egalax_ts.c

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