1/*
2 * Driver for EETI eGalax Multiple Touch Controller
3 *
4 * Copyright (C) 2011 Freescale Semiconductor, Inc.
5 *
6 * based on max11801_ts.c
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13/* EETI eGalax serial touch screen controller is a I2C based multiple
14 * touch screen controller, it supports 5 point multiple touch. */
15
16/* TODO:
17  - auto idle mode support
18*/
19
20#include <linux/module.h>
21#include <linux/init.h>
22#include <linux/i2c.h>
23#include <linux/interrupt.h>
24#include <linux/input.h>
25#include <linux/irq.h>
26#include <linux/gpio.h>
27#include <linux/delay.h>
28#include <linux/slab.h>
29#include <linux/bitops.h>
30#include <linux/input/mt.h>
31
32/*
33 * Mouse Mode: some panel may configure the controller to mouse mode,
34 * which can only report one point at a given time.
35 * This driver will ignore events in this mode.
36 */
37#define REPORT_MODE_MOUSE		0x1
38/*
39 * Vendor Mode: this mode is used to transfer some vendor specific
40 * messages.
41 * This driver will ignore events in this mode.
42 */
43#define REPORT_MODE_VENDOR		0x3
44/* Multiple Touch Mode */
45#define REPORT_MODE_MTTOUCH		0x4
46
47#define MAX_SUPPORT_POINTS		5
48
49#define EVENT_VALID_OFFSET	7
50#define EVENT_VALID_MASK	(0x1 << EVENT_VALID_OFFSET)
51#define EVENT_ID_OFFSET		2
52#define EVENT_ID_MASK		(0xf << EVENT_ID_OFFSET)
53#define EVENT_IN_RANGE		(0x1 << 1)
54#define EVENT_DOWN_UP		(0X1 << 0)
55
56#define MAX_I2C_DATA_LEN	10
57
58#define EGALAX_MAX_X	32760
59#define EGALAX_MAX_Y	32760
60#define EGALAX_MAX_TRIES 100
61
62struct egalax_ts {
63	struct i2c_client		*client;
64	struct input_dev		*input_dev;
65};
66
67static irqreturn_t egalax_ts_interrupt(int irq, void *dev_id)
68{
69	struct egalax_ts *ts = dev_id;
70	struct input_dev *input_dev = ts->input_dev;
71	struct i2c_client *client = ts->client;
72	u8 buf[MAX_I2C_DATA_LEN];
73	int id, ret, x, y, z;
74	int tries = 0;
75	bool down, valid;
76	u8 state;
77
78	do {
79		ret = i2c_master_recv(client, buf, MAX_I2C_DATA_LEN);
80	} while (ret == -EAGAIN && tries++ < EGALAX_MAX_TRIES);
81
82	if (ret < 0)
83		return IRQ_HANDLED;
84
85	if (buf[0] != REPORT_MODE_MTTOUCH) {
86		/* ignore mouse events and vendor events */
87		return IRQ_HANDLED;
88	}
89
90	state = buf[1];
91	x = (buf[3] << 8) | buf[2];
92	y = (buf[5] << 8) | buf[4];
93	z = (buf[7] << 8) | buf[6];
94
95	valid = state & EVENT_VALID_MASK;
96	id = (state & EVENT_ID_MASK) >> EVENT_ID_OFFSET;
97	down = state & EVENT_DOWN_UP;
98
99	if (!valid || id > MAX_SUPPORT_POINTS) {
100		dev_dbg(&client->dev, "point invalid\n");
101		return IRQ_HANDLED;
102	}
103
104	input_mt_slot(input_dev, id);
105	input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, down);
106
107	dev_dbg(&client->dev, "%s id:%d x:%d y:%d z:%d",
108		down ? "down" : "up", id, x, y, z);
109
110	if (down) {
111		input_report_abs(input_dev, ABS_MT_POSITION_X, x);
112		input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
113		input_report_abs(input_dev, ABS_MT_PRESSURE, z);
114	}
115
116	input_mt_report_pointer_emulation(input_dev, true);
117	input_sync(input_dev);
118
119	return IRQ_HANDLED;
120}
121
122/* wake up controller by an falling edge of interrupt gpio.  */
123static int egalax_wake_up_device(struct i2c_client *client)
124{
125	int gpio = irq_to_gpio(client->irq);
126	int ret;
127
128	ret = gpio_request(gpio, "egalax_irq");
129	if (ret < 0) {
130		dev_err(&client->dev,
131			"request gpio failed, cannot wake up controller: %d\n",
132			ret);
133		return ret;
134	}
135
136	/* wake up controller via an falling edge on IRQ gpio. */
137	gpio_direction_output(gpio, 0);
138	gpio_set_value(gpio, 1);
139
140	/* controller should be waken up, return irq.  */
141	gpio_direction_input(gpio);
142	gpio_free(gpio);
143
144	return 0;
145}
146
147static int __devinit egalax_firmware_version(struct i2c_client *client)
148{
149	static const u8 cmd[MAX_I2C_DATA_LEN] = { 0x03, 0x03, 0xa, 0x01, 0x41 };
150	int ret;
151
152	ret = i2c_master_send(client, cmd, MAX_I2C_DATA_LEN);
153	if (ret < 0)
154		return ret;
155
156	return 0;
157}
158
159static int __devinit egalax_ts_probe(struct i2c_client *client,
160				       const struct i2c_device_id *id)
161{
162	struct egalax_ts *ts;
163	struct input_dev *input_dev;
164	int ret;
165	int error;
166
167	ts = kzalloc(sizeof(struct egalax_ts), GFP_KERNEL);
168	if (!ts) {
169		dev_err(&client->dev, "Failed to allocate memory\n");
170		return -ENOMEM;
171	}
172
173	input_dev = input_allocate_device();
174	if (!input_dev) {
175		dev_err(&client->dev, "Failed to allocate memory\n");
176		error = -ENOMEM;
177		goto err_free_ts;
178	}
179
180	ts->client = client;
181	ts->input_dev = input_dev;
182
183	/* controller may be in sleep, wake it up. */
184	egalax_wake_up_device(client);
185
186	ret = egalax_firmware_version(client);
187	if (ret < 0) {
188		dev_err(&client->dev, "Failed to read firmware version\n");
189		error = -EIO;
190		goto err_free_dev;
191	}
192
193	input_dev->name = "EETI eGalax Touch Screen";
194	input_dev->id.bustype = BUS_I2C;
195	input_dev->dev.parent = &client->dev;
196
197	__set_bit(EV_ABS, input_dev->evbit);
198	__set_bit(EV_KEY, input_dev->evbit);
199	__set_bit(BTN_TOUCH, input_dev->keybit);
200
201	input_set_abs_params(input_dev, ABS_X, 0, EGALAX_MAX_X, 0, 0);
202	input_set_abs_params(input_dev, ABS_Y, 0, EGALAX_MAX_Y, 0, 0);
203	input_set_abs_params(input_dev,
204			     ABS_MT_POSITION_X, 0, EGALAX_MAX_X, 0, 0);
205	input_set_abs_params(input_dev,
206			     ABS_MT_POSITION_X, 0, EGALAX_MAX_Y, 0, 0);
207	input_mt_init_slots(input_dev, MAX_SUPPORT_POINTS);
208
209	input_set_drvdata(input_dev, ts);
210
211	error = request_threaded_irq(client->irq, NULL, egalax_ts_interrupt,
212				     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
213				     "egalax_ts", ts);
214	if (error < 0) {
215		dev_err(&client->dev, "Failed to register interrupt\n");
216		goto err_free_dev;
217	}
218
219	error = input_register_device(ts->input_dev);
220	if (error)
221		goto err_free_irq;
222
223	i2c_set_clientdata(client, ts);
224	return 0;
225
226err_free_irq:
227	free_irq(client->irq, ts);
228err_free_dev:
229	input_free_device(input_dev);
230err_free_ts:
231	kfree(ts);
232
233	return error;
234}
235
236static __devexit int egalax_ts_remove(struct i2c_client *client)
237{
238	struct egalax_ts *ts = i2c_get_clientdata(client);
239
240	free_irq(client->irq, ts);
241
242	input_unregister_device(ts->input_dev);
243	kfree(ts);
244
245	return 0;
246}
247
248static const struct i2c_device_id egalax_ts_id[] = {
249	{ "egalax_ts", 0 },
250	{ }
251};
252MODULE_DEVICE_TABLE(i2c, egalax_ts_id);
253
254#ifdef CONFIG_PM_SLEEP
255static int egalax_ts_suspend(struct device *dev)
256{
257	static const u8 suspend_cmd[MAX_I2C_DATA_LEN] = {
258		0x3, 0x6, 0xa, 0x3, 0x36, 0x3f, 0x2, 0, 0, 0
259	};
260	struct i2c_client *client = to_i2c_client(dev);
261	int ret;
262
263	ret = i2c_master_send(client, suspend_cmd, MAX_I2C_DATA_LEN);
264	return ret > 0 ? 0 : ret;
265}
266
267static int egalax_ts_resume(struct device *dev)
268{
269	struct i2c_client *client = to_i2c_client(dev);
270
271	return egalax_wake_up_device(client);
272}
273#endif
274
275static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);
276
277static struct i2c_driver egalax_ts_driver = {
278	.driver = {
279		.name	= "egalax_ts",
280		.owner	= THIS_MODULE,
281		.pm	= &egalax_ts_pm_ops,
282	},
283	.id_table	= egalax_ts_id,
284	.probe		= egalax_ts_probe,
285	.remove		= __devexit_p(egalax_ts_remove),
286};
287
288static int __init egalax_ts_init(void)
289{
290	return i2c_add_driver(&egalax_ts_driver);
291}
292
293static void __exit egalax_ts_exit(void)
294{
295	i2c_del_driver(&egalax_ts_driver);
296}
297
298module_init(egalax_ts_init);
299module_exit(egalax_ts_exit);
300
301MODULE_AUTHOR("Freescale Semiconductor, Inc.");
302MODULE_DESCRIPTION("Touchscreen driver for EETI eGalax touch controller");
303MODULE_LICENSE("GPL");
304