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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/config.h>
#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>
#define NAME "scx200_gpio"
#define DEVNAME NAME
static struct platform_device *pdev;
MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
MODULE_DESCRIPTION("NatSemi 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");
extern void scx200_gpio_dump(unsigned index);
static ssize_t scx200_gpio_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
unsigned m = iminor(file->f_dentry->d_inode);
size_t i;
for (i = 0; i < len; ++i) {
char c;
if (get_user(c, data + i))
return -EFAULT;
switch (c) {
case '0':
scx200_gpio_set(m, 0);
break;
case '1':
scx200_gpio_set(m, 1);
break;
case 'O':
printk(KERN_INFO NAME ": GPIO%d output enabled\n", m);
scx200_gpio_configure(m, ~1, 1);
break;
case 'o':
printk(KERN_INFO NAME ": GPIO%d output disabled\n", m);
scx200_gpio_configure(m, ~1, 0);
break;
case 'T':
printk(KERN_INFO NAME ": GPIO%d output is push pull\n", m);
scx200_gpio_configure(m, ~2, 2);
break;
case 't':
printk(KERN_INFO NAME ": GPIO%d output is open drain\n", m);
scx200_gpio_configure(m, ~2, 0);
break;
case 'P':
printk(KERN_INFO NAME ": GPIO%d pull up enabled\n", m);
scx200_gpio_configure(m, ~4, 4);
break;
case 'p':
printk(KERN_INFO NAME ": GPIO%d pull up disabled\n", m);
scx200_gpio_configure(m, ~4, 0);
break;
}
}
return len;
}
static ssize_t scx200_gpio_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
unsigned m = iminor(file->f_dentry->d_inode);
int value;
value = scx200_gpio_get(m);
if (put_user(value ? '1' : '0', buf))
return -EFAULT;
return 1;
}
static int scx200_gpio_open(struct inode *inode, struct file *file)
{
unsigned m = iminor(inode);
if (m > 63)
return -EINVAL;
return nonseekable_open(inode, file);
}
static int scx200_gpio_release(struct inode *inode, struct file *file)
{
return 0;
}
static struct file_operations scx200_gpio_fops = {
.owner = THIS_MODULE,
.write = scx200_gpio_write,
.read = scx200_gpio_read,
.open = scx200_gpio_open,
.release = scx200_gpio_release,
};
struct cdev *scx200_devices;
static int num_pins = 32;
static int __init scx200_gpio_init(void)
{
int rc, i;
dev_t dev = MKDEV(major, 0);
if (!scx200_gpio_present()) {
printk(KERN_ERR NAME ": no SCx200 gpio present\n");
return -ENODEV;
}
/* support dev_dbg() with pdev->dev */
pdev = platform_device_alloc(DEVNAME, 0);
if (!pdev)
return -ENOMEM;
rc = platform_device_add(pdev);
if (rc)
goto undo_malloc;
if (major)
rc = register_chrdev_region(dev, num_pins, "scx200_gpio");
else {
rc = alloc_chrdev_region(&dev, 0, num_pins, "scx200_gpio");
major = MAJOR(dev);
}
if (rc < 0) {
dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc);
goto undo_platform_device_add;
}
scx200_devices = kzalloc(num_pins * sizeof(struct cdev), GFP_KERNEL);
if (!scx200_devices) {
rc = -ENOMEM;
goto undo_chrdev_region;
}
for (i = 0; i < num_pins; i++) {
struct cdev *cdev = &scx200_devices[i];
cdev_init(cdev, &scx200_gpio_fops);
cdev->owner = THIS_MODULE;
rc = cdev_add(cdev, MKDEV(major, i), 1);
/* tolerate 'minor' errors */
if (rc)
dev_err(&pdev->dev, "Error %d on minor %d", rc, i);
}
return 0; /* succeed */
undo_chrdev_region:
unregister_chrdev_region(dev, num_pins);
undo_platform_device_add:
platform_device_put(pdev);
undo_malloc:
kfree(pdev);
return rc;
}
static void __exit scx200_gpio_cleanup(void)
{
kfree(scx200_devices);
unregister_chrdev_region(MKDEV(major, 0), num_pins);
platform_device_put(pdev);
platform_device_unregister(pdev);
/* kfree(pdev); */
}
module_init(scx200_gpio_init);
module_exit(scx200_gpio_cleanup);
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