1 /*
2  * MicroTouch (3M) serial touchscreen driver
3  *
4  * Copyright (c) 2004 Vojtech Pavlik
5  */
6 
7 /*
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License version 2 as published by
10  * the Free Software Foundation.
11  */
12 
13 /*
14  * 2005/02/19 Dan Streetman <ddstreet@ieee.org>
15  *   Copied elo.c and edited for MicroTouch protocol
16  */
17 
18 #include <linux/errno.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <linux/input.h>
23 #include <linux/serio.h>
24 
25 #define DRIVER_DESC	"MicroTouch serial touchscreen driver"
26 
27 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
28 MODULE_DESCRIPTION(DRIVER_DESC);
29 MODULE_LICENSE("GPL");
30 
31 /*
32  * Definitions & global arrays.
33  */
34 
35 #define MTOUCH_FORMAT_TABLET_STATUS_BIT 0x80
36 #define MTOUCH_FORMAT_TABLET_TOUCH_BIT 0x40
37 #define MTOUCH_FORMAT_TABLET_LENGTH 5
38 #define MTOUCH_RESPONSE_BEGIN_BYTE 0x01
39 #define MTOUCH_RESPONSE_END_BYTE 0x0d
40 
41 /* todo: check specs for max length of all responses */
42 #define MTOUCH_MAX_LENGTH 16
43 
44 #define MTOUCH_MIN_XC 0
45 #define MTOUCH_MAX_XC 0x3fff
46 #define MTOUCH_MIN_YC 0
47 #define MTOUCH_MAX_YC 0x3fff
48 
49 #define MTOUCH_GET_XC(data) (((data[2])<<7) | data[1])
50 #define MTOUCH_GET_YC(data) (((data[4])<<7) | data[3])
51 #define MTOUCH_GET_TOUCHED(data) (MTOUCH_FORMAT_TABLET_TOUCH_BIT & data[0])
52 
53 /*
54  * Per-touchscreen data.
55  */
56 
57 struct mtouch {
58 	struct input_dev *dev;
59 	struct serio *serio;
60 	int idx;
61 	unsigned char data[MTOUCH_MAX_LENGTH];
62 	char phys[32];
63 };
64 
65 static void mtouch_process_format_tablet(struct mtouch *mtouch)
66 {
67 	struct input_dev *dev = mtouch->dev;
68 
69 	if (MTOUCH_FORMAT_TABLET_LENGTH == ++mtouch->idx) {
70 		input_report_abs(dev, ABS_X, MTOUCH_GET_XC(mtouch->data));
71 		input_report_abs(dev, ABS_Y, MTOUCH_MAX_YC - MTOUCH_GET_YC(mtouch->data));
72 		input_report_key(dev, BTN_TOUCH, MTOUCH_GET_TOUCHED(mtouch->data));
73 		input_sync(dev);
74 
75 		mtouch->idx = 0;
76 	}
77 }
78 
79 static void mtouch_process_response(struct mtouch *mtouch)
80 {
81 	if (MTOUCH_RESPONSE_END_BYTE == mtouch->data[mtouch->idx++]) {
82 		/* FIXME - process response */
83 		mtouch->idx = 0;
84 	} else if (MTOUCH_MAX_LENGTH == mtouch->idx) {
85 		printk(KERN_ERR "mtouch.c: too many response bytes\n");
86 		mtouch->idx = 0;
87 	}
88 }
89 
90 static irqreturn_t mtouch_interrupt(struct serio *serio,
91 		unsigned char data, unsigned int flags)
92 {
93 	struct mtouch *mtouch = serio_get_drvdata(serio);
94 
95 	mtouch->data[mtouch->idx] = data;
96 
97 	if (MTOUCH_FORMAT_TABLET_STATUS_BIT & mtouch->data[0])
98 		mtouch_process_format_tablet(mtouch);
99 	else if (MTOUCH_RESPONSE_BEGIN_BYTE == mtouch->data[0])
100 		mtouch_process_response(mtouch);
101 	else
102 		printk(KERN_DEBUG "mtouch.c: unknown/unsynchronized data from device, byte %x\n",mtouch->data[0]);
103 
104 	return IRQ_HANDLED;
105 }
106 
107 /*
108  * mtouch_disconnect() is the opposite of mtouch_connect()
109  */
110 
111 static void mtouch_disconnect(struct serio *serio)
112 {
113 	struct mtouch *mtouch = serio_get_drvdata(serio);
114 
115 	input_get_device(mtouch->dev);
116 	input_unregister_device(mtouch->dev);
117 	serio_close(serio);
118 	serio_set_drvdata(serio, NULL);
119 	input_put_device(mtouch->dev);
120 	kfree(mtouch);
121 }
122 
123 /*
124  * mtouch_connect() is the routine that is called when someone adds a
125  * new serio device that supports MicroTouch (Format Tablet) protocol and registers it as
126  * an input device.
127  */
128 
129 static int mtouch_connect(struct serio *serio, struct serio_driver *drv)
130 {
131 	struct mtouch *mtouch;
132 	struct input_dev *input_dev;
133 	int err;
134 
135 	mtouch = kzalloc(sizeof(struct mtouch), GFP_KERNEL);
136 	input_dev = input_allocate_device();
137 	if (!mtouch || !input_dev) {
138 		err = -ENOMEM;
139 		goto fail1;
140 	}
141 
142 	mtouch->serio = serio;
143 	mtouch->dev = input_dev;
144 	snprintf(mtouch->phys, sizeof(mtouch->phys), "%s/input0", serio->phys);
145 
146 	input_dev->name = "MicroTouch Serial TouchScreen";
147 	input_dev->phys = mtouch->phys;
148 	input_dev->id.bustype = BUS_RS232;
149 	input_dev->id.vendor = SERIO_MICROTOUCH;
150 	input_dev->id.product = 0;
151 	input_dev->id.version = 0x0100;
152 	input_dev->dev.parent = &serio->dev;
153 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
154 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
155 	input_set_abs_params(mtouch->dev, ABS_X, MTOUCH_MIN_XC, MTOUCH_MAX_XC, 0, 0);
156 	input_set_abs_params(mtouch->dev, ABS_Y, MTOUCH_MIN_YC, MTOUCH_MAX_YC, 0, 0);
157 
158 	serio_set_drvdata(serio, mtouch);
159 
160 	err = serio_open(serio, drv);
161 	if (err)
162 		goto fail2;
163 
164 	err = input_register_device(mtouch->dev);
165 	if (err)
166 		goto fail3;
167 
168 	return 0;
169 
170  fail3:	serio_close(serio);
171  fail2:	serio_set_drvdata(serio, NULL);
172  fail1:	input_free_device(input_dev);
173 	kfree(mtouch);
174 	return err;
175 }
176 
177 /*
178  * The serio driver structure.
179  */
180 
181 static const struct serio_device_id mtouch_serio_ids[] = {
182 	{
183 		.type	= SERIO_RS232,
184 		.proto	= SERIO_MICROTOUCH,
185 		.id	= SERIO_ANY,
186 		.extra	= SERIO_ANY,
187 	},
188 	{ 0 }
189 };
190 
191 MODULE_DEVICE_TABLE(serio, mtouch_serio_ids);
192 
193 static struct serio_driver mtouch_drv = {
194 	.driver		= {
195 		.name	= "mtouch",
196 	},
197 	.description	= DRIVER_DESC,
198 	.id_table	= mtouch_serio_ids,
199 	.interrupt	= mtouch_interrupt,
200 	.connect	= mtouch_connect,
201 	.disconnect	= mtouch_disconnect,
202 };
203 
204 module_serio_driver(mtouch_drv);
205