1/*
2 * TSC-40 serial touchscreen driver. It should be compatible with
3 * TSC-10 and 25.
4 *
5 * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
6 * License: GPLv2 as published by the FSF.
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/input.h>
13#include <linux/serio.h>
14#include <linux/init.h>
15
16#define PACKET_LENGTH  5
17struct tsc_ser {
18	struct input_dev *dev;
19	struct serio *serio;
20	u32 idx;
21	unsigned char data[PACKET_LENGTH];
22	char phys[32];
23};
24
25static void tsc_process_data(struct tsc_ser *ptsc)
26{
27	struct input_dev *dev = ptsc->dev;
28	u8 *data = ptsc->data;
29	u32 x;
30	u32 y;
31
32	x = ((data[1] & 0x03) << 8) | data[2];
33	y = ((data[3] & 0x03) << 8) | data[4];
34
35	input_report_abs(dev, ABS_X, x);
36	input_report_abs(dev, ABS_Y, y);
37	input_report_key(dev, BTN_TOUCH, 1);
38
39	input_sync(dev);
40}
41
42static irqreturn_t tsc_interrupt(struct serio *serio,
43		unsigned char data, unsigned int flags)
44{
45	struct tsc_ser *ptsc = serio_get_drvdata(serio);
46	struct input_dev *dev = ptsc->dev;
47
48	ptsc->data[ptsc->idx] = data;
49	switch (ptsc->idx++) {
50	case 0:
51		if (unlikely((data & 0x3e) != 0x10)) {
52			dev_dbg(&serio->dev,
53				"unsynchronized packet start (0x%02x)\n", data);
54			ptsc->idx = 0;
55		} else if (!(data & 0x01)) {
56			input_report_key(dev, BTN_TOUCH, 0);
57			input_sync(dev);
58			ptsc->idx = 0;
59		}
60		break;
61
62	case 1:
63	case 3:
64		if (unlikely(data & 0xfc)) {
65			dev_dbg(&serio->dev,
66				"unsynchronized data 0x%02x at offset %d\n",
67				data, ptsc->idx - 1);
68			ptsc->idx = 0;
69		}
70		break;
71
72	case 4:
73		tsc_process_data(ptsc);
74		ptsc->idx = 0;
75		break;
76	}
77
78	return IRQ_HANDLED;
79}
80
81static int tsc_connect(struct serio *serio, struct serio_driver *drv)
82{
83	struct tsc_ser *ptsc;
84	struct input_dev *input_dev;
85	int error;
86
87	ptsc = kzalloc(sizeof(struct tsc_ser), GFP_KERNEL);
88	input_dev = input_allocate_device();
89	if (!ptsc || !input_dev) {
90		error = -ENOMEM;
91		goto fail1;
92	}
93
94	ptsc->serio = serio;
95	ptsc->dev = input_dev;
96	snprintf(ptsc->phys, sizeof(ptsc->phys), "%s/input0", serio->phys);
97
98	input_dev->name = "TSC-10/25/40 Serial TouchScreen";
99	input_dev->phys = ptsc->phys;
100	input_dev->id.bustype = BUS_RS232;
101	input_dev->id.vendor = SERIO_TSC40;
102	input_dev->id.product = 40;
103	input_dev->id.version = 0x0001;
104	input_dev->dev.parent = &serio->dev;
105
106	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
107	__set_bit(BTN_TOUCH, input_dev->keybit);
108	input_set_abs_params(ptsc->dev, ABS_X, 0, 0x3ff, 0, 0);
109	input_set_abs_params(ptsc->dev, ABS_Y, 0, 0x3ff, 0, 0);
110	input_set_abs_params(ptsc->dev, ABS_PRESSURE, 0, 0, 0, 0);
111
112	serio_set_drvdata(serio, ptsc);
113
114	error = serio_open(serio, drv);
115	if (error)
116		goto fail2;
117
118	error = input_register_device(ptsc->dev);
119	if (error)
120		goto fail3;
121
122	return 0;
123
124fail3:
125	serio_close(serio);
126fail2:
127	serio_set_drvdata(serio, NULL);
128fail1:
129	input_free_device(input_dev);
130	kfree(ptsc);
131	return error;
132}
133
134static void tsc_disconnect(struct serio *serio)
135{
136	struct tsc_ser *ptsc = serio_get_drvdata(serio);
137
138	serio_close(serio);
139
140	input_unregister_device(ptsc->dev);
141	kfree(ptsc);
142
143	serio_set_drvdata(serio, NULL);
144}
145
146static struct serio_device_id tsc_serio_ids[] = {
147	{
148		.type   = SERIO_RS232,
149		.proto  = SERIO_TSC40,
150		.id     = SERIO_ANY,
151		.extra  = SERIO_ANY,
152	},
153	{ 0 }
154};
155MODULE_DEVICE_TABLE(serio, tsc_serio_ids);
156
157#define DRIVER_DESC    "TSC-10/25/40 serial touchscreen driver"
158
159static struct serio_driver tsc_drv = {
160	.driver	= {
161		.name   = "tsc40",
162	},
163	.description    = DRIVER_DESC,
164	.id_table	= tsc_serio_ids,
165	.interrupt      = tsc_interrupt,
166	.connect	= tsc_connect,
167	.disconnect     = tsc_disconnect,
168};
169
170static int __init tsc_ser_init(void)
171{
172	return serio_register_driver(&tsc_drv);
173}
174module_init(tsc_ser_init);
175
176static void __exit tsc_exit(void)
177{
178	serio_unregister_driver(&tsc_drv);
179}
180module_exit(tsc_exit);
181
182MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>");
183MODULE_DESCRIPTION(DRIVER_DESC);
184MODULE_LICENSE("GPL v2");
185