#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>

#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/irq.h>

#include <linux/spi/spi.h>
#include <linux/gpio.h>

#include "fpgaSPI.h"

#define GPIO_TO_PIN(bank, gpio) (32 * (bank) + (gpio))

const char this_driver_name[] = "fpgaSPI";

struct cardConfig
{

  int cardPosition;
  int readLatch;
  int writeLatch;
  int bus;
  unsigned int interrupt;
  unsigned int irq;

};

static struct cardConfig cards[] =
{

  {
    .cardPosition = 0,
    .readLatch = GPIO_TO_PIN(1,16),
    .writeLatch = GPIO_TO_PIN(1,17),
    .bus = 2,
    .interrupt = 60,
  },

  {
    .cardPosition = 1,
    .readLatch = GPIO_TO_PIN(3,21),
    .writeLatch = GPIO_TO_PIN(3,19),
    .bus = 2,
  },

  {
    .cardPosition = 2,
    .readLatch = GPIO_TO_PIN(1,6),
    .writeLatch = GPIO_TO_PIN(1,15),
    .bus = 1,
  },

};

/****************
 * IRQ Handling *
 ***************/

static irqreturn_t fpgaSPI_irqHandler(int irq, void* devID)
{

  pr_debug("%s: IRQ: %d\n", __func__, irq);

  return IRQ_HANDLED;

}

/*****************************************
 * Module Intialisation/Deinitialisation *
 *****************************************/

static int __init fpgaSPI_init(void)
{

  unsigned int irq_num;
  int status = 0;

  pr_debug("%s: Inititialising Driver fpgaSPI-v2\n", __func__);

  status = gpio_request_one(cards[0].interrupt, GPIOF_IN, "Card 0 Interrupt");

  if (status < 0)
  {
    pr_debug("%s: Failed to aquire gpio, bailing: -%d\n", __func__, status);
    return 0;
  }

  gpio_direction_input(cards[0].interrupt);

  irq_num = gpio_to_irq(cards[0].interrupt);

  if (irq_num < 0)
  {
    pr_debug("%s: Failed to aquire irq_num: -%d\n", __func__, irq_num);
    goto err0;
  }

  cards[0].irq = request_irq(irq_num, fpgaSPI_irqHandler, IRQF_SHARED | IRQF_TRIGGER_FALLING, "Card 0 Interrupt IRQ", NULL);

  if (cards[0].irq < 0)
  {
    pr_debug("%s: Failed to requst irq: %d\n", __func__, cards[0].irq);
    goto err0;
  }

  return 0;

  err0:
    gpio_free(cards[0].interrupt);

  return 0;

}

static void __exit fpgaSPI_exit(void)
{

  gpio_free(cards[0].interrupt);

  if (cards[0].irq)
  {
    free_irq(cards[0].irq, NULL);
  }

  pr_debug("%s: Exiting Driver fpgaSPI-v2\n", __func__);

}

module_init(fpgaSPI_init);
module_exit(fpgaSPI_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jack Mitchell <jack.mitchell@dbbroadcast.co.uk>");
MODULE_DESCRIPTION("fpgaSPI driver");