release/src/shared/linux_gpio.c

   1 /*
   2  * Linux Broadcom BCM47xx GPIO char driver
   3  *
   4  * Copyright 2007, Broadcom Corporation
   5  * All Rights Reserved.
   6  *
   7  * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
   8  * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
   9  * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
  10  * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
  11  * $Id$
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/fs.h>
  18 #include <linux/miscdevice.h>
  19 #include <asm/uaccess.h>
  20
  21 #include <typedefs.h>
  22 #include <bcmutils.h>
  23 #include <sbutils.h>
  24 #include <bcmdevs.h>
  25
  26 #include <linux_gpio.h>
  27
  28 /* handle to the sb */
  29 static sb_t *gpio_sbh;
  30
  31 /* major number assigned to the device and device handles */
  32 static int gpio_major;
  33 devfs_handle_t gpiodev_handle;
  34
  35 static int
  36 gpio_open(struct inode *inode, struct file * file)
  37 {
  38         MOD_INC_USE_COUNT;
  39         return 0;
  40 }
  41
  42 static int
  43 gpio_release(struct inode *inode, struct file * file)
  44 {
  45         MOD_DEC_USE_COUNT;
  46         return 0;
  47 }
  48
  49 static int
  50 gpio_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
  51 {
  52         struct gpio_ioctl gpioioc;
  53
  54         if (copy_from_user(&gpioioc, (struct gpio_ioctl *)arg, sizeof(struct gpio_ioctl)))
  55                 return -EFAULT;
  56
  57         switch (cmd) {
  58                 case GPIO_IOC_RESERVE:
  59                         gpioioc.val = sb_gpioreserve(gpio_sbh, gpioioc.mask, GPIO_APP_PRIORITY);
  60                         break;
  61                 case GPIO_IOC_RELEASE:
  62                         /*
  63                          * releasing the gpio doesn't change the current
  64                          * value on the GPIO last write value
  65                          * persists till some one overwrites it
  66                          */
  67                         gpioioc.val = sb_gpiorelease(gpio_sbh, gpioioc.mask, GPIO_APP_PRIORITY);
  68                         break;
  69                 case GPIO_IOC_OUT:
  70                         gpioioc.val = sb_gpioout(gpio_sbh, gpioioc.mask, gpioioc.val,
  71                                                  GPIO_APP_PRIORITY);
  72                         break;
  73                 case GPIO_IOC_OUTEN:
  74                         gpioioc.val = sb_gpioouten(gpio_sbh, gpioioc.mask, gpioioc.val,
  75                                                    GPIO_APP_PRIORITY);
  76                         break;
  77                 case GPIO_IOC_IN:
  78                         gpioioc.val = sb_gpioin(gpio_sbh);
  79                         break;
  80                 default:
  81                         break;
  82         }
  83         if (copy_to_user((struct gpio_ioctl *)arg, &gpioioc, sizeof(struct gpio_ioctl)))
  84                 return -EFAULT;
  85
  86         return 0;
  87
  88 }
  89 static struct file_operations gpio_fops = {
  90         owner:          THIS_MODULE,
  91         open:           gpio_open,
  92         release:        gpio_release,
  93         ioctl:          gpio_ioctl,
  94         };
  95
  96 static int __init
  97 gpio_init(void)
  98 {
  99         if (!(gpio_sbh = sb_kattach(SB_OSH)))
 100                 return -ENODEV;
 101
 102         if ((gpio_major = devfs_register_chrdev(0, "gpio", &gpio_fops)) < 0)
 103                 return gpio_major;
 104
 105         gpiodev_handle = devfs_register(NULL, "gpio", DEVFS_FL_DEFAULT,
 106                                         gpio_major, 0, S_IFCHR | S_IRUGO | S_IWUGO,
 107                                         &gpio_fops, NULL);
 108
 109         return 0;
 110 }
 111
 112 static void __exit
 113 gpio_exit(void)
 114 {
 115         if (gpiodev_handle != NULL)
 116                 devfs_unregister(gpiodev_handle);
 117         gpiodev_handle = NULL;
 118         devfs_unregister_chrdev(gpio_major, "gpio");
 119         sb_detach(gpio_sbh);
 120 }
 121
 122 module_init(gpio_init);
 123 module_exit(gpio_exit);