/*********************************************************************
 *                
 * Filename:      ma600.c
 * Version:       0.1
 * Description:   Implementation of the MA600 dongle
 * Status:        Experimental.
 * Author:        Leung <95Etwl@alumni.ee.ust.hk> http://www.engsvr.ust/~eetwl95
 * Created at:    Sat Jun 10 20:02:35 2000
 * Modified at:   Sat Aug 16 09:34:13 2003
 * Modified by:   Martin Diehl <mad@mdiehl.de> (modified for new sir_dev)
 *
 * Note: very thanks to Mr. Maru Wang <maru@mobileaction.com.tw> for providing 
 *       information on the MA600 dongle
 * 
 *     Copyright (c) 2000 Leung, 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.
 *  
 *     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, see <http://www.gnu.org/licenses/>.
 *     
 ********************************************************************/

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

#include <net/irda/irda.h>

#include "sir-dev.h"

static int ma600_open(struct sir_dev *);
static int ma600_close(struct sir_dev *);
static int ma600_change_speed(struct sir_dev *, unsigned);
static int ma600_reset(struct sir_dev *);

/* control byte for MA600 */
#define MA600_9600	0x00
#define MA600_19200	0x01
#define MA600_38400	0x02
#define MA600_57600	0x03
#define MA600_115200	0x04
#define MA600_DEV_ID1	0x05
#define MA600_DEV_ID2	0x06
#define MA600_2400	0x08

static struct dongle_driver ma600 = {
	.owner          = THIS_MODULE,
	.driver_name    = "MA600",
	.type           = IRDA_MA600_DONGLE,
	.open           = ma600_open,
	.close          = ma600_close,
	.reset          = ma600_reset,
	.set_speed      = ma600_change_speed,
};


static int __init ma600_sir_init(void)
{
	IRDA_DEBUG(2, "%s()\n", __func__);
	return irda_register_dongle(&ma600);
}

static void __exit ma600_sir_cleanup(void)
{
	IRDA_DEBUG(2, "%s()\n", __func__);
	irda_unregister_dongle(&ma600);
}

/*
	Power on:
		(0) Clear RTS and DTR for 1 second
		(1) Set RTS and DTR for 1 second
		(2) 9600 bps now
	Note: assume RTS, DTR are clear before
*/
static int ma600_open(struct sir_dev *dev)
{
	struct qos_info *qos = &dev->qos;

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

	sirdev_set_dtr_rts(dev, TRUE, TRUE);

	/* Explicitly set the speeds we can accept */
	qos->baud_rate.bits &= IR_2400|IR_9600|IR_19200|IR_38400
				|IR_57600|IR_115200;
	/* Hm, 0x01 means 10ms - for >= 1ms we would need 0x07 */
	qos->min_turn_time.bits = 0x01;		/* Needs at least 1 ms */	
	irda_qos_bits_to_value(qos);

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

	return 0;
}

static int ma600_close(struct sir_dev *dev)
{
	IRDA_DEBUG(2, "%s()\n", __func__);

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

	return 0;
}

static __u8 get_control_byte(__u32 speed)
{
	__u8 byte;

	switch (speed) {
	default:
	case 115200:
		byte = MA600_115200;
		break;
	case 57600:
		byte = MA600_57600;
		break;
	case 38400:
		byte = MA600_38400;
		break;
	case 19200:
		byte = MA600_19200;
		break;
	case 9600:
		byte = MA600_9600;
		break;
	case 2400:
		byte = MA600_2400;
		break;
	}

	return byte;
}

/*
 * Function ma600_change_speed (dev, speed)
 *
 *    Set the speed for the MA600 type dongle.
 *
 *    The dongle has already been reset to a known state (dongle default)
 *    We cycle through speeds by pulsing RTS low and then high.
 */

/*
 * Function ma600_change_speed (dev, speed)
 *
 *    Set the speed for the MA600 type dongle.
 *
 *    Algorithm
 *    1. Reset (already done by irda thread state machine)
 *    2. clear RTS, set DTR and wait for 1ms
 *    3. send Control Byte to the MA600 through TXD to set new baud rate
 *       wait until the stop bit of Control Byte is sent (for 9600 baud rate, 
 *       it takes about 10 msec)
 *    4. set RTS, set DTR (return to NORMAL Operation)
 *    5. wait at least 10 ms, new setting (baud rate, etc) takes effect here 
 *       after
 */

/* total delays are only about 20ms - let's just sleep for now to
 * avoid the state machine complexity before we get things working
 */

static int ma600_change_speed(struct sir_dev *dev, unsigned speed)
{
	u8	byte;
	
	IRDA_DEBUG(2, "%s(), speed=%d (was %d)\n", __func__,
		speed, dev->speed);

	/* dongle already reset, dongle and port at default speed (9600) */

	/* Set RTS low for 1 ms */
	sirdev_set_dtr_rts(dev, TRUE, FALSE);
	mdelay(1);

	/* Write control byte */
	byte = get_control_byte(speed);
	sirdev_raw_write(dev, &byte, sizeof(byte));

	/* Wait at least 10ms: fake wait_until_sent - 10 bits at 9600 baud*/
	msleep(15);					/* old ma600 uses 15ms */

#if 1
	/* read-back of the control byte. ma600 is the first dongle driver
	 * which uses this so there might be some unidentified issues.
	 * Disable this in case of problems with readback.
	 */

	sirdev_raw_read(dev, &byte, sizeof(byte));
	if (byte != get_control_byte(speed))  {
		net_warn_ratelimited("%s(): bad control byte read-back %02x != %02x\n",
				     __func__, (unsigned)byte,
				     (unsigned)get_control_byte(speed));
		return -1;
	}
	else
		IRDA_DEBUG(2, "%s() control byte write read OK\n", __func__);
#endif

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

	/* Wait at least 10ms */
	msleep(10);

	/* dongle is now switched to the new speed */
	dev->speed = speed;

	return 0;
}

/*
 * Function ma600_reset (dev)
 *
 *      This function resets the ma600 dongle.
 *
 *      Algorithm:
 *    	  0. DTR=0, RTS=1 and wait 10 ms
 *    	  1. DTR=1, RTS=1 and wait 10 ms
 *        2. 9600 bps now
 */

/* total delays are only about 20ms - let's just sleep for now to
 * avoid the state machine complexity before we get things working
 */

static int ma600_reset(struct sir_dev *dev)
{
	IRDA_DEBUG(2, "%s()\n", __func__);

	/* Reset the dongle : set DTR low for 10 ms */
	sirdev_set_dtr_rts(dev, FALSE, TRUE);
	msleep(10);

	/* Go back to normal mode */
	sirdev_set_dtr_rts(dev, TRUE, TRUE);
	msleep(10);

	dev->speed = 9600;      /* That's the dongle-default */

	return 0;
}

MODULE_AUTHOR("Leung <95Etwl@alumni.ee.ust.hk> http://www.engsvr.ust/~eetwl95");
MODULE_DESCRIPTION("MA600 dongle driver version 0.1");
MODULE_LICENSE("GPL");
MODULE_ALIAS("irda-dongle-11"); /* IRDA_MA600_DONGLE */
		
module_init(ma600_sir_init);
module_exit(ma600_sir_cleanup);