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ans-lcd.c

/*
 * /dev/lcd driver for Apple Network Servers.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/fs.h>

#include <asm/uaccess.h>
#include <asm/sections.h>
#include <asm/prom.h>
#include <asm/io.h>

#include "ans-lcd.h"

#define ANSLCD_ADDR           0xf301c000
#define ANSLCD_CTRL_IX 0x00
#define ANSLCD_DATA_IX 0x10

static unsigned long anslcd_short_delay = 80;
static unsigned long anslcd_long_delay = 3280;
static volatile unsigned char __iomem *anslcd_ptr;

#undef DEBUG

static void
anslcd_write_byte_ctrl ( unsigned char c )
{
#ifdef DEBUG
      printk(KERN_DEBUG "LCD: CTRL byte: %02x\n",c);
#endif
      out_8(anslcd_ptr + ANSLCD_CTRL_IX, c);
      switch(c) {
            case 1:
            case 2:
            case 3:
                  udelay(anslcd_long_delay); break;
            default: udelay(anslcd_short_delay);
      }
}

static void
anslcd_write_byte_data ( unsigned char c )
{
      out_8(anslcd_ptr + ANSLCD_DATA_IX, c);
      udelay(anslcd_short_delay);
}

static ssize_t
anslcd_write( struct file * file, const char __user * buf, 
                        size_t count, loff_t *ppos )
{
      const char __user *p = buf;
      int i;

#ifdef DEBUG
      printk(KERN_DEBUG "LCD: write\n");
#endif

      if (!access_ok(VERIFY_READ, buf, count))
            return -EFAULT;
      for ( i = *ppos; count > 0; ++i, ++p, --count ) 
      {
            char c;
            __get_user(c, p);
            anslcd_write_byte_data( c );
      }
      *ppos = i;
      return p - buf;
}

static int
anslcd_ioctl( struct inode * inode, struct file * file,
                        unsigned int cmd, unsigned long arg )
{
      char ch, __user *temp;

#ifdef DEBUG
      printk(KERN_DEBUG "LCD: ioctl(%d,%d)\n",cmd,arg);
#endif

      switch ( cmd )
      {
      case ANSLCD_CLEAR:
            anslcd_write_byte_ctrl ( 0x38 );
            anslcd_write_byte_ctrl ( 0x0f );
            anslcd_write_byte_ctrl ( 0x06 );
            anslcd_write_byte_ctrl ( 0x01 );
            anslcd_write_byte_ctrl ( 0x02 );
            return 0;
      case ANSLCD_SENDCTRL:
            temp = (char __user *) arg;
            __get_user(ch, temp);
            for (; ch; temp++) { /* FIXME: This is ugly, but should work, as a \0 byte is not a valid command code */
                  anslcd_write_byte_ctrl ( ch );
                  __get_user(ch, temp);
            }
            return 0;
      case ANSLCD_SETSHORTDELAY:
            if (!capable(CAP_SYS_ADMIN))
                  return -EACCES;
            anslcd_short_delay=arg;
            return 0;
      case ANSLCD_SETLONGDELAY:
            if (!capable(CAP_SYS_ADMIN))
                  return -EACCES;
            anslcd_long_delay=arg;
            return 0;
      default:
            return -EINVAL;
      }
}

static int
anslcd_open( struct inode * inode, struct file * file )
{
      return 0;
}

const struct file_operations anslcd_fops = {
      .write      = anslcd_write,
      .ioctl      = anslcd_ioctl,
      .open = anslcd_open,
};

static struct miscdevice anslcd_dev = {
      ANSLCD_MINOR,
      "anslcd",
      &anslcd_fops
};

const char anslcd_logo[] =    "********************"  /* Line #1 */
                        "*      LINUX!      *"  /* Line #3 */
                        "*    Welcome to    *"  /* Line #2 */
                        "********************"; /* Line #4 */

static int __init
anslcd_init(void)
{
      int a;
      int retval;
      struct device_node* node;

      node = of_find_node_by_name(NULL, "lcd");
      if (!node || !node->parent || strcmp(node->parent->name, "gc")) {
            of_node_put(node);
            return -ENODEV;
      }
      of_node_put(node);

      anslcd_ptr = ioremap(ANSLCD_ADDR, 0x20);
      
      retval = misc_register(&anslcd_dev);
      if(retval < 0){
            printk(KERN_INFO "LCD: misc_register failed\n");
            iounmap(anslcd_ptr);
            return retval;
      }

#ifdef DEBUG
      printk(KERN_DEBUG "LCD: init\n");
#endif

      anslcd_write_byte_ctrl ( 0x38 );
      anslcd_write_byte_ctrl ( 0x0c );
      anslcd_write_byte_ctrl ( 0x06 );
      anslcd_write_byte_ctrl ( 0x01 );
      anslcd_write_byte_ctrl ( 0x02 );
      for(a=0;a<80;a++) {
            anslcd_write_byte_data(anslcd_logo[a]);
      }
      return 0;
}

static void __exit
anslcd_exit(void)
{
      misc_deregister(&anslcd_dev);
      iounmap(anslcd_ptr);
}

module_init(anslcd_init);
module_exit(anslcd_exit);

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