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/i2c.h>
22#include <linux/interrupt.h>
23#include <linux/input.h>
24#include <linux/irq.h>
25#include <linux/gpio.h>
26#include <linux/delay.h>
27#include <linux/slab.h>
28#include <linux/bitops.h>
29#include <linux/input/mt.h>
30#include <linux/of_gpio.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	struct device_node *np = client->dev.of_node;
126	int gpio;
127	int ret;
128
129	if (!np)
130		return -ENODEV;
131
132	gpio = of_get_named_gpio(np, "wakeup-gpios", 0);
133	if (!gpio_is_valid(gpio))
134		return -ENODEV;
135
136	ret = gpio_request(gpio, "egalax_irq");
137	if (ret < 0) {
138		dev_err(&client->dev,
139			"request gpio failed, cannot wake up controller: %d\n",
140			ret);
141		return ret;
142	}
143
144	/* wake up controller via an falling edge on IRQ gpio. */
145	gpio_direction_output(gpio, 0);
146	gpio_set_value(gpio, 1);
147
148	/* controller should be waken up, return irq.  */
149	gpio_direction_input(gpio);
150	gpio_free(gpio);
151
152	return 0;
153}
154
155static int egalax_firmware_version(struct i2c_client *client)
156{
157	static const u8 cmd[MAX_I2C_DATA_LEN] = { 0x03, 0x03, 0xa, 0x01, 0x41 };
158	int ret;
159
160	ret = i2c_master_send(client, cmd, MAX_I2C_DATA_LEN);
161	if (ret < 0)
162		return ret;
163
164	return 0;
165}
166
167static int egalax_ts_probe(struct i2c_client *client,
168			   const struct i2c_device_id *id)
169{
170	struct egalax_ts *ts;
171	struct input_dev *input_dev;
172	int error;
173
174	ts = devm_kzalloc(&client->dev, sizeof(struct egalax_ts), GFP_KERNEL);
175	if (!ts) {
176		dev_err(&client->dev, "Failed to allocate memory\n");
177		return -ENOMEM;
178	}
179
180	input_dev = devm_input_allocate_device(&client->dev);
181	if (!input_dev) {
182		dev_err(&client->dev, "Failed to allocate memory\n");
183		return -ENOMEM;
184	}
185
186	ts->client = client;
187	ts->input_dev = input_dev;
188
189	/* controller may be in sleep, wake it up. */
190	error = egalax_wake_up_device(client);
191	if (error) {
192		dev_err(&client->dev, "Failed to wake up the controller\n");
193		return error;
194	}
195
196	error = egalax_firmware_version(client);
197	if (error < 0) {
198		dev_err(&client->dev, "Failed to read firmware version\n");
199		return error;
200	}
201
202	input_dev->name = "EETI eGalax Touch Screen";
203	input_dev->id.bustype = BUS_I2C;
204
205	__set_bit(EV_ABS, input_dev->evbit);
206	__set_bit(EV_KEY, input_dev->evbit);
207	__set_bit(BTN_TOUCH, input_dev->keybit);
208
209	input_set_abs_params(input_dev, ABS_X, 0, EGALAX_MAX_X, 0, 0);
210	input_set_abs_params(input_dev, ABS_Y, 0, EGALAX_MAX_Y, 0, 0);
211	input_set_abs_params(input_dev,
212			     ABS_MT_POSITION_X, 0, EGALAX_MAX_X, 0, 0);
213	input_set_abs_params(input_dev,
214			     ABS_MT_POSITION_Y, 0, EGALAX_MAX_Y, 0, 0);
215	input_mt_init_slots(input_dev, MAX_SUPPORT_POINTS, 0);
216
217	input_set_drvdata(input_dev, ts);
218
219	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
220					  egalax_ts_interrupt,
221					  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
222					  "egalax_ts", ts);
223	if (error < 0) {
224		dev_err(&client->dev, "Failed to register interrupt\n");
225		return error;
226	}
227
228	error = input_register_device(ts->input_dev);
229	if (error)
230		return error;
231
232	i2c_set_clientdata(client, ts);
233	return 0;
234}
235
236static const struct i2c_device_id egalax_ts_id[] = {
237	{ "egalax_ts", 0 },
238	{ }
239};
240MODULE_DEVICE_TABLE(i2c, egalax_ts_id);
241
242static int __maybe_unused egalax_ts_suspend(struct device *dev)
243{
244	static const u8 suspend_cmd[MAX_I2C_DATA_LEN] = {
245		0x3, 0x6, 0xa, 0x3, 0x36, 0x3f, 0x2, 0, 0, 0
246	};
247	struct i2c_client *client = to_i2c_client(dev);
248	int ret;
249
250	ret = i2c_master_send(client, suspend_cmd, MAX_I2C_DATA_LEN);
251	return ret > 0 ? 0 : ret;
252}
253
254static int __maybe_unused egalax_ts_resume(struct device *dev)
255{
256	struct i2c_client *client = to_i2c_client(dev);
257
258	return egalax_wake_up_device(client);
259}
260
261static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);
262
263static const struct of_device_id egalax_ts_dt_ids[] = {
264	{ .compatible = "eeti,egalax_ts" },
265	{ /* sentinel */ }
266};
267MODULE_DEVICE_TABLE(of, egalax_ts_dt_ids);
268
269static struct i2c_driver egalax_ts_driver = {
270	.driver = {
271		.name	= "egalax_ts",
272		.pm	= &egalax_ts_pm_ops,
273		.of_match_table	= egalax_ts_dt_ids,
274	},
275	.id_table	= egalax_ts_id,
276	.probe		= egalax_ts_probe,
277};
278
279module_i2c_driver(egalax_ts_driver);
280
281MODULE_AUTHOR("Freescale Semiconductor, Inc.");
282MODULE_DESCRIPTION("Touchscreen driver for EETI eGalax touch controller");
283MODULE_LICENSE("GPL");
284