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
29 MODULE_AUTHOR("Rick Koch <n1gp@hotmail.com>");
30 MODULE_DESCRIPTION(DRIVER_DESC);
31 MODULE_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
48 struct 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
tw_interrupt(struct serio * serio,unsigned char data,unsigned int flags)57 static 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
tw_disconnect(struct serio * serio)88 static 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
tw_connect(struct serio * serio,struct serio_driver * drv)106 static 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
158 static 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
168 MODULE_DEVICE_TABLE(serio, tw_serio_ids);
169
170 static 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
181 module_serio_driver(tw_drv);
182