/* 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/fs.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/init.h> #include <asm/uaccess.h> #include <asm/io.h> #include <linux/scx200_gpio.h> #define NAME "scx200_gpio" 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"); 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, }; static int __init scx200_gpio_init(void) { int r; printk(KERN_DEBUG NAME ": NatSemi SCx200 GPIO Driver\n"); if (!scx200_gpio_present()) { printk(KERN_ERR NAME ": no SCx200 gpio pins available\n"); return -ENODEV; } r = register_chrdev(major, NAME, &scx200_gpio_fops); if (r < 0) { printk(KERN_ERR NAME ": unable to register character device\n"); return r; } if (!major) { major = r; printk(KERN_DEBUG NAME ": got dynamic major %d\n", major); } return 0; } static void __exit scx200_gpio_cleanup(void) { unregister_chrdev(major, NAME); } module_init(scx200_gpio_init); module_exit(scx200_gpio_cleanup); /* Local variables: compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" c-basic-offset: 8 End: */