| /* |
| * character device wrapper for generic gpio layer |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA02111-1307USA |
| * |
| * Feedback, Bugs... blogic@openwrt.org |
| * |
| * dpg 20100106 |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/errno.h> |
| #include <linux/init.h> |
| #include <asm/uaccess.h> |
| #include <asm/io.h> |
| #include <asm/gpio.h> |
| #include <asm/atomic.h> |
| #include <linux/init.h> |
| #include <linux/genhd.h> |
| #include <linux/device.h> |
| #include <linux/platform_device.h> |
| #include <linux/gpio_dev.h> |
| #include <linux/fs.h> |
| |
| #define DRVNAME "gpiodev" |
| #define DEVNAME "gpio" |
| |
| static int dev_major; |
| static struct class *gpiodev_class; |
| |
| |
| /* third argument of user space ioctl ('arg' here) contains the <pin> */ |
| static int |
| gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| int retval = 0; |
| |
| switch (cmd) |
| { |
| case GPIO_GET: |
| retval = gpio_get_value(arg); |
| break; |
| case GPIO_SET: |
| gpio_set_value(arg, 1); |
| break; |
| case GPIO_CLEAR: |
| gpio_set_value(arg, 0); |
| break; |
| case GPIO_DIR_IN: |
| retval = gpio_direction_input(arg); |
| break; |
| case GPIO_DIR_OUT: |
| retval = gpio_direction_output(arg, 0); |
| break; |
| case GPIO_DIR_HIGH: |
| retval = gpio_direction_output(arg, 1); |
| break; |
| case GPIO_REQUEST: |
| /* should be first ioctl operation on <pin> */ |
| retval = gpio_request(arg, DRVNAME); |
| break; |
| case GPIO_FREE: |
| /* should be last ioctl operation on <pin> */ |
| /* may be needed first if previous user missed this ioctl */ |
| gpio_free(arg); |
| break; |
| case GPIO_CAN_SLEEP: |
| retval = gpio_cansleep(arg); |
| break; |
| default: |
| retval = -EINVAL; |
| /* = -ENOTTY; // correct return but ... */ |
| break; |
| } |
| return retval; |
| } |
| |
| /* Allow co-incident opens */ |
| static int |
| gpio_open(struct inode *inode, struct file *file) |
| { |
| int result = 0; |
| unsigned int dev_minor = MINOR(inode->i_rdev); |
| |
| if (dev_minor != 0) |
| { |
| printk(KERN_ERR DRVNAME ": trying to access unknown minor device -> %d\n", dev_minor); |
| result = -ENODEV; |
| goto out; |
| } |
| out: |
| return result; |
| } |
| |
| static int |
| gpio_close(struct inode * inode, struct file * file) |
| { |
| /* could track all <pin>s requested by this fd and gpio_free() |
| * them here |
| */ |
| return 0; |
| } |
| |
| struct file_operations gpio_fops = { |
| unlocked_ioctl: gpio_ioctl, |
| open: gpio_open, |
| release: gpio_close |
| }; |
| |
| static int |
| gpio_probe(struct platform_device *dev) |
| { |
| int result = 0; |
| |
| dev_major = register_chrdev(0, DEVNAME, &gpio_fops); |
| if (!dev_major) |
| { |
| printk(KERN_ERR DRVNAME ": Error whilst opening %s \n", DEVNAME); |
| result = -ENODEV; |
| goto out; |
| } |
| gpiodev_class = class_create(THIS_MODULE, DRVNAME); |
| device_create(gpiodev_class, NULL, MKDEV(dev_major, 0), dev, DEVNAME); |
| printk(KERN_INFO DRVNAME ": gpio device registered with major %d\n", dev_major); |
| out: |
| return result; |
| } |
| |
| static int |
| gpio_remove(struct platform_device *dev) |
| { |
| device_destroy(gpiodev_class, MKDEV(dev_major, 0)); |
| class_destroy(gpiodev_class); |
| unregister_chrdev(dev_major, DEVNAME); |
| return 0; |
| } |
| |
| static struct |
| platform_driver gpio_driver = { |
| .probe = gpio_probe, |
| .remove = gpio_remove, |
| .driver = { |
| .name = "GPIODEV", |
| .owner = THIS_MODULE, |
| }, |
| }; |
| |
| static int __init |
| gpio_mod_init(void) |
| { |
| int ret = platform_driver_register(&gpio_driver); |
| if (ret) |
| printk(KERN_INFO DRVNAME ": Error registering platfom driver!\n"); |
| |
| return ret; |
| } |
| |
| static void __exit |
| gpio_mod_exit(void) |
| { |
| platform_driver_unregister(&gpio_driver); |
| } |
| |
| module_init (gpio_mod_init); |
| module_exit (gpio_mod_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("John Crispin / OpenWrt +"); |
| MODULE_DESCRIPTION("Character device for for generic gpio api"); |