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 transceiver.
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 #include <linux/sched.h>
124
125 #include <net/irda/irda.h>
126
127 #include "sir-dev.h"
128
129 static int toim3232delay = 150; /* default is 150 ms */
130 module_param(toim3232delay, int, 0);
131 MODULE_PARM_DESC(toim3232delay, "toim3232 dongle write complete delay");
132
133 #if 0
134 static int toim3232flipdtr = 0; /* default is DTR high to reset */
135 module_param(toim3232flipdtr, int, 0);
136 MODULE_PARM_DESC(toim3232flipdtr, "toim3232 dongle invert DTR (Reset)");
137
138 static int toim3232fliprts = 0; /* default is RTS high for baud change */
139 module_param(toim3232fliptrs, int, 0);
140 MODULE_PARM_DESC(toim3232fliprts, "toim3232 dongle invert RTS (BR/D)");
141 #endif
142
143 static int toim3232_open(struct sir_dev *);
144 static int toim3232_close(struct sir_dev *);
145 static int toim3232_change_speed(struct sir_dev *, unsigned);
146 static int toim3232_reset(struct sir_dev *);
147
148 #define TOIM3232_115200 0x00
149 #define TOIM3232_57600 0x01
150 #define TOIM3232_38400 0x02
151 #define TOIM3232_19200 0x03
152 #define TOIM3232_9600 0x06
153 #define TOIM3232_2400 0x0A
154
155 #define TOIM3232_PW 0x10 /* Pulse select bit */
156
157 static struct dongle_driver toim3232 = {
158 .owner = THIS_MODULE,
159 .driver_name = "Vishay TOIM3232",
160 .type = IRDA_TOIM3232_DONGLE,
161 .open = toim3232_open,
162 .close = toim3232_close,
163 .reset = toim3232_reset,
164 .set_speed = toim3232_change_speed,
165 };
166
toim3232_sir_init(void)167 static int __init toim3232_sir_init(void)
168 {
169 if (toim3232delay < 1 || toim3232delay > 500)
170 toim3232delay = 200;
171 IRDA_DEBUG(1, "%s - using %d ms delay\n",
172 toim3232.driver_name, toim3232delay);
173 return irda_register_dongle(&toim3232);
174 }
175
toim3232_sir_cleanup(void)176 static void __exit toim3232_sir_cleanup(void)
177 {
178 irda_unregister_dongle(&toim3232);
179 }
180
toim3232_open(struct sir_dev * dev)181 static int toim3232_open(struct sir_dev *dev)
182 {
183 struct qos_info *qos = &dev->qos;
184
185 IRDA_DEBUG(2, "%s()\n", __func__);
186
187 /* Pull the lines high to start with.
188 *
189 * For the IR320ST-2, we need to charge the main supply capacitor to
190 * switch the device on. We keep DTR high throughout to do this.
191 * When RTS, TD and RD are high, they will also trickle-charge the
192 * cap. RTS is high for data transmission, and low for baud rate select.
193 * -- DGB
194 */
195 sirdev_set_dtr_rts(dev, TRUE, TRUE);
196
197 /* The TOI3232 supports many speeds between 1200bps and 115000bps.
198 * We really only care about those supported by the IRDA spec, but
199 * 38400 seems to be implemented in many places */
200 qos->baud_rate.bits &= IR_2400|IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;
201
202 /* From the tekram driver. Not sure what a reasonable value is -- DGB */
203 qos->min_turn_time.bits = 0x01; /* Needs at least 10 ms */
204 irda_qos_bits_to_value(qos);
205
206 /* irda thread waits 50 msec for power settling */
207
208 return 0;
209 }
210
toim3232_close(struct sir_dev * dev)211 static int toim3232_close(struct sir_dev *dev)
212 {
213 IRDA_DEBUG(2, "%s()\n", __func__);
214
215 /* Power off dongle */
216 sirdev_set_dtr_rts(dev, FALSE, FALSE);
217
218 return 0;
219 }
220
221 /*
222 * Function toim3232change_speed (dev, state, speed)
223 *
224 * Set the speed for the TOIM3232 based dongle. Warning, this
225 * function must be called with a process context!
226 *
227 * Algorithm
228 * 1. keep DTR high but clear RTS to bring into baud programming mode
229 * 2. wait at least 7us to enter programming mode
230 * 3. send control word to set baud rate and timing
231 * 4. wait at least 1us
232 * 5. bring RTS high to enter DATA mode (RS232 is passed through to transceiver)
233 * 6. should take effect immediately (although probably worth waiting)
234 */
235
236 #define TOIM3232_STATE_WAIT_SPEED (SIRDEV_STATE_DONGLE_SPEED + 1)
237
toim3232_change_speed(struct sir_dev * dev,unsigned speed)238 static int toim3232_change_speed(struct sir_dev *dev, unsigned speed)
239 {
240 unsigned state = dev->fsm.substate;
241 unsigned delay = 0;
242 u8 byte;
243 static int ret = 0;
244
245 IRDA_DEBUG(2, "%s()\n", __func__);
246
247 switch(state) {
248 case SIRDEV_STATE_DONGLE_SPEED:
249
250 /* Figure out what we are going to send as a control byte */
251 switch (speed) {
252 case 2400:
253 byte = TOIM3232_PW|TOIM3232_2400;
254 break;
255 default:
256 speed = 9600;
257 ret = -EINVAL;
258 /* fall thru */
259 case 9600:
260 byte = TOIM3232_PW|TOIM3232_9600;
261 break;
262 case 19200:
263 byte = TOIM3232_PW|TOIM3232_19200;
264 break;
265 case 38400:
266 byte = TOIM3232_PW|TOIM3232_38400;
267 break;
268 case 57600:
269 byte = TOIM3232_PW|TOIM3232_57600;
270 break;
271 case 115200:
272 byte = TOIM3232_115200;
273 break;
274 }
275
276 /* Set DTR, Clear RTS: Go into baud programming mode */
277 sirdev_set_dtr_rts(dev, TRUE, FALSE);
278
279 /* Wait at least 7us */
280 udelay(14);
281
282 /* Write control byte */
283 sirdev_raw_write(dev, &byte, 1);
284
285 dev->speed = speed;
286
287 state = TOIM3232_STATE_WAIT_SPEED;
288 delay = toim3232delay;
289 break;
290
291 case TOIM3232_STATE_WAIT_SPEED:
292 /* Have transmitted control byte * Wait for 'at least 1us' */
293 udelay(14);
294
295 /* Set DTR, Set RTS: Go into normal data mode */
296 sirdev_set_dtr_rts(dev, TRUE, TRUE);
297
298 /* Wait (TODO: check this is needed) */
299 udelay(50);
300 break;
301
302 default:
303 printk(KERN_ERR "%s - undefined state %d\n", __func__, state);
304 ret = -EINVAL;
305 break;
306 }
307
308 dev->fsm.substate = state;
309 return (delay > 0) ? delay : ret;
310 }
311
312 /*
313 * Function toim3232reset (driver)
314 *
315 * This function resets the toim3232 dongle. Warning, this function
316 * must be called with a process context!!
317 *
318 * What we should do is:
319 * 0. Pull RESET high
320 * 1. Wait for at least 7us
321 * 2. Pull RESET low
322 * 3. Wait for at least 7us
323 * 4. Pull BR/~D high
324 * 5. Wait for at least 7us
325 * 6. Send control byte to set baud rate
326 * 7. Wait at least 1us after stop bit
327 * 8. Pull BR/~D low
328 * 9. Should then be in data mode
329 *
330 * Because the IR320ST-2 doesn't have the RESET line connected for some reason,
331 * we'll have to do something else.
332 *
333 * The default speed after a RESET is 9600, so lets try just bringing it up in
334 * data mode after switching it off, waiting for the supply capacitor to
335 * discharge, and then switch it back on. This isn't actually pulling RESET
336 * high, but it seems to have the same effect.
337 *
338 * This behaviour will probably work on dongles that have the RESET line connected,
339 * but if not, add a flag for the IR320ST-2, and implment the above-listed proper
340 * behaviour.
341 *
342 * RTS is inverted and then fed to BR/~D, so to put it in programming mode, we
343 * need to have pull RTS low
344 */
345
toim3232_reset(struct sir_dev * dev)346 static int toim3232_reset(struct sir_dev *dev)
347 {
348 IRDA_DEBUG(2, "%s()\n", __func__);
349
350 /* Switch off both DTR and RTS to switch off dongle */
351 sirdev_set_dtr_rts(dev, FALSE, FALSE);
352
353 /* Should sleep a while. This might be evil doing it this way.*/
354 set_current_state(TASK_UNINTERRUPTIBLE);
355 schedule_timeout(msecs_to_jiffies(50));
356
357 /* Set DTR, Set RTS (data mode) */
358 sirdev_set_dtr_rts(dev, TRUE, TRUE);
359
360 /* Wait at least 10 ms for power to stabilize again */
361 set_current_state(TASK_UNINTERRUPTIBLE);
362 schedule_timeout(msecs_to_jiffies(10));
363
364 /* Speed should now be 9600 */
365 dev->speed = 9600;
366
367 return 0;
368 }
369
370 MODULE_AUTHOR("David Basden <davidb-linux@rcpt.to>");
371 MODULE_DESCRIPTION("Vishay/Temic TOIM3232 based dongle driver");
372 MODULE_LICENSE("GPL");
373 MODULE_ALIAS("irda-dongle-12"); /* IRDA_TOIM3232_DONGLE */
374
375 module_init(toim3232_sir_init);
376 module_exit(toim3232_sir_cleanup);
377