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/module.h>
18 #include <linux/i2c.h>
19 #include <linux/interrupt.h>
20 #include <linux/input.h>
21 #include <linux/irq.h>
22 #include <linux/gpio.h>
23 #include <linux/delay.h>
24 #include <linux/slab.h>
25 #include <linux/bitops.h>
26 #include <linux/input/mt.h>
27 #include <linux/of_gpio.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 device_node *np = client->dev.of_node;
123 	int gpio;
124 	int ret;
125 
126 	if (!np)
127 		return -ENODEV;
128 
129 	gpio = of_get_named_gpio(np, "wakeup-gpios", 0);
130 	if (!gpio_is_valid(gpio))
131 		return -ENODEV;
132 
133 	ret = gpio_request(gpio, "egalax_irq");
134 	if (ret < 0) {
135 		dev_err(&client->dev,
136 			"request gpio failed, cannot wake up controller: %d\n",
137 			ret);
138 		return ret;
139 	}
140 
141 	/* wake up controller via an falling edge on IRQ gpio. */
142 	gpio_direction_output(gpio, 0);
143 	gpio_set_value(gpio, 1);
144 
145 	/* controller should be waken up, return irq.  */
146 	gpio_direction_input(gpio);
147 	gpio_free(gpio);
148 
149 	return 0;
150 }
151 
152 static int egalax_firmware_version(struct i2c_client *client)
153 {
154 	static const u8 cmd[MAX_I2C_DATA_LEN] = { 0x03, 0x03, 0xa, 0x01, 0x41 };
155 	int ret;
156 
157 	ret = i2c_master_send(client, cmd, MAX_I2C_DATA_LEN);
158 	if (ret < 0)
159 		return ret;
160 
161 	return 0;
162 }
163 
164 static int egalax_ts_probe(struct i2c_client *client,
165 			   const struct i2c_device_id *id)
166 {
167 	struct egalax_ts *ts;
168 	struct input_dev *input_dev;
169 	int error;
170 
171 	ts = devm_kzalloc(&client->dev, sizeof(struct egalax_ts), GFP_KERNEL);
172 	if (!ts) {
173 		dev_err(&client->dev, "Failed to allocate memory\n");
174 		return -ENOMEM;
175 	}
176 
177 	input_dev = devm_input_allocate_device(&client->dev);
178 	if (!input_dev) {
179 		dev_err(&client->dev, "Failed to allocate memory\n");
180 		return -ENOMEM;
181 	}
182 
183 	ts->client = client;
184 	ts->input_dev = input_dev;
185 
186 	/* controller may be in sleep, wake it up. */
187 	error = egalax_wake_up_device(client);
188 	if (error) {
189 		dev_err(&client->dev, "Failed to wake up the controller\n");
190 		return error;
191 	}
192 
193 	error = egalax_firmware_version(client);
194 	if (error < 0) {
195 		dev_err(&client->dev, "Failed to read firmware version\n");
196 		return error;
197 	}
198 
199 	input_dev->name = "EETI eGalax Touch Screen";
200 	input_dev->id.bustype = BUS_I2C;
201 
202 	__set_bit(EV_ABS, input_dev->evbit);
203 	__set_bit(EV_KEY, input_dev->evbit);
204 	__set_bit(BTN_TOUCH, input_dev->keybit);
205 
206 	input_set_abs_params(input_dev, ABS_X, 0, EGALAX_MAX_X, 0, 0);
207 	input_set_abs_params(input_dev, ABS_Y, 0, EGALAX_MAX_Y, 0, 0);
208 	input_set_abs_params(input_dev,
209 			     ABS_MT_POSITION_X, 0, EGALAX_MAX_X, 0, 0);
210 	input_set_abs_params(input_dev,
211 			     ABS_MT_POSITION_Y, 0, EGALAX_MAX_Y, 0, 0);
212 	input_mt_init_slots(input_dev, MAX_SUPPORT_POINTS, 0);
213 
214 	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
215 					  egalax_ts_interrupt,
216 					  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
217 					  "egalax_ts", ts);
218 	if (error < 0) {
219 		dev_err(&client->dev, "Failed to register interrupt\n");
220 		return error;
221 	}
222 
223 	error = input_register_device(ts->input_dev);
224 	if (error)
225 		return error;
226 
227 	return 0;
228 }
229 
230 static const struct i2c_device_id egalax_ts_id[] = {
231 	{ "egalax_ts", 0 },
232 	{ }
233 };
234 MODULE_DEVICE_TABLE(i2c, egalax_ts_id);
235 
236 static int __maybe_unused egalax_ts_suspend(struct device *dev)
237 {
238 	static const u8 suspend_cmd[MAX_I2C_DATA_LEN] = {
239 		0x3, 0x6, 0xa, 0x3, 0x36, 0x3f, 0x2, 0, 0, 0
240 	};
241 	struct i2c_client *client = to_i2c_client(dev);
242 	int ret;
243 
244 	if (device_may_wakeup(dev))
245 		return enable_irq_wake(client->irq);
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 	if (device_may_wakeup(dev))
256 		return disable_irq_wake(client->irq);
257 
258 	return egalax_wake_up_device(client);
259 }
260 
261 static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);
262 
263 static const struct of_device_id egalax_ts_dt_ids[] = {
264 	{ .compatible = "eeti,egalax_ts" },
265 	{ /* sentinel */ }
266 };
267 MODULE_DEVICE_TABLE(of, egalax_ts_dt_ids);
268 
269 static 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 
279 module_i2c_driver(egalax_ts_driver);
280 
281 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
282 MODULE_DESCRIPTION("Touchscreen driver for EETI eGalax touch controller");
283 MODULE_LICENSE("GPL");
284