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
23MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
24MODULE_DESCRIPTION(DRIVER_DESC);
25MODULE_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
53struct 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
61static 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
75static 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
86static 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
107static 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
125static 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
177static 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
187MODULE_DEVICE_TABLE(serio, mtouch_serio_ids);
188
189static 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
200module_serio_driver(mtouch_drv);
201