aboutsummaryrefslogtreecommitdiff
path: root/drivers/input/serio/ps2mult.c
blob: 6bce22e4e495d64d750fbf66d6c1b011e077bc64 (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
/*
 * TQC PS/2 Multiplexer driver
 *
 * Copyright (C) 2010 Dmitry Eremin-Solenikov
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */


#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/serio.h>

MODULE_AUTHOR("Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>");
MODULE_DESCRIPTION("TQC PS/2 Multiplexer driver");
MODULE_LICENSE("GPL");

#define PS2MULT_KB_SELECTOR		0xA0
#define PS2MULT_MS_SELECTOR		0xA1
#define PS2MULT_ESCAPE			0x7D
#define PS2MULT_BSYNC			0x7E
#define PS2MULT_SESSION_START		0x55
#define PS2MULT_SESSION_END		0x56

struct ps2mult_port {
	struct serio *serio;
	unsigned char sel;
	bool registered;
};

#define PS2MULT_NUM_PORTS	2
#define PS2MULT_KBD_PORT	0
#define PS2MULT_MOUSE_PORT	1

struct ps2mult {
	struct serio *mx_serio;
	struct ps2mult_port ports[PS2MULT_NUM_PORTS];

	spinlock_t lock;
	struct ps2mult_port *in_port;
	struct ps2mult_port *out_port;
	bool escape;
};

/* First MUST come PS2MULT_NUM_PORTS selectors */
static const unsigned char ps2mult_controls[] = {
	PS2MULT_KB_SELECTOR, PS2MULT_MS_SELECTOR,
	PS2MULT_ESCAPE, PS2MULT_BSYNC,
	PS2MULT_SESSION_START, PS2MULT_SESSION_END,
};

static const struct serio_device_id ps2mult_serio_ids[] = {
	{
		.type	= SERIO_RS232,
		.proto	= SERIO_PS2MULT,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, ps2mult_serio_ids);

static void ps2mult_select_port(struct ps2mult *psm, struct ps2mult_port *port)
{
	struct serio *mx_serio = psm->mx_serio;

	serio_write(mx_serio, port->sel);
	psm->out_port = port;
	dev_dbg(&mx_serio->dev, "switched to sel %02x\n", port->sel);
}

static int ps2mult_serio_write(struct serio *serio, unsigned char data)
{
	struct serio *mx_port = serio->parent;
	struct ps2mult *psm = serio_get_drvdata(mx_port);
	struct ps2mult_port *port = serio->port_data;
	bool need_escape;
	unsigned long flags;

	spin_lock_irqsave(&psm->lock, flags);

	if (psm->out_port != port)
		ps2mult_select_port(psm, port);

	need_escape = memchr(ps2mult_controls, data, sizeof(ps2mult_controls));

	dev_dbg(&serio->dev,
		"write: %s%02x\n", need_escape ? "ESC " : "", data);

	if (need_escape)
		serio_write(mx_port, PS2MULT_ESCAPE);

	serio_write(mx_port, data);

	spin_unlock_irqrestore(&psm->lock, flags);

	return 0;
}

static int ps2mult_serio_start(struct serio *serio)
{
	struct ps2mult *psm = serio_get_drvdata(serio->parent);
	struct ps2mult_port *port = serio->port_data;
	unsigned long flags;

	spin_lock_irqsave(&psm->lock, flags);
	port->registered = true;
	spin_unlock_irqrestore(&psm->lock, flags);

	return 0;
}

static void ps2mult_serio_stop(struct serio *serio)
{
	struct ps2mult *psm = serio_get_drvdata(serio->parent);
	struct ps2mult_port *port = serio->port_data;
	unsigned long flags;

	spin_lock_irqsave(&psm->lock, flags);
	port->registered = false;
	spin_unlock_irqrestore(&psm->lock, flags);
}

static int ps2mult_create_port(struct ps2mult *psm, int i)
{
	struct serio *mx_serio = psm->mx_serio;
	struct serio *serio;

	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
	if (!serio)
		return -ENOMEM;

	strlcpy(serio->name, "TQC PS/2 Multiplexer", sizeof(serio->name));
	snprintf(serio->phys, sizeof(serio->phys),
		 "%s/port%d", mx_serio->phys, i);
	serio->id.type = SERIO_8042;
	serio->write = ps2mult_serio_write;
	serio->start = ps2mult_serio_start;
	serio->stop = ps2mult_serio_stop;
	serio->parent = psm->mx_serio;
	serio->port_data = &psm->ports[i];

	psm->ports[i].serio = serio;

	return 0;
}

static void ps2mult_reset(struct ps2mult *psm)
{
	unsigned long flags;

	spin_lock_irqsave(&psm->lock, flags);

	serio_write(psm->mx_serio, PS2MULT_SESSION_END);
	serio_write(psm->mx_serio, PS2MULT_SESSION_START);

	ps2mult_select_port(psm, &psm->ports[PS2MULT_KBD_PORT]);

	spin_unlock_irqrestore(&psm->lock, flags);
}

static int ps2mult_connect(struct serio *serio, struct serio_driver *drv)
{
	struct ps2mult *psm;
	int i;
	int error;

	if (!serio->write)
		return -EINVAL;

	psm = kzalloc(sizeof(*psm), GFP_KERNEL);
	if (!psm)
		return -ENOMEM;

	spin_lock_init(&psm->lock);
	psm->mx_serio = serio;

	for (i = 0; i < PS2MULT_NUM_PORTS; i++) {
		psm->ports[i].sel = ps2mult_controls[i];
		error = ps2mult_create_port(psm, i);
		if (error)
			goto err_out;
	}

	psm->in_port = psm->out_port = &psm->ports[PS2MULT_KBD_PORT];

	serio_set_drvdata(serio, psm);
	error = serio_open(serio, drv);
	if (error)
		goto err_out;

	ps2mult_reset(psm);

	for (i = 0; i <  PS2MULT_NUM_PORTS; i++) {
		struct serio *s = psm->ports[i].serio;

		dev_info(&serio->dev, "%s port at %s\n", s->name, serio->phys);
		serio_register_port(s);
	}

	return 0;

err_out:
	while (--i >= 0)
		kfree(psm->ports[i].serio);
	kfree(serio);
	return error;
}

static void ps2mult_disconnect(struct serio *serio)
{
	struct ps2mult *psm = serio_get_drvdata(serio);

	/* Note that serio core already take care of children ports */
	serio_write(serio, PS2MULT_SESSION_END);
	serio_close(serio);
	kfree(psm);

	serio_set_drvdata(serio, NULL);
}

static int ps2mult_reconnect(struct serio *serio)
{
	struct ps2mult *psm = serio_get_drvdata(serio);

	ps2mult_reset(psm);

	return 0;
}

static irqreturn_t ps2mult_interrupt(struct serio *serio,
				     unsigned char data, unsigned int dfl)
{
	struct ps2mult *psm = serio_get_drvdata(serio);
	struct ps2mult_port *in_port;
	unsigned long flags;

	dev_dbg(&serio->dev, "Received %02x flags %02x\n", data, dfl);

	spin_lock_irqsave(&psm->lock, flags);

	if (psm->escape) {
		psm->escape = false;
		in_port = psm->in_port;
		if (in_port->registered)
			serio_interrupt(in_port->serio, data, dfl);
		goto out;
	}

	switch (data) {
	case PS2MULT_ESCAPE:
		dev_dbg(&serio->dev, "ESCAPE\n");
		psm->escape = true;
		break;

	case PS2MULT_BSYNC:
		dev_dbg(&serio->dev, "BSYNC\n");
		psm->in_port = psm->out_port;
		break;

	case PS2MULT_SESSION_START:
		dev_dbg(&serio->dev, "SS\n");
		break;

	case PS2MULT_SESSION_END:
		dev_dbg(&serio->dev, "SE\n");
		break;

	case PS2MULT_KB_SELECTOR:
		dev_dbg(&serio->dev, "KB\n");
		psm->in_port = &psm->ports[PS2MULT_KBD_PORT];
		break;

	case PS2MULT_MS_SELECTOR:
		dev_dbg(&serio->dev, "MS\n");
		psm->in_port = &psm->ports[PS2MULT_MOUSE_PORT];
		break;

	default:
		in_port = psm->in_port;
		if (in_port->registered)
			serio_interrupt(in_port->serio, data, dfl);
		break;
	}

 out:
	spin_unlock_irqrestore(&psm->lock, flags);
	return IRQ_HANDLED;
}

static struct serio_driver ps2mult_drv = {
	.driver		= {
		.name	= "ps2mult",
	},
	.description	= "TQC PS/2 Multiplexer driver",
	.id_table	= ps2mult_serio_ids,
	.interrupt	= ps2mult_interrupt,
	.connect	= ps2mult_connect,
	.disconnect	= ps2mult_disconnect,
	.reconnect	= ps2mult_reconnect,
};

static int __init ps2mult_init(void)
{
	return serio_register_driver(&ps2mult_drv);
}

static void __exit ps2mult_exit(void)
{
	serio_unregister_driver(&ps2mult_drv);
}

module_init(ps2mult_init);
module_exit(ps2mult_exit);