/*********************************************************************
 *                
 * Filename:      tekram.c
 * Version:       1.3
 * Description:   Implementation of the Tekram IrMate IR-210B dongle
 * Status:        Experimental.
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Wed Oct 21 20:02:35 1998
 * Modified at:   Sun Oct 27 22:02:38 2002
 * Modified by:   Martin Diehl <mad@mdiehl.de>
 * 
 *     Copyright (c) 1998-1999 Dag Brattli,
 *     Copyright (c) 2002 Martin Diehl,
 *     All Rights Reserved.
 *      
 *     This program is free software; you can redistribute it and/or 
 *     modify it under the terms of the GNU General Public License as 
 *     published by the Free Software Foundation; either version 2 of 
 *     the License, or (at your option) any later version.
 *  
 *     Neither Dag Brattli nor University of Tromsø admit liability nor
 *     provide warranty for any of this software. This material is 
 *     provided "AS-IS" and at no charge.
 *     
 ********************************************************************/

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>

#include <net/irda/irda.h>

#include "sir-dev.h"

static int tekram_delay = 150;          /* default is 150 ms */
module_param(tekram_delay, int, 0);
MODULE_PARM_DESC(tekram_delay, "tekram dongle write complete delay");

static int tekram_open(struct sir_dev *);
static int tekram_close(struct sir_dev *);
static int tekram_change_speed(struct sir_dev *, unsigned);
static int tekram_reset(struct sir_dev *);

#define TEKRAM_115200 0x00
#define TEKRAM_57600  0x01
#define TEKRAM_38400  0x02
#define TEKRAM_19200  0x03
#define TEKRAM_9600   0x04

#define TEKRAM_PW     0x10 /* Pulse select bit */

static struct dongle_driver tekram = {
        .owner          = THIS_MODULE,
        .driver_name    = "Tekram IR-210B",
        .type           = IRDA_TEKRAM_DONGLE,
        .open           = tekram_open,
        .close          = tekram_close,
        .reset          = tekram_reset,
        .set_speed      = tekram_change_speed,
};

static int __init tekram_sir_init(void)
{
        if (tekram_delay < 1  ||  tekram_delay > 500)
                tekram_delay = 200;
        IRDA_DEBUG(1, "%s - using %d ms delay\n",
                tekram.driver_name, tekram_delay);
        return irda_register_dongle(&tekram);
}

static void __exit tekram_sir_cleanup(void)
{
        irda_unregister_dongle(&tekram);
}

static int tekram_open(struct sir_dev *dev)
{
        struct qos_info *qos = &dev->qos;

        IRDA_DEBUG(2, "%s()\n", __func__);

        sirdev_set_dtr_rts(dev, TRUE, TRUE);

        qos->baud_rate.bits &= IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;
        qos->min_turn_time.bits = 0x01; /* Needs at least 10 ms */      
        irda_qos_bits_to_value(qos);

        /* irda thread waits 50 msec for power settling */

        return 0;
}

static int tekram_close(struct sir_dev *dev)
{
        IRDA_DEBUG(2, "%s()\n", __func__);

        /* Power off dongle */
        sirdev_set_dtr_rts(dev, FALSE, FALSE);

        return 0;
}

/*
 * Function tekram_change_speed (dev, state, speed)
 *
 *    Set the speed for the Tekram IRMate 210 type dongle. Warning, this 
 *    function must be called with a process context!
 *
 *    Algorithm
 *    1. clear DTR 
 *    2. set RTS, and wait at least 7 us
 *    3. send Control Byte to the IR-210 through TXD to set new baud rate
 *       wait until the stop bit of Control Byte is sent (for 9600 baud rate, 
 *       it takes about 100 msec)
 *
 *      [oops, why 100 msec? sending 1 byte (10 bits) takes 1.05 msec
 *       - is this probably to compensate for delays in tty layer?]
 *
 *    5. clear RTS (return to NORMAL Operation)
 *    6. wait at least 50 us, new setting (baud rate, etc) takes effect here 
 *       after
 */

#define TEKRAM_STATE_WAIT_SPEED (SIRDEV_STATE_DONGLE_SPEED + 1)

static int tekram_change_speed(struct sir_dev *dev, unsigned speed)
{
        unsigned state = dev->fsm.substate;
        unsigned delay = 0;
        u8 byte;
        static int ret = 0;
        
        IRDA_DEBUG(2, "%s()\n", __func__);

        switch(state) {
        case SIRDEV_STATE_DONGLE_SPEED:

                switch (speed) {
                default:
                        speed = 9600;
                        ret = -EINVAL;
                        /* fall thru */
                case 9600:
                        byte = TEKRAM_PW|TEKRAM_9600;
                        break;
                case 19200:
                        byte = TEKRAM_PW|TEKRAM_19200;
                        break;
                case 38400:
                        byte = TEKRAM_PW|TEKRAM_38400;
                        break;
                case 57600:
                        byte = TEKRAM_PW|TEKRAM_57600;
                        break;
                case 115200:
                        byte = TEKRAM_115200;
                        break;
                }

                /* Set DTR, Clear RTS */
                sirdev_set_dtr_rts(dev, TRUE, FALSE);
        
                /* Wait at least 7us */
                udelay(14);

                /* Write control byte */
                sirdev_raw_write(dev, &byte, 1);
                
                dev->speed = speed;

                state = TEKRAM_STATE_WAIT_SPEED;
                delay = tekram_delay;
                break;

        case TEKRAM_STATE_WAIT_SPEED:
                /* Set DTR, Set RTS */
                sirdev_set_dtr_rts(dev, TRUE, TRUE);
                udelay(50);
                break;

        default:
                IRDA_ERROR("%s - undefined state %d\n", __func__, state);
                ret = -EINVAL;
                break;
        }

        dev->fsm.substate = state;
        return (delay > 0) ? delay : ret;
}

/*
 * Function tekram_reset (driver)
 *
 *      This function resets the tekram dongle. Warning, this function 
 *      must be called with a process context!! 
 *
 *      Algorithm:
 *        0. Clear RTS and DTR, and wait 50 ms (power off the IR-210 )
 *        1. clear RTS 
 *        2. set DTR, and wait at least 1 ms 
 *        3. clear DTR to SPACE state, wait at least 50 us for further 
 *         operation
 */

static int tekram_reset(struct sir_dev *dev)
{
        IRDA_DEBUG(2, "%s()\n", __func__);

        /* Clear DTR, Set RTS */
        sirdev_set_dtr_rts(dev, FALSE, TRUE); 

        /* Should sleep 1 ms */
        msleep(1);

        /* Set DTR, Set RTS */
        sirdev_set_dtr_rts(dev, TRUE, TRUE);
        
        /* Wait at least 50 us */
        udelay(75);

        dev->speed = 9600;

        return 0;
}

MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
MODULE_DESCRIPTION("Tekram IrMate IR-210B dongle driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("irda-dongle-0"); /* IRDA_TEKRAM_DONGLE */
                
module_init(tekram_sir_init);
module_exit(tekram_sir_cleanup);