150 lines
3.3 KiB
C
150 lines
3.3 KiB
C
/* linux/drivers/char/scx200_gpio.c
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National Semiconductor SCx200 GPIO driver. Allows a user space
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process to play with the GPIO pins.
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Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */
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#include <linux/config.h>
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include <linux/scx200_gpio.h>
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#define NAME "scx200_gpio"
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MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
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MODULE_DESCRIPTION("NatSemi SCx200 GPIO Pin Driver");
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MODULE_LICENSE("GPL");
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static int major = 0; /* default to dynamic major */
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module_param(major, int, 0);
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MODULE_PARM_DESC(major, "Major device number");
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static ssize_t scx200_gpio_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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{
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unsigned m = iminor(file->f_dentry->d_inode);
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size_t i;
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for (i = 0; i < len; ++i) {
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char c;
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if (get_user(c, data+i))
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return -EFAULT;
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switch (c)
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{
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case '0':
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scx200_gpio_set(m, 0);
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break;
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case '1':
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scx200_gpio_set(m, 1);
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break;
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case 'O':
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printk(KERN_INFO NAME ": GPIO%d output enabled\n", m);
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scx200_gpio_configure(m, ~1, 1);
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break;
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case 'o':
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printk(KERN_INFO NAME ": GPIO%d output disabled\n", m);
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scx200_gpio_configure(m, ~1, 0);
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break;
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case 'T':
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printk(KERN_INFO NAME ": GPIO%d output is push pull\n", m);
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scx200_gpio_configure(m, ~2, 2);
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break;
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case 't':
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printk(KERN_INFO NAME ": GPIO%d output is open drain\n", m);
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scx200_gpio_configure(m, ~2, 0);
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break;
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case 'P':
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printk(KERN_INFO NAME ": GPIO%d pull up enabled\n", m);
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scx200_gpio_configure(m, ~4, 4);
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break;
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case 'p':
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printk(KERN_INFO NAME ": GPIO%d pull up disabled\n", m);
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scx200_gpio_configure(m, ~4, 0);
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break;
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}
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}
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return len;
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}
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static ssize_t scx200_gpio_read(struct file *file, char __user *buf,
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size_t len, loff_t *ppos)
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{
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unsigned m = iminor(file->f_dentry->d_inode);
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int value;
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value = scx200_gpio_get(m);
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if (put_user(value ? '1' : '0', buf))
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return -EFAULT;
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return 1;
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}
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static int scx200_gpio_open(struct inode *inode, struct file *file)
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{
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unsigned m = iminor(inode);
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if (m > 63)
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return -EINVAL;
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return nonseekable_open(inode, file);
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}
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static int scx200_gpio_release(struct inode *inode, struct file *file)
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{
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return 0;
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}
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static struct file_operations scx200_gpio_fops = {
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.owner = THIS_MODULE,
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.write = scx200_gpio_write,
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.read = scx200_gpio_read,
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.open = scx200_gpio_open,
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.release = scx200_gpio_release,
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};
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static int __init scx200_gpio_init(void)
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{
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int r;
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printk(KERN_DEBUG NAME ": NatSemi SCx200 GPIO Driver\n");
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if (!scx200_gpio_present()) {
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printk(KERN_ERR NAME ": no SCx200 gpio pins available\n");
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return -ENODEV;
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}
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r = register_chrdev(major, NAME, &scx200_gpio_fops);
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if (r < 0) {
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printk(KERN_ERR NAME ": unable to register character device\n");
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return r;
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}
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if (!major) {
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major = r;
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printk(KERN_DEBUG NAME ": got dynamic major %d\n", major);
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}
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return 0;
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}
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static void __exit scx200_gpio_cleanup(void)
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{
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unregister_chrdev(major, NAME);
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}
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module_init(scx200_gpio_init);
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module_exit(scx200_gpio_cleanup);
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/*
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Local variables:
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compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
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c-basic-offset: 8
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End:
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*/
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