drivers/input/touchscreen/goodix.c - kernel/msm-4.9 - Gitiles

 /*
  *  Driver for Goodix Touchscreens
  *
  *  Copyright (c) 2014 Red Hat Inc.
  *
  *  This code is based on gt9xx.c authored by andrew@goodix.com:
  *
  *  2010 - 2012 Goodix Technology.
  */

 /*
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
  * Software Foundation; version 2 of the License.
  */

 #include <linux/kernel.h>
 #include <linux/dmi.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
 #include <linux/input/mt.h>
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
 #include <linux/of.h>
 #include <asm/unaligned.h>

 struct goodix_ts_data {
 	struct i2c_client *client;
 	struct input_dev *input_dev;
 	int abs_x_max;
 	int abs_y_max;
 	unsigned int max_touch_num;
 	unsigned int int_trigger_type;
 	bool rotated_screen;
 };

 #define GOODIX_MAX_HEIGHT		4096
 #define GOODIX_MAX_WIDTH		4096
 #define GOODIX_INT_TRIGGER		1
 #define GOODIX_CONTACT_SIZE		8
 #define GOODIX_MAX_CONTACTS		10

 #define GOODIX_CONFIG_MAX_LENGTH	240

 /* Register defines */
 #define GOODIX_READ_COOR_ADDR		0x814E
 #define GOODIX_REG_CONFIG_DATA		0x8047
 #define GOODIX_REG_ID			0x8140

 #define RESOLUTION_LOC		1
 #define MAX_CONTACTS_LOC	5
 #define TRIGGER_LOC		6

 static const unsigned long goodix_irq_flags[] = {
 	IRQ_TYPE_EDGE_RISING,
 	IRQ_TYPE_EDGE_FALLING,
 	IRQ_TYPE_LEVEL_LOW,
 	IRQ_TYPE_LEVEL_HIGH,
 };

 /*
  * Those tablets have their coordinates origin at the bottom right
  * of the tablet, as if rotated 180 degrees
  */
 static const struct dmi_system_id rotated_screen[] = {
 #if defined(CONFIG_DMI) && defined(CONFIG_X86)
 	{
 		.ident = "WinBook TW100",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "TW100")
 		}
 	},
 	{
 		.ident = "WinBook TW700",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "TW700")
 		},
 	},
 #endif
 	{}
 };

 /**
  * goodix_i2c_read - read data from a register of the i2c slave device.
  *
  * @client: i2c device.
  * @reg: the register to read from.
  * @buf: raw write data buffer.
  * @len: length of the buffer to write
  */
 static int goodix_i2c_read(struct i2c_client *client,
 			   u16 reg, u8 *buf, int len)
 {
 	struct i2c_msg msgs[2];
 	u16 wbuf = cpu_to_be16(reg);
 	int ret;

 	msgs[0].flags = 0;
 	msgs[0].addr  = client->addr;
 	msgs[0].len   = 2;
 	msgs[0].buf   = (u8 *)&wbuf;

 	msgs[1].flags = I2C_M_RD;
 	msgs[1].addr  = client->addr;
 	msgs[1].len   = len;
 	msgs[1].buf   = buf;

 	ret = i2c_transfer(client->adapter, msgs, 2);
 	return ret < 0 ? ret : (ret != ARRAY_SIZE(msgs) ? -EIO : 0);
 }

 static int goodix_ts_read_input_report(struct goodix_ts_data *ts, u8 *data)
 {
 	int touch_num;
 	int error;

 	error = goodix_i2c_read(ts->client, GOODIX_READ_COOR_ADDR, data,
 				GOODIX_CONTACT_SIZE + 1);
 	if (error) {
 		dev_err(&ts->client->dev, "I2C transfer error: %d\n", error);
 		return error;
 	}

 	if (!(data[0] & 0x80))
 		return -EAGAIN;

 	touch_num = data[0] & 0x0f;
 	if (touch_num > ts->max_touch_num)
 		return -EPROTO;

 	if (touch_num > 1) {
 		data += 1 + GOODIX_CONTACT_SIZE;
 		error = goodix_i2c_read(ts->client,
 					GOODIX_READ_COOR_ADDR +
 						1 + GOODIX_CONTACT_SIZE,
 					data,
 					GOODIX_CONTACT_SIZE * (touch_num - 1));
 		if (error)
 			return error;
 	}

 	return touch_num;
 }

 static void goodix_ts_report_touch(struct goodix_ts_data *ts, u8 *coor_data)
 {
 	int id = coor_data[0] & 0x0F;
 	int input_x = get_unaligned_le16(&coor_data[1]);
 	int input_y = get_unaligned_le16(&coor_data[3]);
 	int input_w = get_unaligned_le16(&coor_data[5]);

 	if (ts->rotated_screen) {
 		input_x = ts->abs_x_max - input_x;
 		input_y = ts->abs_y_max - input_y;
 	}

 	input_mt_slot(ts->input_dev, id);
 	input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
 	input_report_abs(ts->input_dev, ABS_MT_POSITION_X, input_x);
 	input_report_abs(ts->input_dev, ABS_MT_POSITION_Y, input_y);
 	input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR, input_w);
 	input_report_abs(ts->input_dev, ABS_MT_WIDTH_MAJOR, input_w);
 }

 /**
  * goodix_process_events - Process incoming events
  *
  * @ts: our goodix_ts_data pointer
  *
  * Called when the IRQ is triggered. Read the current device state, and push
  * the input events to the user space.
  */
 static void goodix_process_events(struct goodix_ts_data *ts)
 {
 	u8  point_data[1 + GOODIX_CONTACT_SIZE * GOODIX_MAX_CONTACTS];
 	int touch_num;
 	int i;

 	touch_num = goodix_ts_read_input_report(ts, point_data);
 	if (touch_num < 0)
 		return;

 	for (i = 0; i < touch_num; i++)
 		goodix_ts_report_touch(ts,
 				&point_data[1 + GOODIX_CONTACT_SIZE * i]);

 	input_mt_sync_frame(ts->input_dev);
 	input_sync(ts->input_dev);
 }

 /**
  * goodix_ts_irq_handler - The IRQ handler
  *
  * @irq: interrupt number.
  * @dev_id: private data pointer.
  */
 static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
 {
 	static const u8 end_cmd[] = {
 		GOODIX_READ_COOR_ADDR >> 8,
 		GOODIX_READ_COOR_ADDR & 0xff,
 		0
 	};
 	struct goodix_ts_data *ts = dev_id;

 	goodix_process_events(ts);

 	if (i2c_master_send(ts->client, end_cmd, sizeof(end_cmd)) < 0)
 		dev_err(&ts->client->dev, "I2C write end_cmd error\n");

 	return IRQ_HANDLED;
 }

 /**
  * goodix_read_config - Read the embedded configuration of the panel
  *
  * @ts: our goodix_ts_data pointer
  *
  * Must be called during probe
  */
 static void goodix_read_config(struct goodix_ts_data *ts)
 {
 	u8 config[GOODIX_CONFIG_MAX_LENGTH];
 	int error;

 	error = goodix_i2c_read(ts->client, GOODIX_REG_CONFIG_DATA,
 				config,
 				GOODIX_CONFIG_MAX_LENGTH);
 	if (error) {
 		dev_warn(&ts->client->dev,
 			 "Error reading config (%d), using defaults\n",
 			 error);
 		ts->abs_x_max = GOODIX_MAX_WIDTH;
 		ts->abs_y_max = GOODIX_MAX_HEIGHT;
 		ts->int_trigger_type = GOODIX_INT_TRIGGER;
 		ts->max_touch_num = GOODIX_MAX_CONTACTS;
 		return;
 	}

 	ts->abs_x_max = get_unaligned_le16(&config[RESOLUTION_LOC]);
 	ts->abs_y_max = get_unaligned_le16(&config[RESOLUTION_LOC + 2]);
 	ts->int_trigger_type = config[TRIGGER_LOC] & 0x03;
 	ts->max_touch_num = config[MAX_CONTACTS_LOC] & 0x0f;
 	if (!ts->abs_x_max || !ts->abs_y_max || !ts->max_touch_num) {
 		dev_err(&ts->client->dev,
 			"Invalid config, using defaults\n");
 		ts->abs_x_max = GOODIX_MAX_WIDTH;
 		ts->abs_y_max = GOODIX_MAX_HEIGHT;
 		ts->max_touch_num = GOODIX_MAX_CONTACTS;
 	}

 	ts->rotated_screen = dmi_check_system(rotated_screen);
 	if (ts->rotated_screen)
 		dev_dbg(&ts->client->dev,
 			 "Applying '180 degrees rotated screen' quirk\n");
 }

 /**
  * goodix_read_version - Read goodix touchscreen version
  *
  * @client: the i2c client
  * @version: output buffer containing the version on success
  * @id: output buffer containing the id on success
  */
 static int goodix_read_version(struct i2c_client *client, u16 *version, u16 *id)
 {
 	int error;
 	u8 buf[6];
 	char id_str[5];

 	error = goodix_i2c_read(client, GOODIX_REG_ID, buf, sizeof(buf));
 	if (error) {
 		dev_err(&client->dev, "read version failed: %d\n", error);
 		return error;
 	}

 	memcpy(id_str, buf, 4);
 	id_str[4] = 0;
 	if (kstrtou16(id_str, 10, id))
 		*id = 0x1001;

 	*version = get_unaligned_le16(&buf[4]);

 	dev_info(&client->dev, "ID %d, version: %04x\n", *id, *version);

 	return 0;
 }

 /**
  * goodix_i2c_test - I2C test function to check if the device answers.
  *
  * @client: the i2c client
  */
 static int goodix_i2c_test(struct i2c_client *client)
 {
 	int retry = 0;
 	int error;
 	u8 test;

 	while (retry++ < 2) {
 		error = goodix_i2c_read(client, GOODIX_REG_CONFIG_DATA,
 					&test, 1);
 		if (!error)
 			return 0;

 		dev_err(&client->dev, "i2c test failed attempt %d: %d\n",
 			retry, error);
 		msleep(20);
 	}

 	return error;
 }

 /**
  * goodix_request_input_dev - Allocate, populate and register the input device
  *
  * @ts: our goodix_ts_data pointer
  * @version: device firmware version
  * @id: device ID
  *
  * Must be called during probe
  */
 static int goodix_request_input_dev(struct goodix_ts_data *ts, u16 version,
 				    u16 id)
 {
 	int error;

 	ts->input_dev = devm_input_allocate_device(&ts->client->dev);
 	if (!ts->input_dev) {
 		dev_err(&ts->client->dev, "Failed to allocate input device.");
 		return -ENOMEM;
 	}

 	input_set_abs_params(ts->input_dev, ABS_MT_POSITION_X,
 			     0, ts->abs_x_max, 0, 0);
 	input_set_abs_params(ts->input_dev, ABS_MT_POSITION_Y,
 			     0, ts->abs_y_max, 0, 0);
 	input_set_abs_params(ts->input_dev, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
 	input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);

 	input_mt_init_slots(ts->input_dev, ts->max_touch_num,
 			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);

 	ts->input_dev->name = "Goodix Capacitive TouchScreen";
 	ts->input_dev->phys = "input/ts";
 	ts->input_dev->id.bustype = BUS_I2C;
 	ts->input_dev->id.vendor = 0x0416;
 	ts->input_dev->id.product = id;
 	ts->input_dev->id.version = version;

 	error = input_register_device(ts->input_dev);
 	if (error) {
 		dev_err(&ts->client->dev,
 			"Failed to register input device: %d", error);
 		return error;
 	}

 	return 0;
 }

 static int goodix_ts_probe(struct i2c_client *client,
 			   const struct i2c_device_id *id)
 {
 	struct goodix_ts_data *ts;
 	unsigned long irq_flags;
 	int error;
 	u16 version_info, id_info;

 	dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 		dev_err(&client->dev, "I2C check functionality failed.\n");
 		return -ENXIO;
 	}

 	ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
 	if (!ts)
 		return -ENOMEM;

 	ts->client = client;
 	i2c_set_clientdata(client, ts);

 	error = goodix_i2c_test(client);
 	if (error) {
 		dev_err(&client->dev, "I2C communication failure: %d\n", error);
 		return error;
 	}

 	error = goodix_read_version(client, &version_info, &id_info);
 	if (error) {
 		dev_err(&client->dev, "Read version failed.\n");
 		return error;
 	}

 	goodix_read_config(ts);

 	error = goodix_request_input_dev(ts, version_info, id_info);
 	if (error)
 		return error;

 	irq_flags = goodix_irq_flags[ts->int_trigger_type] | IRQF_ONESHOT;
 	error = devm_request_threaded_irq(&ts->client->dev, client->irq,
 					  NULL, goodix_ts_irq_handler,
 					  irq_flags, client->name, ts);
 	if (error) {
 		dev_err(&client->dev, "request IRQ failed: %d\n", error);
 		return error;
 	}

 	return 0;
 }

 static const struct i2c_device_id goodix_ts_id[] = {
 	{ "GDIX1001:00", 0 },
 	{ }
 };

 #ifdef CONFIG_ACPI
 static const struct acpi_device_id goodix_acpi_match[] = {
 	{ "GDIX1001", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, goodix_acpi_match);
 #endif

 #ifdef CONFIG_OF
 static const struct of_device_id goodix_of_match[] = {
 	{ .compatible = "goodix,gt911" },
 	{ .compatible = "goodix,gt9110" },
 	{ .compatible = "goodix,gt912" },
 	{ .compatible = "goodix,gt927" },
 	{ .compatible = "goodix,gt9271" },
 	{ .compatible = "goodix,gt928" },
 	{ .compatible = "goodix,gt967" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, goodix_of_match);
 #endif

 static struct i2c_driver goodix_ts_driver = {
 	.probe = goodix_ts_probe,
 	.id_table = goodix_ts_id,
 	.driver = {
 		.name = "Goodix-TS",
 		.owner = THIS_MODULE,
 		.acpi_match_table = ACPI_PTR(goodix_acpi_match),
 		.of_match_table = of_match_ptr(goodix_of_match),
 	},
 };
 module_i2c_driver(goodix_ts_driver);

 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
 MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
 MODULE_DESCRIPTION("Goodix touchscreen driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Driver for Goodix Touchscreens
	*
	* Copyright (c) 2014 Red Hat Inc.
	*
	* This code is based on gt9xx.c authored by andrew@goodix.com:
	*
	* 2010 - 2012 Goodix Technology.
	*/

	/*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License as published by the Free
	* Software Foundation; version 2 of the License.
	*/

	#include <linux/kernel.h>
	#include <linux/dmi.h>
	#include <linux/i2c.h>
	#include <linux/input.h>
	#include <linux/input/mt.h>
	#include <linux/module.h>
	#include <linux/delay.h>
	#include <linux/irq.h>
	#include <linux/interrupt.h>
	#include <linux/slab.h>
	#include <linux/acpi.h>
	#include <linux/of.h>
	#include <asm/unaligned.h>

	struct goodix_ts_data {
	struct i2c_client *client;
	struct input_dev *input_dev;
	int abs_x_max;
	int abs_y_max;
	unsigned int max_touch_num;
	unsigned int int_trigger_type;
	bool rotated_screen;
	};

	#define GOODIX_MAX_HEIGHT 4096
	#define GOODIX_MAX_WIDTH 4096
	#define GOODIX_INT_TRIGGER 1
	#define GOODIX_CONTACT_SIZE 8
	#define GOODIX_MAX_CONTACTS 10

	#define GOODIX_CONFIG_MAX_LENGTH 240

	/* Register defines */
	#define GOODIX_READ_COOR_ADDR 0x814E
	#define GOODIX_REG_CONFIG_DATA 0x8047
	#define GOODIX_REG_ID 0x8140

	#define RESOLUTION_LOC 1
	#define MAX_CONTACTS_LOC 5
	#define TRIGGER_LOC 6

	static const unsigned long goodix_irq_flags[] = {
	IRQ_TYPE_EDGE_RISING,
	IRQ_TYPE_EDGE_FALLING,
	IRQ_TYPE_LEVEL_LOW,
	IRQ_TYPE_LEVEL_HIGH,
	};

	/*
	* Those tablets have their coordinates origin at the bottom right
	* of the tablet, as if rotated 180 degrees
	*/
	static const struct dmi_system_id rotated_screen[] = {
	#if defined(CONFIG_DMI) && defined(CONFIG_X86)
	{
	.ident = "WinBook TW100",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
	DMI_MATCH(DMI_PRODUCT_NAME, "TW100")
	}
	},
	{
	.ident = "WinBook TW700",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
	DMI_MATCH(DMI_PRODUCT_NAME, "TW700")
	},
	},
	#endif
	{}
	};

	/**
	* goodix_i2c_read - read data from a register of the i2c slave device.
	*
	* @client: i2c device.
	* @reg: the register to read from.
	* @buf: raw write data buffer.
	* @len: length of the buffer to write
	*/
	static int goodix_i2c_read(struct i2c_client *client,
	u16 reg, u8 *buf, int len)
	{
	struct i2c_msg msgs[2];
	u16 wbuf = cpu_to_be16(reg);
	int ret;

	msgs[0].flags = 0;
	msgs[0].addr = client->addr;
	msgs[0].len = 2;
	msgs[0].buf = (u8 *)&wbuf;

	msgs[1].flags = I2C_M_RD;
	msgs[1].addr = client->addr;
	msgs[1].len = len;
	msgs[1].buf = buf;

	ret = i2c_transfer(client->adapter, msgs, 2);
	return ret < 0 ? ret : (ret != ARRAY_SIZE(msgs) ? -EIO : 0);
	}

	static int goodix_ts_read_input_report(struct goodix_ts_data ts, u8 data)
	{
	int touch_num;
	int error;

	error = goodix_i2c_read(ts->client, GOODIX_READ_COOR_ADDR, data,
	GOODIX_CONTACT_SIZE + 1);
	if (error) {
	dev_err(&ts->client->dev, "I2C transfer error: %d\n", error);
	return error;
	}

	if (!(data[0] & 0x80))
	return -EAGAIN;

	touch_num = data[0] & 0x0f;
	if (touch_num > ts->max_touch_num)
	return -EPROTO;

	if (touch_num > 1) {
	data += 1 + GOODIX_CONTACT_SIZE;
	error = goodix_i2c_read(ts->client,
	GOODIX_READ_COOR_ADDR +
	1 + GOODIX_CONTACT_SIZE,
	data,
	GOODIX_CONTACT_SIZE * (touch_num - 1));
	if (error)
	return error;
	}

	return touch_num;
	}

	static void goodix_ts_report_touch(struct goodix_ts_data ts, u8 coor_data)
	{
	int id = coor_data[0] & 0x0F;
	int input_x = get_unaligned_le16(&coor_data[1]);
	int input_y = get_unaligned_le16(&coor_data[3]);
	int input_w = get_unaligned_le16(&coor_data[5]);

	if (ts->rotated_screen) {
	input_x = ts->abs_x_max - input_x;
	input_y = ts->abs_y_max - input_y;
	}

	input_mt_slot(ts->input_dev, id);
	input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
	input_report_abs(ts->input_dev, ABS_MT_POSITION_X, input_x);
	input_report_abs(ts->input_dev, ABS_MT_POSITION_Y, input_y);
	input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR, input_w);
	input_report_abs(ts->input_dev, ABS_MT_WIDTH_MAJOR, input_w);
	}

	/**
	* goodix_process_events - Process incoming events
	*
	* @ts: our goodix_ts_data pointer
	*
	* Called when the IRQ is triggered. Read the current device state, and push
	* the input events to the user space.
	*/
	static void goodix_process_events(struct goodix_ts_data *ts)
	{
	u8 point_data[1 + GOODIX_CONTACT_SIZE * GOODIX_MAX_CONTACTS];
	int touch_num;
	int i;

	touch_num = goodix_ts_read_input_report(ts, point_data);
	if (touch_num < 0)
	return;

	for (i = 0; i < touch_num; i++)
	goodix_ts_report_touch(ts,
	&point_data[1 + GOODIX_CONTACT_SIZE * i]);

	input_mt_sync_frame(ts->input_dev);
	input_sync(ts->input_dev);
	}

	/**
	* goodix_ts_irq_handler - The IRQ handler
	*
	* @irq: interrupt number.
	* @dev_id: private data pointer.
	*/
	static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
	{
	static const u8 end_cmd[] = {
	GOODIX_READ_COOR_ADDR >> 8,
	GOODIX_READ_COOR_ADDR & 0xff,
	0
	};
	struct goodix_ts_data *ts = dev_id;

	goodix_process_events(ts);

	if (i2c_master_send(ts->client, end_cmd, sizeof(end_cmd)) < 0)
	dev_err(&ts->client->dev, "I2C write end_cmd error\n");

	return IRQ_HANDLED;
	}

	/**
	* goodix_read_config - Read the embedded configuration of the panel
	*
	* @ts: our goodix_ts_data pointer
	*
	* Must be called during probe
	*/
	static void goodix_read_config(struct goodix_ts_data *ts)
	{
	u8 config[GOODIX_CONFIG_MAX_LENGTH];
	int error;

	error = goodix_i2c_read(ts->client, GOODIX_REG_CONFIG_DATA,
	config,
	GOODIX_CONFIG_MAX_LENGTH);
	if (error) {
	dev_warn(&ts->client->dev,
	"Error reading config (%d), using defaults\n",
	error);
	ts->abs_x_max = GOODIX_MAX_WIDTH;
	ts->abs_y_max = GOODIX_MAX_HEIGHT;
	ts->int_trigger_type = GOODIX_INT_TRIGGER;
	ts->max_touch_num = GOODIX_MAX_CONTACTS;
	return;
	}

	ts->abs_x_max = get_unaligned_le16(&config[RESOLUTION_LOC]);
	ts->abs_y_max = get_unaligned_le16(&config[RESOLUTION_LOC + 2]);
	ts->int_trigger_type = config[TRIGGER_LOC] & 0x03;
	ts->max_touch_num = config[MAX_CONTACTS_LOC] & 0x0f;
	if (!ts->abs_x_max \|\| !ts->abs_y_max \|\| !ts->max_touch_num) {
	dev_err(&ts->client->dev,
	"Invalid config, using defaults\n");
	ts->abs_x_max = GOODIX_MAX_WIDTH;
	ts->abs_y_max = GOODIX_MAX_HEIGHT;
	ts->max_touch_num = GOODIX_MAX_CONTACTS;
	}

	ts->rotated_screen = dmi_check_system(rotated_screen);
	if (ts->rotated_screen)
	dev_dbg(&ts->client->dev,
	"Applying '180 degrees rotated screen' quirk\n");
	}

	/**
	* goodix_read_version - Read goodix touchscreen version
	*
	* @client: the i2c client
	* @version: output buffer containing the version on success
	* @id: output buffer containing the id on success
	*/
	static int goodix_read_version(struct i2c_client client, u16 version, u16 *id)
	{
	int error;
	u8 buf[6];
	char id_str[5];

	error = goodix_i2c_read(client, GOODIX_REG_ID, buf, sizeof(buf));
	if (error) {
	dev_err(&client->dev, "read version failed: %d\n", error);
	return error;
	}

	memcpy(id_str, buf, 4);
	id_str[4] = 0;
	if (kstrtou16(id_str, 10, id))
	*id = 0x1001;

	*version = get_unaligned_le16(&buf[4]);

	dev_info(&client->dev, "ID %d, version: %04x\n", id, version);

	return 0;
	}

	/**
	* goodix_i2c_test - I2C test function to check if the device answers.
	*
	* @client: the i2c client
	*/
	static int goodix_i2c_test(struct i2c_client *client)
	{
	int retry = 0;
	int error;
	u8 test;

	while (retry++ < 2) {
	error = goodix_i2c_read(client, GOODIX_REG_CONFIG_DATA,
	&test, 1);
	if (!error)
	return 0;

	dev_err(&client->dev, "i2c test failed attempt %d: %d\n",
	retry, error);
	msleep(20);
	}

	return error;
	}

	/**
	* goodix_request_input_dev - Allocate, populate and register the input device
	*
	* @ts: our goodix_ts_data pointer
	* @version: device firmware version
	* @id: device ID
	*
	* Must be called during probe
	*/
	static int goodix_request_input_dev(struct goodix_ts_data *ts, u16 version,
	u16 id)
	{
	int error;

	ts->input_dev = devm_input_allocate_device(&ts->client->dev);
	if (!ts->input_dev) {
	dev_err(&ts->client->dev, "Failed to allocate input device.");
	return -ENOMEM;
	}

	input_set_abs_params(ts->input_dev, ABS_MT_POSITION_X,
	0, ts->abs_x_max, 0, 0);
	input_set_abs_params(ts->input_dev, ABS_MT_POSITION_Y,
	0, ts->abs_y_max, 0, 0);
	input_set_abs_params(ts->input_dev, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
	input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);

	input_mt_init_slots(ts->input_dev, ts->max_touch_num,
	INPUT_MT_DIRECT \| INPUT_MT_DROP_UNUSED);

	ts->input_dev->name = "Goodix Capacitive TouchScreen";
	ts->input_dev->phys = "input/ts";
	ts->input_dev->id.bustype = BUS_I2C;
	ts->input_dev->id.vendor = 0x0416;
	ts->input_dev->id.product = id;
	ts->input_dev->id.version = version;

	error = input_register_device(ts->input_dev);
	if (error) {
	dev_err(&ts->client->dev,
	"Failed to register input device: %d", error);
	return error;
	}

	return 0;
	}

	static int goodix_ts_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct goodix_ts_data *ts;
	unsigned long irq_flags;
	int error;
	u16 version_info, id_info;

	dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	dev_err(&client->dev, "I2C check functionality failed.\n");
	return -ENXIO;
	}

	ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
	if (!ts)
	return -ENOMEM;

	ts->client = client;
	i2c_set_clientdata(client, ts);

	error = goodix_i2c_test(client);
	if (error) {
	dev_err(&client->dev, "I2C communication failure: %d\n", error);
	return error;
	}

	error = goodix_read_version(client, &version_info, &id_info);
	if (error) {
	dev_err(&client->dev, "Read version failed.\n");
	return error;
	}

	goodix_read_config(ts);

	error = goodix_request_input_dev(ts, version_info, id_info);
	if (error)
	return error;

	irq_flags = goodix_irq_flags[ts->int_trigger_type] \| IRQF_ONESHOT;
	error = devm_request_threaded_irq(&ts->client->dev, client->irq,
	NULL, goodix_ts_irq_handler,
	irq_flags, client->name, ts);
	if (error) {
	dev_err(&client->dev, "request IRQ failed: %d\n", error);
	return error;
	}

	return 0;
	}

	static const struct i2c_device_id goodix_ts_id[] = {
	{ "GDIX1001:00", 0 },
	{ }
	};

	#ifdef CONFIG_ACPI
	static const struct acpi_device_id goodix_acpi_match[] = {
	{ "GDIX1001", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(acpi, goodix_acpi_match);
	#endif

	#ifdef CONFIG_OF
	static const struct of_device_id goodix_of_match[] = {
	{ .compatible = "goodix,gt911" },
	{ .compatible = "goodix,gt9110" },
	{ .compatible = "goodix,gt912" },
	{ .compatible = "goodix,gt927" },
	{ .compatible = "goodix,gt9271" },
	{ .compatible = "goodix,gt928" },
	{ .compatible = "goodix,gt967" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, goodix_of_match);
	#endif

	static struct i2c_driver goodix_ts_driver = {
	.probe = goodix_ts_probe,
	.id_table = goodix_ts_id,
	.driver = {
	.name = "Goodix-TS",
	.owner = THIS_MODULE,
	.acpi_match_table = ACPI_PTR(goodix_acpi_match),
	.of_match_table = of_match_ptr(goodix_of_match),
	},
	};
	module_i2c_driver(goodix_ts_driver);

	MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
	MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
	MODULE_DESCRIPTION("Goodix touchscreen driver");
	MODULE_LICENSE("GPL v2");