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/*

 *    Filename: ks0108.c

 *     Version: 0.1.0

 * Description: ks0108 LCD Controller driver

 *     License: GPLv2

 *     Depends: parport

 *

 *      Author: Copyright (C) Miguel Ojeda Sandonis <maxextreme@gmail.com>

 *        Date: 2006-10-31

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License version 2 as

 *  published by the Free Software Foundation.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 */

#include <linux/init.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/delay.h>

#include <linux/fs.h>

#include <linux/io.h>

#include <linux/parport.h>

#include <linux/uaccess.h>

#include <linux/ks0108.h>

#define KS0108_NAME "ks0108"

/*

 * Module Parameters

 */

static unsigned int ks0108_port = CONFIG_KS0108_PORT;

module_param(ks0108_port, uint, S_IRUGO);

MODULE_PARM_DESC(ks0108_port, "Parallel port where the LCD is connected");

static unsigned int ks0108_delay = CONFIG_KS0108_DELAY;

module_param(ks0108_delay, uint, S_IRUGO);

MODULE_PARM_DESC(ks0108_delay, "Delay between each control writing (microseconds)");

/*

 * Device

 */

static struct parport *ks0108_parport;

static struct pardevice *ks0108_pardevice;

/*

 * ks0108 Exported Commands (don't lock)

 *

 *   You _should_ lock in the top driver: This functions _should not_

 *   get race conditions in any way. Locking for each byte here would be

 *   so slow and useless.

 *

 *   There are not bit definitions because they are not flags,

 *   just arbitrary combinations defined by the documentation for each

 *   function in the ks0108 LCD controller. If you want to know what means

 *   a specific combination, look at the function's name.

 *

 *   The ks0108_writecontrol bits need to be reverted ^(0,1,3) because

 *   the parallel port also revert them using a "not" logic gate.

 */

#define bit(n) (((unsigned char)1)<<(n))

void ks0108_writedata(unsigned char byte)

{

        parport_write_data(ks0108_parport, byte);

}

void ks0108_writecontrol(unsigned char byte)

{

        udelay(ks0108_delay);

        parport_write_control(ks0108_parport, byte ^ (bit(0) | bit(1) | bit(3)));

}

void ks0108_displaystate(unsigned char state)

{

        ks0108_writedata((state ? bit(0) : 0) | bit(1) | bit(2) | bit(3) | bit(4) | bit(5));

}

void ks0108_startline(unsigned char startline)

{

        ks0108_writedata(min(startline,(unsigned char)63) | bit(6) | bit(7));

}

void ks0108_address(unsigned char address)

{

        ks0108_writedata(min(address,(unsigned char)63) | bit(6));

}

void ks0108_page(unsigned char page)

{

        ks0108_writedata(min(page,(unsigned char)7) | bit(3) | bit(4) | bit(5) | bit(7));

}

EXPORT_SYMBOL_GPL(ks0108_writedata);

EXPORT_SYMBOL_GPL(ks0108_writecontrol);

EXPORT_SYMBOL_GPL(ks0108_displaystate);

EXPORT_SYMBOL_GPL(ks0108_startline);

EXPORT_SYMBOL_GPL(ks0108_address);

EXPORT_SYMBOL_GPL(ks0108_page);

/*

 * Is the module inited?

 */

static unsigned char ks0108_inited;

unsigned char ks0108_isinited(void)

{

        return ks0108_inited;

}

EXPORT_SYMBOL_GPL(ks0108_isinited);

/*

 * Module Init & Exit

 */

static int __init ks0108_init(void)

{

        int result;

        int ret = -EINVAL;

        ks0108_parport = parport_find_base(ks0108_port);

        if (ks0108_parport == NULL) {

                printk(KERN_ERR KS0108_NAME ": ERROR: "

                        "parport didn't find %i port\n", ks0108_port);

                goto none;

        }

        ks0108_pardevice = parport_register_device(ks0108_parport, KS0108_NAME,

                NULL, NULL, NULL, PARPORT_DEV_EXCL, NULL);

        if (ks0108_pardevice == NULL) {

                printk(KERN_ERR KS0108_NAME ": ERROR: "

                        "parport didn't register new device\n");

                goto none;

        }

        result = parport_claim(ks0108_pardevice);

        if (result != 0) {

                printk(KERN_ERR KS0108_NAME ": ERROR: "

                        "can't claim %i parport, maybe in use\n", ks0108_port);

                ret = result;

                goto registered;

        }

        ks0108_inited = 1;

        return 0;

registered:

        parport_unregister_device(ks0108_pardevice);

none:

        return ret;

}

static void __exit ks0108_exit(void)

{

        parport_release(ks0108_pardevice);

        parport_unregister_device(ks0108_pardevice);

}

module_init(ks0108_init);

module_exit(ks0108_exit);

MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Miguel Ojeda Sandonis <maxextreme@gmail.com>");

MODULE_DESCRIPTION("ks0108 LCD Controller driver");