PIN_TO_GPIO(IRQ_PIN));
set_irq_type(gpio_to_irq(MXS_PIN_TO_GPIO(IRQ_PIN)), IRQ_TYPE_EDGE_FALLING);

ret = request_irq(gpio_to_irq(MXS_PIN_TO_GPIO(IRQ_PIN)),
tstdrv_interrupt, IRQF_TRIGGER_FALLING, "IRQ_PIN", NULL);
if (ret < 0) {
printk("TSTDRV: IRQ request failed: %d\n", ret);
return ret;
}

return 0;
}

static int __init driver_init(void)
{
printk("TSTDRV: driver init\n");
return irq_init();
}

static void __exit driver_exit(void)
{
printk("TSTDRV: driver exit\n");
free_irq(gpio_to_irq(MXS_PIN_TO_GPIO(IRQ_PIN)), NULL);
}

module_init(driver_init);
module_exit(driver_exit);
MODULE_LICENSE("GPL");