1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * MicroTouch (3M) serial touchscreen driver
4  *
5  * Copyright (c) 2004 Vojtech Pavlik
6  */
7 
8 
9 /*
10  * 2005/02/19 Dan Streetman <ddstreet@ieee.org>
11  *   Copied elo.c and edited for MicroTouch protocol
12  */
13 
14 #include <linux/errno.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/input.h>
19 #include <linux/serio.h>
20 
21 #define DRIVER_DESC	"MicroTouch serial touchscreen driver"
22 
23 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
24 MODULE_DESCRIPTION(DRIVER_DESC);
25 MODULE_LICENSE("GPL");
26 
27 /*
28  * Definitions & global arrays.
29  */
30 
31 #define MTOUCH_FORMAT_TABLET_STATUS_BIT 0x80
32 #define MTOUCH_FORMAT_TABLET_TOUCH_BIT 0x40
33 #define MTOUCH_FORMAT_TABLET_LENGTH 5
34 #define MTOUCH_RESPONSE_BEGIN_BYTE 0x01
35 #define MTOUCH_RESPONSE_END_BYTE 0x0d
36 
37 /* todo: check specs for max length of all responses */
38 #define MTOUCH_MAX_LENGTH 16
39 
40 #define MTOUCH_MIN_XC 0
41 #define MTOUCH_MAX_XC 0x3fff
42 #define MTOUCH_MIN_YC 0
43 #define MTOUCH_MAX_YC 0x3fff
44 
45 #define MTOUCH_GET_XC(data) (((data[2])<<7) | data[1])
46 #define MTOUCH_GET_YC(data) (((data[4])<<7) | data[3])
47 #define MTOUCH_GET_TOUCHED(data) (MTOUCH_FORMAT_TABLET_TOUCH_BIT & data[0])
48 
49 /*
50  * Per-touchscreen data.
51  */
52 
53 struct mtouch {
54 	struct input_dev *dev;
55 	struct serio *serio;
56 	int idx;
57 	unsigned char data[MTOUCH_MAX_LENGTH];
58 	char phys[32];
59 };
60 
mtouch_process_format_tablet(struct mtouch * mtouch)61 static void mtouch_process_format_tablet(struct mtouch *mtouch)
62 {
63 	struct input_dev *dev = mtouch->dev;
64 
65 	if (MTOUCH_FORMAT_TABLET_LENGTH == ++mtouch->idx) {
66 		input_report_abs(dev, ABS_X, MTOUCH_GET_XC(mtouch->data));
67 		input_report_abs(dev, ABS_Y, MTOUCH_MAX_YC - MTOUCH_GET_YC(mtouch->data));
68 		input_report_key(dev, BTN_TOUCH, MTOUCH_GET_TOUCHED(mtouch->data));
69 		input_sync(dev);
70 
71 		mtouch->idx = 0;
72 	}
73 }
74 
mtouch_process_response(struct mtouch * mtouch)75 static void mtouch_process_response(struct mtouch *mtouch)
76 {
77 	if (MTOUCH_RESPONSE_END_BYTE == mtouch->data[mtouch->idx++]) {
78 		/* FIXME - process response */
79 		mtouch->idx = 0;
80 	} else if (MTOUCH_MAX_LENGTH == mtouch->idx) {
81 		printk(KERN_ERR "mtouch.c: too many response bytes\n");
82 		mtouch->idx = 0;
83 	}
84 }
85 
mtouch_interrupt(struct serio * serio,unsigned char data,unsigned int flags)86 static irqreturn_t mtouch_interrupt(struct serio *serio,
87 		unsigned char data, unsigned int flags)
88 {
89 	struct mtouch *mtouch = serio_get_drvdata(serio);
90 
91 	mtouch->data[mtouch->idx] = data;
92 
93 	if (MTOUCH_FORMAT_TABLET_STATUS_BIT & mtouch->data[0])
94 		mtouch_process_format_tablet(mtouch);
95 	else if (MTOUCH_RESPONSE_BEGIN_BYTE == mtouch->data[0])
96 		mtouch_process_response(mtouch);
97 	else
98 		printk(KERN_DEBUG "mtouch.c: unknown/unsynchronized data from device, byte %x\n",mtouch->data[0]);
99 
100 	return IRQ_HANDLED;
101 }
102 
103 /*
104  * mtouch_disconnect() is the opposite of mtouch_connect()
105  */
106 
mtouch_disconnect(struct serio * serio)107 static void mtouch_disconnect(struct serio *serio)
108 {
109 	struct mtouch *mtouch = serio_get_drvdata(serio);
110 
111 	input_get_device(mtouch->dev);
112 	input_unregister_device(mtouch->dev);
113 	serio_close(serio);
114 	serio_set_drvdata(serio, NULL);
115 	input_put_device(mtouch->dev);
116 	kfree(mtouch);
117 }
118 
119 /*
120  * mtouch_connect() is the routine that is called when someone adds a
121  * new serio device that supports MicroTouch (Format Tablet) protocol and registers it as
122  * an input device.
123  */
124 
mtouch_connect(struct serio * serio,struct serio_driver * drv)125 static int mtouch_connect(struct serio *serio, struct serio_driver *drv)
126 {
127 	struct mtouch *mtouch;
128 	struct input_dev *input_dev;
129 	int err;
130 
131 	mtouch = kzalloc(sizeof(struct mtouch), GFP_KERNEL);
132 	input_dev = input_allocate_device();
133 	if (!mtouch || !input_dev) {
134 		err = -ENOMEM;
135 		goto fail1;
136 	}
137 
138 	mtouch->serio = serio;
139 	mtouch->dev = input_dev;
140 	snprintf(mtouch->phys, sizeof(mtouch->phys), "%s/input0", serio->phys);
141 
142 	input_dev->name = "MicroTouch Serial TouchScreen";
143 	input_dev->phys = mtouch->phys;
144 	input_dev->id.bustype = BUS_RS232;
145 	input_dev->id.vendor = SERIO_MICROTOUCH;
146 	input_dev->id.product = 0;
147 	input_dev->id.version = 0x0100;
148 	input_dev->dev.parent = &serio->dev;
149 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
150 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
151 	input_set_abs_params(mtouch->dev, ABS_X, MTOUCH_MIN_XC, MTOUCH_MAX_XC, 0, 0);
152 	input_set_abs_params(mtouch->dev, ABS_Y, MTOUCH_MIN_YC, MTOUCH_MAX_YC, 0, 0);
153 
154 	serio_set_drvdata(serio, mtouch);
155 
156 	err = serio_open(serio, drv);
157 	if (err)
158 		goto fail2;
159 
160 	err = input_register_device(mtouch->dev);
161 	if (err)
162 		goto fail3;
163 
164 	return 0;
165 
166  fail3:	serio_close(serio);
167  fail2:	serio_set_drvdata(serio, NULL);
168  fail1:	input_free_device(input_dev);
169 	kfree(mtouch);
170 	return err;
171 }
172 
173 /*
174  * The serio driver structure.
175  */
176 
177 static const struct serio_device_id mtouch_serio_ids[] = {
178 	{
179 		.type	= SERIO_RS232,
180 		.proto	= SERIO_MICROTOUCH,
181 		.id	= SERIO_ANY,
182 		.extra	= SERIO_ANY,
183 	},
184 	{ 0 }
185 };
186 
187 MODULE_DEVICE_TABLE(serio, mtouch_serio_ids);
188 
189 static struct serio_driver mtouch_drv = {
190 	.driver		= {
191 		.name	= "mtouch",
192 	},
193 	.description	= DRIVER_DESC,
194 	.id_table	= mtouch_serio_ids,
195 	.interrupt	= mtouch_interrupt,
196 	.connect	= mtouch_connect,
197 	.disconnect	= mtouch_disconnect,
198 };
199 
200 module_serio_driver(mtouch_drv);
201