1 /* linux/drivers/char/nsc_gpio.c
3 National Semiconductor common GPIO device-file/VFS methods.
4 Allows a user space process to control the GPIO pins.
6 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
7 Copyright (c) 2005 Jim Cromie <jim.cromie@gmail.com>
10 #include <linux/config.h>
12 #include <linux/module.h>
13 #include <linux/errno.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/nsc_gpio.h>
17 #include <asm/uaccess.h>
20 #define NAME "nsc_gpio"
22 ssize_t nsc_gpio_write(struct file *file, const char __user *data,
23 size_t len, loff_t *ppos)
25 unsigned m = iminor(file->f_dentry->d_inode);
26 struct nsc_gpio_ops *amp = file->private_data;
30 for (i = 0; i < len; ++i) {
32 if (get_user(c, data + i))
42 printk(KERN_INFO NAME ": GPIO%d output enabled\n", m);
43 amp->gpio_config(m, ~1, 1);
46 printk(KERN_INFO NAME ": GPIO%d output disabled\n", m);
47 amp->gpio_config(m, ~1, 0);
50 printk(KERN_INFO NAME ": GPIO%d output is push pull\n",
52 amp->gpio_config(m, ~2, 2);
55 printk(KERN_INFO NAME ": GPIO%d output is open drain\n",
57 amp->gpio_config(m, ~2, 0);
60 printk(KERN_INFO NAME ": GPIO%d pull up enabled\n", m);
61 amp->gpio_config(m, ~4, 4);
64 printk(KERN_INFO NAME ": GPIO%d pull up disabled\n", m);
65 amp->gpio_config(m, ~4, 0);
69 /* View Current pin settings */
73 /* end of settings string, do nothing */
77 ": GPIO-%2d bad setting: chr<0x%2x>\n", m,
83 return -EINVAL; /* full string handled, report error */
88 ssize_t nsc_gpio_read(struct file *file, char __user * buf,
89 size_t len, loff_t * ppos)
91 unsigned m = iminor(file->f_dentry->d_inode);
93 struct nsc_gpio_ops *amp = file->private_data;
95 value = amp->gpio_get(m);
96 if (put_user(value ? '1' : '0', buf))
102 /* common routines for both scx200_gpio and pc87360_gpio */
103 EXPORT_SYMBOL(nsc_gpio_write);
104 EXPORT_SYMBOL(nsc_gpio_read);
106 static int __init nsc_gpio_init(void)
108 printk(KERN_DEBUG NAME " initializing\n");
112 static void __exit nsc_gpio_cleanup(void)
114 printk(KERN_DEBUG NAME " cleanup\n");
117 module_init(nsc_gpio_init);
118 module_exit(nsc_gpio_cleanup);
120 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
121 MODULE_DESCRIPTION("NatSemi GPIO Common Methods");
122 MODULE_LICENSE("GPL");