1 /*
2  * Touchwindow serial touchscreen driver
3  *
4  * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com>
5  *
6  * Based on MicroTouch driver (drivers/input/touchscreen/mtouch.c)
7  * Copyright (c) 2004 Vojtech Pavlik
8  * and Dan Streetman <ddstreet@ieee.org>
9  */
10 
11 /*
12  * This program is free software; you can redistribute it and/or modify it
13  * under the terms of the GNU General Public License version 2 as published
14  * by the Free Software Foundation.
15  */
16 
17 /*
18  * 2005/02/19 Rick Koch:
19  *   The Touchwindow I used is made by Edmark Corp. and
20  *   constantly outputs a stream of 0's unless it is touched.
21  *   It then outputs 3 bytes: X, Y, and a copy of Y.
22  */
23 
24 #include <linux/errno.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/slab.h>
28 #include <linux/input.h>
29 #include <linux/serio.h>
30 #include <linux/init.h>
31 
32 #define DRIVER_DESC	"Touchwindow serial touchscreen driver"
33 
34 MODULE_AUTHOR("Rick Koch <n1gp@hotmail.com>");
35 MODULE_DESCRIPTION(DRIVER_DESC);
36 MODULE_LICENSE("GPL");
37 
38 /*
39  * Definitions & global arrays.
40  */
41 
42 #define TW_LENGTH 3
43 
44 #define TW_MIN_XC 0
45 #define TW_MAX_XC 0xff
46 #define TW_MIN_YC 0
47 #define TW_MAX_YC 0xff
48 
49 /*
50  * Per-touchscreen data.
51  */
52 
53 struct tw {
54 	struct input_dev *dev;
55 	struct serio *serio;
56 	int idx;
57 	int touched;
58 	unsigned char data[TW_LENGTH];
59 	char phys[32];
60 };
61 
62 static irqreturn_t tw_interrupt(struct serio *serio,
63 		unsigned char data, unsigned int flags)
64 {
65 	struct tw *tw = serio_get_drvdata(serio);
66 	struct input_dev *dev = tw->dev;
67 
68 	if (data) {		/* touch */
69 		tw->touched = 1;
70 		tw->data[tw->idx++] = data;
71 		/* verify length and that the two Y's are the same */
72 		if (tw->idx == TW_LENGTH && tw->data[1] == tw->data[2]) {
73 			input_report_abs(dev, ABS_X, tw->data[0]);
74 			input_report_abs(dev, ABS_Y, tw->data[1]);
75 			input_report_key(dev, BTN_TOUCH, 1);
76 			input_sync(dev);
77 			tw->idx = 0;
78 		}
79 	} else if (tw->touched) {	/* untouch */
80 		input_report_key(dev, BTN_TOUCH, 0);
81 		input_sync(dev);
82 		tw->idx = 0;
83 		tw->touched = 0;
84 	}
85 
86 	return IRQ_HANDLED;
87 }
88 
89 /*
90  * tw_disconnect() is the opposite of tw_connect()
91  */
92 
93 static void tw_disconnect(struct serio *serio)
94 {
95 	struct tw *tw = serio_get_drvdata(serio);
96 
97 	input_get_device(tw->dev);
98 	input_unregister_device(tw->dev);
99 	serio_close(serio);
100 	serio_set_drvdata(serio, NULL);
101 	input_put_device(tw->dev);
102 	kfree(tw);
103 }
104 
105 /*
106  * tw_connect() is the routine that is called when someone adds a
107  * new serio device that supports the Touchwin protocol and registers it as
108  * an input device.
109  */
110 
111 static int tw_connect(struct serio *serio, struct serio_driver *drv)
112 {
113 	struct tw *tw;
114 	struct input_dev *input_dev;
115 	int err;
116 
117 	tw = kzalloc(sizeof(struct tw), GFP_KERNEL);
118 	input_dev = input_allocate_device();
119 	if (!tw || !input_dev) {
120 		err = -ENOMEM;
121 		goto fail1;
122 	}
123 
124 	tw->serio = serio;
125 	tw->dev = input_dev;
126 	snprintf(tw->phys, sizeof(tw->phys), "%s/input0", serio->phys);
127 
128 	input_dev->name = "Touchwindow Serial TouchScreen";
129 	input_dev->phys = tw->phys;
130 	input_dev->id.bustype = BUS_RS232;
131 	input_dev->id.vendor = SERIO_TOUCHWIN;
132 	input_dev->id.product = 0;
133 	input_dev->id.version = 0x0100;
134 	input_dev->dev.parent = &serio->dev;
135 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
136 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
137 	input_set_abs_params(tw->dev, ABS_X, TW_MIN_XC, TW_MAX_XC, 0, 0);
138 	input_set_abs_params(tw->dev, ABS_Y, TW_MIN_YC, TW_MAX_YC, 0, 0);
139 
140 	serio_set_drvdata(serio, tw);
141 
142 	err = serio_open(serio, drv);
143 	if (err)
144 		goto fail2;
145 
146 	err = input_register_device(tw->dev);
147 	if (err)
148 		goto fail3;
149 
150 	return 0;
151 
152  fail3:	serio_close(serio);
153  fail2:	serio_set_drvdata(serio, NULL);
154  fail1:	input_free_device(input_dev);
155 	kfree(tw);
156 	return err;
157 }
158 
159 /*
160  * The serio driver structure.
161  */
162 
163 static struct serio_device_id tw_serio_ids[] = {
164 	{
165 		.type	= SERIO_RS232,
166 		.proto	= SERIO_TOUCHWIN,
167 		.id	= SERIO_ANY,
168 		.extra	= SERIO_ANY,
169 	},
170 	{ 0 }
171 };
172 
173 MODULE_DEVICE_TABLE(serio, tw_serio_ids);
174 
175 static struct serio_driver tw_drv = {
176 	.driver		= {
177 		.name	= "touchwin",
178 	},
179 	.description	= DRIVER_DESC,
180 	.id_table	= tw_serio_ids,
181 	.interrupt	= tw_interrupt,
182 	.connect	= tw_connect,
183 	.disconnect	= tw_disconnect,
184 };
185 
186 module_serio_driver(tw_drv);
187