| 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 | |
| 35 | MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>"); |
| 36 | MODULE_DESCRIPTION(LONGNAME); |
| 37 | MODULE_LICENSE("GPL"); |
| 38 | |
| 39 | static int ar7_gpio_major; |
| 40 | |
| 41 | static 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 | |
| 84 | static 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 | |
| 97 | static 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 | |
| 107 | static int ar7_gpio_release(struct inode *inode, struct file *file) |
| 108 | { |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | static 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 | |
| 121 | static struct platform_device *ar7_gpio_device; |
| 122 | |
| 123 | static 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 | |
| 145 | out_put: |
| 146 | platform_device_put(ar7_gpio_device); |
| 147 | out: |
| 148 | return rc; |
| 149 | } |
| 150 | |
| 151 | static void __exit ar7_gpio_char_exit(void) |
| 152 | { |
| 153 | unregister_chrdev(ar7_gpio_major, DRVNAME); |
| 154 | platform_device_unregister(ar7_gpio_device); |
| 155 | } |
| 156 | |
| 157 | module_init(ar7_gpio_char_init); |
| 158 | module_exit(ar7_gpio_char_exit); |
| 159 | |
