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 
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 
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 
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