1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Hampshire serial touchscreen driver
4 *
5 * Copyright (c) 2010 Adam Bennett
6 * Based on the dynapro driver (c) Tias Guns
7 */
8
9
10/*
11 * 2010/04/08 Adam Bennett <abennett72@gmail.com>
12 *   Copied dynapro.c and edited for Hampshire 4-byte protocol
13 */
14
15#include <linux/errno.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/input.h>
20#include <linux/serio.h>
21
22#define DRIVER_DESC	"Hampshire serial touchscreen driver"
23
24MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
25MODULE_DESCRIPTION(DRIVER_DESC);
26MODULE_LICENSE("GPL");
27
28/*
29 * Definitions & global arrays.
30 */
31
32#define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
33#define HAMPSHIRE_FORMAT_LENGTH 4
34#define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
35
36#define HAMPSHIRE_MIN_XC 0
37#define HAMPSHIRE_MAX_XC 0x1000
38#define HAMPSHIRE_MIN_YC 0
39#define HAMPSHIRE_MAX_YC 0x1000
40
41#define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
42#define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
43#define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
44
45/*
46 * Per-touchscreen data.
47 */
48
49struct hampshire {
50	struct input_dev *dev;
51	struct serio *serio;
52	int idx;
53	unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
54	char phys[32];
55};
56
57static void hampshire_process_data(struct hampshire *phampshire)
58{
59	struct input_dev *dev = phampshire->dev;
60
61	if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
62		input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
63		input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
64		input_report_key(dev, BTN_TOUCH,
65				 HAMPSHIRE_GET_TOUCHED(phampshire->data));
66		input_sync(dev);
67
68		phampshire->idx = 0;
69	}
70}
71
72static irqreturn_t hampshire_interrupt(struct serio *serio,
73		unsigned char data, unsigned int flags)
74{
75	struct hampshire *phampshire = serio_get_drvdata(serio);
76
77	phampshire->data[phampshire->idx] = data;
78
79	if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
80		hampshire_process_data(phampshire);
81	else
82		dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
83			phampshire->data[0]);
84
85	return IRQ_HANDLED;
86}
87
88static void hampshire_disconnect(struct serio *serio)
89{
90	struct hampshire *phampshire = serio_get_drvdata(serio);
91
92	input_get_device(phampshire->dev);
93	input_unregister_device(phampshire->dev);
94	serio_close(serio);
95	serio_set_drvdata(serio, NULL);
96	input_put_device(phampshire->dev);
97	kfree(phampshire);
98}
99
100/*
101 * hampshire_connect() is the routine that is called when someone adds a
102 * new serio device that supports hampshire protocol and registers it as
103 * an input device. This is usually accomplished using inputattach.
104 */
105
106static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
107{
108	struct hampshire *phampshire;
109	struct input_dev *input_dev;
110	int err;
111
112	phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL);
113	input_dev = input_allocate_device();
114	if (!phampshire || !input_dev) {
115		err = -ENOMEM;
116		goto fail1;
117	}
118
119	phampshire->serio = serio;
120	phampshire->dev = input_dev;
121	snprintf(phampshire->phys, sizeof(phampshire->phys),
122		 "%s/input0", serio->phys);
123
124	input_dev->name = "Hampshire Serial TouchScreen";
125	input_dev->phys = phampshire->phys;
126	input_dev->id.bustype = BUS_RS232;
127	input_dev->id.vendor = SERIO_HAMPSHIRE;
128	input_dev->id.product = 0;
129	input_dev->id.version = 0x0001;
130	input_dev->dev.parent = &serio->dev;
131	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
132	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
133	input_set_abs_params(phampshire->dev, ABS_X,
134			     HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
135	input_set_abs_params(phampshire->dev, ABS_Y,
136			     HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
137
138	serio_set_drvdata(serio, phampshire);
139
140	err = serio_open(serio, drv);
141	if (err)
142		goto fail2;
143
144	err = input_register_device(phampshire->dev);
145	if (err)
146		goto fail3;
147
148	return 0;
149
150 fail3:	serio_close(serio);
151 fail2:	serio_set_drvdata(serio, NULL);
152 fail1:	input_free_device(input_dev);
153	kfree(phampshire);
154	return err;
155}
156
157/*
158 * The serio driver structure.
159 */
160
161static const struct serio_device_id hampshire_serio_ids[] = {
162	{
163		.type	= SERIO_RS232,
164		.proto	= SERIO_HAMPSHIRE,
165		.id	= SERIO_ANY,
166		.extra	= SERIO_ANY,
167	},
168	{ 0 }
169};
170
171MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
172
173static struct serio_driver hampshire_drv = {
174	.driver		= {
175		.name	= "hampshire",
176	},
177	.description	= DRIVER_DESC,
178	.id_table	= hampshire_serio_ids,
179	.interrupt	= hampshire_interrupt,
180	.connect	= hampshire_connect,
181	.disconnect	= hampshire_disconnect,
182};
183
184module_serio_driver(hampshire_drv);
185