1/*
2 * Hampshire serial touchscreen driver
3 *
4 * Copyright (c) 2010 Adam Bennett
5 * Based on the dynapro driver (c) Tias Guns
6 *
7 */
8
9/*
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License version 2 as published by
12 * the Free Software Foundation.
13 */
14
15/*
16 * 2010/04/08 Adam Bennett <abennett72@gmail.com>
17 *   Copied dynapro.c and edited for Hampshire 4-byte protocol
18 */
19
20#include <linux/errno.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/slab.h>
24#include <linux/input.h>
25#include <linux/serio.h>
26
27#define DRIVER_DESC	"Hampshire serial touchscreen driver"
28
29MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
30MODULE_DESCRIPTION(DRIVER_DESC);
31MODULE_LICENSE("GPL");
32
33/*
34 * Definitions & global arrays.
35 */
36
37#define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
38#define HAMPSHIRE_FORMAT_LENGTH 4
39#define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
40
41#define HAMPSHIRE_MIN_XC 0
42#define HAMPSHIRE_MAX_XC 0x1000
43#define HAMPSHIRE_MIN_YC 0
44#define HAMPSHIRE_MAX_YC 0x1000
45
46#define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
47#define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
48#define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
49
50/*
51 * Per-touchscreen data.
52 */
53
54struct hampshire {
55	struct input_dev *dev;
56	struct serio *serio;
57	int idx;
58	unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
59	char phys[32];
60};
61
62static void hampshire_process_data(struct hampshire *phampshire)
63{
64	struct input_dev *dev = phampshire->dev;
65
66	if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
67		input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
68		input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
69		input_report_key(dev, BTN_TOUCH,
70				 HAMPSHIRE_GET_TOUCHED(phampshire->data));
71		input_sync(dev);
72
73		phampshire->idx = 0;
74	}
75}
76
77static irqreturn_t hampshire_interrupt(struct serio *serio,
78		unsigned char data, unsigned int flags)
79{
80	struct hampshire *phampshire = serio_get_drvdata(serio);
81
82	phampshire->data[phampshire->idx] = data;
83
84	if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
85		hampshire_process_data(phampshire);
86	else
87		dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
88			phampshire->data[0]);
89
90	return IRQ_HANDLED;
91}
92
93static void hampshire_disconnect(struct serio *serio)
94{
95	struct hampshire *phampshire = serio_get_drvdata(serio);
96
97	input_get_device(phampshire->dev);
98	input_unregister_device(phampshire->dev);
99	serio_close(serio);
100	serio_set_drvdata(serio, NULL);
101	input_put_device(phampshire->dev);
102	kfree(phampshire);
103}
104
105/*
106 * hampshire_connect() is the routine that is called when someone adds a
107 * new serio device that supports hampshire protocol and registers it as
108 * an input device. This is usually accomplished using inputattach.
109 */
110
111static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
112{
113	struct hampshire *phampshire;
114	struct input_dev *input_dev;
115	int err;
116
117	phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL);
118	input_dev = input_allocate_device();
119	if (!phampshire || !input_dev) {
120		err = -ENOMEM;
121		goto fail1;
122	}
123
124	phampshire->serio = serio;
125	phampshire->dev = input_dev;
126	snprintf(phampshire->phys, sizeof(phampshire->phys),
127		 "%s/input0", serio->phys);
128
129	input_dev->name = "Hampshire Serial TouchScreen";
130	input_dev->phys = phampshire->phys;
131	input_dev->id.bustype = BUS_RS232;
132	input_dev->id.vendor = SERIO_HAMPSHIRE;
133	input_dev->id.product = 0;
134	input_dev->id.version = 0x0001;
135	input_dev->dev.parent = &serio->dev;
136	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
137	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
138	input_set_abs_params(phampshire->dev, ABS_X,
139			     HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
140	input_set_abs_params(phampshire->dev, ABS_Y,
141			     HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
142
143	serio_set_drvdata(serio, phampshire);
144
145	err = serio_open(serio, drv);
146	if (err)
147		goto fail2;
148
149	err = input_register_device(phampshire->dev);
150	if (err)
151		goto fail3;
152
153	return 0;
154
155 fail3:	serio_close(serio);
156 fail2:	serio_set_drvdata(serio, NULL);
157 fail1:	input_free_device(input_dev);
158	kfree(phampshire);
159	return err;
160}
161
162/*
163 * The serio driver structure.
164 */
165
166static struct serio_device_id hampshire_serio_ids[] = {
167	{
168		.type	= SERIO_RS232,
169		.proto	= SERIO_HAMPSHIRE,
170		.id	= SERIO_ANY,
171		.extra	= SERIO_ANY,
172	},
173	{ 0 }
174};
175
176MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
177
178static struct serio_driver hampshire_drv = {
179	.driver		= {
180		.name	= "hampshire",
181	},
182	.description	= DRIVER_DESC,
183	.id_table	= hampshire_serio_ids,
184	.interrupt	= hampshire_interrupt,
185	.connect	= hampshire_connect,
186	.disconnect	= hampshire_disconnect,
187};
188
189module_serio_driver(hampshire_drv);
190