aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/irda/toim3232-sir.c
blob: aa1a9b0ed83e7feab4390e3ecaeb078b23f60ee1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
/*********************************************************************
 *
 * 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", __FUNCTION__);

	/* 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", __FUNCTION__);

	/* 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", __FUNCTION__);

	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", __FUNCTION__, 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", __FUNCTION__);

	/* 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);