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 
62 struct egalax_ts {
63 	struct i2c_client		*client;
64 	struct input_dev		*input_dev;
65 };
66 
67 static 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.  */
123 static 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 
155 static 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 
167 static 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 	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
218 					  egalax_ts_interrupt,
219 					  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
220 					  "egalax_ts", ts);
221 	if (error < 0) {
222 		dev_err(&client->dev, "Failed to register interrupt\n");
223 		return error;
224 	}
225 
226 	error = input_register_device(ts->input_dev);
227 	if (error)
228 		return error;
229 
230 	return 0;
231 }
232 
233 static const struct i2c_device_id egalax_ts_id[] = {
234 	{ "egalax_ts", 0 },
235 	{ }
236 };
237 MODULE_DEVICE_TABLE(i2c, egalax_ts_id);
238 
239 static int __maybe_unused egalax_ts_suspend(struct device *dev)
240 {
241 	static const u8 suspend_cmd[MAX_I2C_DATA_LEN] = {
242 		0x3, 0x6, 0xa, 0x3, 0x36, 0x3f, 0x2, 0, 0, 0
243 	};
244 	struct i2c_client *client = to_i2c_client(dev);
245 	int ret;
246 
247 	ret = i2c_master_send(client, suspend_cmd, MAX_I2C_DATA_LEN);
248 	return ret > 0 ? 0 : ret;
249 }
250 
251 static int __maybe_unused egalax_ts_resume(struct device *dev)
252 {
253 	struct i2c_client *client = to_i2c_client(dev);
254 
255 	return egalax_wake_up_device(client);
256 }
257 
258 static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);
259 
260 static const struct of_device_id egalax_ts_dt_ids[] = {
261 	{ .compatible = "eeti,egalax_ts" },
262 	{ /* sentinel */ }
263 };
264 MODULE_DEVICE_TABLE(of, egalax_ts_dt_ids);
265 
266 static struct i2c_driver egalax_ts_driver = {
267 	.driver = {
268 		.name	= "egalax_ts",
269 		.pm	= &egalax_ts_pm_ops,
270 		.of_match_table	= egalax_ts_dt_ids,
271 	},
272 	.id_table	= egalax_ts_id,
273 	.probe		= egalax_ts_probe,
274 };
275 
276 module_i2c_driver(egalax_ts_driver);
277 
278 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
279 MODULE_DESCRIPTION("Touchscreen driver for EETI eGalax touch controller");
280 MODULE_LICENSE("GPL");
281