2 * character device wrapper for generic gpio layer
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.
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.
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
18 * Feedback, Bugs... blogic@openwrt.org
23 #include <linux/module.h>
24 #include <linux/errno.h>
25 #include <linux/init.h>
26 #include <asm/uaccess.h>
29 #include <asm/atomic.h>
30 #include <linux/init.h>
31 #include <linux/genhd.h>
32 #include <linux/device.h>
33 #include <linux/platform_device.h>
34 #include <linux/gpio_dev.h>
37 #define DRVNAME "gpiodev"
38 #define DEVNAME "gpio"
41 static struct class *gpiodev_class;
44 /* third argument of user space ioctl ('arg' here) contains the <pin> */
46 gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
53 retval = gpio_get_value(arg);
56 gpio_set_value(arg, 1);
59 gpio_set_value(arg, 0);
62 retval = gpio_direction_input(arg);
65 retval = gpio_direction_output(arg, 0);
68 retval = gpio_direction_output(arg, 1);
71 /* should be first ioctl operation on <pin> */
72 retval = gpio_request(arg, DRVNAME);
75 /* should be last ioctl operation on <pin> */
76 /* may be needed first if previous user missed this ioctl */
80 retval = gpio_cansleep(arg);
84 /* = -ENOTTY; // correct return but ... */
90 /* Allow co-incident opens */
92 gpio_open(struct inode *inode, struct file *file)
95 unsigned int dev_minor = MINOR(inode->i_rdev);
99 printk(KERN_ERR DRVNAME ": trying to access unknown minor device -> %d\n", dev_minor);
108 gpio_close(struct inode * inode, struct file * file)
110 /* could track all <pin>s requested by this fd and gpio_free()
116 struct file_operations gpio_fops = {
117 unlocked_ioctl: gpio_ioctl,
123 gpio_probe(struct platform_device *dev)
127 dev_major = register_chrdev(0, DEVNAME, &gpio_fops);
130 printk(KERN_ERR DRVNAME ": Error whilst opening %s \n", DEVNAME);
134 gpiodev_class = class_create(THIS_MODULE, DRVNAME);
135 device_create(gpiodev_class, NULL, MKDEV(dev_major, 0), dev, DEVNAME);
136 printk(KERN_INFO DRVNAME ": gpio device registered with major %d\n", dev_major);
142 gpio_remove(struct platform_device *dev)
144 device_destroy(gpiodev_class, MKDEV(dev_major, 0));
145 class_destroy(gpiodev_class);
146 unregister_chrdev(dev_major, DEVNAME);
151 platform_driver gpio_driver = {
153 .remove = gpio_remove,
156 .owner = THIS_MODULE,
163 int ret = platform_driver_register(&gpio_driver);
165 printk(KERN_INFO DRVNAME ": Error registering platfom driver!\n");
173 platform_driver_unregister(&gpio_driver);
176 module_init (gpio_mod_init);
177 module_exit (gpio_mod_exit);
179 MODULE_LICENSE("GPL");
180 MODULE_AUTHOR("John Crispin / OpenWrt +");
181 MODULE_DESCRIPTION("Character device for for generic gpio api");