/* linux/drivers/char/scx200_gpio.c

  
     National Semiconductor SCx200 GPIO driver.  Allows a user space
     process to play with the GPIO pins.
  
     Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */

  #include <linux/device.h>

  #include <linux/fs.h>
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/init.h>

  #include <linux/platform_device.h>

  #include <linux/uaccess.h>

  #include <asm/io.h>

  #include <linux/types.h>
  #include <linux/cdev.h>

  #include <linux/scx200_gpio.h>

  #include <linux/nsc_gpio.h>

  #define DRVNAME "scx200_gpio"

  
  static struct platform_device *pdev;

  
  MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");

  MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver");

  MODULE_LICENSE("GPL");
  
  static int major = 0;		/* default to dynamic major */
  module_param(major, int, 0);
  MODULE_PARM_DESC(major, "Major device number");

  #define MAX_PINS 32		/* 64 later, when known ok */

  struct nsc_gpio_ops scx200_gpio_ops = {

  	.owner		= THIS_MODULE,
  	.gpio_config	= scx200_gpio_configure,

  	.gpio_dump	= nsc_gpio_dump,

  	.gpio_get	= scx200_gpio_get,
  	.gpio_set	= scx200_gpio_set,

  	.gpio_change	= scx200_gpio_change,
  	.gpio_current	= scx200_gpio_current
  };

  EXPORT_SYMBOL_GPL(scx200_gpio_ops);

  static int scx200_gpio_open(struct inode *inode, struct file *file)
  {
  	unsigned m = iminor(inode);

  	file->private_data = &scx200_gpio_ops;

  	if (m >= MAX_PINS)

  		return -EINVAL;
  	return nonseekable_open(inode, file);
  }
  
  static int scx200_gpio_release(struct inode *inode, struct file *file)
  {
  	return 0;
  }

  static const struct file_operations scx200_gpio_fileops = {

  	.owner   = THIS_MODULE,

  	.write   = nsc_gpio_write,
  	.read    = nsc_gpio_read,

  	.open    = scx200_gpio_open,
  	.release = scx200_gpio_release,

  	.llseek  = no_llseek,

  };

  static struct cdev scx200_gpio_cdev;  /* use 1 cdev for all pins */

  static int __init scx200_gpio_init(void)
  {

  	int rc;

  	dev_t devid;

  	if (!scx200_gpio_present()) {

  		printk(KERN_ERR DRVNAME ": no SCx200 gpio present
  ");

  		return -ENODEV;
  	}

  
  	/* support dev_dbg() with pdev->dev */

  	pdev = platform_device_alloc(DRVNAME, 0);

  	if (!pdev)
  		return -ENOMEM;
  
  	rc = platform_device_add(pdev);
  	if (rc)
  		goto undo_malloc;

  	/* nsc_gpio uses dev_dbg(), so needs this */

  	scx200_gpio_ops.dev = &pdev->dev;

  	if (major) {
  		devid = MKDEV(major, 0);
  		rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio");
  	} else {
  		rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio");
  		major = MAJOR(devid);

  	}

  	if (rc < 0) {

  		dev_err(&pdev->dev, "SCx200 chrdev_region err: %d
  ", rc);
  		goto undo_platform_device_add;

  	}

  	cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops);

  	cdev_add(&scx200_gpio_cdev, devid, MAX_PINS);

  	return 0; /* succeed */

  undo_platform_device_add:

  	platform_device_del(pdev);

  undo_malloc:

  	platform_device_put(pdev);

  	return rc;

  }
  
  static void __exit scx200_gpio_cleanup(void)
  {

  	cdev_del(&scx200_gpio_cdev);
  	/* cdev_put(&scx200_gpio_cdev); */

  	unregister_chrdev_region(MKDEV(major, 0), MAX_PINS);

  	platform_device_unregister(pdev);

  }
  
  module_init(scx200_gpio_init);
  module_exit(scx200_gpio_cleanup);