#include <linux/module.h>
#include <linux/version.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <mach/cputype.h>
#include <mach/hardware.h>
#include <mach/mux.h>
#include <asm/gpio.h>

static int gpio_num;
static int gpio_pin;

DECLARE_COMPLETION(work);

static irqreturn_t handler (int irq, void * dev)
{
    complete_all(&work);
    return IRQ_HANDLED;
}

int init_module()
{
    int status;
    init_completion(&work);

    gpio_num = 87;    /* gpio_num = (bank_num * 16) + pin_num */
    gpio_pin = DA830_GPIO5_7;

    printk("\nTesting gpio %d (connected to boot pin S2-7)\n", gpio_num);

    /* init/set pinmux */
    status = davinci_cfg_reg(gpio_pin);
    if (status < 0) {printk("pin could not be muxed for GPIO functionality %d\n", gpio_num);
        return status;
    }
    
    status = gpio_request(gpio_num, "gpio_test\n");
    if (status < 0) {printk("ERROR can not open GPIO %d\n", gpio_num);
        return status;
    }

    gpio_direction_input(gpio_num);

    printk("The current state of S2-7 pin is ");

    if(gpio_get_value(gpio_num) == 0)  printk("OFF. \n\tWaiting for the pin to be on..\n");
    else printk("ON. \n\tWaiting for the pin to be off..\n");

    status = request_irq(gpio_to_irq(gpio_num), handler, 0, "gpio_test", NULL);
    if(status < 0) {printk(KERN_ERR "error %d requesting GPIO IRQ %d\n", status, gpio_num);
        return status;
    }

    set_irq_type(gpio_to_irq(gpio_num), IRQ_TYPE_EDGE_RISING);

    wait_for_completion_interruptible(&work);

    printk(".. done\n");

    return 0;
}

void cleanup_module(void)
{
    
    gpio_free(gpio_num);
    free_irq(gpio_to_irq(gpio_num), NULL);
}

MODULE_LICENSE("GPL");