drivers/input/touchscreen/zinitix.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only

 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>

 /* Register Map */

 #define BT541_SWRESET_CMD			0x0000
 #define BT541_WAKEUP_CMD			0x0001

 #define BT541_IDLE_CMD				0x0004
 #define BT541_SLEEP_CMD				0x0005

 #define BT541_CLEAR_INT_STATUS_CMD		0x0003
 #define BT541_CALIBRATE_CMD			0x0006
 #define BT541_SAVE_STATUS_CMD			0x0007
 #define BT541_SAVE_CALIBRATION_CMD		0x0008
 #define BT541_RECALL_FACTORY_CMD		0x000f

 #define BT541_THRESHOLD				0x0020

 #define BT541_LARGE_PALM_REJECT_AREA_TH		0x003F

 #define BT541_DEBUG_REG				0x0115 /* 0~7 */

 #define BT541_TOUCH_MODE			0x0010
 #define BT541_CHIP_REVISION			0x0011
 #define BT541_FIRMWARE_VERSION			0x0012

 #define ZINITIX_USB_DETECT			0x116

 #define BT541_MINOR_FW_VERSION			0x0121

 #define BT541_VENDOR_ID				0x001C
 #define BT541_HW_ID				0x0014

 #define BT541_DATA_VERSION_REG			0x0013
 #define BT541_SUPPORTED_FINGER_NUM		0x0015
 #define BT541_EEPROM_INFO			0x0018
 #define BT541_INITIAL_TOUCH_MODE		0x0019

 #define BT541_TOTAL_NUMBER_OF_X			0x0060
 #define BT541_TOTAL_NUMBER_OF_Y			0x0061

 #define BT541_DELAY_RAW_FOR_HOST		0x007f

 #define BT541_BUTTON_SUPPORTED_NUM		0x00B0
 #define BT541_BUTTON_SENSITIVITY		0x00B2
 #define BT541_DUMMY_BUTTON_SENSITIVITY		0X00C8

 #define BT541_X_RESOLUTION			0x00C0
 #define BT541_Y_RESOLUTION			0x00C1

 #define BT541_POINT_STATUS_REG			0x0080
 #define BT541_ICON_STATUS_REG			0x00AA

 #define BT541_POINT_COORD_REG			(BT541_POINT_STATUS_REG + 2)

 #define BT541_AFE_FREQUENCY			0x0100
 #define BT541_DND_N_COUNT			0x0122
 #define BT541_DND_U_COUNT			0x0135

 #define BT541_RAWDATA_REG			0x0200

 #define BT541_EEPROM_INFO_REG			0x0018

 #define BT541_INT_ENABLE_FLAG			0x00f0
 #define BT541_PERIODICAL_INTERRUPT_INTERVAL	0x00f1

 #define BT541_BTN_WIDTH				0x016d

 #define BT541_CHECKSUM_RESULT			0x012c

 #define BT541_INIT_FLASH			0x01d0
 #define BT541_WRITE_FLASH			0x01d1
 #define BT541_READ_FLASH			0x01d2

 #define ZINITIX_INTERNAL_FLAG_02		0x011e
 #define ZINITIX_INTERNAL_FLAG_03		0x011f

 #define ZINITIX_I2C_CHECKSUM_WCNT		0x016a
 #define ZINITIX_I2C_CHECKSUM_RESULT		0x016c

 /* Interrupt & status register flags */

 #define BIT_PT_CNT_CHANGE			BIT(0)
 #define BIT_DOWN				BIT(1)
 #define BIT_MOVE				BIT(2)
 #define BIT_UP					BIT(3)
 #define BIT_PALM				BIT(4)
 #define BIT_PALM_REJECT				BIT(5)
 #define BIT_RESERVED_0				BIT(6)
 #define BIT_RESERVED_1				BIT(7)
 #define BIT_WEIGHT_CHANGE			BIT(8)
 #define BIT_PT_NO_CHANGE			BIT(9)
 #define BIT_REJECT				BIT(10)
 #define BIT_PT_EXIST				BIT(11)
 #define BIT_RESERVED_2				BIT(12)
 #define BIT_ERROR				BIT(13)
 #define BIT_DEBUG				BIT(14)
 #define BIT_ICON_EVENT				BIT(15)

 #define SUB_BIT_EXIST				BIT(0)
 #define SUB_BIT_DOWN				BIT(1)
 #define SUB_BIT_MOVE				BIT(2)
 #define SUB_BIT_UP				BIT(3)
 #define SUB_BIT_UPDATE				BIT(4)
 #define SUB_BIT_WAIT				BIT(5)

 #define DEFAULT_TOUCH_POINT_MODE		2
 #define MAX_SUPPORTED_FINGER_NUM		5

 #define CHIP_ON_DELAY				15 // ms
 #define FIRMWARE_ON_DELAY			40 // ms

 struct point_coord {
 	__le16	x;
 	__le16	y;
 	u8	width;
 	u8	sub_status;
 	// currently unused, but needed as padding:
 	u8	minor_width;
 	u8	angle;
 };

 struct touch_event {
 	__le16	status;
 	u8	finger_cnt;
 	u8	time_stamp;
 	struct point_coord point_coord[MAX_SUPPORTED_FINGER_NUM];
 };

 struct bt541_ts_data {
 	struct i2c_client *client;
 	struct input_dev *input_dev;
 	struct touchscreen_properties prop;
 	struct regulator_bulk_data supplies[2];
 	u32 zinitix_mode;
 };

 static int zinitix_read_data(struct i2c_client *client,
 			     u16 reg, void *values, size_t length)
 {
 	__le16 reg_le = cpu_to_le16(reg);
 	int ret;

 	/* A single i2c_transfer() transaction does not work here. */
 	ret = i2c_master_send(client, (u8 *)&reg_le, sizeof(reg_le));
 	if (ret != sizeof(reg_le))
 		return ret < 0 ? ret : -EIO;

 	ret = i2c_master_recv(client, (u8 *)values, length);
 	if (ret != length)
 		return ret < 0 ? ret : -EIO; ;

 	return 0;
 }

 static int zinitix_write_u16(struct i2c_client *client, u16 reg, u16 value)
 {
 	__le16 packet[2] = {cpu_to_le16(reg), cpu_to_le16(value)};
 	int ret;

 	ret = i2c_master_send(client, (u8 *)packet, sizeof(packet));
 	if (ret != sizeof(packet))
 		return ret < 0 ? ret : -EIO;

 	return 0;
 }

 static int zinitix_write_cmd(struct i2c_client *client, u16 reg)
 {
 	__le16 reg_le = cpu_to_le16(reg);
 	int ret;

 	ret = i2c_master_send(client, (u8 *)&reg_le, sizeof(reg_le));
 	if (ret != sizeof(reg_le))
 		return ret < 0 ? ret : -EIO;

 	return 0;
 }

 static int zinitix_init_touch(struct bt541_ts_data *bt541)
 {
 	struct i2c_client *client = bt541->client;
 	int i;
 	int error;

 	error = zinitix_write_cmd(client, BT541_SWRESET_CMD);
 	if (error) {
 		dev_err(&client->dev, "Failed to write reset command\n");
 		return error;
 	}

 	error = zinitix_write_u16(client, BT541_INT_ENABLE_FLAG, 0x0);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to reset interrupt enable flag\n");
 		return error;
 	}

 	/* initialize */
 	error = zinitix_write_u16(client, BT541_X_RESOLUTION,
 				  bt541->prop.max_x);
 	if (error)
 		return error;

 	error = zinitix_write_u16(client, BT541_Y_RESOLUTION,
 				  bt541->prop.max_y);
 	if (error)
 		return error;

 	error = zinitix_write_u16(client, BT541_SUPPORTED_FINGER_NUM,
 				  MAX_SUPPORTED_FINGER_NUM);
 	if (error)
 		return error;

 	error = zinitix_write_u16(client, BT541_INITIAL_TOUCH_MODE,
 				  bt541->zinitix_mode);
 	if (error)
 		return error;

 	error = zinitix_write_u16(client, BT541_TOUCH_MODE,
 				  bt541->zinitix_mode);
 	if (error)
 		return error;

 	error = zinitix_write_u16(client, BT541_INT_ENABLE_FLAG,
 				  BIT_PT_CNT_CHANGE | BIT_DOWN | BIT_MOVE |
 					BIT_UP);
 	if (error)
 		return error;

 	/* clear queue */
 	for (i = 0; i < 10; i++) {
 		zinitix_write_cmd(client, BT541_CLEAR_INT_STATUS_CMD);
 		udelay(10);
 	}

 	return 0;
 }

 static int zinitix_init_regulators(struct bt541_ts_data *bt541)
 {
 	struct i2c_client *client = bt541->client;
 	int error;

 	bt541->supplies[0].supply = "vdd";
 	bt541->supplies[1].supply = "vddo";
 	error = devm_regulator_bulk_get(&client->dev,
 					ARRAY_SIZE(bt541->supplies),
 					bt541->supplies);
 	if (error < 0) {
 		dev_err(&client->dev, "Failed to get regulators: %d\n", error);
 		return error;
 	}

 	return 0;
 }

 static int zinitix_send_power_on_sequence(struct bt541_ts_data *bt541)
 {
 	int error;
 	struct i2c_client *client = bt541->client;

 	error = zinitix_write_u16(client, 0xc000, 0x0001);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to send power sequence(vendor cmd enable)\n");
 		return error;
 	}
 	udelay(10);

 	error = zinitix_write_cmd(client, 0xc004);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to send power sequence (intn clear)\n");
 		return error;
 	}
 	udelay(10);

 	error = zinitix_write_u16(client, 0xc002, 0x0001);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to send power sequence (nvm init)\n");
 		return error;
 	}
 	mdelay(2);

 	error = zinitix_write_u16(client, 0xc001, 0x0001);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to send power sequence (program start)\n");
 		return error;
 	}
 	msleep(FIRMWARE_ON_DELAY);

 	return 0;
 }

 static void zinitix_report_finger(struct bt541_ts_data *bt541, int slot,
 				  const struct point_coord *p)
 {
 	input_mt_slot(bt541->input_dev, slot);
 	input_mt_report_slot_state(bt541->input_dev, MT_TOOL_FINGER, true);
 	touchscreen_report_pos(bt541->input_dev, &bt541->prop,
 			       le16_to_cpu(p->x), le16_to_cpu(p->y), true);
 	input_report_abs(bt541->input_dev, ABS_MT_TOUCH_MAJOR, p->width);
 }

 static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
 {
 	struct bt541_ts_data *bt541 = bt541_handler;
 	struct i2c_client *client = bt541->client;
 	struct touch_event touch_event;
 	int error;
 	int i;

 	memset(&touch_event, 0, sizeof(struct touch_event));

 	error = zinitix_read_data(bt541->client, BT541_POINT_STATUS_REG,
 				  &touch_event, sizeof(struct touch_event));
 	if (error) {
 		dev_err(&client->dev, "Failed to read in touchpoint struct\n");
 		goto out;
 	}

 	for (i = 0; i < MAX_SUPPORTED_FINGER_NUM; i++)
 		if (touch_event.point_coord[i].sub_status & SUB_BIT_EXIST)
 			zinitix_report_finger(bt541, i,
 					      &touch_event.point_coord[i]);

 	input_mt_sync_frame(bt541->input_dev);
 	input_sync(bt541->input_dev);

 out:
 	zinitix_write_cmd(bt541->client, BT541_CLEAR_INT_STATUS_CMD);
 	return IRQ_HANDLED;
 }

 static int zinitix_start(struct bt541_ts_data *bt541)
 {
 	int error;

 	error = regulator_bulk_enable(ARRAY_SIZE(bt541->supplies),
 				      bt541->supplies);
 	if (error) {
 		dev_err(&bt541->client->dev,
 			"Failed to enable regulators: %d\n", error);
 		return error;
 	}

 	msleep(CHIP_ON_DELAY);

 	error = zinitix_send_power_on_sequence(bt541);
 	if (error) {
 		dev_err(&bt541->client->dev,
 			"Error while sending power-on sequence: %d\n", error);
 		return error;
 	}

 	error = zinitix_init_touch(bt541);
 	if (error) {
 		dev_err(&bt541->client->dev,
 			"Error while configuring touch IC\n");
 		return error;
 	}

 	enable_irq(bt541->client->irq);

 	return 0;
 }

 static int zinitix_stop(struct bt541_ts_data *bt541)
 {
 	int error;

 	disable_irq(bt541->client->irq);

 	error = regulator_bulk_disable(ARRAY_SIZE(bt541->supplies),
 				       bt541->supplies);
 	if (error) {
 		dev_err(&bt541->client->dev,
 			"Failed to disable regulators: %d\n", error);
 		return error;
 	}

 	return 0;
 }

 static int zinitix_input_open(struct input_dev *dev)
 {
 	struct bt541_ts_data *bt541 = input_get_drvdata(dev);

 	return zinitix_start(bt541);
 }

 static void zinitix_input_close(struct input_dev *dev)
 {
 	struct bt541_ts_data *bt541 = input_get_drvdata(dev);

 	zinitix_stop(bt541);
 }

 static int zinitix_init_input_dev(struct bt541_ts_data *bt541)
 {
 	struct input_dev *input_dev;
 	int error;

 	input_dev = devm_input_allocate_device(&bt541->client->dev);
 	if (!input_dev) {
 		dev_err(&bt541->client->dev,
 			"Failed to allocate input device.");
 		return -ENOMEM;
 	}

 	input_set_drvdata(input_dev, bt541);
 	bt541->input_dev = input_dev;

 	input_dev->name = "Zinitix Capacitive TouchScreen";
 	input_dev->phys = "input/ts";
 	input_dev->id.bustype = BUS_I2C;
 	input_dev->open = zinitix_input_open;
 	input_dev->close = zinitix_input_close;

 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
 	input_set_abs_params(input_dev, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);

 	touchscreen_parse_properties(input_dev, true, &bt541->prop);
 	if (!bt541->prop.max_x || !bt541->prop.max_y) {
 		dev_err(&bt541->client->dev,
 			"Touchscreen-size-x and/or touchscreen-size-y not set in dts\n");
 		return -EINVAL;
 	}

 	error = input_mt_init_slots(input_dev, MAX_SUPPORTED_FINGER_NUM,
 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
 	if (error) {
 		dev_err(&bt541->client->dev,
 			"Failed to initialize MT slots: %d", error);
 		return error;
 	}

 	error = input_register_device(input_dev);
 	if (error) {
 		dev_err(&bt541->client->dev,
 			"Failed to register input device: %d", error);
 		return error;
 	}

 	return 0;
 }

 static int zinitix_ts_probe(struct i2c_client *client)
 {
 	struct bt541_ts_data *bt541;
 	int error;

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 		dev_err(&client->dev,
 			"Failed to assert adapter's support for plain I2C.\n");
 		return -ENXIO;
 	}

 	bt541 = devm_kzalloc(&client->dev, sizeof(*bt541), GFP_KERNEL);
 	if (!bt541)
 		return -ENOMEM;

 	bt541->client = client;
 	i2c_set_clientdata(client, bt541);

 	error = zinitix_init_regulators(bt541);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to initialize regulators: %d\n", error);
 		return error;
 	}

 	error = zinitix_init_input_dev(bt541);
 	if (error) {
 		dev_err(&client->dev,
 			"Failed to initialize input device: %d\n", error);
 		return error;
 	}

 	error = device_property_read_u32(&client->dev, "zinitix,mode",
 					 &bt541->zinitix_mode);
 	if (error < 0) {
 		/* fall back to mode 2 */
 		bt541->zinitix_mode = DEFAULT_TOUCH_POINT_MODE;
 	}

 	if (bt541->zinitix_mode != 2) {
 		/*
 		 * If there are devices that don't support mode 2, support
 		 * for other modes (0, 1) will be needed.
 		 */
 		dev_err(&client->dev,
 			"Malformed zinitix,mode property, must be 2 (supplied: %d)\n",
 			bt541->zinitix_mode);
 		return -EINVAL;
 	}

 	irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
 	error = devm_request_threaded_irq(&client->dev, client->irq,
 					  NULL, zinitix_ts_irq_handler,
 					  IRQF_ONESHOT, client->name, bt541);
 	if (error) {
 		dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
 		return error;
 	}

 	return 0;
 }

 static int __maybe_unused zinitix_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct bt541_ts_data *bt541 = i2c_get_clientdata(client);

 	mutex_lock(&bt541->input_dev->mutex);

 	if (bt541->input_dev->users)
 		zinitix_stop(bt541);

 	mutex_unlock(&bt541->input_dev->mutex);

 	return 0;
 }

 static int __maybe_unused zinitix_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct bt541_ts_data *bt541 = i2c_get_clientdata(client);
 	int ret = 0;

 	mutex_lock(&bt541->input_dev->mutex);

 	if (bt541->input_dev->users)
 		ret = zinitix_start(bt541);

 	mutex_unlock(&bt541->input_dev->mutex);

 	return ret;
 }

 static SIMPLE_DEV_PM_OPS(zinitix_pm_ops, zinitix_suspend, zinitix_resume);

 #ifdef CONFIG_OF
 static const struct of_device_id zinitix_of_match[] = {
 	{ .compatible = "zinitix,bt541" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, zinitix_of_match);
 #endif

 static struct i2c_driver zinitix_ts_driver = {
 	.probe_new = zinitix_ts_probe,
 	.driver = {
 		.name = "Zinitix-TS",
 		.pm = &zinitix_pm_ops,
 		.of_match_table = of_match_ptr(zinitix_of_match),
 	},
 };
 module_i2c_driver(zinitix_ts_driver);

 MODULE_AUTHOR("Michael Srba <Michael.Srba@seznam.cz>");
 MODULE_DESCRIPTION("Zinitix touchscreen driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only

	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/input.h>
	#include <linux/input/mt.h>
	#include <linux/input/touchscreen.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/regulator/consumer.h>
	#include <linux/slab.h>

	/* Register Map */

	#define BT541_SWRESET_CMD 0x0000
	#define BT541_WAKEUP_CMD 0x0001

	#define BT541_IDLE_CMD 0x0004
	#define BT541_SLEEP_CMD 0x0005

	#define BT541_CLEAR_INT_STATUS_CMD 0x0003
	#define BT541_CALIBRATE_CMD 0x0006
	#define BT541_SAVE_STATUS_CMD 0x0007
	#define BT541_SAVE_CALIBRATION_CMD 0x0008
	#define BT541_RECALL_FACTORY_CMD 0x000f

	#define BT541_THRESHOLD 0x0020

	#define BT541_LARGE_PALM_REJECT_AREA_TH 0x003F

	#define BT541_DEBUG_REG 0x0115 /* 0~7 */

	#define BT541_TOUCH_MODE 0x0010
	#define BT541_CHIP_REVISION 0x0011
	#define BT541_FIRMWARE_VERSION 0x0012

	#define ZINITIX_USB_DETECT 0x116

	#define BT541_MINOR_FW_VERSION 0x0121

	#define BT541_VENDOR_ID 0x001C
	#define BT541_HW_ID 0x0014

	#define BT541_DATA_VERSION_REG 0x0013
	#define BT541_SUPPORTED_FINGER_NUM 0x0015
	#define BT541_EEPROM_INFO 0x0018
	#define BT541_INITIAL_TOUCH_MODE 0x0019

	#define BT541_TOTAL_NUMBER_OF_X 0x0060
	#define BT541_TOTAL_NUMBER_OF_Y 0x0061

	#define BT541_DELAY_RAW_FOR_HOST 0x007f

	#define BT541_BUTTON_SUPPORTED_NUM 0x00B0
	#define BT541_BUTTON_SENSITIVITY 0x00B2
	#define BT541_DUMMY_BUTTON_SENSITIVITY 0X00C8

	#define BT541_X_RESOLUTION 0x00C0
	#define BT541_Y_RESOLUTION 0x00C1

	#define BT541_POINT_STATUS_REG 0x0080
	#define BT541_ICON_STATUS_REG 0x00AA

	#define BT541_POINT_COORD_REG (BT541_POINT_STATUS_REG + 2)

	#define BT541_AFE_FREQUENCY 0x0100
	#define BT541_DND_N_COUNT 0x0122
	#define BT541_DND_U_COUNT 0x0135

	#define BT541_RAWDATA_REG 0x0200

	#define BT541_EEPROM_INFO_REG 0x0018

	#define BT541_INT_ENABLE_FLAG 0x00f0
	#define BT541_PERIODICAL_INTERRUPT_INTERVAL 0x00f1

	#define BT541_BTN_WIDTH 0x016d

	#define BT541_CHECKSUM_RESULT 0x012c

	#define BT541_INIT_FLASH 0x01d0
	#define BT541_WRITE_FLASH 0x01d1
	#define BT541_READ_FLASH 0x01d2

	#define ZINITIX_INTERNAL_FLAG_02 0x011e
	#define ZINITIX_INTERNAL_FLAG_03 0x011f

	#define ZINITIX_I2C_CHECKSUM_WCNT 0x016a
	#define ZINITIX_I2C_CHECKSUM_RESULT 0x016c

	/* Interrupt & status register flags */

	#define BIT_PT_CNT_CHANGE BIT(0)
	#define BIT_DOWN BIT(1)
	#define BIT_MOVE BIT(2)
	#define BIT_UP BIT(3)
	#define BIT_PALM BIT(4)
	#define BIT_PALM_REJECT BIT(5)
	#define BIT_RESERVED_0 BIT(6)
	#define BIT_RESERVED_1 BIT(7)
	#define BIT_WEIGHT_CHANGE BIT(8)
	#define BIT_PT_NO_CHANGE BIT(9)
	#define BIT_REJECT BIT(10)
	#define BIT_PT_EXIST BIT(11)
	#define BIT_RESERVED_2 BIT(12)
	#define BIT_ERROR BIT(13)
	#define BIT_DEBUG BIT(14)
	#define BIT_ICON_EVENT BIT(15)

	#define SUB_BIT_EXIST BIT(0)
	#define SUB_BIT_DOWN BIT(1)
	#define SUB_BIT_MOVE BIT(2)
	#define SUB_BIT_UP BIT(3)
	#define SUB_BIT_UPDATE BIT(4)
	#define SUB_BIT_WAIT BIT(5)

	#define DEFAULT_TOUCH_POINT_MODE 2
	#define MAX_SUPPORTED_FINGER_NUM 5

	#define CHIP_ON_DELAY 15 // ms
	#define FIRMWARE_ON_DELAY 40 // ms

	struct point_coord {
	__le16 x;
	__le16 y;
	u8 width;
	u8 sub_status;
	// currently unused, but needed as padding:
	u8 minor_width;
	u8 angle;
	};

	struct touch_event {
	__le16 status;
	u8 finger_cnt;
	u8 time_stamp;
	struct point_coord point_coord[MAX_SUPPORTED_FINGER_NUM];
	};

	struct bt541_ts_data {
	struct i2c_client *client;
	struct input_dev *input_dev;
	struct touchscreen_properties prop;
	struct regulator_bulk_data supplies[2];
	u32 zinitix_mode;
	};

	static int zinitix_read_data(struct i2c_client *client,
	u16 reg, void *values, size_t length)
	{
	__le16 reg_le = cpu_to_le16(reg);
	int ret;

	/* A single i2c_transfer() transaction does not work here. */
	ret = i2c_master_send(client, (u8 *)&reg_le, sizeof(reg_le));
	if (ret != sizeof(reg_le))
	return ret < 0 ? ret : -EIO;

	ret = i2c_master_recv(client, (u8 *)values, length);
	if (ret != length)
	return ret < 0 ? ret : -EIO; ;

	return 0;
	}

	static int zinitix_write_u16(struct i2c_client *client, u16 reg, u16 value)
	{
	__le16 packet[2] = {cpu_to_le16(reg), cpu_to_le16(value)};
	int ret;

	ret = i2c_master_send(client, (u8 *)packet, sizeof(packet));
	if (ret != sizeof(packet))
	return ret < 0 ? ret : -EIO;

	return 0;
	}

	static int zinitix_write_cmd(struct i2c_client *client, u16 reg)
	{
	__le16 reg_le = cpu_to_le16(reg);
	int ret;

	ret = i2c_master_send(client, (u8 *)&reg_le, sizeof(reg_le));
	if (ret != sizeof(reg_le))
	return ret < 0 ? ret : -EIO;

	return 0;
	}

	static int zinitix_init_touch(struct bt541_ts_data *bt541)
	{
	struct i2c_client *client = bt541->client;
	int i;
	int error;

	error = zinitix_write_cmd(client, BT541_SWRESET_CMD);
	if (error) {
	dev_err(&client->dev, "Failed to write reset command\n");
	return error;
	}

	error = zinitix_write_u16(client, BT541_INT_ENABLE_FLAG, 0x0);
	if (error) {
	dev_err(&client->dev,
	"Failed to reset interrupt enable flag\n");
	return error;
	}

	/* initialize */
	error = zinitix_write_u16(client, BT541_X_RESOLUTION,
	bt541->prop.max_x);
	if (error)
	return error;

	error = zinitix_write_u16(client, BT541_Y_RESOLUTION,
	bt541->prop.max_y);
	if (error)
	return error;

	error = zinitix_write_u16(client, BT541_SUPPORTED_FINGER_NUM,
	MAX_SUPPORTED_FINGER_NUM);
	if (error)
	return error;

	error = zinitix_write_u16(client, BT541_INITIAL_TOUCH_MODE,
	bt541->zinitix_mode);
	if (error)
	return error;

	error = zinitix_write_u16(client, BT541_TOUCH_MODE,
	bt541->zinitix_mode);
	if (error)
	return error;

	error = zinitix_write_u16(client, BT541_INT_ENABLE_FLAG,
	BIT_PT_CNT_CHANGE \| BIT_DOWN \| BIT_MOVE \|
	BIT_UP);
	if (error)
	return error;

	/* clear queue */
	for (i = 0; i < 10; i++) {
	zinitix_write_cmd(client, BT541_CLEAR_INT_STATUS_CMD);
	udelay(10);
	}

	return 0;
	}

	static int zinitix_init_regulators(struct bt541_ts_data *bt541)
	{
	struct i2c_client *client = bt541->client;
	int error;

	bt541->supplies[0].supply = "vdd";
	bt541->supplies[1].supply = "vddo";
	error = devm_regulator_bulk_get(&client->dev,
	ARRAY_SIZE(bt541->supplies),
	bt541->supplies);
	if (error < 0) {
	dev_err(&client->dev, "Failed to get regulators: %d\n", error);
	return error;
	}

	return 0;
	}

	static int zinitix_send_power_on_sequence(struct bt541_ts_data *bt541)
	{
	int error;
	struct i2c_client *client = bt541->client;

	error = zinitix_write_u16(client, 0xc000, 0x0001);
	if (error) {
	dev_err(&client->dev,
	"Failed to send power sequence(vendor cmd enable)\n");
	return error;
	}
	udelay(10);

	error = zinitix_write_cmd(client, 0xc004);
	if (error) {
	dev_err(&client->dev,
	"Failed to send power sequence (intn clear)\n");
	return error;
	}
	udelay(10);

	error = zinitix_write_u16(client, 0xc002, 0x0001);
	if (error) {
	dev_err(&client->dev,
	"Failed to send power sequence (nvm init)\n");
	return error;
	}
	mdelay(2);

	error = zinitix_write_u16(client, 0xc001, 0x0001);
	if (error) {
	dev_err(&client->dev,
	"Failed to send power sequence (program start)\n");
	return error;
	}
	msleep(FIRMWARE_ON_DELAY);

	return 0;
	}

	static void zinitix_report_finger(struct bt541_ts_data *bt541, int slot,
	const struct point_coord *p)
	{
	input_mt_slot(bt541->input_dev, slot);
	input_mt_report_slot_state(bt541->input_dev, MT_TOOL_FINGER, true);
	touchscreen_report_pos(bt541->input_dev, &bt541->prop,
	le16_to_cpu(p->x), le16_to_cpu(p->y), true);
	input_report_abs(bt541->input_dev, ABS_MT_TOUCH_MAJOR, p->width);
	}

	static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
	{
	struct bt541_ts_data *bt541 = bt541_handler;
	struct i2c_client *client = bt541->client;
	struct touch_event touch_event;
	int error;
	int i;

	memset(&touch_event, 0, sizeof(struct touch_event));

	error = zinitix_read_data(bt541->client, BT541_POINT_STATUS_REG,
	&touch_event, sizeof(struct touch_event));
	if (error) {
	dev_err(&client->dev, "Failed to read in touchpoint struct\n");
	goto out;
	}

	for (i = 0; i < MAX_SUPPORTED_FINGER_NUM; i++)
	if (touch_event.point_coord[i].sub_status & SUB_BIT_EXIST)
	zinitix_report_finger(bt541, i,
	&touch_event.point_coord[i]);

	input_mt_sync_frame(bt541->input_dev);
	input_sync(bt541->input_dev);

	out:
	zinitix_write_cmd(bt541->client, BT541_CLEAR_INT_STATUS_CMD);
	return IRQ_HANDLED;
	}

	static int zinitix_start(struct bt541_ts_data *bt541)
	{
	int error;

	error = regulator_bulk_enable(ARRAY_SIZE(bt541->supplies),
	bt541->supplies);
	if (error) {
	dev_err(&bt541->client->dev,
	"Failed to enable regulators: %d\n", error);
	return error;
	}

	msleep(CHIP_ON_DELAY);

	error = zinitix_send_power_on_sequence(bt541);
	if (error) {
	dev_err(&bt541->client->dev,
	"Error while sending power-on sequence: %d\n", error);
	return error;
	}

	error = zinitix_init_touch(bt541);
	if (error) {
	dev_err(&bt541->client->dev,
	"Error while configuring touch IC\n");
	return error;
	}

	enable_irq(bt541->client->irq);

	return 0;
	}

	static int zinitix_stop(struct bt541_ts_data *bt541)
	{
	int error;

	disable_irq(bt541->client->irq);

	error = regulator_bulk_disable(ARRAY_SIZE(bt541->supplies),
	bt541->supplies);
	if (error) {
	dev_err(&bt541->client->dev,
	"Failed to disable regulators: %d\n", error);
	return error;
	}

	return 0;
	}

	static int zinitix_input_open(struct input_dev *dev)
	{
	struct bt541_ts_data *bt541 = input_get_drvdata(dev);

	return zinitix_start(bt541);
	}

	static void zinitix_input_close(struct input_dev *dev)
	{
	struct bt541_ts_data *bt541 = input_get_drvdata(dev);

	zinitix_stop(bt541);
	}

	static int zinitix_init_input_dev(struct bt541_ts_data *bt541)
	{
	struct input_dev *input_dev;
	int error;

	input_dev = devm_input_allocate_device(&bt541->client->dev);
	if (!input_dev) {
	dev_err(&bt541->client->dev,
	"Failed to allocate input device.");
	return -ENOMEM;
	}

	input_set_drvdata(input_dev, bt541);
	bt541->input_dev = input_dev;

	input_dev->name = "Zinitix Capacitive TouchScreen";
	input_dev->phys = "input/ts";
	input_dev->id.bustype = BUS_I2C;
	input_dev->open = zinitix_input_open;
	input_dev->close = zinitix_input_close;

	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
	input_set_abs_params(input_dev, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);

	touchscreen_parse_properties(input_dev, true, &bt541->prop);
	if (!bt541->prop.max_x \|\| !bt541->prop.max_y) {
	dev_err(&bt541->client->dev,
	"Touchscreen-size-x and/or touchscreen-size-y not set in dts\n");
	return -EINVAL;
	}

	error = input_mt_init_slots(input_dev, MAX_SUPPORTED_FINGER_NUM,
	INPUT_MT_DIRECT \| INPUT_MT_DROP_UNUSED);
	if (error) {
	dev_err(&bt541->client->dev,
	"Failed to initialize MT slots: %d", error);
	return error;
	}

	error = input_register_device(input_dev);
	if (error) {
	dev_err(&bt541->client->dev,
	"Failed to register input device: %d", error);
	return error;
	}

	return 0;
	}

	static int zinitix_ts_probe(struct i2c_client *client)
	{
	struct bt541_ts_data *bt541;
	int error;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	dev_err(&client->dev,
	"Failed to assert adapter's support for plain I2C.\n");
	return -ENXIO;
	}

	bt541 = devm_kzalloc(&client->dev, sizeof(*bt541), GFP_KERNEL);
	if (!bt541)
	return -ENOMEM;

	bt541->client = client;
	i2c_set_clientdata(client, bt541);

	error = zinitix_init_regulators(bt541);
	if (error) {
	dev_err(&client->dev,
	"Failed to initialize regulators: %d\n", error);
	return error;
	}

	error = zinitix_init_input_dev(bt541);
	if (error) {
	dev_err(&client->dev,
	"Failed to initialize input device: %d\n", error);
	return error;
	}

	error = device_property_read_u32(&client->dev, "zinitix,mode",
	&bt541->zinitix_mode);
	if (error < 0) {
	/* fall back to mode 2 */
	bt541->zinitix_mode = DEFAULT_TOUCH_POINT_MODE;
	}

	if (bt541->zinitix_mode != 2) {
	/*
	* If there are devices that don't support mode 2, support
	* for other modes (0, 1) will be needed.
	*/
	dev_err(&client->dev,
	"Malformed zinitix,mode property, must be 2 (supplied: %d)\n",
	bt541->zinitix_mode);
	return -EINVAL;
	}

	irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
	error = devm_request_threaded_irq(&client->dev, client->irq,
	NULL, zinitix_ts_irq_handler,
	IRQF_ONESHOT, client->name, bt541);
	if (error) {
	dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
	return error;
	}

	return 0;
	}

	static int __maybe_unused zinitix_suspend(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct bt541_ts_data *bt541 = i2c_get_clientdata(client);

	mutex_lock(&bt541->input_dev->mutex);

	if (bt541->input_dev->users)
	zinitix_stop(bt541);

	mutex_unlock(&bt541->input_dev->mutex);

	return 0;
	}

	static int __maybe_unused zinitix_resume(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct bt541_ts_data *bt541 = i2c_get_clientdata(client);
	int ret = 0;

	mutex_lock(&bt541->input_dev->mutex);

	if (bt541->input_dev->users)
	ret = zinitix_start(bt541);

	mutex_unlock(&bt541->input_dev->mutex);

	return ret;
	}

	static SIMPLE_DEV_PM_OPS(zinitix_pm_ops, zinitix_suspend, zinitix_resume);

	#ifdef CONFIG_OF
	static const struct of_device_id zinitix_of_match[] = {
	{ .compatible = "zinitix,bt541" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, zinitix_of_match);
	#endif

	static struct i2c_driver zinitix_ts_driver = {
	.probe_new = zinitix_ts_probe,
	.driver = {
	.name = "Zinitix-TS",
	.pm = &zinitix_pm_ops,
	.of_match_table = of_match_ptr(zinitix_of_match),
	},
	};
	module_i2c_driver(zinitix_ts_driver);

	MODULE_AUTHOR("Michael Srba <Michael.Srba@seznam.cz>");
	MODULE_DESCRIPTION("Zinitix touchscreen driver");
	MODULE_LICENSE("GPL v2");