aboutsummaryrefslogtreecommitdiff
path: root/drivers/input/touchscreen/touchit213.c
blob: 98a16698be8ef6f8d07ff67e64b6379f31e2eaa9 (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
/*
 * Sahara TouchIT-213 serial touchscreen driver
 *
 * Copyright (c) 2007-2008 Claudio Nieder <private@claudio.ch>
 *
 * Based on Touchright driver (drivers/input/touchscreen/touchright.c)
 * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com>
 * Copyright (c) 2004 Vojtech Pavlik
 * and Dan Streetman <ddstreet@ieee.org>
 */

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

#define DRIVER_DESC	"Sahara TouchIT-213 serial touchscreen driver"

MODULE_AUTHOR("Claudio Nieder <private@claudio.ch>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Definitions & global arrays.
 */

/*
 * Data is received through COM1 at 9600bit/s,8bit,no parity in packets
 * of 5 byte each.
 *
 *   +--------+   +--------+   +--------+   +--------+   +--------+
 *   |1000000p|   |0xxxxxxx|   |0xxxxxxx|   |0yyyyyyy|   |0yyyyyyy|
 *   +--------+   +--------+   +--------+   +--------+   +--------+
 *                    MSB          LSB          MSB          LSB
 *
 * The value of p is 1 as long as the screen is touched and 0 when
 * reporting the location where touching stopped, e.g. where the pen was
 * lifted from the screen.
 *
 * When holding the screen in landscape mode as the BIOS text output is
 * presented, x is the horizontal axis with values growing from left to
 * right and y is the vertical axis with values growing from top to
 * bottom.
 *
 * When holding the screen in portrait mode with the Sahara logo in its
 * correct position, x ist the vertical axis with values growing from
 * top to bottom and y is the horizontal axis with values growing from
 * right to left.
 */

#define T213_FORMAT_TOUCH_BIT	0x01
#define T213_FORMAT_STATUS_BYTE	0x80
#define T213_FORMAT_STATUS_MASK	~T213_FORMAT_TOUCH_BIT

/*
 * On my Sahara Touch-IT 213 I have observed x values from 0 to 0x7f0
 * and y values from 0x1d to 0x7e9, so the actual measurement is
 * probably done with an 11 bit precision.
 */
#define T213_MIN_XC 0
#define T213_MAX_XC 0x07ff
#define T213_MIN_YC 0
#define T213_MAX_YC 0x07ff

/*
 * Per-touchscreen data.
 */

struct touchit213 {
	struct input_dev *dev;
	struct serio *serio;
	int idx;
	unsigned char csum;
	unsigned char data[5];
	char phys[32];
};

static irqreturn_t touchit213_interrupt(struct serio *serio,
		unsigned char data, unsigned int flags)
{
	struct touchit213 *touchit213 = serio_get_drvdata(serio);
	struct input_dev *dev = touchit213->dev;

	touchit213->data[touchit213->idx] = data;

	switch (touchit213->idx++) {
	case 0:
		if ((touchit213->data[0] & T213_FORMAT_STATUS_MASK) !=
				T213_FORMAT_STATUS_BYTE) {
			pr_debug("unsynchronized data: 0x%02x\n", data);
			touchit213->idx = 0;
		}
		break;

	case 4:
		touchit213->idx = 0;
		input_report_abs(dev, ABS_X,
			(touchit213->data[1] << 7) | touchit213->data[2]);
		input_report_abs(dev, ABS_Y,
			(touchit213->data[3] << 7) | touchit213->data[4]);
		input_report_key(dev, BTN_TOUCH,
			touchit213->data[0] & T213_FORMAT_TOUCH_BIT);
		input_sync(dev);
		break;
	}

	return IRQ_HANDLED;
}

/*
 * touchit213_disconnect() is the opposite of touchit213_connect()
 */

static void touchit213_disconnect(struct serio *serio)
{
	struct touchit213 *touchit213 = serio_get_drvdata(serio);

	input_get_device(touchit213->dev);
	input_unregister_device(touchit213->dev);
	serio_close(serio);
	serio_set_drvdata(serio, NULL);
	input_put_device(touchit213->dev);
	kfree(touchit213);
}

/*
 * touchit213_connect() is the routine that is called when someone adds a
 * new serio device that supports the Touchright protocol and registers it as
 * an input device.
 */

static int touchit213_connect(struct serio *serio, struct serio_driver *drv)
{
	struct touchit213 *touchit213;
	struct input_dev *input_dev;
	int err;

	touchit213 = kzalloc(sizeof(struct touchit213), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!touchit213 || !input_dev) {
		err = -ENOMEM;
		goto fail1;
	}

	touchit213->serio = serio;
	touchit213->dev = input_dev;
	snprintf(touchit213->phys, sizeof(touchit213->phys),
		 "%s/input0", serio->phys);

	input_dev->name = "Sahara Touch-iT213 Serial TouchScreen";
	input_dev->phys = touchit213->phys;
	input_dev->id.bustype = BUS_RS232;
	input_dev->id.vendor = SERIO_TOUCHIT213;
	input_dev->id.product = 0;
	input_dev->id.version = 0x0100;
	input_dev->dev.parent = &serio->dev;
	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
	input_set_abs_params(touchit213->dev, ABS_X,
			     T213_MIN_XC, T213_MAX_XC, 0, 0);
	input_set_abs_params(touchit213->dev, ABS_Y,
			     T213_MIN_YC, T213_MAX_YC, 0, 0);

	serio_set_drvdata(serio, touchit213);

	err = serio_open(serio, drv);
	if (err)
		goto fail2;

	err = input_register_device(touchit213->dev);
	if (err)
		goto fail3;

	return 0;

 fail3:	serio_close(serio);
 fail2:	serio_set_drvdata(serio, NULL);
 fail1:	input_free_device(input_dev);
	kfree(touchit213);
	return err;
}

/*
 * The serio driver structure.
 */

static const struct serio_device_id touchit213_serio_ids[] = {
	{
		.type	= SERIO_RS232,
		.proto	= SERIO_TOUCHIT213,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, touchit213_serio_ids);

static struct serio_driver touchit213_drv = {
	.driver		= {
		.name	= "touchit213",
	},
	.description	= DRIVER_DESC,
	.id_table	= touchit213_serio_ids,
	.interrupt	= touchit213_interrupt,
	.connect	= touchit213_connect,
	.disconnect	= touchit213_disconnect,
};

module_serio_driver(touchit213_drv);