Update ps3 linux banner and hostname
[openwrt/svn-archive/archive.git] / target / linux / generic-2.6 / files-2.6.25 / drivers / gpio / gpio_dev.c
1 /*
2 * character device wrapper for generic gpio layer
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., 59 Temple Place, Suite 330, Boston, MA02111-1307USA
17 *
18 * Feedback, Bugs... blogic@openwrt.org
19 *
20 */
21
22 #include <linux/module.h>
23 #include <linux/errno.h>
24 #include <linux/init.h>
25 #include <asm/uaccess.h>
26 #include <asm/io.h>
27 #include <asm/gpio.h>
28 #include <asm/atomic.h>
29 #include <linux/init.h>
30 #include <linux/genhd.h>
31 #include <linux/device.h>
32 #include <linux/platform_device.h>
33 #include <linux/gpio_dev.h>
34
35 #define DRVNAME "gpiodev"
36 #define DEVNAME "gpio"
37
38 static int dev_major;
39 static unsigned int gpio_access_mask;
40 static struct class *gpio_class;
41
42 /* Counter is 1, if the device is not opened and zero (or less) if opened. */
43 static atomic_t gpio_open_cnt = ATOMIC_INIT(1);
44
45 static int
46 gpio_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg)
47 {
48 int retval = 0;
49
50 if (((1 << arg) & gpio_access_mask) != (1 << arg))
51 {
52 retval = -EINVAL;
53 goto out;
54 }
55
56 switch (cmd)
57 {
58 case GPIO_GET:
59 retval = gpio_get_value(arg);
60 break;
61
62 case GPIO_SET:
63 gpio_set_value(arg, 1);
64 break;
65
66 case GPIO_CLEAR:
67 gpio_set_value(arg, 0);
68 break;
69
70 case GPIO_DIR_IN:
71 gpio_direction_input(arg);
72 break;
73
74 case GPIO_DIR_OUT:
75 gpio_direction_output(arg, 0);
76 break;
77
78 default:
79 retval = -EINVAL;
80 break;
81 }
82
83 out:
84 return retval;
85 }
86
87 static int
88 gpio_open(struct inode *inode, struct file *file)
89 {
90 int result = 0;
91 unsigned int dev_minor = MINOR(inode->i_rdev);
92
93 if (dev_minor != 0)
94 {
95 printk(KERN_ERR DRVNAME ": trying to access unknown minor device -> %d\n", dev_minor);
96 result = -ENODEV;
97 goto out;
98 }
99
100 /* FIXME: We should really allow multiple applications to open the device
101 * at the same time, as long as the apps access different IO pins.
102 * The generic gpio-registration functions can be used for that.
103 * Two new IOCTLs have to be introduced for that. Need to check userspace
104 * compatibility first. --mb */
105 if (!atomic_dec_and_test(&gpio_open_cnt)) {
106 atomic_inc(&gpio_open_cnt);
107 printk(KERN_ERR DRVNAME ": Device with minor ID %d already in use\n", dev_minor);
108 result = -EBUSY;
109 goto out;
110 }
111
112 out:
113 return result;
114 }
115
116 static int
117 gpio_close(struct inode * inode, struct file * file)
118 {
119 smp_mb__before_atomic_inc();
120 atomic_inc(&gpio_open_cnt);
121
122 return 0;
123 }
124
125 struct file_operations gpio_fops = {
126 ioctl: gpio_ioctl,
127 open: gpio_open,
128 release: gpio_close
129 };
130
131 static int
132 gpio_probe(struct platform_device *dev)
133 {
134 int result = 0;
135
136 dev_major = register_chrdev(0, DEVNAME, &gpio_fops);
137 if (!dev_major)
138 {
139 printk(KERN_ERR DRVNAME ": Error whilst opening %s \n", DEVNAME);
140 result = -ENODEV;
141 goto out;
142 }
143
144 gpio_class = class_create(THIS_MODULE, DEVNAME);
145 class_device_create(gpio_class, NULL, MKDEV(dev_major, 0), NULL, DEVNAME);
146
147 printk(KERN_INFO DRVNAME ": gpio device registered with major %d\n", dev_major);
148
149 if (dev->num_resources != 1)
150 {
151 printk(KERN_ERR DRVNAME ": device may only have 1 resource\n");
152 result = -ENODEV;
153 goto out;
154 }
155
156 gpio_access_mask = dev->resource[0].start;
157
158 printk(KERN_INFO DRVNAME ": gpio platform device registered with access mask %08X\n", gpio_access_mask);
159 out:
160 return result;
161 }
162
163 static int
164 gpio_remove(struct platform_device *dev)
165 {
166 unregister_chrdev(dev_major, DEVNAME);
167 return 0;
168 }
169
170 static struct
171 platform_driver gpio_driver = {
172 .probe = gpio_probe,
173 .remove = gpio_remove,
174 .driver = {
175 .name = "GPIODEV",
176 .owner = THIS_MODULE,
177 },
178 };
179
180 static int __init
181 gpio_mod_init(void)
182 {
183 int ret = platform_driver_register(&gpio_driver);
184 if (ret)
185 printk(KERN_INFO DRVNAME ": Error registering platfom driver!");
186
187 return ret;
188 }
189
190 static void __exit
191 gpio_mod_exit(void)
192 {
193 platform_driver_unregister(&gpio_driver);
194 }
195
196 module_init (gpio_mod_init);
197 module_exit (gpio_mod_exit);
198
199 MODULE_LICENSE("GPL");
200 MODULE_AUTHOR("John Crispin / OpenWrt");
201 MODULE_DESCRIPTION("Character device for for generic gpio api");