drivers/net/irda/toim3232-sir.c

   1 /*********************************************************************
   2  *
   3  * Filename:      toim3232-sir.c
   4  * Version:       1.0
   5  * Description:   Implementation of dongles based on the Vishay/Temic
   6  *                TOIM3232 SIR Endec chipset. Currently only the
   7  *                IRWave IR320ST-2 is tested, although it should work
   8  *                with any TOIM3232 or TOIM4232 chipset based RS232
   9  *                dongle with minimal modification.
  10  *                Based heavily on the Tekram driver (tekram.c),
  11  *                with thanks to Dag Brattli and Martin Diehl.
  12  * Status:        Experimental.
  13  * Author:        David Basden <davidb-irda@rcpt.to>
  14  * Created at:    Thu Feb 09 23:47:32 2006
  15  *
  16  *     Copyright (c) 2006 David Basden.
  17  *     Copyright (c) 1998-1999 Dag Brattli,
  18  *     Copyright (c) 2002 Martin Diehl,
  19  *     All Rights Reserved.
  20  *
  21  *     This program is free software; you can redistribute it and/or
  22  *     modify it under the terms of the GNU General Public License as
  23  *     published by the Free Software Foundation; either version 2 of
  24  *     the License, or (at your option) any later version.
  25  *
  26  *     Neither Dag Brattli nor University of Tromsø admit liability nor
  27  *     provide warranty for any of this software. This material is
  28  *     provided "AS-IS" and at no charge.
  29  *
  30  ********************************************************************/
  31
  32 /*
  33  * This driver has currently only been tested on the IRWave IR320ST-2
  34  *
  35  * PROTOCOL:
  36  *
  37  * The protocol for talking to the TOIM3232 is quite easy, and is
  38  * designed to interface with RS232 with only level convertors. The
  39  * BR/~D line on the chip is brought high to signal 'command mode',
  40  * where a command byte is sent to select the baudrate of the RS232
  41  * interface and the pulse length of the IRDA output. When BR/~D
  42  * is brought low, the dongle then changes to the selected baudrate,
  43  * and the RS232 interface is used for data until BR/~D is brought
  44  * high again. The initial speed for the TOIMx323 after RESET is
  45  * 9600 baud.  The baudrate for command-mode is the last selected
  46  * baud-rate, or 9600 after a RESET.
  47  *
  48  * The  dongle I have (below) adds some extra hardware on the front end,
  49  * but this is mostly directed towards pariasitic power from the RS232
  50  * line rather than changing very much about how to communicate with
  51  * the TOIM3232.
  52  *
  53  * The protocol to talk to the TOIM4232 chipset seems to be almost
  54  * identical to the TOIM3232 (and the 4232 datasheet is more detailed)
  55  * so this code will probably work on that as well, although I haven't
  56  * tested it on that hardware.
  57  *
  58  * Target dongle variations that might be common:
  59  *
  60  * DTR and RTS function:
  61  *   The data sheet for the 4232 has a sample implementation that hooks the
  62  *   DTR and RTS lines to the RESET and BaudRate/~Data lines of the
  63  *   chip (through line-converters). Given both DTR and RTS would have to
  64  *   be held low in normal operation, and the TOIMx232 requires +5V to
  65  *   signal ground, most dongle designers would almost certainly choose
  66  *   an implementation that kept at least one of DTR or RTS high in
  67  *   normal operation to provide power to the dongle, but will likely
  68  *   vary between designs.
  69  *
  70  * User specified command bits:
  71  *  There are two user-controllable output lines from the TOIMx232 that
  72  *  can be set low or high by setting the appropriate bits in the
  73  *  high-nibble of the command byte (when setting speed and pulse length).
  74  *  These might be used to switch on and off added hardware or extra
  75  *  dongle features.
  76  *
  77  *
  78  * Target hardware: IRWave IR320ST-2
  79  *
  80  *      The IRWave IR320ST-2 is a simple dongle based on the Vishay/Temic
  81  *      TOIM3232 SIR Endec and the Vishay/Temic TFDS4500 SIR IRDA transciever.
  82  *      It uses a hex inverter and some discrete components to buffer and
  83  *      line convert the RS232 down to 5V.
  84  *
  85  *      The dongle is powered through a voltage regulator, fed by a large
  86  *      capacitor. To switch the dongle on, DTR is brought high to charge
  87  *      the capacitor and drive the voltage regulator. DTR isn't associated
  88  *      with any control lines on the TOIM3232. Parisitic power is also taken
  89  *      from the RTS, TD and RD lines when brought high, but through resistors.
  90  *      When DTR is low, the circuit might lose power even with RTS high.
  91  *
  92  *      RTS is inverted and attached to the BR/~D input pin. When RTS
  93  *      is high, BR/~D is low, and the TOIM3232 is in the normal 'data' mode.
  94  *      RTS is brought low, BR/~D is high, and the TOIM3232 is in 'command
  95  *      mode'.
  96  *
  97  *      For some unknown reason, the RESET line isn't actually connected
  98  *      to anything. This means to reset the dongle to get it to a known
  99  *      state (9600 baud) you must drop DTR and RTS low, wait for the power
 100  *      capacitor to discharge, and then bring DTR (and RTS for data mode)
 101  *      high again, and wait for the capacitor to charge, the power supply
 102  *      to stabilise, and the oscillator clock to stabilise.
 103  *
 104  *      Fortunately, if the current baudrate is known, the chipset can
 105  *      easily change speed by entering command mode without having to
 106  *      reset the dongle first.
 107  *
 108  *      Major Components:
 109  *
 110  *      - Vishay/Temic TOIM3232 SIR Endec to change RS232 pulse timings
 111  *        to IRDA pulse timings
 112  *      - 3.6864MHz crystal to drive TOIM3232 clock oscillator
 113  *      - DM74lS04M Inverting Hex line buffer for RS232 input buffering
 114  *        and level conversion
 115  *      - PJ2951AC 150mA voltage regulator
 116  *      - Vishay/Temic TFDS4500 SIR IRDA front-end transceiver
 117  *
 118  */
 119
 120 #include <linux/module.h>
 121 #include <linux/delay.h>
 122 #include <linux/init.h>
 123
 124 #include <net/irda/irda.h>
 125
 126 #include "sir-dev.h"
 127
 128 static int toim3232delay = 150; /* default is 150 ms */
 129 module_param(toim3232delay, int, 0);
 130 MODULE_PARM_DESC(toim3232delay, "toim3232 dongle write complete delay");
 131
 132 #if 0
 133 static int toim3232flipdtr = 0; /* default is DTR high to reset */
 134 module_param(toim3232flipdtr, int, 0);
 135 MODULE_PARM_DESC(toim3232flipdtr, "toim3232 dongle invert DTR (Reset)");
 136
 137 static int toim3232fliprts = 0; /* default is RTS high for baud change */
 138 module_param(toim3232fliptrs, int, 0);
 139 MODULE_PARM_DESC(toim3232fliprts, "toim3232 dongle invert RTS (BR/D)");
 140 #endif
 141
 142 static int toim3232_open(struct sir_dev *);
 143 static int toim3232_close(struct sir_dev *);
 144 static int toim3232_change_speed(struct sir_dev *, unsigned);
 145 static int toim3232_reset(struct sir_dev *);
 146
 147 #define TOIM3232_115200 0x00
 148 #define TOIM3232_57600  0x01
 149 #define TOIM3232_38400  0x02
 150 #define TOIM3232_19200  0x03
 151 #define TOIM3232_9600   0x06
 152 #define TOIM3232_2400   0x0A
 153
 154 #define TOIM3232_PW     0x10 /* Pulse select bit */
 155
 156 static struct dongle_driver toim3232 = {
 157         .owner          = THIS_MODULE,
 158         .driver_name    = "Vishay TOIM3232",
 159         .type           = IRDA_TOIM3232_DONGLE,
 160         .open           = toim3232_open,
 161         .close          = toim3232_close,
 162         .reset          = toim3232_reset,
 163         .set_speed      = toim3232_change_speed,
 164 };
 165
 166 static int __init toim3232_sir_init(void)
 167 {
 168         if (toim3232delay < 1  ||  toim3232delay > 500)
 169                 toim3232delay = 200;
 170         IRDA_DEBUG(1, "%s - using %d ms delay\n",
 171                 toim3232.driver_name, toim3232delay);
 172         return irda_register_dongle(&toim3232);
 173 }
 174
 175 static void __exit toim3232_sir_cleanup(void)
 176 {
 177         irda_unregister_dongle(&toim3232);
 178 }
 179
 180 static int toim3232_open(struct sir_dev *dev)
 181 {
 182         struct qos_info *qos = &dev->qos;
 183
 184         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 185
 186         /* Pull the lines high to start with.
 187          *
 188          * For the IR320ST-2, we need to charge the main supply capacitor to
 189          * switch the device on. We keep DTR high throughout to do this.
 190          * When RTS, TD and RD are high, they will also trickle-charge the
 191          * cap. RTS is high for data transmission, and low for baud rate select.
 192          *      -- DGB
 193          */
 194         sirdev_set_dtr_rts(dev, TRUE, TRUE);
 195
 196         /* The TOI3232 supports many speeds between 1200bps and 115000bps.
 197          * We really only care about those supported by the IRDA spec, but
 198          * 38400 seems to be implemented in many places */
 199         qos->baud_rate.bits &= IR_2400|IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;
 200
 201         /* From the tekram driver. Not sure what a reasonable value is -- DGB */
 202         qos->min_turn_time.bits = 0x01; /* Needs at least 10 ms */
 203         irda_qos_bits_to_value(qos);
 204
 205         /* irda thread waits 50 msec for power settling */
 206
 207         return 0;
 208 }
 209
 210 static int toim3232_close(struct sir_dev *dev)
 211 {
 212         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 213
 214         /* Power off dongle */
 215         sirdev_set_dtr_rts(dev, FALSE, FALSE);
 216
 217         return 0;
 218 }
 219
 220 /*
 221  * Function toim3232change_speed (dev, state, speed)
 222  *
 223  *    Set the speed for the TOIM3232 based dongle. Warning, this
 224  *    function must be called with a process context!
 225  *
 226  *    Algorithm
 227  *    1. keep DTR high but clear RTS to bring into baud programming mode
 228  *    2. wait at least 7us to enter programming mode
 229  *    3. send control word to set baud rate and timing
 230  *    4. wait at least 1us
 231  *    5. bring RTS high to enter DATA mode (RS232 is passed through to transceiver)
 232  *    6. should take effect immediately (although probably worth waiting)
 233  */
 234
 235 #define TOIM3232_STATE_WAIT_SPEED       (SIRDEV_STATE_DONGLE_SPEED + 1)
 236
 237 static int toim3232_change_speed(struct sir_dev *dev, unsigned speed)
 238 {
 239         unsigned state = dev->fsm.substate;
 240         unsigned delay = 0;
 241         u8 byte;
 242         static int ret = 0;
 243
 244         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 245
 246         switch(state) {
 247         case SIRDEV_STATE_DONGLE_SPEED:
 248
 249                 /* Figure out what we are going to send as a control byte */
 250                 switch (speed) {
 251                 case 2400:
 252                         byte = TOIM3232_PW|TOIM3232_2400;
 253                         break;
 254                 default:
 255                         speed = 9600;
 256                         ret = -EINVAL;
 257                         /* fall thru */
 258                 case 9600:
 259                         byte = TOIM3232_PW|TOIM3232_9600;
 260                         break;
 261                 case 19200:
 262                         byte = TOIM3232_PW|TOIM3232_19200;
 263                         break;
 264                 case 38400:
 265                         byte = TOIM3232_PW|TOIM3232_38400;
 266                         break;
 267                 case 57600:
 268                         byte = TOIM3232_PW|TOIM3232_57600;
 269                         break;
 270                 case 115200:
 271                         byte = TOIM3232_115200;
 272                         break;
 273                 }
 274
 275                 /* Set DTR, Clear RTS: Go into baud programming mode */
 276                 sirdev_set_dtr_rts(dev, TRUE, FALSE);
 277
 278                 /* Wait at least 7us */
 279                 udelay(14);
 280
 281                 /* Write control byte */
 282                 sirdev_raw_write(dev, &byte, 1);
 283
 284                 dev->speed = speed;
 285
 286                 state = TOIM3232_STATE_WAIT_SPEED;
 287                 delay = toim3232delay;
 288                 break;
 289
 290         case TOIM3232_STATE_WAIT_SPEED:
 291                 /* Have transmitted control byte * Wait for 'at least 1us' */
 292                 udelay(14);
 293
 294                 /* Set DTR, Set RTS: Go into normal data mode */
 295                 sirdev_set_dtr_rts(dev, TRUE, TRUE);
 296
 297                 /* Wait (TODO: check this is needed) */
 298                 udelay(50);
 299                 break;
 300
 301         default:
 302                 printk(KERN_ERR "%s - undefined state %d\n", __FUNCTION__, state);
 303                 ret = -EINVAL;
 304                 break;
 305         }
 306
 307         dev->fsm.substate = state;
 308         return (delay > 0) ? delay : ret;
 309 }
 310
 311 /*
 312  * Function toim3232reset (driver)
 313  *
 314  *      This function resets the toim3232 dongle. Warning, this function
 315  *      must be called with a process context!!
 316  *
 317  * What we should do is:
 318  *      0. Pull RESET high
 319  *      1. Wait for at least 7us
 320  *      2. Pull RESET low
 321  *      3. Wait for at least 7us
 322  *      4. Pull BR/~D high
 323  *      5. Wait for at least 7us
 324  *      6. Send control byte to set baud rate
 325  *      7. Wait at least 1us after stop bit
 326  *      8. Pull BR/~D low
 327  *      9. Should then be in data mode
 328  *
 329  * Because the IR320ST-2 doesn't have the RESET line connected for some reason,
 330  * we'll have to do something else.
 331  *
 332  * The default speed after a RESET is 9600, so lets try just bringing it up in
 333  * data mode after switching it off, waiting for the supply capacitor to
 334  * discharge, and then switch it back on. This isn't actually pulling RESET
 335  * high, but it seems to have the same effect.
 336  *
 337  * This behaviour will probably work on dongles that have the RESET line connected,
 338  * but if not, add a flag for the IR320ST-2, and implment the above-listed proper
 339  * behaviour.
 340  *
 341  * RTS is inverted and then fed to BR/~D, so to put it in programming mode, we
 342  * need to have pull RTS low
 343  */
 344
 345 static int toim3232_reset(struct sir_dev *dev)
 346 {
 347         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 348
 349         /* Switch off both DTR and RTS to switch off dongle */
 350         sirdev_set_dtr_rts(dev, FALSE, FALSE);
 351
 352         /* Should sleep a while. This might be evil doing it this way.*/
 353         set_current_state(TASK_UNINTERRUPTIBLE);
 354         schedule_timeout(msecs_to_jiffies(50));
 355
 356         /* Set DTR, Set RTS (data mode) */
 357         sirdev_set_dtr_rts(dev, TRUE, TRUE);
 358
 359         /* Wait at least 10 ms for power to stabilize again */
 360         set_current_state(TASK_UNINTERRUPTIBLE);
 361         schedule_timeout(msecs_to_jiffies(10));
 362
 363         /* Speed should now be 9600 */
 364         dev->speed = 9600;
 365
 366         return 0;
 367 }
 368
 369 MODULE_AUTHOR("David Basden <davidb-linux@rcpt.to>");
 370 MODULE_DESCRIPTION("Vishay/Temic TOIM3232 based dongle driver");
 371 MODULE_LICENSE("GPL");
 372 MODULE_ALIAS("irda-dongle-12"); /* IRDA_TOIM3232_DONGLE */
 373
 374 module_init(toim3232_sir_init);
 375 module_exit(toim3232_sir_cleanup);