1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/* 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/types.h>
#include <linux/cdev.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");
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;
int num_devs = 32;
static int __init scx200_gpio_init(void)
{
int rc, i;
dev_t dev = MKDEV(major, 0);
printk(KERN_DEBUG NAME ": NatSemi SCx200 GPIO Driver\n");
if (!scx200_gpio_present()) {
printk(KERN_ERR NAME ": no SCx200 gpio present\n");
return -ENODEV;
}
if (major)
rc = register_chrdev_region(dev, num_devs, "scx200_gpio");
else {
rc = alloc_chrdev_region(&dev, 0, num_devs, "scx200_gpio");
major = MAJOR(dev);
}
if (rc < 0) {
printk(KERN_ERR NAME ": SCx200 chrdev_region: %d\n", rc);
return rc;
}
scx200_devices = kzalloc(num_devs * sizeof(struct cdev), GFP_KERNEL);
if (!scx200_devices) {
rc = -ENOMEM;
goto fail_malloc;
}
for (i = 0; i < num_devs; i++) {
struct cdev *cdev = &scx200_devices[i];
cdev_init(cdev, &scx200_gpio_fops);
cdev->owner = THIS_MODULE;
cdev->ops = &scx200_gpio_fops;
rc = cdev_add(cdev, MKDEV(major, i), 1);
/* Fail gracefully if need be */
if (rc)
printk(KERN_ERR NAME "Error %d on minor %d", rc, i);
}
return 0; /* succeed */
fail_malloc:
unregister_chrdev_region(dev, num_devs);
return rc;
}
static void __exit scx200_gpio_cleanup(void)
{
kfree(scx200_devices);
unregister_chrdev_region(MKDEV(major, 0), num_devs);
}
module_init(scx200_gpio_init);
module_exit(scx200_gpio_cleanup);
|
