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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Touchwindow serial touchscreen driver
4 *
5 * Copyright (c) 2006 Rick Koch <[email protected]>
6 *
7 * Based on MicroTouch driver (drivers/input/touchscreen/mtouch.c)
8 * Copyright (c) 2004 Vojtech Pavlik
9 * and Dan Streetman <[email protected]>
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 <[email protected]>");
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 /* a full packet ends the accumulation, valid or not */
67 if (tw->idx == TW_LENGTH) {
68 /* report only if the two Y's are the same */
69 if (tw->data[1] == tw->data[2]) {
70 input_report_abs(dev, ABS_X, tw->data[0]);
71 input_report_abs(dev, ABS_Y, tw->data[1]);
72 input_report_key(dev, BTN_TOUCH, 1);
73 input_sync(dev);
74 }
75 tw->idx = 0;
76 }
77 } else if (tw->touched) { /* untouch */
78 input_report_key(dev, BTN_TOUCH, 0);
79 input_sync(dev);
80 tw->idx = 0;
81 tw->touched = 0;
82 }
83
84 return IRQ_HANDLED;
85}
86
87/*
88 * tw_disconnect() is the opposite of tw_connect()
89 */
90
91static void tw_disconnect(struct serio *serio)
92{
93 struct tw *tw = serio_get_drvdata(serio);
94
95 input_get_device(tw->dev);
96 input_unregister_device(tw->dev);
97 serio_close(serio);
98 serio_set_drvdata(serio, NULL);
99 input_put_device(tw->dev);
100 kfree(tw);
101}
102
103/*
104 * tw_connect() is the routine that is called when someone adds a
105 * new serio device that supports the Touchwin protocol and registers it as
106 * an input device.
107 */
108
109static int tw_connect(struct serio *serio, struct serio_driver *drv)
110{
111 struct tw *tw;
112 struct input_dev *input_dev;
113 int err;
114
115 tw = kzalloc_obj(*tw);
116 input_dev = input_allocate_device();
117 if (!tw || !input_dev) {
118 err = -ENOMEM;
119 goto fail1;
120 }
121
122 tw->serio = serio;
123 tw->dev = input_dev;
124 scnprintf(tw->phys, sizeof(tw->phys), "%s/input0", serio->phys);
125
126 input_dev->name = "Touchwindow Serial TouchScreen";
127 input_dev->phys = tw->phys;
128 input_dev->id.bustype = BUS_RS232;
129 input_dev->id.vendor = SERIO_TOUCHWIN;
130 input_dev->id.product = 0;
131 input_dev->id.version = 0x0100;
132 input_dev->dev.parent = &serio->dev;
133 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
134 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
135 input_set_abs_params(tw->dev, ABS_X, TW_MIN_XC, TW_MAX_XC, 0, 0);
136 input_set_abs_params(tw->dev, ABS_Y, TW_MIN_YC, TW_MAX_YC, 0, 0);
137
138 serio_set_drvdata(serio, tw);
139
140 err = serio_open(serio, drv);
141 if (err)
142 goto fail2;
143
144 err = input_register_device(tw->dev);
145 if (err)
146 goto fail3;
147
148 return 0;
149
150 fail3: serio_close(serio);
151 fail2: serio_set_drvdata(serio, NULL);
152 fail1: input_free_device(input_dev);
153 kfree(tw);
154 return err;
155}
156
157/*
158 * The serio driver structure.
159 */
160
161static const struct serio_device_id tw_serio_ids[] = {
162 {
163 .type = SERIO_RS232,
164 .proto = SERIO_TOUCHWIN,
165 .id = SERIO_ANY,
166 .extra = SERIO_ANY,
167 },
168 { 0 }
169};
170
171MODULE_DEVICE_TABLE(serio, tw_serio_ids);
172
173static struct serio_driver tw_drv = {
174 .driver = {
175 .name = "touchwin",
176 },
177 .description = DRIVER_DESC,
178 .id_table = tw_serio_ids,
179 .interrupt = tw_interrupt,
180 .connect = tw_connect,
181 .disconnect = tw_disconnect,
182};
183
184module_serio_driver(tw_drv);