1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Driver for EETI eGalax Multiple Touch Controller
4  *
5  * Copyright (C) 2011 Freescale Semiconductor, Inc.
6  *
7  * based on max11801_ts.c
8  */
9 
10 /* EETI eGalax serial touch screen controller is a I2C based multiple
11  * touch screen controller, it supports 5 point multiple touch. */
12 
13 /* TODO:
14   - auto idle mode support
15 */
16 
17 #include <linux/err.h>
18 #include <linux/module.h>
19 #include <linux/i2c.h>
20 #include <linux/interrupt.h>
21 #include <linux/input.h>
22 #include <linux/irq.h>
23 #include <linux/gpio/consumer.h>
24 #include <linux/delay.h>
25 #include <linux/slab.h>
26 #include <linux/bitops.h>
27 #include <linux/input/mt.h>
28 
29 /*
30  * Mouse Mode: some panel may configure the controller to mouse mode,
31  * which can only report one point at a given time.
32  * This driver will ignore events in this mode.
33  */
34 #define REPORT_MODE_MOUSE		0x1
35 /*
36  * Vendor Mode: this mode is used to transfer some vendor specific
37  * messages.
38  * This driver will ignore events in this mode.
39  */
40 #define REPORT_MODE_VENDOR		0x3
41 /* Multiple Touch Mode */
42 #define REPORT_MODE_MTTOUCH		0x4
43 
44 #define MAX_SUPPORT_POINTS		5
45 
46 #define EVENT_VALID_OFFSET	7
47 #define EVENT_VALID_MASK	(0x1 << EVENT_VALID_OFFSET)
48 #define EVENT_ID_OFFSET		2
49 #define EVENT_ID_MASK		(0xf << EVENT_ID_OFFSET)
50 #define EVENT_IN_RANGE		(0x1 << 1)
51 #define EVENT_DOWN_UP		(0X1 << 0)
52 
53 #define MAX_I2C_DATA_LEN	10
54 
55 #define EGALAX_MAX_X	32760
56 #define EGALAX_MAX_Y	32760
57 #define EGALAX_MAX_TRIES 100
58 
59 struct egalax_ts {
60 	struct i2c_client		*client;
61 	struct input_dev		*input_dev;
62 };
63 
64 static irqreturn_t egalax_ts_interrupt(int irq, void *dev_id)
65 {
66 	struct egalax_ts *ts = dev_id;
67 	struct input_dev *input_dev = ts->input_dev;
68 	struct i2c_client *client = ts->client;
69 	u8 buf[MAX_I2C_DATA_LEN];
70 	int id, ret, x, y, z;
71 	int tries = 0;
72 	bool down, valid;
73 	u8 state;
74 
75 	do {
76 		ret = i2c_master_recv(client, buf, MAX_I2C_DATA_LEN);
77 	} while (ret == -EAGAIN && tries++ < EGALAX_MAX_TRIES);
78 
79 	if (ret < 0)
80 		return IRQ_HANDLED;
81 
82 	if (buf[0] != REPORT_MODE_MTTOUCH) {
83 		/* ignore mouse events and vendor events */
84 		return IRQ_HANDLED;
85 	}
86 
87 	state = buf[1];
88 	x = (buf[3] << 8) | buf[2];
89 	y = (buf[5] << 8) | buf[4];
90 	z = (buf[7] << 8) | buf[6];
91 
92 	valid = state & EVENT_VALID_MASK;
93 	id = (state & EVENT_ID_MASK) >> EVENT_ID_OFFSET;
94 	down = state & EVENT_DOWN_UP;
95 
96 	if (!valid || id > MAX_SUPPORT_POINTS) {
97 		dev_dbg(&client->dev, "point invalid\n");
98 		return IRQ_HANDLED;
99 	}
100 
101 	input_mt_slot(input_dev, id);
102 	input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, down);
103 
104 	dev_dbg(&client->dev, "%s id:%d x:%d y:%d z:%d",
105 		down ? "down" : "up", id, x, y, z);
106 
107 	if (down) {
108 		input_report_abs(input_dev, ABS_MT_POSITION_X, x);
109 		input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
110 		input_report_abs(input_dev, ABS_MT_PRESSURE, z);
111 	}
112 
113 	input_mt_report_pointer_emulation(input_dev, true);
114 	input_sync(input_dev);
115 
116 	return IRQ_HANDLED;
117 }
118 
119 /* wake up controller by an falling edge of interrupt gpio.  */
120 static int egalax_wake_up_device(struct i2c_client *client)
121 {
122 	struct gpio_desc *gpio;
123 	int ret;
124 
125 	/* wake up controller via an falling edge on IRQ gpio. */
126 	gpio = gpiod_get(&client->dev, "wakeup", GPIOD_OUT_HIGH);
127 	ret = PTR_ERR_OR_ZERO(gpio);
128 	if (ret) {
129 		if (ret != -EPROBE_DEFER)
130 			dev_err(&client->dev,
131 				"failed to request wakeup gpio, cannot wake up controller: %d\n",
132 				ret);
133 		return ret;
134 	}
135 
136 	/* release the line */
137 	gpiod_set_value_cansleep(gpio, 0);
138 
139 	/* controller should be woken up, return irq.  */
140 	gpiod_direction_input(gpio);
141 	gpiod_put(gpio);
142 
143 	return 0;
144 }
145 
146 static int egalax_firmware_version(struct i2c_client *client)
147 {
148 	static const u8 cmd[MAX_I2C_DATA_LEN] = { 0x03, 0x03, 0xa, 0x01, 0x41 };
149 	int ret;
150 
151 	ret = i2c_master_send(client, cmd, MAX_I2C_DATA_LEN);
152 	if (ret < 0)
153 		return ret;
154 
155 	return 0;
156 }
157 
158 static int egalax_ts_probe(struct i2c_client *client)
159 {
160 	struct egalax_ts *ts;
161 	struct input_dev *input_dev;
162 	int error;
163 
164 	ts = devm_kzalloc(&client->dev, sizeof(struct egalax_ts), GFP_KERNEL);
165 	if (!ts) {
166 		dev_err(&client->dev, "Failed to allocate memory\n");
167 		return -ENOMEM;
168 	}
169 
170 	input_dev = devm_input_allocate_device(&client->dev);
171 	if (!input_dev) {
172 		dev_err(&client->dev, "Failed to allocate memory\n");
173 		return -ENOMEM;
174 	}
175 
176 	ts->client = client;
177 	ts->input_dev = input_dev;
178 
179 	/* controller may be in sleep, wake it up. */
180 	error = egalax_wake_up_device(client);
181 	if (error)
182 		return error;
183 
184 	error = egalax_firmware_version(client);
185 	if (error < 0) {
186 		dev_err(&client->dev, "Failed to read firmware version\n");
187 		return error;
188 	}
189 
190 	input_dev->name = "EETI eGalax Touch Screen";
191 	input_dev->id.bustype = BUS_I2C;
192 
193 	__set_bit(EV_ABS, input_dev->evbit);
194 	__set_bit(EV_KEY, input_dev->evbit);
195 	__set_bit(BTN_TOUCH, input_dev->keybit);
196 
197 	input_set_abs_params(input_dev, ABS_X, 0, EGALAX_MAX_X, 0, 0);
198 	input_set_abs_params(input_dev, ABS_Y, 0, EGALAX_MAX_Y, 0, 0);
199 	input_set_abs_params(input_dev,
200 			     ABS_MT_POSITION_X, 0, EGALAX_MAX_X, 0, 0);
201 	input_set_abs_params(input_dev,
202 			     ABS_MT_POSITION_Y, 0, EGALAX_MAX_Y, 0, 0);
203 	input_mt_init_slots(input_dev, MAX_SUPPORT_POINTS, 0);
204 
205 	error = devm_request_threaded_irq(&client->dev, client->irq,
206 					  NULL, egalax_ts_interrupt,
207 					  IRQF_ONESHOT, "egalax_ts", ts);
208 	if (error < 0) {
209 		dev_err(&client->dev, "Failed to register interrupt\n");
210 		return error;
211 	}
212 
213 	error = input_register_device(ts->input_dev);
214 	if (error)
215 		return error;
216 
217 	return 0;
218 }
219 
220 static const struct i2c_device_id egalax_ts_id[] = {
221 	{ "egalax_ts", 0 },
222 	{ }
223 };
224 MODULE_DEVICE_TABLE(i2c, egalax_ts_id);
225 
226 static int egalax_ts_suspend(struct device *dev)
227 {
228 	static const u8 suspend_cmd[MAX_I2C_DATA_LEN] = {
229 		0x3, 0x6, 0xa, 0x3, 0x36, 0x3f, 0x2, 0, 0, 0
230 	};
231 	struct i2c_client *client = to_i2c_client(dev);
232 	int ret;
233 
234 	if (device_may_wakeup(dev))
235 		return enable_irq_wake(client->irq);
236 
237 	ret = i2c_master_send(client, suspend_cmd, MAX_I2C_DATA_LEN);
238 	return ret > 0 ? 0 : ret;
239 }
240 
241 static int egalax_ts_resume(struct device *dev)
242 {
243 	struct i2c_client *client = to_i2c_client(dev);
244 
245 	if (device_may_wakeup(dev))
246 		return disable_irq_wake(client->irq);
247 
248 	return egalax_wake_up_device(client);
249 }
250 
251 static DEFINE_SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops,
252 				egalax_ts_suspend, egalax_ts_resume);
253 
254 static const struct of_device_id egalax_ts_dt_ids[] = {
255 	{ .compatible = "eeti,egalax_ts" },
256 	{ /* sentinel */ }
257 };
258 MODULE_DEVICE_TABLE(of, egalax_ts_dt_ids);
259 
260 static struct i2c_driver egalax_ts_driver = {
261 	.driver = {
262 		.name	= "egalax_ts",
263 		.pm	= pm_sleep_ptr(&egalax_ts_pm_ops),
264 		.of_match_table	= egalax_ts_dt_ids,
265 	},
266 	.id_table	= egalax_ts_id,
267 	.probe_new	= egalax_ts_probe,
268 };
269 
270 module_i2c_driver(egalax_ts_driver);
271 
272 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
273 MODULE_DESCRIPTION("Touchscreen driver for EETI eGalax touch controller");
274 MODULE_LICENSE("GPL");
275