release/src-rt/shared/linux_gpio.c

   1 /*
   2  * Linux Broadcom BCM47xx GPIO char driver
   3  *
   4  * Copyright (C) 2010, Broadcom Corporation. All Rights Reserved.
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  13  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  15  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  16  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  * $Id: linux_gpio.c,v 1.10 2008-03-28 19:25:35 Exp $
  18  *
  19  */
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/fs.h>
  23 #include <linux/miscdevice.h>
  24 #include <asm/uaccess.h>
  25
  26 #include <typedefs.h>
  27 #include <bcmutils.h>
  28 #include <siutils.h>
  29 #include <bcmdevs.h>
  30
  31 #include <linux_gpio.h>
  32
  33 /* handle to the sb */
  34 static si_t *gpio_sih;
  35
  36 /* major number assigned to the device and device handles */
  37 static int gpio_major;
  38 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
  39 static struct class *gpiodev_class = NULL;
  40 #else
  41 devfs_handle_t gpiodev_handle;
  42 #endif
  43
  44 static int
  45 gpio_open(struct inode *inode, struct file * file)
  46 {
  47         MOD_INC_USE_COUNT;
  48         return 0;
  49 }
  50
  51 static int
  52 gpio_release(struct inode *inode, struct file * file)
  53 {
  54         MOD_DEC_USE_COUNT;
  55         return 0;
  56 }
  57
  58 static int
  59 gpio_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
  60 {
  61         struct gpio_ioctl gpioioc;
  62
  63         if (copy_from_user(&gpioioc, (struct gpio_ioctl *)arg, sizeof(struct gpio_ioctl)))
  64                 return -EFAULT;
  65
  66         switch (cmd) {
  67                 case GPIO_IOC_RESERVE:
  68                         gpioioc.val = si_gpioreserve(gpio_sih, gpioioc.mask, GPIO_APP_PRIORITY);
  69                         break;
  70                 case GPIO_IOC_RELEASE:
  71                         /*
  72                          * releasing the gpio doesn't change the current
  73                          * value on the GPIO last write value
  74                          * persists till some one overwrites it
  75                          */
  76                         gpioioc.val = si_gpiorelease(gpio_sih, gpioioc.mask, GPIO_APP_PRIORITY);
  77                         break;
  78                 case GPIO_IOC_OUT:
  79                         gpioioc.val = si_gpioout(gpio_sih, gpioioc.mask, gpioioc.val,
  80                                                  GPIO_APP_PRIORITY);
  81                         break;
  82                 case GPIO_IOC_OUTEN:
  83                         gpioioc.val = si_gpioouten(gpio_sih, gpioioc.mask, gpioioc.val,
  84                                                    GPIO_APP_PRIORITY);
  85                         break;
  86                 case GPIO_IOC_IN:
  87                         gpioioc.val = si_gpioin(gpio_sih);
  88                         break;
  89                 default:
  90                         break;
  91         }
  92         if (copy_to_user((struct gpio_ioctl *)arg, &gpioioc, sizeof(struct gpio_ioctl)))
  93                 return -EFAULT;
  94
  95         return 0;
  96
  97 }
  98 static struct file_operations gpio_fops = {
  99         owner:          THIS_MODULE,
 100         open:           gpio_open,
 101         release:        gpio_release,
 102         ioctl:          gpio_ioctl
 103 };
 104
 105 static int __init
 106 gpio_init(void)
 107 {
 108         if (!(gpio_sih = si_kattach(SI_OSH)))
 109                 return -ENODEV;
 110
 111 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
 112         if ((gpio_major = register_chrdev(0, "gpio", &gpio_fops)) < 0)
 113 #else
 114         if ((gpio_major = devfs_register_chrdev(0, "gpio", &gpio_fops)) < 0)
 115 #endif
 116                 return gpio_major;
 117 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
 118         gpiodev_class = class_create(THIS_MODULE, "gpio");
 119         if (IS_ERR(gpiodev_class)) {
 120                 printk("Error creating gpio class\n");
 121                 return -1;
 122         }
 123
 124         /* Add the device gpio0 */
 125         class_device_create(gpiodev_class, NULL, MKDEV(gpio_major, 0), NULL, "gpio");
 126 #else
 127         gpiodev_handle = devfs_register(NULL, "gpio", DEVFS_FL_DEFAULT,
 128                                         gpio_major, 0, S_IFCHR | S_IRUGO | S_IWUGO,
 129                                         &gpio_fops, NULL);
 130 #endif
 131
 132         return 0;
 133 }
 134
 135 static void __exit
 136 gpio_exit(void)
 137 {
 138 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
 139         if (gpiodev_class != NULL) {
 140                 class_device_destroy(gpiodev_class, MKDEV(gpio_major, 0));
 141                 class_destroy(gpiodev_class);
 142         }
 143
 144         gpiodev_class = NULL;
 145         if (gpio_major >= 0)
 146                 unregister_chrdev(gpio_major, "gpio");
 147 #else
 148         if (gpiodev_handle != NULL)
 149                 devfs_unregister(gpiodev_handle);
 150         gpiodev_handle = NULL;
 151         devfs_unregister_chrdev(gpio_major, "gpio");
 152 #endif
 153         si_detach(gpio_sih);
 154 }
 155
 156 module_init(gpio_init);
 157 module_exit(gpio_exit);