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 void nsc_gpio_dump(unsigned index, u32 config)
24 printk(KERN_INFO NAME ": GPIO-%02u: 0x%08lx %s %s %s %s %s %s %s\n",
25 index, (unsigned long)config,
26 (config & 1) ? "OE" : "TS", /* output-enabled/tristate */
27 (config & 2) ? "PP" : "OD", /* push pull / open drain */
28 (config & 4) ? "PUE" : "PUD", /* pull up enabled/disabled */
29 (config & 8) ? "LOCKED" : "", /* locked / unlocked */
30 (config & 16) ? "LEVEL" : "EDGE",/* level/edge input */
31 (config & 32) ? "HI" : "LO", /* trigger on rise/fall edge */
32 (config & 64) ? "DEBOUNCE" : ""); /* debounce */
35 ssize_t nsc_gpio_write(struct file *file, const char __user *data,
36 size_t len, loff_t *ppos)
38 unsigned m = iminor(file->f_dentry->d_inode);
39 struct nsc_gpio_ops *amp = file->private_data;
43 for (i = 0; i < len; ++i) {
45 if (get_user(c, data + i))
55 printk(KERN_INFO NAME ": GPIO%d output enabled\n", m);
56 amp->gpio_config(m, ~1, 1);
59 printk(KERN_INFO NAME ": GPIO%d output disabled\n", m);
60 amp->gpio_config(m, ~1, 0);
63 printk(KERN_INFO NAME ": GPIO%d output is push pull\n",
65 amp->gpio_config(m, ~2, 2);
68 printk(KERN_INFO NAME ": GPIO%d output is open drain\n",
70 amp->gpio_config(m, ~2, 0);
73 printk(KERN_INFO NAME ": GPIO%d pull up enabled\n", m);
74 amp->gpio_config(m, ~4, 4);
77 printk(KERN_INFO NAME ": GPIO%d pull up disabled\n", m);
78 amp->gpio_config(m, ~4, 0);
81 /* View Current pin settings */
85 /* end of settings string, do nothing */
89 ": GPIO-%2d bad setting: chr<0x%2x>\n", m,
95 return -EINVAL; /* full string handled, report error */
100 ssize_t nsc_gpio_read(struct file *file, char __user * buf,
101 size_t len, loff_t * ppos)
103 unsigned m = iminor(file->f_dentry->d_inode);
105 struct nsc_gpio_ops *amp = file->private_data;
107 value = amp->gpio_get(m);
108 if (put_user(value ? '1' : '0', buf))
114 /* common file-ops routines for both scx200_gpio and pc87360_gpio */
115 EXPORT_SYMBOL(nsc_gpio_write);
116 EXPORT_SYMBOL(nsc_gpio_read);
117 EXPORT_SYMBOL(nsc_gpio_dump);
119 static int __init nsc_gpio_init(void)
121 printk(KERN_DEBUG NAME " initializing\n");
125 static void __exit nsc_gpio_cleanup(void)
127 printk(KERN_DEBUG NAME " cleanup\n");
130 module_init(nsc_gpio_init);
131 module_exit(nsc_gpio_cleanup);
133 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
134 MODULE_DESCRIPTION("NatSemi GPIO Common Methods");
135 MODULE_LICENSE("GPL");