1/*
2 * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17 */
18
19#include <linux/device.h>
20#include <linux/fs.h>
21#include <linux/module.h>
22#include <linux/errno.h>
23#include <linux/kernel.h>
24#include <linux/init.h>
25#include <linux/platform_device.h>
26#include <linux/uaccess.h>
27#include <linux/io.h>
28#include <linux/types.h>
29#include <linux/cdev.h>
30#include <gpio.h>
31
32#define DRVNAME "ar7_gpio"
33#define LONGNAME "TI AR7 GPIOs Driver"
34
35MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
36MODULE_DESCRIPTION(LONGNAME);
37MODULE_LICENSE("GPL");
38
39static int ar7_gpio_major;
40
41static ssize_t ar7_gpio_write(struct file *file, const char __user *buf,
42	size_t len, loff_t *ppos)
43{
44	int pin = iminor(file->f_dentry->d_inode);
45	size_t i;
46
47	for (i = 0; i < len; ++i) {
48		char c;
49		if (get_user(c, buf + i))
50			return -EFAULT;
51		switch (c) {
52		case '0':
53			gpio_set_value(pin, 0);
54			break;
55		case '1':
56			gpio_set_value(pin, 1);
57			break;
58		case 'd':
59		case 'D':
60			ar7_gpio_disable(pin);
61			break;
62		case 'e':
63		case 'E':
64			ar7_gpio_enable(pin);
65			break;
66		case 'i':
67		case 'I':
68		case '<':
69			gpio_direction_input(pin);
70			break;
71		case 'o':
72		case 'O':
73		case '>':
74			gpio_direction_output(pin, 0);
75			break;
76		default:
77			return -EINVAL;
78		}
79	}
80
81	return len;
82}
83
84static ssize_t ar7_gpio_read(struct file *file, char __user *buf,
85	size_t len, loff_t *ppos)
86{
87	int pin = iminor(file->f_dentry->d_inode);
88	int value;
89
90	value = gpio_get_value(pin);
91	if (put_user(value ? '1' : '0', buf))
92		return -EFAULT;
93
94	return 1;
95}
96
97static int ar7_gpio_open(struct inode *inode, struct file *file)
98{
99	int m = iminor(inode);
100
101	if (m >= (ar7_is_titan() ? TITAN_GPIO_MAX : AR7_GPIO_MAX))
102		return -EINVAL;
103
104	return nonseekable_open(inode, file);
105}
106
107static int ar7_gpio_release(struct inode *inode, struct file *file)
108{
109	return 0;
110}
111
112static const struct file_operations ar7_gpio_fops = {
113	.owner   = THIS_MODULE,
114	.write   = ar7_gpio_write,
115	.read    = ar7_gpio_read,
116	.open    = ar7_gpio_open,
117	.release = ar7_gpio_release,
118	.llseek  = no_llseek,
119};
120
121static struct platform_device *ar7_gpio_device;
122
123static int __init ar7_gpio_char_init(void)
124{
125	int rc;
126
127	ar7_gpio_device = platform_device_alloc(DRVNAME, -1);
128	if (!ar7_gpio_device)
129		return -ENOMEM;
130
131	rc = platform_device_add(ar7_gpio_device);
132	if (rc < 0)
133		goto out_put;
134
135	rc = register_chrdev(ar7_gpio_major, DRVNAME, &ar7_gpio_fops);
136	if (rc < 0)
137		goto out_put;
138
139	ar7_gpio_major = rc;
140
141	rc = 0;
142
143	goto out;
144
145out_put:
146	platform_device_put(ar7_gpio_device);
147out:
148	return rc;
149}
150
151static void __exit ar7_gpio_char_exit(void)
152{
153	unregister_chrdev(ar7_gpio_major, DRVNAME);
154	platform_device_unregister(ar7_gpio_device);
155}
156
157module_init(ar7_gpio_char_init);
158module_exit(ar7_gpio_char_exit);
159