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// SPDX-License-Identifier: GPL-2.0-only
/* 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\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);
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