Hi everybody...

        A few weeks ago, I was complaining that the timming in the
Actisys dongle driver in Linux IrDA were absurd. Today I received my
batch of Actisys dongle, and guess what, I could not make it work with
Linux IrDA.
        So, I wiped out the initialisation code and the code to change
speed in the old driver and replaced it with something simpler, faster
and more robust. I have to thanks Lichen Wang from Actisys who sent me
a nice e-mail detailing the secret of their dongle.
        Anyway, the result is a new dongle driver that work for me.
        Enjoy...

        Jean

--------------------------------------------------
/*********************************************************************
 *                
 * Filename:      actisys.c
 * Version:       0.9999
 * Description:   Implementation for the ACTiSYS IR-220L and IR-220L+ 
 *                dongles
 * Status:        Beta.
 * Authors:       Dag Brattli <[EMAIL PROTECTED]> (initially)
 *                Jean Tourrilhes <[EMAIL PROTECTED]> (new version)
 * Created at:    Wed Oct 21 20:02:35 1998
 * Modified at:   1/12/99
 * Modified by:   Jean
 * 
 *     Copyright (c) 1998-1999 Dag Brattli, All Rights Reserved.
 *     Copyright (c) 1999 Jean Tourrilhes
 *      
 *     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 Troms� admit liability nor
 *     provide warranty for any of this software. This material is 
 *     provided "AS-IS" and at no charge.
 *     
 ********************************************************************/

/*
 * Changelog
 *
 * 0.8 -> 0.9999 - Jean
 *      o New initialisation procedure : much safer and correct
 *      o New procedure the change speed : much faster and simpler
 *      o Other cleanups & comments
 *      Thanks to Lichen Wang @ Actisys for his excellent help...
 */

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

#include <net/irda/irda.h>
#include <net/irda/irmod.h>
#include <net/irda/irda_device.h>

/*
 *      Define the timing of the pulses we send to the dongle (to reset
 * it, and to toggle speeds).
 *      Basically, the limit here is the propagation speed of the
 * signals through the serial port, the dongle being much faster.
 *      Any serial port support 115 kb/s, so we are sure that pulses
 * 8.5 us wide can go through cleanly .
 *      If you are on the wild side, you can try to lower this value
 * (Actisys recommended me 2 us, and 0 us work for me on a P233 !!!)
 */
#define MIN_DELAY 10    /* 10 us to be on the conservative side */

static int  actisys_change_speed(struct irda_task *task);
static int  actisys_reset(struct irda_task *task);
static void actisys_open(dongle_t *self, struct qos_info *qos);
static void actisys_close(dongle_t *self);

/* These are the baudrates supported, in the order available */
/* Note : the 220L doesn't support 38400, but we will fix that below */
static __u32 baud_rates[] = { 9600, 19200, 57600, 115200, 38400 };

static struct dongle_reg dongle = {
        Q_NULL,
        IRDA_ACTISYS_DONGLE,
        actisys_open,
        actisys_close,
        actisys_reset,
        actisys_change_speed,
};

static struct dongle_reg dongle_plus = {
        Q_NULL,
        IRDA_ACTISYS_PLUS_DONGLE,
        actisys_open,
        actisys_close,
        actisys_reset,
        actisys_change_speed,
};

/*
 * Function actisys_change_speed (task)
 *
 *      There is two model of Actisys dongle we are dealing with,
 * the 220L and 220L+. At this point, only irattach knows with
 * kind the user has requested (it was an argument on irattach
 * command line).
 *      So, we register a dongle of each sort and let irattach
 * pick the right one...
 */
int __init actisys_init(void)
{
        int ret;

        /* First, register an Actisys 220L dongle */
        ret = irda_device_register_dongle(&dongle);
        if (ret < 0)
                return ret;
        /* Now, register an Actisys 220L+ dongle */
        ret = irda_device_register_dongle(&dongle_plus);
        if (ret < 0) {
                irda_device_unregister_dongle(&dongle);
                return ret;
        }       
        return 0;
}

void actisys_cleanup(void)
{
        /* We have to remove both dongles */
        irda_device_unregister_dongle(&dongle);
        irda_device_unregister_dongle(&dongle_plus);
}

static void actisys_open(dongle_t *self, struct qos_info *qos)
{
        /* Power on the dongle */
        self->set_dtr_rts(self->dev, TRUE, TRUE);

        /* Set the speeds we can accept */
        qos->baud_rate.bits &= IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;

        /* Remove support for 38400 if this is not a 220L+ dongle */
        if (self->issue->type == IRDA_ACTISYS_DONGLE)
                qos->baud_rate.bits &= ~IR_38400;
        
        qos->min_turn_time.bits &= 0x40; /* Needs 0.01 ms */

        MOD_INC_USE_COUNT;
}

static void actisys_close(dongle_t *self)
{
        /* Power off the dongle */
        self->set_dtr_rts(self->dev, FALSE, FALSE);

        MOD_DEC_USE_COUNT;
}

/*
 * Function actisys_change_speed (task)
 *
 *    Change speed of the ACTiSYS IR-220L and IR-220L+ type IrDA dongles.
 *    To cycle through the available baud rates, pulse RTS low for a few us.
 *
 *      First, we reset the dongle to always start from a known state.
 *      Then, we cycle through the speeds by pulsing RTS low and then up.
 *      The dongle allow us to pulse quite fast, se we can set speed in one go,
 * which is must faster ( < 100 us) and less complex than what is found
 * in some other dongle drivers...
 *      Note that even if the new speed is the same as the current speed,
 * we reassert the speed. This make sure that things are all right,
 * and it's fast anyway...
 *      By the way, this function will work for both type of dongles,
 * because the additional speed is at the end of the sequence...
 */
static int actisys_change_speed(struct irda_task *task)
{
        dongle_t *self = (dongle_t *) task->instance;
        __u32 speed = (__u32) task->param;      /* Target speed */
        int index = 0;
        int ret = 0;
        
        IRDA_DEBUG(4, __FUNCTION__ "(), speed=%d (was %d)\n",
                   speed, self->speed);

        /* Go to a known state by reseting the dongle */

        /* Reset the dongle : set DTR low for 10 us */
        self->set_dtr_rts(self->dev, FALSE, TRUE);
        udelay(MIN_DELAY);

        /* Go back to normal mode (we are now at 9600 b/s) */
        self->set_dtr_rts(self->dev, TRUE, TRUE);
 
        /* Now, we can set the speed requested */

        /* Send RTS pulses until we reach the target speed */
        while((index < 5) && (speed != baud_rates[index++]))
        {
                /* Make sure previous pulse is finished */
                udelay(MIN_DELAY);

                /* Set RTS low for 10 us */
                self->set_dtr_rts(self->dev, TRUE, FALSE);
                udelay(MIN_DELAY);

                /* Set RTS high for 10 us */
                self->set_dtr_rts(self->dev, TRUE, TRUE);
        }

        /* Check if life is sweet... */
        if(speed != baud_rates[index])
                ret = -1;       /* This should not happen */
        self->speed = baud_rates[index];        /* Do we care ? */

        /* Basta lavoro, on se casse d'ici... */
        irda_task_next_state(task, IRDA_TASK_DONE);

        return ret;
}

/*
 * Function actisys_reset (task)
 *
 *      Reset the Actisys type dongle. Warning, this function must only be
 *      called with a process context!
 *
 * We need to do two things in this function :
 *      o first make sure that the dongle is in a state where it can operate
 *      o second put the dongle in a know state
 *
 *      The dongle is powered of the RTS and DTR lines. In the dongle, there
 * is a big capacitor to accomodate the current spikes. This capacitor
 * takes a least 50 ms to be charged. In theory, the Bios set those lines
 * up, so by the time we arrive here we should be set. It doesn't hurt
 * to be on the conservative side, so we will wait...
 *      Then, we set the speed to 9600 b/s to get in a known state (see in
 * change_speed for details). It is needed because the IrDA stack
 * has tried to set the speed immediately after our first return,
 * so before we can be sure the dongle is up and running.
 */
static int actisys_reset(struct irda_task *task)
{
        dongle_t *self = (dongle_t *) task->instance;
        int ret = 0;

        ASSERT(task != NULL, return -1;);

        self->reset_task = task;

        switch (task->state) {
        case IRDA_TASK_INIT:
                /* Set both DTR & RTS to power up the dongle */
                /* In theory redundant with power up in actisys_open() */
                self->set_dtr_rts(self->dev, TRUE, TRUE);
                
                /* Sleep 50 ms to make sure capacitor is charged */
                ret = MSECS_TO_JIFFIES(50);
                irda_task_next_state(task, IRDA_TASK_WAIT);
                break;
        case IRDA_TASK_WAIT:                    
                /* Reset the dongle : set DTR low for 10 us */
                self->set_dtr_rts(self->dev, FALSE, TRUE);
                udelay(MIN_DELAY);

                /* Go back to normal mode */
                self->set_dtr_rts(self->dev, TRUE, TRUE);
        
                irda_task_next_state(task, IRDA_TASK_DONE);
                self->reset_task = NULL;
                self->speed = 9600;     /* That's the default */
                break;
        default:
                ERROR(__FUNCTION__ "(), unknown state %d\n", task->state);
                irda_task_next_state(task, IRDA_TASK_DONE);
                self->reset_task = NULL;
                ret = -1;
                break;
        }
        return ret;
}

#ifdef MODULE
MODULE_AUTHOR("Dag Brattli <[EMAIL PROTECTED]> - Jean Tourrilhes <[EMAIL PROTECTED]>");
MODULE_DESCRIPTION("ACTiSYS IR-220L and IR-220L+ dongle driver");       
                
/*
 * Function init_module (void)
 *
 *    Initialize Actisys module
 *
 */
int init_module(void)
{
        return actisys_init();
}

/*
 * Function cleanup_module (void)
 *
 *    Cleanup Actisys module
 *
 */
void cleanup_module(void)
{
        actisys_cleanup();
}
#endif /* MODULE */

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