1/*
2 * Sahara TouchIT-213 serial touchscreen driver
3 *
4 * Copyright (c) 2007-2008 Claudio Nieder <private@claudio.ch>
5 *
6 * Based on Touchright driver (drivers/input/touchscreen/touchright.c)
7 * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com>
8 * Copyright (c) 2004 Vojtech Pavlik
9 * and Dan Streetman <ddstreet@ieee.org>
10 */
11
12/*
13 * This program is free software; you can redistribute it and/or modify it
14 * under the terms of the GNU General Public License version 2 as published
15 * by the Free Software Foundation.
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	"Sahara TouchIT-213 serial touchscreen driver"
26
27MODULE_AUTHOR("Claudio Nieder <private@claudio.ch>");
28MODULE_DESCRIPTION(DRIVER_DESC);
29MODULE_LICENSE("GPL");
30
31/*
32 * Definitions & global arrays.
33 */
34
35/*
36 * Data is received through COM1 at 9600bit/s,8bit,no parity in packets
37 * of 5 byte each.
38 *
39 *   +--------+   +--------+   +--------+   +--------+   +--------+
40 *   |1000000p|   |0xxxxxxx|   |0xxxxxxx|   |0yyyyyyy|   |0yyyyyyy|
41 *   +--------+   +--------+   +--------+   +--------+   +--------+
42 *                    MSB          LSB          MSB          LSB
43 *
44 * The value of p is 1 as long as the screen is touched and 0 when
45 * reporting the location where touching stopped, e.g. where the pen was
46 * lifted from the screen.
47 *
48 * When holding the screen in landscape mode as the BIOS text output is
49 * presented, x is the horizontal axis with values growing from left to
50 * right and y is the vertical axis with values growing from top to
51 * bottom.
52 *
53 * When holding the screen in portrait mode with the Sahara logo in its
54 * correct position, x ist the vertical axis with values growing from
55 * top to bottom and y is the horizontal axis with values growing from
56 * right to left.
57 */
58
59#define T213_FORMAT_TOUCH_BIT	0x01
60#define T213_FORMAT_STATUS_BYTE	0x80
61#define T213_FORMAT_STATUS_MASK	~T213_FORMAT_TOUCH_BIT
62
63/*
64 * On my Sahara Touch-IT 213 I have observed x values from 0 to 0x7f0
65 * and y values from 0x1d to 0x7e9, so the actual measurement is
66 * probably done with an 11 bit precision.
67 */
68#define T213_MIN_XC 0
69#define T213_MAX_XC 0x07ff
70#define T213_MIN_YC 0
71#define T213_MAX_YC 0x07ff
72
73/*
74 * Per-touchscreen data.
75 */
76
77struct touchit213 {
78	struct input_dev *dev;
79	struct serio *serio;
80	int idx;
81	unsigned char csum;
82	unsigned char data[5];
83	char phys[32];
84};
85
86static irqreturn_t touchit213_interrupt(struct serio *serio,
87		unsigned char data, unsigned int flags)
88{
89	struct touchit213 *touchit213 = serio_get_drvdata(serio);
90	struct input_dev *dev = touchit213->dev;
91
92	touchit213->data[touchit213->idx] = data;
93
94	switch (touchit213->idx++) {
95	case 0:
96		if ((touchit213->data[0] & T213_FORMAT_STATUS_MASK) !=
97				T213_FORMAT_STATUS_BYTE) {
98			pr_debug("unsynchronized data: 0x%02x\n", data);
99			touchit213->idx = 0;
100		}
101		break;
102
103	case 4:
104		touchit213->idx = 0;
105		input_report_abs(dev, ABS_X,
106			(touchit213->data[1] << 7) | touchit213->data[2]);
107		input_report_abs(dev, ABS_Y,
108			(touchit213->data[3] << 7) | touchit213->data[4]);
109		input_report_key(dev, BTN_TOUCH,
110			touchit213->data[0] & T213_FORMAT_TOUCH_BIT);
111		input_sync(dev);
112		break;
113	}
114
115	return IRQ_HANDLED;
116}
117
118/*
119 * touchit213_disconnect() is the opposite of touchit213_connect()
120 */
121
122static void touchit213_disconnect(struct serio *serio)
123{
124	struct touchit213 *touchit213 = serio_get_drvdata(serio);
125
126	input_get_device(touchit213->dev);
127	input_unregister_device(touchit213->dev);
128	serio_close(serio);
129	serio_set_drvdata(serio, NULL);
130	input_put_device(touchit213->dev);
131	kfree(touchit213);
132}
133
134/*
135 * touchit213_connect() is the routine that is called when someone adds a
136 * new serio device that supports the Touchright protocol and registers it as
137 * an input device.
138 */
139
140static int touchit213_connect(struct serio *serio, struct serio_driver *drv)
141{
142	struct touchit213 *touchit213;
143	struct input_dev *input_dev;
144	int err;
145
146	touchit213 = kzalloc(sizeof(struct touchit213), GFP_KERNEL);
147	input_dev = input_allocate_device();
148	if (!touchit213 || !input_dev) {
149		err = -ENOMEM;
150		goto fail1;
151	}
152
153	touchit213->serio = serio;
154	touchit213->dev = input_dev;
155	snprintf(touchit213->phys, sizeof(touchit213->phys),
156		 "%s/input0", serio->phys);
157
158	input_dev->name = "Sahara Touch-iT213 Serial TouchScreen";
159	input_dev->phys = touchit213->phys;
160	input_dev->id.bustype = BUS_RS232;
161	input_dev->id.vendor = SERIO_TOUCHIT213;
162	input_dev->id.product = 0;
163	input_dev->id.version = 0x0100;
164	input_dev->dev.parent = &serio->dev;
165	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
166	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
167	input_set_abs_params(touchit213->dev, ABS_X,
168			     T213_MIN_XC, T213_MAX_XC, 0, 0);
169	input_set_abs_params(touchit213->dev, ABS_Y,
170			     T213_MIN_YC, T213_MAX_YC, 0, 0);
171
172	serio_set_drvdata(serio, touchit213);
173
174	err = serio_open(serio, drv);
175	if (err)
176		goto fail2;
177
178	err = input_register_device(touchit213->dev);
179	if (err)
180		goto fail3;
181
182	return 0;
183
184 fail3:	serio_close(serio);
185 fail2:	serio_set_drvdata(serio, NULL);
186 fail1:	input_free_device(input_dev);
187	kfree(touchit213);
188	return err;
189}
190
191/*
192 * The serio driver structure.
193 */
194
195static struct serio_device_id touchit213_serio_ids[] = {
196	{
197		.type	= SERIO_RS232,
198		.proto	= SERIO_TOUCHIT213,
199		.id	= SERIO_ANY,
200		.extra	= SERIO_ANY,
201	},
202	{ 0 }
203};
204
205MODULE_DEVICE_TABLE(serio, touchit213_serio_ids);
206
207static struct serio_driver touchit213_drv = {
208	.driver		= {
209		.name	= "touchit213",
210	},
211	.description	= DRIVER_DESC,
212	.id_table	= touchit213_serio_ids,
213	.interrupt	= touchit213_interrupt,
214	.connect	= touchit213_connect,
215	.disconnect	= touchit213_disconnect,
216};
217
218module_serio_driver(touchit213_drv);
219