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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/* 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/device.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.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"
#define DEVNAME NAME
static struct platform_device *pdev;
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;
int err = 0;
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;
case 'v':
/* View Current pin settings */
scx200_gpio_dump(m);
break;
case '\n':
/* end of settings string, do nothing */
break;
default:
printk(KERN_ERR NAME
": GPIO-%2d bad setting: chr<0x%2x>\n", m,
(int)c);
err++;
}
}
if (err)
return -EINVAL; /* full string handled, report error */
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;
static int num_pins = 32;
static int __init scx200_gpio_init(void)
{
int rc, i;
dev_t dev = MKDEV(major, 0);
if (!scx200_gpio_present()) {
printk(KERN_ERR NAME ": no SCx200 gpio present\n");
return -ENODEV;
}
/* support dev_dbg() with pdev->dev */
pdev = platform_device_alloc(DEVNAME, 0);
if (!pdev)
return -ENOMEM;
rc = platform_device_add(pdev);
if (rc)
goto undo_malloc;
if (major)
rc = register_chrdev_region(dev, num_pins, "scx200_gpio");
else {
rc = alloc_chrdev_region(&dev, 0, num_pins, "scx200_gpio");
major = MAJOR(dev);
}
if (rc < 0) {
dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc);
goto undo_platform_device_add;
}
scx200_devices = kzalloc(num_pins * sizeof(struct cdev), GFP_KERNEL);
if (!scx200_devices) {
rc = -ENOMEM;
goto undo_chrdev_region;
}
for (i = 0; i < num_pins; i++) {
struct cdev *cdev = &scx200_devices[i];
cdev_init(cdev, &scx200_gpio_fops);
cdev->owner = THIS_MODULE;
rc = cdev_add(cdev, MKDEV(major, i), 1);
/* tolerate 'minor' errors */
if (rc)
dev_err(&pdev->dev, "Error %d on minor %d", rc, i);
}
return 0; /* succeed */
undo_chrdev_region:
unregister_chrdev_region(dev, num_pins);
undo_platform_device_add:
platform_device_put(pdev);
undo_malloc:
kfree(pdev);
return rc;
}
static void __exit scx200_gpio_cleanup(void)
{
kfree(scx200_devices);
unregister_chrdev_region(MKDEV(major, 0), num_pins);
platform_device_put(pdev);
platform_device_unregister(pdev);
/* kfree(pdev); */
}
module_init(scx200_gpio_init);
module_exit(scx200_gpio_cleanup);
|
