drivers/input/touchscreen/synaptics_dsx_2.6/synaptics_dsx_rmi_hid_i2c.c

/*
 * Synaptics DSX touchscreen driver
 *
 * Copyright (C) 2012-2015 Synaptics Incorporated. All rights reserved.
 *
 * Copyright (C) 2012 Alexandra Chin <alexandra.chin@tw.synaptics.com>
 * Copyright (C) 2012 Scott Lin <scott.lin@tw.synaptics.com>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * INFORMATION CONTAINED IN THIS DOCUMENT IS PROVIDED "AS-IS," AND SYNAPTICS
 * EXPRESSLY DISCLAIMS ALL EXPRESS AND IMPLIED WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE,
 * AND ANY WARRANTIES OF NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHTS.
 * IN NO EVENT SHALL SYNAPTICS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OF THE INFORMATION CONTAINED IN THIS DOCUMENT, HOWEVER CAUSED
 * AND BASED ON ANY THEORY OF LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, AND EVEN IF SYNAPTICS WAS ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE. IF A TRIBUNAL OF COMPETENT JURISDICTION DOES
 * NOT PERMIT THE DISCLAIMER OF DIRECT DAMAGES OR ANY OTHER DAMAGES, SYNAPTICS'
 * TOTAL CUMULATIVE LIABILITY TO ANY PARTY SHALL NOT EXCEED ONE HUNDRED U.S.
 * DOLLARS.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/gpio.h>
#include <linux/types.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/input/synaptics_dsx_v2_6.h>
#include "synaptics_dsx_core.h"

#define SYN_I2C_RETRY_TIMES 10

#define REPORT_ID_GET_BLOB 0x07
#define REPORT_ID_WRITE 0x09
#define REPORT_ID_READ_ADDRESS 0x0a
#define REPORT_ID_READ_DATA 0x0b
#define REPORT_ID_SET_RMI_MODE 0x0f

#define PREFIX_USAGE_PAGE_1BYTE 0x05
#define PREFIX_USAGE_PAGE_2BYTES 0x06
#define PREFIX_USAGE 0x09
#define PREFIX_REPORT_ID 0x85
#define PREFIX_REPORT_COUNT_1BYTE 0x95
#define PREFIX_REPORT_COUNT_2BYTES 0x96

#define USAGE_GET_BLOB 0xc5
#define USAGE_WRITE 0x02
#define USAGE_READ_ADDRESS 0x03
#define USAGE_READ_DATA 0x04
#define USAGE_SET_MODE 0x06

#define FEATURE_REPORT_TYPE 0x03

#define VENDOR_DEFINED_PAGE 0xff00

#define BLOB_REPORT_SIZE 256

#define RESET_COMMAND 0x01
#define GET_REPORT_COMMAND 0x02
#define SET_REPORT_COMMAND 0x03
#define SET_POWER_COMMAND 0x08

#define FINGER_MODE 0x00
#define RMI_MODE 0x02

struct hid_report_info {
	unsigned char get_blob_id;
	unsigned char write_id;
	unsigned char read_addr_id;
	unsigned char read_data_id;
	unsigned char set_mode_id;
	unsigned int blob_size;
};

static struct hid_report_info hid_report;

struct hid_device_descriptor {
	unsigned short device_descriptor_length;
	unsigned short format_version;
	unsigned short report_descriptor_length;
	unsigned short report_descriptor_index;
	unsigned short input_register_index;
	unsigned short input_report_max_length;
	unsigned short output_register_index;
	unsigned short output_report_max_length;
	unsigned short command_register_index;
	unsigned short data_register_index;
	unsigned short vendor_id;
	unsigned short product_id;
	unsigned short version_id;
	unsigned int reserved;
};

static struct hid_device_descriptor hid_dd;

struct i2c_rw_buffer {
	unsigned char *read;
	unsigned char *write;
	unsigned short read_size;
	unsigned short write_size;
};

static struct i2c_rw_buffer buffer;

#ifdef CONFIG_OF
static int parse_dt(struct device *dev, struct synaptics_dsx_board_data *bdata)
{
	int retval;
	u32 value;
	const char *name;
	struct property *prop;
	struct device_node *np = dev->of_node;

	bdata->irq_gpio = of_get_named_gpio_flags(np,
			"synaptics,irq-gpio", 0,
			(enum of_gpio_flags *)&bdata->irq_flags);

	retval = of_property_read_u32(np, "synaptics,irq-on-state",
			&value);
	if (retval < 0)
		bdata->irq_on_state = 0;
	else
		bdata->irq_on_state = value;

	retval = of_property_read_string(np, "synaptics,pwr-reg-name", &name);
	if (retval < 0)
		bdata->pwr_reg_name = NULL;
	else
		bdata->pwr_reg_name = name;

	retval = of_property_read_string(np, "synaptics,bus-reg-name", &name);
	if (retval < 0)
		bdata->bus_reg_name = NULL;
	else
		bdata->bus_reg_name = name;

	prop = of_find_property(np, "synaptics,power-gpio", NULL);
	if (prop && prop->length) {
		bdata->power_gpio = of_get_named_gpio_flags(np,
				"synaptics,power-gpio", 0, NULL);
		retval = of_property_read_u32(np, "synaptics,power-on-state",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,power-on-state property\n",
					__func__);
			return retval;
		} else {
			bdata->power_on_state = value;
		}
	} else {
		bdata->power_gpio = -1;
	}

	prop = of_find_property(np, "synaptics,power-delay-ms", NULL);
	if (prop && prop->length) {
		retval = of_property_read_u32(np, "synaptics,power-delay-ms",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,power-delay-ms property\n",
					__func__);
			return retval;
		} else {
			bdata->power_delay_ms = value;
		}
	} else {
		bdata->power_delay_ms = 0;
	}

	prop = of_find_property(np, "synaptics,reset-gpio", NULL);
	if (prop && prop->length) {
		bdata->reset_gpio = of_get_named_gpio_flags(np,
				"synaptics,reset-gpio", 0, NULL);
		retval = of_property_read_u32(np, "synaptics,reset-on-state",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,reset-on-state property\n",
					__func__);
			return retval;
		} else {
			bdata->reset_on_state = value;
		}
		retval = of_property_read_u32(np, "synaptics,reset-active-ms",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,reset-active-ms property\n",
					__func__);
			return retval;
		} else {
			bdata->reset_active_ms = value;
		}
	} else {
		bdata->reset_gpio = -1;
	}

	prop = of_find_property(np, "synaptics,reset-delay-ms", NULL);
	if (prop && prop->length) {
		retval = of_property_read_u32(np, "synaptics,reset-delay-ms",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,reset-delay-ms property\n",
					__func__);
			return retval;
		} else {
			bdata->reset_delay_ms = value;
		}
	} else {
		bdata->reset_delay_ms = 0;
	}

	prop = of_find_property(np, "synaptics,dev-dscrptr-addr", NULL);
	if (prop && prop->length) {
		retval = of_property_read_u32(np, "synaptics,dev-dscrptr-addr",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,dev-dscrptr-addr property\n",
					__func__);
			return retval;
		} else {
			bdata->device_descriptor_addr = (unsigned short)value;
		}
	} else {
		bdata->device_descriptor_addr = 0;
	}

	prop = of_find_property(np, "synaptics,max-y-for-2d", NULL);
	if (prop && prop->length) {
		retval = of_property_read_u32(np, "synaptics,max-y-for-2d",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,max-y-for-2d property\n",
					__func__);
			return retval;
		} else {
			bdata->max_y_for_2d = value;
		}
	} else {
		bdata->max_y_for_2d = -1;
	}

	prop = of_find_property(np, "synaptics,swap-axes", NULL);
	bdata->swap_axes = prop > 0 ? true : false;

	prop = of_find_property(np, "synaptics,x-flip", NULL);
	bdata->x_flip = prop > 0 ? true : false;

	prop = of_find_property(np, "synaptics,y-flip", NULL);
	bdata->y_flip = prop > 0 ? true : false;

	prop = of_find_property(np, "synaptics,ub-i2c-addr", NULL);
	if (prop && prop->length) {
		retval = of_property_read_u32(np, "synaptics,ub-i2c-addr",
				&value);
		if (retval < 0) {
			dev_err(dev, "%s: Unable to read synaptics,ub-i2c-addr property\n",
					__func__);
			return retval;
		} else {
			bdata->ub_i2c_addr = (unsigned short)value;
		}
	} else {
		bdata->ub_i2c_addr = -1;
	}

	prop = of_find_property(np, "synaptics,cap-button-codes", NULL);
	if (prop && prop->length) {
		bdata->cap_button_map->map = devm_kzalloc(dev,
				prop->length,
				GFP_KERNEL);
		if (!bdata->cap_button_map->map)
			return -ENOMEM;
		bdata->cap_button_map->nbuttons = prop->length / sizeof(u32);
		retval = of_property_read_u32_array(np,
				"synaptics,cap-button-codes",
				bdata->cap_button_map->map,
				bdata->cap_button_map->nbuttons);
		if (retval < 0) {
			bdata->cap_button_map->nbuttons = 0;
			bdata->cap_button_map->map = NULL;
		}
	} else {
		bdata->cap_button_map->nbuttons = 0;
		bdata->cap_button_map->map = NULL;
	}

	prop = of_find_property(np, "synaptics,vir-button-codes", NULL);
	if (prop && prop->length) {
		bdata->vir_button_map->map = devm_kzalloc(dev,
				prop->length,
				GFP_KERNEL);
		if (!bdata->vir_button_map->map)
			return -ENOMEM;
		bdata->vir_button_map->nbuttons = prop->length / sizeof(u32);
		bdata->vir_button_map->nbuttons /= 5;
		retval = of_property_read_u32_array(np,
				"synaptics,vir-button-codes",
				bdata->vir_button_map->map,
				bdata->vir_button_map->nbuttons * 5);
		if (retval < 0) {
			bdata->vir_button_map->nbuttons = 0;
			bdata->vir_button_map->map = NULL;
		}
	} else {
		bdata->vir_button_map->nbuttons = 0;
		bdata->vir_button_map->map = NULL;
	}

	return 0;
}
#endif

static int do_i2c_transfer(struct i2c_client *client, struct i2c_msg *msg)
{
	unsigned char retry;

	for (retry = 0; retry < SYN_I2C_RETRY_TIMES; retry++) {
		if (i2c_transfer(client->adapter, msg, 1) == 1)
			break;
		dev_err(&client->dev,
				"%s: I2C retry %d\n",
				__func__, retry + 1);
		msleep(20);
	}

	if (retry == SYN_I2C_RETRY_TIMES) {
		dev_err(&client->dev,
				"%s: I2C transfer over retry limit\n",
				__func__);
		return -EIO;
	}

	return 0;
}

static int check_buffer(unsigned char **buffer, unsigned short *buffer_size,
		unsigned short length)
{
	if (*buffer_size < length) {
		if (*buffer_size)
			kfree(*buffer);
		*buffer = kzalloc(length, GFP_KERNEL);
		if (!(*buffer))
			return -ENOMEM;
		*buffer_size = length;
	}

	return 0;
}

static int generic_read(struct i2c_client *client, unsigned short length)
{
	int retval;
	struct i2c_msg msg[] = {
		{
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = length,
		}
	};

	check_buffer(&buffer.read, &buffer.read_size, length);
	msg[0].buf = buffer.read;

	retval = do_i2c_transfer(client, msg);

	return retval;
}

static int generic_write(struct i2c_client *client, unsigned short length)
{
	int retval;
	struct i2c_msg msg[] = {
		{
			.addr = client->addr,
			.flags = 0,
			.len = length,
			.buf = buffer.write,
		}
	};

	retval = do_i2c_transfer(client, msg);

	return retval;
}

static void traverse_report_descriptor(unsigned int *index)
{
	unsigned char size;
	unsigned char *buf = buffer.read;

	size = buf[*index] & MASK_2BIT;
	switch (size) {
	case 0: /* 0 bytes */
		*index += 1;
		break;
	case 1: /* 1 byte */
		*index += 2;
		break;
	case 2: /* 2 bytes */
		*index += 3;
		break;
	case 3: /* 4 bytes */
		*index += 5;
		break;
	default:
		break;
	}

	return;
}

static void find_blob_size(unsigned int index)
{
	unsigned int ii = index;
	unsigned char *buf = buffer.read;

	while (ii < hid_dd.report_descriptor_length) {
		if (buf[ii] == PREFIX_REPORT_COUNT_1BYTE) {
			hid_report.blob_size = buf[ii + 1];
			return;
		} else if (buf[ii] == PREFIX_REPORT_COUNT_2BYTES) {
			hid_report.blob_size = buf[ii + 1] | (buf[ii + 2] << 8);
			return;
		}
		traverse_report_descriptor(&ii);
	}

	return;
}

static void find_reports(unsigned int index)
{
	unsigned int ii = index;
	unsigned char *buf = buffer.read;
	static unsigned int report_id_index;
	static unsigned char report_id;
	static unsigned short usage_page;

	if (buf[ii] == PREFIX_REPORT_ID) {
		report_id = buf[ii + 1];
		report_id_index = ii;
		return;
	}

	if (buf[ii] == PREFIX_USAGE_PAGE_1BYTE) {
		usage_page = buf[ii + 1];
		return;
	} else if (buf[ii] == PREFIX_USAGE_PAGE_2BYTES) {
		usage_page = buf[ii + 1] | (buf[ii + 2] << 8);
		return;
	}

	if ((usage_page == VENDOR_DEFINED_PAGE) && (buf[ii] == PREFIX_USAGE)) {
		switch (buf[ii + 1]) {
		case USAGE_GET_BLOB:
			hid_report.get_blob_id = report_id;
			find_blob_size(report_id_index);
			break;
		case USAGE_WRITE:
			hid_report.write_id = report_id;
			break;
		case USAGE_READ_ADDRESS:
			hid_report.read_addr_id = report_id;
			break;
		case USAGE_READ_DATA:
			hid_report.read_data_id = report_id;
			break;
		case USAGE_SET_MODE:
			hid_report.set_mode_id = report_id;
			break;
		default:
			break;
		}
	}

	return;
}

static int parse_report_descriptor(struct synaptics_rmi4_data *rmi4_data)
{
	int retval;
	unsigned int ii = 0;
	unsigned char *buf;
	struct i2c_client *i2c = to_i2c_client(rmi4_data->pdev->dev.parent);

	buffer.write[0] = hid_dd.report_descriptor_index & MASK_8BIT;
	buffer.write[1] = hid_dd.report_descriptor_index >> 8;
	retval = generic_write(i2c, 2);
	if (retval < 0)
		return retval;
	retval = generic_read(i2c, hid_dd.report_descriptor_length);
	if (retval < 0)
		return retval;

	buf = buffer.read;

	hid_report.get_blob_id = REPORT_ID_GET_BLOB;
	hid_report.write_id = REPORT_ID_WRITE;
	hid_report.read_addr_id = REPORT_ID_READ_ADDRESS;
	hid_report.read_data_id = REPORT_ID_READ_DATA;
	hid_report.set_mode_id = REPORT_ID_SET_RMI_MODE;
	hid_report.blob_size = BLOB_REPORT_SIZE;

	while (ii < hid_dd.report_descriptor_length) {
		find_reports(ii);
		traverse_report_descriptor(&ii);
	}

	return 0;
}

static int switch_to_rmi(struct synaptics_rmi4_data *rmi4_data)
{
	int retval;
	struct i2c_client *i2c = to_i2c_client(rmi4_data->pdev->dev.parent);

	mutex_lock(&rmi4_data->rmi4_io_ctrl_mutex);

	check_buffer(&buffer.write, &buffer.write_size, 11);

	/* set rmi mode */
	buffer.write[0] = hid_dd.command_register_index & MASK_8BIT;
	buffer.write[1] = hid_dd.command_register_index >> 8;
	buffer.write[2] = (FEATURE_REPORT_TYPE << 4) | hid_report.set_mode_id;
	buffer.write[3] = SET_REPORT_COMMAND;
	buffer.write[4] = hid_report.set_mode_id;
	buffer.write[5] = hid_dd.data_register_index & MASK_8BIT;
	buffer.write[6] = hid_dd.data_register_index >> 8;
	buffer.write[7] = 0x04;
	buffer.write[8] = 0x00;
	buffer.write[9] = hid_report.set_mode_id;
	buffer.write[10] = RMI_MODE;

	retval = generic_write(i2c, 11);

	mutex_unlock(&rmi4_data->rmi4_io_ctrl_mutex);

	return retval;
}

static int check_report_mode(struct synaptics_rmi4_data *rmi4_data)
{
	int retval;
	unsigned short report_size;
	struct i2c_client *i2c = to_i2c_client(rmi4_data->pdev->dev.parent);

	mutex_lock(&rmi4_data->rmi4_io_ctrl_mutex);

	check_buffer(&buffer.write, &buffer.write_size, 7);

	buffer.write[0] = hid_dd.command_register_index & MASK_8BIT;
	buffer.write[1] = hid_dd.command_register_index >> 8;
	buffer.write[2] = (FEATURE_REPORT_TYPE << 4) | hid_report.set_mode_id;
	buffer.write[3] = GET_REPORT_COMMAND;
	buffer.write[4] = hid_report.set_mode_id;
	buffer.write[5] = hid_dd.data_register_index & MASK_8BIT;
	buffer.write[6] = hid_dd.data_register_index >> 8;

	retval = generic_write(i2c, 7);
	if (retval < 0)
		goto exit;

	retval = generic_read(i2c, 2);
	if (retval < 0)
		goto exit;

	report_size = (buffer.read[1] << 8) | buffer.read[0];

	retval = generic_write(i2c, 7);
	if (retval < 0)
		goto exit;

	retval = generic_read(i2c, report_size);
	if (retval < 0)
		goto exit;

	retval = buffer.read[3];
	dev_dbg(rmi4_data->pdev->dev.parent,
			"%s: Report mode = %d\n",
			__func__, retval);

exit:
	mutex_unlock(&rmi4_data->rmi4_io_ctrl_mutex);

	return retval;
}

static int hid_i2c_init(struct synaptics_rmi4_data *rmi4_data)
{
	int retval;
	struct i2c_client *i2c = to_i2c_client(rmi4_data->pdev->dev.parent);
	const struct synaptics_dsx_board_data *bdata =
			rmi4_data->hw_if->board_data;

	mutex_lock(&rmi4_data->rmi4_io_ctrl_mutex);

	check_buffer(&buffer.write, &buffer.write_size, 6);

	/* read device descriptor */
	buffer.write[0] = bdata->device_descriptor_addr & MASK_8BIT;
	buffer.write[1] = bdata->device_descriptor_addr >> 8;
	retval = generic_write(i2c, 2);
	if (retval < 0)
		goto exit;
	retval = generic_read(i2c, sizeof(hid_dd));
	if (retval < 0)
		goto exit;
	retval = secure_memcpy((unsigned char *)&hid_dd,
			sizeof(struct hid_device_descriptor),
			buffer.read,
			buffer.read_size,
			sizeof(hid_dd));
	if (retval < 0) {
		dev_err(rmi4_data->pdev->dev.parent,
				"%s: Failed to copy device descriptor data\n",
				__func__);
		goto exit;
	}

	retval = parse_report_descriptor(rmi4_data);
	if (retval < 0)
		goto exit;

	/* set power */
	buffer.write[0] = hid_dd.command_register_index & MASK_8BIT;
	buffer.write[1] = hid_dd.command_register_index >> 8;
	buffer.write[2] = 0x00;
	buffer.write[3] = SET_POWER_COMMAND;
	retval = generic_write(i2c, 4);
	if (retval < 0)
		goto exit;

	/* reset */
	buffer.write[0] = hid_dd.command_register_index & MASK_8BIT;
	buffer.write[1] = hid_dd.command_register_index >> 8;
	buffer.write[2] = 0x00;
	buffer.write[3] = RESET_COMMAND;
	retval = generic_write(i2c, 4);
	if (retval < 0)
		goto exit;

	while (gpio_get_value(bdata->irq_gpio))
		msleep(20);

	retval = generic_read(i2c, hid_dd.input_report_max_length);
	if (retval < 0)
		goto exit;

	/* get blob */
	buffer.write[0] = hid_dd.command_register_index & MASK_8BIT;
	buffer.write[1] = hid_dd.command_register_index >> 8;
	buffer.write[2] = (FEATURE_REPORT_TYPE << 4) | hid_report.get_blob_id;
	buffer.write[3] = 0x02;
	buffer.write[4] = hid_dd.data_register_index & MASK_8BIT;
	buffer.write[5] = hid_dd.data_register_index >> 8;

	retval = generic_write(i2c, 6);
	if (retval < 0)
		goto exit;

	msleep(20);

	retval = generic_read(i2c, hid_report.blob_size + 3);
	if (retval < 0)
		goto exit;

exit:
	mutex_unlock(&rmi4_data->rmi4_io_ctrl_mutex);

	if (retval < 0) {
		dev_err(rmi4_data->pdev->dev.parent,
				"%s: Failed to initialize HID/I2C interface\n",
				__func__);
		return retval;
	}

	retval = switch_to_rmi(rmi4_data);

	return retval;
}

static int synaptics_rmi4_i2c_read(struct synaptics_rmi4_data *rmi4_data,
		unsigned short addr, unsigned char *data, unsigned short length)
{
	int retval;
	unsigned char retry;
	unsigned char recover = 1;
	unsigned short report_length;
	struct i2c_client *i2c = to_i2c_client(rmi4_data->pdev->dev.parent);
	struct i2c_msg msg[] = {
		{
			.addr = i2c->addr,
			.flags = 0,
			.len = hid_dd.output_report_max_length + 2,
		},
		{
			.addr = i2c->addr,
			.flags = I2C_M_RD,
			.len = length + 4,
		},
	};

recover:
	mutex_lock(&rmi4_data->rmi4_io_ctrl_mutex);

	check_buffer(&buffer.write, &buffer.write_size,
			hid_dd.output_report_max_length + 2);
	msg[0].buf = buffer.write;
	buffer.write[0] = hid_dd.output_register_index & MASK_8BIT;
	buffer.write[1] = hid_dd.output_register_index >> 8;
	buffer.write[2] = hid_dd.output_report_max_length & MASK_8BIT;
	buffer.write[3] = hid_dd.output_report_max_length >> 8;
	buffer.write[4] = hid_report.read_addr_id;
	buffer.write[5] = 0x00;
	buffer.write[6] = addr & MASK_8BIT;
	buffer.write[7] = addr >> 8;
	buffer.write[8] = length & MASK_8BIT;
	buffer.write[9] = length >> 8;

	check_buffer(&buffer.read, &buffer.read_size, length + 4);
	msg[1].buf = buffer.read;

	retval = do_i2c_transfer(i2c, &msg[0]);
	if (retval != 0)
		goto exit;

	retry = 0;
	do {
		retval = do_i2c_transfer(i2c, &msg[1]);
		if (retval == 0)
			retval = length;
		else
			goto exit;

		report_length = (buffer.read[1] << 8) | buffer.read[0];
		if (report_length == hid_dd.input_report_max_length) {
			retval = secure_memcpy(&data[0], length,
					&buffer.read[4], buffer.read_size - 4,
					length);
			if (retval < 0) {
				dev_err(rmi4_data->pdev->dev.parent,
						"%s: Failed to copy data\n",
						__func__);
			} else {
				retval = length;
			}
			goto exit;
		}

		msleep(20);
		retry++;
	} while (retry < SYN_I2C_RETRY_TIMES);

	dev_err(rmi4_data->pdev->dev.parent,
			"%s: Failed to receive read report\n",
			__func__);
	retval = -EIO;

exit:
	mutex_unlock(&rmi4_data->rmi4_io_ctrl_mutex);

	if ((retval != length) && (recover == 1)) {
		recover = 0;
		if (check_report_mode(rmi4_data) != RMI_MODE) {
			retval = hid_i2c_init(rmi4_data);
			if (retval == 0)
				goto recover;
		}
	}

	return retval;
}

static int synaptics_rmi4_i2c_write(struct synaptics_rmi4_data *rmi4_data,
		unsigned short addr, unsigned char *data, unsigned short length)
{
	int retval;
	unsigned char recover = 1;
	unsigned char msg_length;
	struct i2c_client *i2c = to_i2c_client(rmi4_data->pdev->dev.parent);
	struct i2c_msg msg[] = {
		{
			.addr = i2c->addr,
			.flags = 0,
		}
	};

	if ((length + 10) < (hid_dd.output_report_max_length + 2))
		msg_length = hid_dd.output_report_max_length + 2;
	else
		msg_length = length + 10;

recover:
	mutex_lock(&rmi4_data->rmi4_io_ctrl_mutex);

	check_buffer(&buffer.write, &buffer.write_size, msg_length);
	msg[0].len = msg_length;
	msg[0].buf = buffer.write;
	buffer.write[0] = hid_dd.output_register_index & MASK_8BIT;
	buffer.write[1] = hid_dd.output_register_index >> 8;
	buffer.write[2] = hid_dd.output_report_max_length & MASK_8BIT;
	buffer.write[3] = hid_dd.output_report_max_length >> 8;
	buffer.write[4] = hid_report.write_id;
	buffer.write[5] = 0x00;
	buffer.write[6] = addr & MASK_8BIT;
	buffer.write[7] = addr >> 8;
	buffer.write[8] = length & MASK_8BIT;
	buffer.write[9] = length >> 8;
	retval = secure_memcpy(&buffer.write[10], buffer.write_size - 10,
			&data[0], length, length);
	if (retval < 0) {
		dev_err(rmi4_data->pdev->dev.parent,
				"%s: Failed to copy data\n",
				__func__);
	} else {
		retval = do_i2c_transfer(i2c, msg);
		if (retval == 0)
			retval = length;
	}

	mutex_unlock(&rmi4_data->rmi4_io_ctrl_mutex);

	if ((retval != length) && (recover == 1)) {
		recover = 0;
		if (check_report_mode(rmi4_data) != RMI_MODE) {
			retval = hid_i2c_init(rmi4_data);
			if (retval == 0)
				goto recover;
		}
	}

	return retval;
}

static struct synaptics_dsx_bus_access bus_access = {
	.type = BUS_I2C,
	.read = synaptics_rmi4_i2c_read,
	.write = synaptics_rmi4_i2c_write,
};

static struct synaptics_dsx_hw_interface hw_if;

static struct platform_device *synaptics_dsx_i2c_device;

static void synaptics_rmi4_i2c_dev_release(struct device *dev)
{
	kfree(synaptics_dsx_i2c_device);

	return;
}

static int synaptics_rmi4_i2c_probe(struct i2c_client *client,
		const struct i2c_device_id *dev_id)
{
	int retval;

	if (!i2c_check_functionality(client->adapter,
			I2C_FUNC_SMBUS_BYTE_DATA)) {
		dev_err(&client->dev,
				"%s: SMBus byte data commands not supported by host\n",
				__func__);
		return -EIO;
	}

	synaptics_dsx_i2c_device = kzalloc(
			sizeof(struct platform_device),
			GFP_KERNEL);
	if (!synaptics_dsx_i2c_device) {
		dev_err(&client->dev,
				"%s: Failed to allocate memory for synaptics_dsx_i2c_device\n",
				__func__);
		return -ENOMEM;
	}

#ifdef CONFIG_OF
	if (client->dev.of_node) {
		hw_if.board_data = devm_kzalloc(&client->dev,
				sizeof(struct synaptics_dsx_board_data),
				GFP_KERNEL);
		if (!hw_if.board_data) {
			dev_err(&client->dev,
					"%s: Failed to allocate memory for board data\n",
					__func__);
			return -ENOMEM;
		}
		hw_if.board_data->cap_button_map = devm_kzalloc(&client->dev,
				sizeof(struct synaptics_dsx_button_map),
				GFP_KERNEL);
		if (!hw_if.board_data->cap_button_map) {
			dev_err(&client->dev,
					"%s: Failed to allocate memory for 0D button map\n",
					__func__);
			return -ENOMEM;
		}
		hw_if.board_data->vir_button_map = devm_kzalloc(&client->dev,
				sizeof(struct synaptics_dsx_button_map),
				GFP_KERNEL);
		if (!hw_if.board_data->vir_button_map) {
			dev_err(&client->dev,
					"%s: Failed to allocate memory for virtual button map\n",
					__func__);
			return -ENOMEM;
		}
		parse_dt(&client->dev, hw_if.board_data);
	}
#else
	hw_if.board_data = client->dev.platform_data;
#endif

	hw_if.bus_access = &bus_access;
	hw_if.bl_hw_init = switch_to_rmi;
	hw_if.ui_hw_init = hid_i2c_init;

	synaptics_dsx_i2c_device->name = PLATFORM_DRIVER_NAME;
	synaptics_dsx_i2c_device->id = 0;
	synaptics_dsx_i2c_device->num_resources = 0;
	synaptics_dsx_i2c_device->dev.parent = &client->dev;
	synaptics_dsx_i2c_device->dev.platform_data = &hw_if;
	synaptics_dsx_i2c_device->dev.release = synaptics_rmi4_i2c_dev_release;

	retval = platform_device_register(synaptics_dsx_i2c_device);
	if (retval) {
		dev_err(&client->dev,
				"%s: Failed to register platform device\n",
				__func__);
		return -ENODEV;
	}

	return 0;
}

static int synaptics_rmi4_i2c_remove(struct i2c_client *client)
{
	if (buffer.read_size)
		kfree(buffer.read);

	if (buffer.write_size)
		kfree(buffer.write);

	platform_device_unregister(synaptics_dsx_i2c_device);

	return 0;
}

static const struct i2c_device_id synaptics_rmi4_id_table[] = {
	{I2C_DRIVER_NAME, 0},
	{},
};
MODULE_DEVICE_TABLE(i2c, synaptics_rmi4_id_table);

#ifdef CONFIG_OF
static struct of_device_id synaptics_rmi4_of_match_table[] = {
	{
		.compatible = "synaptics,dsx-rmi-hid-i2c",
	},
	{},
};
MODULE_DEVICE_TABLE(of, synaptics_rmi4_of_match_table);
#else
#define synaptics_rmi4_of_match_table NULL
#endif

static struct i2c_driver synaptics_rmi4_i2c_driver = {
	.driver = {
		.name = I2C_DRIVER_NAME,
		.owner = THIS_MODULE,
		.of_match_table = synaptics_rmi4_of_match_table,
	},
	.probe = synaptics_rmi4_i2c_probe,
	.remove = synaptics_rmi4_i2c_remove,
	.id_table = synaptics_rmi4_id_table,
};

int synaptics_rmi4_bus_init_v26(void)
{
	return i2c_add_driver(&synaptics_rmi4_i2c_driver);
}
EXPORT_SYMBOL(synaptics_rmi4_bus_init_v26);

void synaptics_rmi4_bus_exit_v26(void)
{
	i2c_del_driver(&synaptics_rmi4_i2c_driver);

	return;
}
EXPORT_SYMBOL(synaptics_rmi4_bus_exit_v26);

MODULE_AUTHOR("Synaptics, Inc.");
MODULE_DESCRIPTION("Synaptics DSX I2C Bus Support Module");
MODULE_LICENSE("GPL v2");