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/* 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 <asm/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,

};

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\n");

                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\n", 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);