1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Touchwindow serial touchscreen driver
4 *
5 * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com>
6 *
7 * Based on MicroTouch driver (drivers/input/touchscreen/mtouch.c)
8 * Copyright (c) 2004 Vojtech Pavlik
9 * and Dan Streetman <ddstreet@ieee.org>
10 */
11
12
13/*
14 * 2005/02/19 Rick Koch:
15 *   The Touchwindow I used is made by Edmark Corp. and
16 *   constantly outputs a stream of 0's unless it is touched.
17 *   It then outputs 3 bytes: X, Y, and a copy of Y.
18 */
19
20#include <linux/errno.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/slab.h>
24#include <linux/input.h>
25#include <linux/serio.h>
26
27#define DRIVER_DESC	"Touchwindow serial touchscreen driver"
28
29MODULE_AUTHOR("Rick Koch <n1gp@hotmail.com>");
30MODULE_DESCRIPTION(DRIVER_DESC);
31MODULE_LICENSE("GPL");
32
33/*
34 * Definitions & global arrays.
35 */
36
37#define TW_LENGTH 3
38
39#define TW_MIN_XC 0
40#define TW_MAX_XC 0xff
41#define TW_MIN_YC 0
42#define TW_MAX_YC 0xff
43
44/*
45 * Per-touchscreen data.
46 */
47
48struct tw {
49	struct input_dev *dev;
50	struct serio *serio;
51	int idx;
52	int touched;
53	unsigned char data[TW_LENGTH];
54	char phys[32];
55};
56
57static irqreturn_t tw_interrupt(struct serio *serio,
58		unsigned char data, unsigned int flags)
59{
60	struct tw *tw = serio_get_drvdata(serio);
61	struct input_dev *dev = tw->dev;
62
63	if (data) {		/* touch */
64		tw->touched = 1;
65		tw->data[tw->idx++] = data;
66		/* verify length and that the two Y's are the same */
67		if (tw->idx == TW_LENGTH && tw->data[1] == tw->data[2]) {
68			input_report_abs(dev, ABS_X, tw->data[0]);
69			input_report_abs(dev, ABS_Y, tw->data[1]);
70			input_report_key(dev, BTN_TOUCH, 1);
71			input_sync(dev);
72			tw->idx = 0;
73		}
74	} else if (tw->touched) {	/* untouch */
75		input_report_key(dev, BTN_TOUCH, 0);
76		input_sync(dev);
77		tw->idx = 0;
78		tw->touched = 0;
79	}
80
81	return IRQ_HANDLED;
82}
83
84/*
85 * tw_disconnect() is the opposite of tw_connect()
86 */
87
88static void tw_disconnect(struct serio *serio)
89{
90	struct tw *tw = serio_get_drvdata(serio);
91
92	input_get_device(tw->dev);
93	input_unregister_device(tw->dev);
94	serio_close(serio);
95	serio_set_drvdata(serio, NULL);
96	input_put_device(tw->dev);
97	kfree(tw);
98}
99
100/*
101 * tw_connect() is the routine that is called when someone adds a
102 * new serio device that supports the Touchwin protocol and registers it as
103 * an input device.
104 */
105
106static int tw_connect(struct serio *serio, struct serio_driver *drv)
107{
108	struct tw *tw;
109	struct input_dev *input_dev;
110	int err;
111
112	tw = kzalloc(sizeof(struct tw), GFP_KERNEL);
113	input_dev = input_allocate_device();
114	if (!tw || !input_dev) {
115		err = -ENOMEM;
116		goto fail1;
117	}
118
119	tw->serio = serio;
120	tw->dev = input_dev;
121	snprintf(tw->phys, sizeof(tw->phys), "%s/input0", serio->phys);
122
123	input_dev->name = "Touchwindow Serial TouchScreen";
124	input_dev->phys = tw->phys;
125	input_dev->id.bustype = BUS_RS232;
126	input_dev->id.vendor = SERIO_TOUCHWIN;
127	input_dev->id.product = 0;
128	input_dev->id.version = 0x0100;
129	input_dev->dev.parent = &serio->dev;
130	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
131	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
132	input_set_abs_params(tw->dev, ABS_X, TW_MIN_XC, TW_MAX_XC, 0, 0);
133	input_set_abs_params(tw->dev, ABS_Y, TW_MIN_YC, TW_MAX_YC, 0, 0);
134
135	serio_set_drvdata(serio, tw);
136
137	err = serio_open(serio, drv);
138	if (err)
139		goto fail2;
140
141	err = input_register_device(tw->dev);
142	if (err)
143		goto fail3;
144
145	return 0;
146
147 fail3:	serio_close(serio);
148 fail2:	serio_set_drvdata(serio, NULL);
149 fail1:	input_free_device(input_dev);
150	kfree(tw);
151	return err;
152}
153
154/*
155 * The serio driver structure.
156 */
157
158static const struct serio_device_id tw_serio_ids[] = {
159	{
160		.type	= SERIO_RS232,
161		.proto	= SERIO_TOUCHWIN,
162		.id	= SERIO_ANY,
163		.extra	= SERIO_ANY,
164	},
165	{ 0 }
166};
167
168MODULE_DEVICE_TABLE(serio, tw_serio_ids);
169
170static struct serio_driver tw_drv = {
171	.driver		= {
172		.name	= "touchwin",
173	},
174	.description	= DRIVER_DESC,
175	.id_table	= tw_serio_ids,
176	.interrupt	= tw_interrupt,
177	.connect	= tw_connect,
178	.disconnect	= tw_disconnect,
179};
180
181module_serio_driver(tw_drv);
182