ans-lcd.c

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/*
 * /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;
static DEFINE_MUTEX(anslcd_mutex);

#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;

    mutex_lock(&anslcd_mutex);
    for ( i = *ppos; count > 0; ++i, ++p, --count ) 
    {
        char c;
        __get_user(c, p);
        anslcd_write_byte_data( c );
    }
    mutex_unlock(&anslcd_mutex);
    *ppos = i;
    return p - buf;
}

static long
anslcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    char ch, __user *temp;
    long ret = 0;

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

    mutex_lock(&anslcd_mutex);

    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 );
        break;
    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);
        }
        break;
    case ANSLCD_SETSHORTDELAY:
        if (!capable(CAP_SYS_ADMIN))
            ret =-EACCES;
        else
            anslcd_short_delay=arg;
        break;
    case ANSLCD_SETLONGDELAY:
        if (!capable(CAP_SYS_ADMIN))
            ret = -EACCES;
        else
            anslcd_long_delay=arg;
        break;
    default:
        ret = -EINVAL;
    }

    mutex_unlock(&anslcd_mutex);
    return ret;
}

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

const struct file_operations anslcd_fops = {
    .write      = anslcd_write,
    .unlocked_ioctl = anslcd_ioctl,
    .open       = anslcd_open,
    .llseek     = default_llseek,
};

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

    mutex_lock(&anslcd_mutex);
    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]);
    }
    mutex_unlock(&anslcd_mutex);
    return 0;
}

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

module_init(anslcd_init);
module_exit(anslcd_exit);