359 lines
12 KiB
C
359 lines
12 KiB
C
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/*********************************************************************
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*
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* Filename: toim3232-sir.c
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* Version: 1.0
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* Description: Implementation of dongles based on the Vishay/Temic
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* TOIM3232 SIR Endec chipset. Currently only the
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* IRWave IR320ST-2 is tested, although it should work
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* with any TOIM3232 or TOIM4232 chipset based RS232
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* dongle with minimal modification.
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* Based heavily on the Tekram driver (tekram.c),
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* with thanks to Dag Brattli and Martin Diehl.
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* Status: Experimental.
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* Author: David Basden <davidb-irda@rcpt.to>
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* Created at: Thu Feb 09 23:47:32 2006
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*
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* Copyright (c) 2006 David Basden.
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* Copyright (c) 1998-1999 Dag Brattli,
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* Copyright (c) 2002 Martin Diehl,
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* Neither Dag Brattli nor University of Tromsø admit liability nor
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* provide warranty for any of this software. This material is
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* provided "AS-IS" and at no charge.
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*
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********************************************************************/
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/*
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* This driver has currently only been tested on the IRWave IR320ST-2
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*
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* PROTOCOL:
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*
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* The protocol for talking to the TOIM3232 is quite easy, and is
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* designed to interface with RS232 with only level convertors. The
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* BR/~D line on the chip is brought high to signal 'command mode',
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* where a command byte is sent to select the baudrate of the RS232
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* interface and the pulse length of the IRDA output. When BR/~D
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* is brought low, the dongle then changes to the selected baudrate,
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* and the RS232 interface is used for data until BR/~D is brought
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* high again. The initial speed for the TOIMx323 after RESET is
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* 9600 baud. The baudrate for command-mode is the last selected
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* baud-rate, or 9600 after a RESET.
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*
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* The dongle I have (below) adds some extra hardware on the front end,
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* but this is mostly directed towards pariasitic power from the RS232
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* line rather than changing very much about how to communicate with
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* the TOIM3232.
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*
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* The protocol to talk to the TOIM4232 chipset seems to be almost
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* identical to the TOIM3232 (and the 4232 datasheet is more detailed)
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* so this code will probably work on that as well, although I haven't
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* tested it on that hardware.
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*
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* Target dongle variations that might be common:
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*
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* DTR and RTS function:
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* The data sheet for the 4232 has a sample implementation that hooks the
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* DTR and RTS lines to the RESET and BaudRate/~Data lines of the
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* chip (through line-converters). Given both DTR and RTS would have to
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* be held low in normal operation, and the TOIMx232 requires +5V to
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* signal ground, most dongle designers would almost certainly choose
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* an implementation that kept at least one of DTR or RTS high in
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* normal operation to provide power to the dongle, but will likely
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* vary between designs.
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*
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* User specified command bits:
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* There are two user-controllable output lines from the TOIMx232 that
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* can be set low or high by setting the appropriate bits in the
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* high-nibble of the command byte (when setting speed and pulse length).
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* These might be used to switch on and off added hardware or extra
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* dongle features.
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*
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*
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* Target hardware: IRWave IR320ST-2
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*
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* The IRWave IR320ST-2 is a simple dongle based on the Vishay/Temic
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* TOIM3232 SIR Endec and the Vishay/Temic TFDS4500 SIR IRDA transceiver.
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* It uses a hex inverter and some discrete components to buffer and
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* line convert the RS232 down to 5V.
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*
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* The dongle is powered through a voltage regulator, fed by a large
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* capacitor. To switch the dongle on, DTR is brought high to charge
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* the capacitor and drive the voltage regulator. DTR isn't associated
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* with any control lines on the TOIM3232. Parisitic power is also taken
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* from the RTS, TD and RD lines when brought high, but through resistors.
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* When DTR is low, the circuit might lose power even with RTS high.
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*
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* RTS is inverted and attached to the BR/~D input pin. When RTS
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* is high, BR/~D is low, and the TOIM3232 is in the normal 'data' mode.
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* RTS is brought low, BR/~D is high, and the TOIM3232 is in 'command
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* mode'.
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*
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* For some unknown reason, the RESET line isn't actually connected
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* to anything. This means to reset the dongle to get it to a known
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* state (9600 baud) you must drop DTR and RTS low, wait for the power
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* capacitor to discharge, and then bring DTR (and RTS for data mode)
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* high again, and wait for the capacitor to charge, the power supply
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* to stabilise, and the oscillator clock to stabilise.
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*
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* Fortunately, if the current baudrate is known, the chipset can
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* easily change speed by entering command mode without having to
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* reset the dongle first.
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*
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* Major Components:
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*
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* - Vishay/Temic TOIM3232 SIR Endec to change RS232 pulse timings
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* to IRDA pulse timings
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* - 3.6864MHz crystal to drive TOIM3232 clock oscillator
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* - DM74lS04M Inverting Hex line buffer for RS232 input buffering
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* and level conversion
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* - PJ2951AC 150mA voltage regulator
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* - Vishay/Temic TFDS4500 SIR IRDA front-end transceiver
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*
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*/
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <net/irda/irda.h>
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#include "sir-dev.h"
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static int toim3232delay = 150; /* default is 150 ms */
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module_param(toim3232delay, int, 0);
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MODULE_PARM_DESC(toim3232delay, "toim3232 dongle write complete delay");
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static int toim3232_open(struct sir_dev *);
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static int toim3232_close(struct sir_dev *);
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static int toim3232_change_speed(struct sir_dev *, unsigned);
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static int toim3232_reset(struct sir_dev *);
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#define TOIM3232_115200 0x00
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#define TOIM3232_57600 0x01
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#define TOIM3232_38400 0x02
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#define TOIM3232_19200 0x03
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#define TOIM3232_9600 0x06
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#define TOIM3232_2400 0x0A
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#define TOIM3232_PW 0x10 /* Pulse select bit */
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static struct dongle_driver toim3232 = {
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.owner = THIS_MODULE,
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.driver_name = "Vishay TOIM3232",
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.type = IRDA_TOIM3232_DONGLE,
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.open = toim3232_open,
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.close = toim3232_close,
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.reset = toim3232_reset,
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.set_speed = toim3232_change_speed,
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};
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static int __init toim3232_sir_init(void)
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{
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if (toim3232delay < 1 || toim3232delay > 500)
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toim3232delay = 200;
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pr_debug("%s - using %d ms delay\n",
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toim3232.driver_name, toim3232delay);
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return irda_register_dongle(&toim3232);
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}
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static void __exit toim3232_sir_cleanup(void)
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{
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irda_unregister_dongle(&toim3232);
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}
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static int toim3232_open(struct sir_dev *dev)
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{
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struct qos_info *qos = &dev->qos;
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/* Pull the lines high to start with.
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*
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* For the IR320ST-2, we need to charge the main supply capacitor to
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* switch the device on. We keep DTR high throughout to do this.
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* When RTS, TD and RD are high, they will also trickle-charge the
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* cap. RTS is high for data transmission, and low for baud rate select.
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* -- DGB
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*/
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sirdev_set_dtr_rts(dev, TRUE, TRUE);
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/* The TOI3232 supports many speeds between 1200bps and 115000bps.
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* We really only care about those supported by the IRDA spec, but
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* 38400 seems to be implemented in many places */
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qos->baud_rate.bits &= IR_2400|IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;
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/* From the tekram driver. Not sure what a reasonable value is -- DGB */
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qos->min_turn_time.bits = 0x01; /* Needs at least 10 ms */
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irda_qos_bits_to_value(qos);
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/* irda thread waits 50 msec for power settling */
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return 0;
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}
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static int toim3232_close(struct sir_dev *dev)
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{
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/* Power off dongle */
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sirdev_set_dtr_rts(dev, FALSE, FALSE);
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return 0;
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}
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/*
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* Function toim3232change_speed (dev, state, speed)
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*
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* Set the speed for the TOIM3232 based dongle. Warning, this
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* function must be called with a process context!
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*
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* Algorithm
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* 1. keep DTR high but clear RTS to bring into baud programming mode
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* 2. wait at least 7us to enter programming mode
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* 3. send control word to set baud rate and timing
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* 4. wait at least 1us
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* 5. bring RTS high to enter DATA mode (RS232 is passed through to transceiver)
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* 6. should take effect immediately (although probably worth waiting)
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*/
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#define TOIM3232_STATE_WAIT_SPEED (SIRDEV_STATE_DONGLE_SPEED + 1)
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static int toim3232_change_speed(struct sir_dev *dev, unsigned speed)
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{
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unsigned state = dev->fsm.substate;
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unsigned delay = 0;
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u8 byte;
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static int ret = 0;
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switch(state) {
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case SIRDEV_STATE_DONGLE_SPEED:
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/* Figure out what we are going to send as a control byte */
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switch (speed) {
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case 2400:
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byte = TOIM3232_PW|TOIM3232_2400;
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break;
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default:
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speed = 9600;
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ret = -EINVAL;
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/* fall thru */
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case 9600:
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byte = TOIM3232_PW|TOIM3232_9600;
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break;
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case 19200:
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byte = TOIM3232_PW|TOIM3232_19200;
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break;
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case 38400:
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byte = TOIM3232_PW|TOIM3232_38400;
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break;
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case 57600:
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byte = TOIM3232_PW|TOIM3232_57600;
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break;
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case 115200:
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byte = TOIM3232_115200;
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break;
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}
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/* Set DTR, Clear RTS: Go into baud programming mode */
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sirdev_set_dtr_rts(dev, TRUE, FALSE);
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/* Wait at least 7us */
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udelay(14);
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/* Write control byte */
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sirdev_raw_write(dev, &byte, 1);
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dev->speed = speed;
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state = TOIM3232_STATE_WAIT_SPEED;
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delay = toim3232delay;
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break;
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case TOIM3232_STATE_WAIT_SPEED:
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/* Have transmitted control byte * Wait for 'at least 1us' */
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udelay(14);
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/* Set DTR, Set RTS: Go into normal data mode */
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sirdev_set_dtr_rts(dev, TRUE, TRUE);
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/* Wait (TODO: check this is needed) */
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udelay(50);
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break;
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default:
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printk(KERN_ERR "%s - undefined state %d\n", __func__, state);
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ret = -EINVAL;
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break;
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}
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dev->fsm.substate = state;
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return (delay > 0) ? delay : ret;
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}
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/*
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* Function toim3232reset (driver)
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*
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* This function resets the toim3232 dongle. Warning, this function
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* must be called with a process context!!
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*
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* What we should do is:
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* 0. Pull RESET high
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* 1. Wait for at least 7us
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* 2. Pull RESET low
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* 3. Wait for at least 7us
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* 4. Pull BR/~D high
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* 5. Wait for at least 7us
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* 6. Send control byte to set baud rate
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* 7. Wait at least 1us after stop bit
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* 8. Pull BR/~D low
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* 9. Should then be in data mode
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*
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* Because the IR320ST-2 doesn't have the RESET line connected for some reason,
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* we'll have to do something else.
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*
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* The default speed after a RESET is 9600, so lets try just bringing it up in
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* data mode after switching it off, waiting for the supply capacitor to
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* discharge, and then switch it back on. This isn't actually pulling RESET
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* high, but it seems to have the same effect.
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*
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* This behaviour will probably work on dongles that have the RESET line connected,
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* but if not, add a flag for the IR320ST-2, and implment the above-listed proper
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* behaviour.
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*
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* RTS is inverted and then fed to BR/~D, so to put it in programming mode, we
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* need to have pull RTS low
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*/
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static int toim3232_reset(struct sir_dev *dev)
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{
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/* Switch off both DTR and RTS to switch off dongle */
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sirdev_set_dtr_rts(dev, FALSE, FALSE);
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/* Should sleep a while. This might be evil doing it this way.*/
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(msecs_to_jiffies(50));
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/* Set DTR, Set RTS (data mode) */
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sirdev_set_dtr_rts(dev, TRUE, TRUE);
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/* Wait at least 10 ms for power to stabilize again */
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(msecs_to_jiffies(10));
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/* Speed should now be 9600 */
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dev->speed = 9600;
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return 0;
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}
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MODULE_AUTHOR("David Basden <davidb-linux@rcpt.to>");
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MODULE_DESCRIPTION("Vishay/Temic TOIM3232 based dongle driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("irda-dongle-12"); /* IRDA_TOIM3232_DONGLE */
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module_init(toim3232_sir_init);
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module_exit(toim3232_sir_cleanup);
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