gio.c

// SPDX-License-Identifier: GPL-2.0
/*
 * arch/sh/boards/landisk/gio.c - driver for landisk
 *
 * This driver will also support the I-O DATA Device, Inc. LANDISK Board.
 * LANDISK and USL-5P Button, LED and GIO driver drive function.
 *
 *   Copylight (C) 2006 kogiidena
 *   Copylight (C) 2002 Atom Create Engineering Co., Ltd. *
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kdev_t.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <mach-landisk/mach/gio.h>
#include <mach-landisk/mach/iodata_landisk.h>

#define DEVCOUNT                4
#define GIO_MINOR	        2	/* GIO minor no. */

static dev_t dev;
static struct cdev *cdev_p;
static int openCnt;

static int gio_open(struct inode *inode, struct file *filp)
{
	int minor = iminor(inode);
	int ret = -ENOENT;

	preempt_disable();
	if (minor < DEVCOUNT) {
		if (openCnt > 0) {
			ret = -EALREADY;
		} else {
			openCnt++;
			ret = 0;
		}
	}
	preempt_enable();
	return ret;
}

static int gio_close(struct inode *inode, struct file *filp)
{
	int minor = iminor(inode);

	if (minor < DEVCOUNT) {
		openCnt--;
	}
	return 0;
}

static long gio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	unsigned int data;
	static unsigned int addr = 0;

	if (cmd & 0x01) {	/* write */
		if (copy_from_user(&data, (int *)arg, sizeof(int))) {
			return -EFAULT;
		}
	}

	switch (cmd) {
	case GIODRV_IOCSGIOSETADDR:	/* address set */
		addr = data;
		break;

	case GIODRV_IOCSGIODATA1:	/* write byte */
		__raw_writeb((unsigned char)(0x0ff & data), addr);
		break;

	case GIODRV_IOCSGIODATA2:	/* write word */
		if (addr & 0x01) {
			return -EFAULT;
		}
		__raw_writew((unsigned short int)(0x0ffff & data), addr);
		break;

	case GIODRV_IOCSGIODATA4:	/* write long */
		if (addr & 0x03) {
			return -EFAULT;
		}
		__raw_writel(data, addr);
		break;

	case GIODRV_IOCGGIODATA1:	/* read byte */
		data = __raw_readb(addr);
		break;

	case GIODRV_IOCGGIODATA2:	/* read word */
		if (addr & 0x01) {
			return -EFAULT;
		}
		data = __raw_readw(addr);
		break;

	case GIODRV_IOCGGIODATA4:	/* read long */
		if (addr & 0x03) {
			return -EFAULT;
		}
		data = __raw_readl(addr);
		break;
	default:
		return -EFAULT;
		break;
	}

	if ((cmd & 0x01) == 0) {	/* read */
		if (copy_to_user((int *)arg, &data, sizeof(int))) {
			return -EFAULT;
		}
	}
	return 0;
}

static const struct file_operations gio_fops = {
	.owner = THIS_MODULE,
	.open = gio_open,	/* open */
	.release = gio_close,	/* release */
	.unlocked_ioctl = gio_ioctl,
	.llseek = noop_llseek,
};

static int __init gio_init(void)
{
	int error;

	printk(KERN_INFO "gio: driver initialized\n");

	openCnt = 0;

	if ((error = alloc_chrdev_region(&dev, 0, DEVCOUNT, "gio")) < 0) {
		printk(KERN_ERR
		       "gio: Couldn't alloc_chrdev_region, error=%d\n",
		       error);
		return 1;
	}

	cdev_p = cdev_alloc();
	cdev_p->ops = &gio_fops;
	error = cdev_add(cdev_p, dev, DEVCOUNT);
	if (error) {
		printk(KERN_ERR
		       "gio: Couldn't cdev_add, error=%d\n", error);
		return 1;
	}

	return 0;
}

static void __exit gio_exit(void)
{
	cdev_del(cdev_p);
	unregister_chrdev_region(dev, DEVCOUNT);
}

module_init(gio_init);
module_exit(gio_exit);

MODULE_LICENSE("GPL");