/*********************************************************************
*
* Filename: toim3232-sir.c
* Version: 1.0
* Description: Implementation of dongles based on the Vishay/Temic
* TOIM3232 SIR Endec chipset. Currently only the
* IRWave IR320ST-2 is tested, although it should work
* with any TOIM3232 or TOIM4232 chipset based RS232
* dongle with minimal modification.
* Based heavily on the Tekram driver (tekram.c),
* with thanks to Dag Brattli and Martin Diehl.
* Status: Experimental.
* Author: David Basden <davidb-irda@rcpt.to>
* Created at: Thu Feb 09 23:47:32 2006
*
* Copyright (c) 2006 David Basden.
* 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.
*
********************************************************************/
/*
* This driver has currently only been tested on the IRWave IR320ST-2
*
* PROTOCOL:
*
* The protocol for talking to the TOIM3232 is quite easy, and is
* designed to interface with RS232 with only level convertors. The
* BR/~D line on the chip is brought high to signal 'command mode',
* where a command byte is sent to select the baudrate of the RS232
* interface and the pulse length of the IRDA output. When BR/~D
* is brought low, the dongle then changes to the selected baudrate,
* and the RS232 interface is used for data until BR/~D is brought
* high again. The initial speed for the TOIMx323 after RESET is
* 9600 baud. The baudrate for command-mode is the last selected
* baud-rate, or 9600 after a RESET.
*
* The dongle I have (below) adds some extra hardware on the front end,
* but this is mostly directed towards pariasitic power from the RS232
* line rather than changing very much about how to communicate with
* the TOIM3232.
*
* The protocol to talk to the TOIM4232 chipset seems to be almost
* identical to the TOIM3232 (and the 4232 datasheet is more detailed)
* so this code will probably work on that as well, although I haven't
* tested it on that hardware.
*
* Target dongle variations that might be common:
*
* DTR and RTS function:
* The data sheet for the 4232 has a sample implementation that hooks the
* DTR and RTS lines to the RESET and BaudRate/~Data lines of the
* chip (through line-converters). Given both DTR and RTS would have to
* be held low in normal operation, and the TOIMx232 requires +5V to
* signal ground, most dongle designers would almost certainly choose
* an implementation that kept at least one of DTR or RTS high in
* normal operation to provide power to the dongle, but will likely
* vary between designs.
*
* User specified command bits:
* There are two user-controllable output lines from the TOIMx232 that
* can be set low or high by setting the appropriate bits in the
* high-nibble of the command byte (when setting speed and pulse length).
* These might be used to switch on and off added hardware or extra
* dongle features.
*
*
* Target hardware: IRWave IR320ST-2
*
* The IRWave IR320ST-2 is a simple dongle based on the Vishay/Temic
* TOIM3232 SIR Endec and the Vishay/Temic TFDS4500 SIR IRDA transciever.
* It uses a hex inverter and some discrete components to buffer and
* line convert the RS232 down to 5V.
*
* The dongle is powered through a voltage regulator, fed by a large
* capacitor. To switch the dongle on, DTR is brought high to charge
* the capacitor and drive the voltage regulator. DTR isn't associated
* with any control lines on the TOIM3232. Parisitic power is also taken
* from the RTS, TD and RD lines when brought high, but through resistors.
* When DTR is low, the circuit might lose power even with RTS high.
*
* RTS is inverted and attached to the BR/~D input pin. When RTS
* is high, BR/~D is low, and the TOIM3232 is in the normal 'data' mode.
* RTS is brought low, BR/~D is high, and the TOIM3232 is in 'command
* mode'.
*
* For some unknown reason, the RESET line isn't actually connected
* to anything. This means to reset the dongle to get it to a known
* state (9600 baud) you must drop DTR and RTS low, wait for the power
* capacitor to discharge, and then bring DTR (and RTS for data mode)
* high again, and wait for the capacitor to charge, the power supply
* to stabilise, and the oscillator clock to stabilise.
*
* Fortunately, if the current baudrate is known, the chipset can
* easily change speed by entering command mode without having to
* reset the dongle first.
*
* Major Components:
*
* - Vishay/Temic TOIM3232 SIR Endec to change RS232 pulse timings
* to IRDA pulse timings
* - 3.6864MHz crystal to drive TOIM3232 clock oscillator
* - DM74lS04M Inverting Hex line buffer for RS232 input buffering
* and level conversion
* - PJ2951AC 150mA voltage regulator
* - Vishay/Temic TFDS4500 SIR IRDA front-end transceiver
*
*/
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <net/irda/irda.h>
#include "sir-dev.h"
static int toim3232delay = 150; /* default is 150 ms */
module_param(toim3232delay, int, 0);
MODULE_PARM_DESC(toim3232delay, "toim3232 dongle write complete delay");
#if 0
static int toim3232flipdtr = 0; /* default is DTR high to reset */
module_param(toim3232flipdtr, int, 0);
MODULE_PARM_DESC(toim3232flipdtr, "toim3232 dongle invert DTR (Reset)");
static int toim3232fliprts = 0; /* default is RTS high for baud change */
module_param(toim3232fliptrs, int, 0);
MODULE_PARM_DESC(toim3232fliprts, "toim3232 dongle invert RTS (BR/D)");
#endif
static int toim3232_open(struct sir_dev *);
static int toim3232_close(struct sir_dev *);
static int toim3232_change_speed(struct sir_dev *, unsigned);
static int toim3232_reset(struct sir_dev *);
#define TOIM3232_115200 0x00
#define TOIM3232_57600 0x01
#define TOIM3232_38400 0x02
#define TOIM3232_19200 0x03
#define TOIM3232_9600 0x06
#define TOIM3232_2400 0x0A
#define TOIM3232_PW 0x10 /* Pulse select bit */
static struct dongle_driver toim3232 = {
.owner = THIS_MODULE,
.driver_name = "Vishay TOIM3232",
.type = IRDA_TOIM3232_DONGLE,
.open = toim3232_open,
.close = toim3232_close,
.reset = toim3232_reset,
.set_speed = toim3232_change_speed,
};
static int __init toim3232_sir_init(void)
{
if (toim3232delay < 1 || toim3232delay > 500)
toim3232delay = 200;
IRDA_DEBUG(1, "%s - using %d ms delay\n",
toim3232.driver_name, toim3232delay);
return irda_register_dongle(&toim3232);
}
static void __exit toim3232_sir_cleanup(void)
{
irda_unregister_dongle(&toim3232);
}
static int toim3232_open(struct sir_dev *dev)
{
struct qos_info *qos = &dev->qos;
IRDA_DEBUG(2, "%s()\n", __func__);
/* Pull the lines high to start with.
*
* For the IR320ST-2, we need to charge the main supply capacitor to
* switch the device on. We keep DTR high throughout to do this.
* When RTS, TD and RD are high, they will also trickle-charge the
* cap. RTS is high for data transmission, and low for baud rate select.
* -- DGB
*/
sirdev_set_dtr_rts(dev, TRUE, TRUE);
/* The TOI3232 supports many speeds between 1200bps and 115000bps.
* We really only care about those supported by the IRDA spec, but
* 38400 seems to be implemented in many places */
qos->baud_rate.bits &= IR_2400|IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;
/* From the tekram driver. Not sure what a reasonable value is -- DGB */
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 toim3232_close(struct sir_dev *dev)
{
IRDA_DEBUG(2, "%s()\n", __func__);
/* Power off dongle */
sirdev_set_dtr_rts(dev, FALSE, FALSE);
return 0;
}
/*
* Function toim3232change_speed (dev, state, speed)
*
* Set the speed for the TOIM3232 based dongle. Warning, this
* function must be called with a process context!
*
* Algorithm
* 1. keep DTR high but clear RTS to bring into baud programming mode
* 2. wait at least 7us to enter programming mode
* 3. send control word to set baud rate and timing
* 4. wait at least 1us
* 5. bring RTS high to enter DATA mode (RS232 is passed through to transceiver)
* 6. should take effect immediately (although probably worth waiting)
*/
#define TOIM3232_STATE_WAIT_SPEED (SIRDEV_STATE_DONGLE_SPEED + 1)
static int toim3232_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:
/* Figure out what we are going to send as a control byte */
switch (speed) {
case 2400:
byte = TOIM3232_PW|TOIM3232_2400;
break;
default:
speed = 9600;
ret = -EINVAL;
/* fall thru */
case 9600:
byte = TOIM3232_PW|TOIM3232_9600;
break;
case 19200:
byte = TOIM3232_PW|TOIM3232_19200;
break;
case 38400:
byte = TOIM3232_PW|TOIM3232_38400;
break;
case 57600:
byte = TOIM3232_PW|TOIM3232_57600;
break;
case 115200:
byte = TOIM3232_115200;
break;
}
/* Set DTR, Clear RTS: Go into baud programming mode */
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 = TOIM3232_STATE_WAIT_SPEED;
delay = toim3232delay;
break;
case TOIM3232_STATE_WAIT_SPEED:
/* Have transmitted control byte * Wait for 'at least 1us' */
udelay(14);
/* Set DTR, Set RTS: Go into normal data mode */
sirdev_set_dtr_rts(dev, TRUE, TRUE);
/* Wait (TODO: check this is needed) */
udelay(50);
break;
default:
printk(KERN_ERR "%s - undefined state %d\n", __func__, state);
ret = -EINVAL;
break;
}
dev->fsm.substate = state;
return (delay > 0) ? delay : ret;
}
/*
* Function toim3232reset (driver)
*
* This function resets the toim3232 dongle. Warning, this function
* must be called with a process context!!
*
* What we should do is:
* 0. Pull RESET high
* 1. Wait for at least 7us
* 2. Pull RESET low
* 3. Wait for at least 7us
* 4. Pull BR/~D high
* 5. Wait for at least 7us
* 6. Send control byte to set baud rate
* 7. Wait at least 1us after stop bit
* 8. Pull BR/~D low
* 9. Should then be in data mode
*
* Because the IR320ST-2 doesn't have the RESET line connected for some reason,
* we'll have to do something else.
*
* The default speed after a RESET is 9600, so lets try just bringing it up in
* data mode after switching it off, waiting for the supply capacitor to
* discharge, and then switch it back on. This isn't actually pulling RESET
* high, but it seems to have the same effect.
*
* This behaviour will probably work on dongles that have the RESET line connected,
* but if not, add a flag for the IR320ST-2, and implment the above-listed proper
* behaviour.
*
* RTS is inverted and then fed to BR/~D, so to put it in programming mode, we
* need to have pull RTS low
*/
static int toim3232_reset(struct sir_dev *dev)
{
IRDA_DEBUG(2, "%s()\n", __func__);
/* Switch off both DTR and RTS to switch off dongle */
sirdev_set_dtr_rts(dev, FALSE, FALSE);
/* Should sleep a while. This might be evil doing it this way.*/
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(msecs_to_jiffies(50));
/* Set DTR, Set RTS (data mode) */
sirdev_set_dtr_rts(dev, TRUE, TRUE);
/* Wait at least 10 ms for power to stabilize again */
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(msecs_to_jiffies(10));
/* Speed should now be 9600 */
dev->speed = 9600;
return 0;
}
MODULE_AUTHOR("David Basden <davidb-linux@rcpt.to>");
MODULE_DESCRIPTION("Vishay/Temic TOIM3232 based dongle driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("irda-dongle-12"); /* IRDA_TOIM3232_DONGLE */
module_init(toim3232_sir_init);
module_exit(toim3232_sir_cleanup);
