goodix_brl_spi.c - kernel/google-modules/touch/goodix_touch - Git at Google

 /*
  * Goodix Touchscreen Driver
  * Copyright (C) 2020 - 2021 Goodix, Inc.
  *
  * 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 a reference
  * to you, when you are integrating the GOODiX's CTP IC into your system,
  * 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.
  *
  */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/spi/spi.h>
 #ifdef CONFIG_GOOG_TOUCH_INTERFACE
 #include <goog_touch_interface.h>
 #endif

 #include "goodix_ts_core.h"
 #define TS_DRIVER_NAME "gtx8_spi"

 #define SPI_TRANS_PREFIX_LEN 1
 #define REGISTER_WIDTH 4
 #define SPI_READ_DUMMY_LEN 4
 #define SPI_READ_PREFIX_LEN                                                    \
 	(SPI_TRANS_PREFIX_LEN + REGISTER_WIDTH + SPI_READ_DUMMY_LEN)
 #define SPI_WRITE_PREFIX_LEN (SPI_TRANS_PREFIX_LEN + REGISTER_WIDTH)
 #define SPI_PREALLOC_RX_BUF_SIZE 4096 + SPI_READ_PREFIX_LEN
 #define SPI_PREALLOC_TX_BUF_SIZE 4096 + SPI_WRITE_PREFIX_LEN

 #define SPI_WRITE_FLAG 0xF0
 #define SPI_READ_FLAG 0xF1

 /**
  * goodix_spi_read_bra- read device register through spi bus
  * @dev: pointer to device data
  * @addr: register address
  * @data: read buffer
  * @len: bytes to read
  * return: 0 - read ok, < 0 - spi transter error
  */
 static int goodix_spi_read_bra(struct device *dev, unsigned int addr,
 	unsigned char *data, unsigned int len)
 {
 	struct spi_device *spi = to_spi_device(dev);
 	struct goodix_ts_core *cd = dev_get_drvdata(dev);
 	struct goodix_bus_interface *bus = cd->bus;
 	u8 *rx_buf = NULL;
 	u8 *tx_buf = NULL;
 	struct spi_transfer xfers;
 	struct spi_message spi_msg;
 	int ret = 0;
 	int buf_len = SPI_READ_PREFIX_LEN + len;

 	mutex_lock(&bus->mutex);

 	if (buf_len <= SPI_PREALLOC_RX_BUF_SIZE &&
 		buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
 		rx_buf = bus->rx_buf;
 		tx_buf = bus->tx_buf;
 		memset(tx_buf, 0, buf_len);
 	} else {
 		rx_buf = kzalloc(buf_len, GFP_KERNEL);
 		if (!rx_buf) {
 			ts_err("alloc rx_buf failed, size:%d", buf_len);
 			ret = -ENOMEM;
 			goto err_alloc_rx_buf;
 		}

 		tx_buf = kzalloc(buf_len, GFP_KERNEL);
 		if (!tx_buf) {
 			ts_err("alloc tx_buf failed, size:%d", buf_len);
 			ret = -ENOMEM;
 			goto err_alloc_tx_buf;
 		}
 	}

 	spi_message_init(&spi_msg);
 	memset(&xfers, 0, sizeof(xfers));

 	/*spi_read tx_buf format: 0xF1 + addr(4bytes) + data*/
 	tx_buf[0] = SPI_READ_FLAG;
 	tx_buf[1] = (addr >> 24) & 0xFF;
 	tx_buf[2] = (addr >> 16) & 0xFF;
 	tx_buf[3] = (addr >> 8) & 0xFF;
 	tx_buf[4] = addr & 0xFF;
 	tx_buf[5] = 0xFF;
 	tx_buf[6] = 0xFF;
 	tx_buf[7] = 0xFF;
 	tx_buf[8] = 0xFF;

 	xfers.tx_buf = tx_buf;
 	xfers.rx_buf = rx_buf;
 	xfers.len = buf_len;
 	xfers.cs_change = 0;
 	spi_message_add_tail(&xfers, &spi_msg);
 	ret = spi_sync(spi, &spi_msg);
 	if (ret < 0) {
 		ts_err("spi transfer error:%d", ret);
 		goto err_spi_transfer;
 	}
 	memcpy(data, &rx_buf[SPI_READ_PREFIX_LEN], len);

 err_spi_transfer:
 	if (tx_buf != bus->tx_buf)
 		kfree(tx_buf);
 err_alloc_tx_buf:
 	if (rx_buf != bus->rx_buf)
 		kfree(rx_buf);
 err_alloc_rx_buf:
 	mutex_unlock(&bus->mutex);
 	return ret;
 }

 static int goodix_spi_read(struct device *dev, unsigned int addr,
 	unsigned char *data, unsigned int len)
 {
 	struct spi_device *spi = to_spi_device(dev);
 	struct goodix_ts_core *cd = dev_get_drvdata(dev);
 	struct goodix_bus_interface *bus = cd->bus;
 	u8 *rx_buf = NULL;
 	u8 *tx_buf = NULL;
 	struct spi_transfer xfers;
 	struct spi_message spi_msg;
 	int ret = 0;
 	int buf_len = SPI_READ_PREFIX_LEN - 1 + len;

 	if (bus->dma_mode_enabled && buf_len >= 64)
 		buf_len = ALIGN(buf_len, 4);

 	mutex_lock(&bus->mutex);

 	if (buf_len <= SPI_PREALLOC_RX_BUF_SIZE &&
 		buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
 		rx_buf = bus->rx_buf;
 		tx_buf = bus->tx_buf;
 		memset(tx_buf, 0, buf_len);
 	} else {
 		rx_buf = kzalloc(buf_len, GFP_KERNEL);
 		if (!rx_buf) {
 			ts_err("alloc rx_buf failed, size:%d", buf_len);
 			ret = -ENOMEM;
 			goto err_alloc_rx_buf;
 		}

 		tx_buf = kzalloc(buf_len, GFP_KERNEL);
 		if (!tx_buf) {
 			ts_err("alloc tx_buf failed, size:%d", buf_len);
 			ret = -ENOMEM;
 			goto err_alloc_tx_buf;
 		}
 	}

 	spi_message_init(&spi_msg);
 	memset(&xfers, 0, sizeof(xfers));

 	/*spi_read tx_buf format: 0xF1 + addr(4bytes) + data*/
 	tx_buf[0] = SPI_READ_FLAG;
 	tx_buf[1] = (addr >> 24) & 0xFF;
 	tx_buf[2] = (addr >> 16) & 0xFF;
 	tx_buf[3] = (addr >> 8) & 0xFF;
 	tx_buf[4] = addr & 0xFF;
 	tx_buf[5] = 0xFF;
 	tx_buf[6] = 0xFF;
 	tx_buf[7] = 0xFF;

 	xfers.tx_buf = tx_buf;
 	xfers.rx_buf = rx_buf;
 	xfers.len = buf_len;
 	xfers.cs_change = 0;
 	if (bus->dma_mode_enabled)
 		xfers.bits_per_word = buf_len >= 64 ? 32 : 8;
 	spi_message_add_tail(&xfers, &spi_msg);
 	ret = spi_sync(spi, &spi_msg);
 	if (ret < 0) {
 		ts_err("spi transfer error:%d", ret);
 		goto err_spi_transfer;
 	}
 	memcpy(data, &rx_buf[SPI_READ_PREFIX_LEN - 1], len);

 err_spi_transfer:
 	if (tx_buf != bus->tx_buf)
 		kfree(tx_buf);
 err_alloc_tx_buf:
 	if (rx_buf != bus->rx_buf)
 		kfree(rx_buf);
 err_alloc_rx_buf:
 	mutex_unlock(&bus->mutex);
 	return ret;
 }

 /* [GOOG]
  * This SPI transaction will direct read into `struct goodix_rx_package`.
  * And, the package are comprised of `SPI prefix header` + `data`.
  */
 static int goodix_spi_read_fast(struct device *dev, unsigned int addr,
 	struct goodix_rx_package *package, unsigned int len)
 {
 	struct spi_device *spi = to_spi_device(dev);
 	struct goodix_ts_core *cd = dev_get_drvdata(dev);
 	struct goodix_bus_interface *bus = cd->bus;
 	u8 *tx_buf = NULL;
 	struct spi_transfer xfers;
 	struct spi_message spi_msg;
 	int ret = 0;
 	int buf_len = SPI_READ_PREFIX_LEN - 1 + len;

 	if (bus->dma_mode_enabled && buf_len >= 64)
 		buf_len = ALIGN(buf_len, 4);

 	if (buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
 		tx_buf = bus->tx_buf;
 	} else {
 		tx_buf = kzalloc(buf_len, GFP_KERNEL);
 		if (!tx_buf) {
 			ts_err("alloc tx_buf failed, size:%d", buf_len);
 			return -ENOMEM;
 		}
 	}

 	spi_message_init(&spi_msg);
 	memset(&xfers, 0, sizeof(xfers));

 	mutex_lock(&bus->mutex);

 	/*spi_read tx_buf format: 0xF1 + addr(4bytes) + data*/
 	tx_buf[0] = SPI_READ_FLAG;
 	tx_buf[1] = (addr >> 24) & 0xFF;
 	tx_buf[2] = (addr >> 16) & 0xFF;
 	tx_buf[3] = (addr >> 8) & 0xFF;
 	tx_buf[4] = addr & 0xFF;
 	tx_buf[5] = 0xFF;
 	tx_buf[6] = 0xFF;
 	tx_buf[7] = 0xFF;

 	xfers.tx_buf = tx_buf;
 	xfers.rx_buf = package->header;
 	xfers.len = buf_len;
 	xfers.cs_change = 0;
 	if (bus->dma_mode_enabled)
 		xfers.bits_per_word = buf_len >= 64 ? 32 : 8;
 	spi_message_add_tail(&xfers, &spi_msg);

 	ret = spi_sync(spi, &spi_msg);

 	mutex_unlock(&bus->mutex);

 	if (ret < 0) {
 		ts_err("spi transfer error:%d", ret);
 		goto err_spi_transfer;
 	}

 err_spi_transfer:
 	if (tx_buf != bus->tx_buf)
 		kfree(tx_buf);
 	return ret;
 }

 /**
  * goodix_spi_write- write device register through spi bus
  * @dev: pointer to device data
  * @addr: register address
  * @data: write buffer
  * @len: bytes to write
  * return: 0 - write ok; < 0 - spi transter error.
  */
 static int goodix_spi_write(struct device *dev, unsigned int addr,
 	unsigned char *data, unsigned int len)
 {
 	struct spi_device *spi = to_spi_device(dev);
 	struct goodix_ts_core *cd = dev_get_drvdata(dev);
 	struct goodix_bus_interface *bus = cd->bus;
 	u8 *tx_buf = NULL;
 	struct spi_transfer xfers;
 	struct spi_message spi_msg;
 	int ret = 0;
 	int buf_len = SPI_WRITE_PREFIX_LEN + len;

 	if (bus->dma_mode_enabled && buf_len >= 64)
 		buf_len = ALIGN(buf_len, 4);

 	if (buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
 		tx_buf = bus->tx_buf;
 	} else {
 		tx_buf = kzalloc(buf_len, GFP_KERNEL);
 		if (!tx_buf) {
 			ts_err("alloc tx_buf failed, size:%d", buf_len);
 			return -ENOMEM;
 		}
 	}

 	spi_message_init(&spi_msg);
 	memset(&xfers, 0, sizeof(xfers));

 	mutex_lock(&bus->mutex);

 	tx_buf[0] = SPI_WRITE_FLAG;
 	tx_buf[1] = (addr >> 24) & 0xFF;
 	tx_buf[2] = (addr >> 16) & 0xFF;
 	tx_buf[3] = (addr >> 8) & 0xFF;
 	tx_buf[4] = addr & 0xFF;
 	memcpy(&tx_buf[SPI_WRITE_PREFIX_LEN], data, len);
 	xfers.tx_buf = tx_buf;
 	xfers.len = buf_len;
 	xfers.cs_change = 0;
 	if (bus->dma_mode_enabled)
 		xfers.bits_per_word = buf_len >= 64 ? 32 : 8;
 	spi_message_add_tail(&xfers, &spi_msg);
 	ret = spi_sync(spi, &spi_msg);

 	mutex_unlock(&bus->mutex);

 	if (ret < 0)
 		ts_err("spi transfer error:%d", ret);

 	if (tx_buf != bus->tx_buf)
 		kfree(tx_buf);
 	return ret;
 }

 static int goodix_spi_probe(struct spi_device *spi)
 {
 	struct goodix_device_resource *dev_res;
 	int ret = 0;

 	ts_info("%s: goodix spi probe in", __func__);

 	/* init spi_device */
 	spi->mode = SPI_MODE_0;
 	spi->bits_per_word = 8;
 	spi->rt = true; /* [GOOG] */

 	ret = spi_setup(spi);
 	if (ret) {
 		ts_err("failed set spi mode, %d", ret);
 		return ret;
 	}

 	dev_res = kzalloc(sizeof(*dev_res), GFP_KERNEL);
 	if (!dev_res)
 		return -ENOMEM;

 	/* get ic type */
 	ret = goodix_get_ic_type(spi->dev.of_node, &dev_res->bus);
 	if (ret < 0)
 		goto err_get_ic_type;

 	dev_res->bus.bus_type = GOODIX_BUS_TYPE_SPI;
 	dev_res->bus.dev = &spi->dev;
 	if (dev_res->bus.ic_type == IC_TYPE_BERLIN_A) {
 		dev_res->bus.read = goodix_spi_read_bra;
 	} else {
 		dev_res->bus.read = goodix_spi_read;
 		dev_res->bus.read_fast = goodix_spi_read_fast;
 	}
 	dev_res->bus.write = goodix_spi_write;

 /* [GOOG]
  * Move goodix_device_register() after `dev_res->bus.dev` assigned.
  * This will help to set the `struct device *dev` early.
  */
 	goodix_device_register(dev_res);

 	dev_res->bus.rx_buf = kzalloc(SPI_PREALLOC_RX_BUF_SIZE, GFP_KERNEL);
 	dev_res->bus.tx_buf = kzalloc(SPI_PREALLOC_TX_BUF_SIZE, GFP_KERNEL);
 	if (!dev_res->bus.rx_buf || !dev_res->bus.tx_buf) {
 		ret = -ENOMEM;
 		goto err_pdev;
 	}
 /*~[GOOG] */
 	mutex_init(&dev_res->bus.mutex);

 	dev_res->bus.dma_mode_enabled = false;
 #ifdef CONFIG_GOOG_TOUCH_INTERFACE
 	dev_res->bus.dma_mode_enabled = goog_check_spi_dma_enabled(spi);
 	ts_info("dma_mode: %s\n", dev_res->bus.dma_mode_enabled ? "enabled" : "disabled");
 #endif

 	// platform device init
 	dev_res->pdev.name = GOODIX_CORE_DRIVER_NAME;
 	dev_res->pdev.id = dev_res->id;
 	dev_res->pdev.num_resources = 0;

 	/* register platform device, then the goodix_ts_core
 	 * module will probe the touch device.
 	 */
 	ret = platform_device_register(&dev_res->pdev);
 	if (ret) {
 		ts_err("failed register goodix platform device, %d", ret);
 		goto err_pdev;
 	}
 	ts_info("spi probe out");
 	return 0;

 err_pdev:
 	kfree(dev_res->bus.rx_buf);
 	kfree(dev_res->bus.tx_buf);
 err_get_ic_type:
 	kfree(dev_res);
 	ts_info("spi probe out, %d", ret);
 	return ret;
 }

 static int goodix_spi_remove(struct spi_device *spi)
 {
 	/* goodix_ts_core_exit() will unregister device(s) */
 	// platform_device_unregister(dev_res->pdev);
 	return 0;
 }

 #ifdef CONFIG_OF
 static const struct of_device_id spi_matches[] = {
 	{
 		.compatible = "goodix,brl-a",
 	},
 	{
 		.compatible = "goodix,brl-b",
 	},
 	{
 		.compatible = "goodix,brl-b,gt7986",
 	},
 	{
 		.compatible = "goodix,brl-d",
 	},
 	{
 		.compatible = "goodix,nottingham",
 	},
 	{},
 };
 #endif

 static const struct spi_device_id spi_id_table[] = {
 	{ TS_DRIVER_NAME, 0 },
 	{},
 };

 static struct spi_driver goodix_spi_driver = {
 	.driver = {
 		.name = TS_DRIVER_NAME,
 		//.owner = THIS_MODULE,
 		.of_match_table = spi_matches,
 	},
 	.id_table = spi_id_table,
 	.probe = goodix_spi_probe,
 	.remove = goodix_spi_remove,
 };

 int goodix_spi_bus_init(void)
 {
 	ts_info("Goodix spi driver init");
 	return spi_register_driver(&goodix_spi_driver);
 }

 void goodix_spi_bus_exit(void)
 {
 	ts_info("Goodix spi driver exit");
 	spi_unregister_driver(&goodix_spi_driver);
 }
	/*
	* Goodix Touchscreen Driver
	* Copyright (C) 2020 - 2021 Goodix, Inc.
	*
	* 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 a reference
	* to you, when you are integrating the GOODiX's CTP IC into your system,
	* 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.
	*
	*/
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/spi/spi.h>
	#ifdef CONFIG_GOOG_TOUCH_INTERFACE
	#include <goog_touch_interface.h>
	#endif

	#include "goodix_ts_core.h"
	#define TS_DRIVER_NAME "gtx8_spi"

	#define SPI_TRANS_PREFIX_LEN 1
	#define REGISTER_WIDTH 4
	#define SPI_READ_DUMMY_LEN 4
	#define SPI_READ_PREFIX_LEN \
	(SPI_TRANS_PREFIX_LEN + REGISTER_WIDTH + SPI_READ_DUMMY_LEN)
	#define SPI_WRITE_PREFIX_LEN (SPI_TRANS_PREFIX_LEN + REGISTER_WIDTH)
	#define SPI_PREALLOC_RX_BUF_SIZE 4096 + SPI_READ_PREFIX_LEN
	#define SPI_PREALLOC_TX_BUF_SIZE 4096 + SPI_WRITE_PREFIX_LEN

	#define SPI_WRITE_FLAG 0xF0
	#define SPI_READ_FLAG 0xF1

	/**
	* goodix_spi_read_bra- read device register through spi bus
	* @dev: pointer to device data
	* @addr: register address
	* @data: read buffer
	* @len: bytes to read
	* return: 0 - read ok, < 0 - spi transter error
	*/
	static int goodix_spi_read_bra(struct device *dev, unsigned int addr,
	unsigned char *data, unsigned int len)
	{
	struct spi_device *spi = to_spi_device(dev);
	struct goodix_ts_core *cd = dev_get_drvdata(dev);
	struct goodix_bus_interface *bus = cd->bus;
	u8 *rx_buf = NULL;
	u8 *tx_buf = NULL;
	struct spi_transfer xfers;
	struct spi_message spi_msg;
	int ret = 0;
	int buf_len = SPI_READ_PREFIX_LEN + len;

	mutex_lock(&bus->mutex);

	if (buf_len <= SPI_PREALLOC_RX_BUF_SIZE &&
	buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
	rx_buf = bus->rx_buf;
	tx_buf = bus->tx_buf;
	memset(tx_buf, 0, buf_len);
	} else {
	rx_buf = kzalloc(buf_len, GFP_KERNEL);
	if (!rx_buf) {
	ts_err("alloc rx_buf failed, size:%d", buf_len);
	ret = -ENOMEM;
	goto err_alloc_rx_buf;
	}

	tx_buf = kzalloc(buf_len, GFP_KERNEL);
	if (!tx_buf) {
	ts_err("alloc tx_buf failed, size:%d", buf_len);
	ret = -ENOMEM;
	goto err_alloc_tx_buf;
	}
	}

	spi_message_init(&spi_msg);
	memset(&xfers, 0, sizeof(xfers));

	/spi_read tx_buf format: 0xF1 + addr(4bytes) + data/
	tx_buf[0] = SPI_READ_FLAG;
	tx_buf[1] = (addr >> 24) & 0xFF;
	tx_buf[2] = (addr >> 16) & 0xFF;
	tx_buf[3] = (addr >> 8) & 0xFF;
	tx_buf[4] = addr & 0xFF;
	tx_buf[5] = 0xFF;
	tx_buf[6] = 0xFF;
	tx_buf[7] = 0xFF;
	tx_buf[8] = 0xFF;

	xfers.tx_buf = tx_buf;
	xfers.rx_buf = rx_buf;
	xfers.len = buf_len;
	xfers.cs_change = 0;
	spi_message_add_tail(&xfers, &spi_msg);
	ret = spi_sync(spi, &spi_msg);
	if (ret < 0) {
	ts_err("spi transfer error:%d", ret);
	goto err_spi_transfer;
	}
	memcpy(data, &rx_buf[SPI_READ_PREFIX_LEN], len);

	err_spi_transfer:
	if (tx_buf != bus->tx_buf)
	kfree(tx_buf);
	err_alloc_tx_buf:
	if (rx_buf != bus->rx_buf)
	kfree(rx_buf);
	err_alloc_rx_buf:
	mutex_unlock(&bus->mutex);
	return ret;
	}

	static int goodix_spi_read(struct device *dev, unsigned int addr,
	unsigned char *data, unsigned int len)
	{
	struct spi_device *spi = to_spi_device(dev);
	struct goodix_ts_core *cd = dev_get_drvdata(dev);
	struct goodix_bus_interface *bus = cd->bus;
	u8 *rx_buf = NULL;
	u8 *tx_buf = NULL;
	struct spi_transfer xfers;
	struct spi_message spi_msg;
	int ret = 0;
	int buf_len = SPI_READ_PREFIX_LEN - 1 + len;

	if (bus->dma_mode_enabled && buf_len >= 64)
	buf_len = ALIGN(buf_len, 4);

	mutex_lock(&bus->mutex);

	if (buf_len <= SPI_PREALLOC_RX_BUF_SIZE &&
	buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
	rx_buf = bus->rx_buf;
	tx_buf = bus->tx_buf;
	memset(tx_buf, 0, buf_len);
	} else {
	rx_buf = kzalloc(buf_len, GFP_KERNEL);
	if (!rx_buf) {
	ts_err("alloc rx_buf failed, size:%d", buf_len);
	ret = -ENOMEM;
	goto err_alloc_rx_buf;
	}

	tx_buf = kzalloc(buf_len, GFP_KERNEL);
	if (!tx_buf) {
	ts_err("alloc tx_buf failed, size:%d", buf_len);
	ret = -ENOMEM;
	goto err_alloc_tx_buf;
	}
	}

	spi_message_init(&spi_msg);
	memset(&xfers, 0, sizeof(xfers));

	/spi_read tx_buf format: 0xF1 + addr(4bytes) + data/
	tx_buf[0] = SPI_READ_FLAG;
	tx_buf[1] = (addr >> 24) & 0xFF;
	tx_buf[2] = (addr >> 16) & 0xFF;
	tx_buf[3] = (addr >> 8) & 0xFF;
	tx_buf[4] = addr & 0xFF;
	tx_buf[5] = 0xFF;
	tx_buf[6] = 0xFF;
	tx_buf[7] = 0xFF;

	xfers.tx_buf = tx_buf;
	xfers.rx_buf = rx_buf;
	xfers.len = buf_len;
	xfers.cs_change = 0;
	if (bus->dma_mode_enabled)
	xfers.bits_per_word = buf_len >= 64 ? 32 : 8;
	spi_message_add_tail(&xfers, &spi_msg);
	ret = spi_sync(spi, &spi_msg);
	if (ret < 0) {
	ts_err("spi transfer error:%d", ret);
	goto err_spi_transfer;
	}
	memcpy(data, &rx_buf[SPI_READ_PREFIX_LEN - 1], len);

	err_spi_transfer:
	if (tx_buf != bus->tx_buf)
	kfree(tx_buf);
	err_alloc_tx_buf:
	if (rx_buf != bus->rx_buf)
	kfree(rx_buf);
	err_alloc_rx_buf:
	mutex_unlock(&bus->mutex);
	return ret;
	}

	/* [GOOG]
	* This SPI transaction will direct read into `struct goodix_rx_package`.
	* And, the package are comprised of `SPI prefix header` + `data`.
	*/
	static int goodix_spi_read_fast(struct device *dev, unsigned int addr,
	struct goodix_rx_package *package, unsigned int len)
	{
	struct spi_device *spi = to_spi_device(dev);
	struct goodix_ts_core *cd = dev_get_drvdata(dev);
	struct goodix_bus_interface *bus = cd->bus;
	u8 *tx_buf = NULL;
	struct spi_transfer xfers;
	struct spi_message spi_msg;
	int ret = 0;
	int buf_len = SPI_READ_PREFIX_LEN - 1 + len;

	if (bus->dma_mode_enabled && buf_len >= 64)
	buf_len = ALIGN(buf_len, 4);

	if (buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
	tx_buf = bus->tx_buf;
	} else {
	tx_buf = kzalloc(buf_len, GFP_KERNEL);
	if (!tx_buf) {
	ts_err("alloc tx_buf failed, size:%d", buf_len);
	return -ENOMEM;
	}
	}

	spi_message_init(&spi_msg);
	memset(&xfers, 0, sizeof(xfers));

	mutex_lock(&bus->mutex);

	/spi_read tx_buf format: 0xF1 + addr(4bytes) + data/
	tx_buf[0] = SPI_READ_FLAG;
	tx_buf[1] = (addr >> 24) & 0xFF;
	tx_buf[2] = (addr >> 16) & 0xFF;
	tx_buf[3] = (addr >> 8) & 0xFF;
	tx_buf[4] = addr & 0xFF;
	tx_buf[5] = 0xFF;
	tx_buf[6] = 0xFF;
	tx_buf[7] = 0xFF;

	xfers.tx_buf = tx_buf;
	xfers.rx_buf = package->header;
	xfers.len = buf_len;
	xfers.cs_change = 0;
	if (bus->dma_mode_enabled)
	xfers.bits_per_word = buf_len >= 64 ? 32 : 8;
	spi_message_add_tail(&xfers, &spi_msg);

	ret = spi_sync(spi, &spi_msg);

	mutex_unlock(&bus->mutex);

	if (ret < 0) {
	ts_err("spi transfer error:%d", ret);
	goto err_spi_transfer;
	}

	err_spi_transfer:
	if (tx_buf != bus->tx_buf)
	kfree(tx_buf);
	return ret;
	}

	/**
	* goodix_spi_write- write device register through spi bus
	* @dev: pointer to device data
	* @addr: register address
	* @data: write buffer
	* @len: bytes to write
	* return: 0 - write ok; < 0 - spi transter error.
	*/
	static int goodix_spi_write(struct device *dev, unsigned int addr,
	unsigned char *data, unsigned int len)
	{
	struct spi_device *spi = to_spi_device(dev);
	struct goodix_ts_core *cd = dev_get_drvdata(dev);
	struct goodix_bus_interface *bus = cd->bus;
	u8 *tx_buf = NULL;
	struct spi_transfer xfers;
	struct spi_message spi_msg;
	int ret = 0;
	int buf_len = SPI_WRITE_PREFIX_LEN + len;

	if (bus->dma_mode_enabled && buf_len >= 64)
	buf_len = ALIGN(buf_len, 4);

	if (buf_len <= SPI_PREALLOC_TX_BUF_SIZE) {
	tx_buf = bus->tx_buf;
	} else {
	tx_buf = kzalloc(buf_len, GFP_KERNEL);
	if (!tx_buf) {
	ts_err("alloc tx_buf failed, size:%d", buf_len);
	return -ENOMEM;
	}
	}

	spi_message_init(&spi_msg);
	memset(&xfers, 0, sizeof(xfers));

	mutex_lock(&bus->mutex);

	tx_buf[0] = SPI_WRITE_FLAG;
	tx_buf[1] = (addr >> 24) & 0xFF;
	tx_buf[2] = (addr >> 16) & 0xFF;
	tx_buf[3] = (addr >> 8) & 0xFF;
	tx_buf[4] = addr & 0xFF;
	memcpy(&tx_buf[SPI_WRITE_PREFIX_LEN], data, len);
	xfers.tx_buf = tx_buf;
	xfers.len = buf_len;
	xfers.cs_change = 0;
	if (bus->dma_mode_enabled)
	xfers.bits_per_word = buf_len >= 64 ? 32 : 8;
	spi_message_add_tail(&xfers, &spi_msg);
	ret = spi_sync(spi, &spi_msg);

	mutex_unlock(&bus->mutex);

	if (ret < 0)
	ts_err("spi transfer error:%d", ret);

	if (tx_buf != bus->tx_buf)
	kfree(tx_buf);
	return ret;
	}

	static int goodix_spi_probe(struct spi_device *spi)
	{
	struct goodix_device_resource *dev_res;
	int ret = 0;

	ts_info("%s: goodix spi probe in", __func__);

	/* init spi_device */
	spi->mode = SPI_MODE_0;
	spi->bits_per_word = 8;
	spi->rt = true; /* [GOOG] */

	ret = spi_setup(spi);
	if (ret) {
	ts_err("failed set spi mode, %d", ret);
	return ret;
	}

	dev_res = kzalloc(sizeof(*dev_res), GFP_KERNEL);
	if (!dev_res)
	return -ENOMEM;

	/* get ic type */
	ret = goodix_get_ic_type(spi->dev.of_node, &dev_res->bus);
	if (ret < 0)
	goto err_get_ic_type;

	dev_res->bus.bus_type = GOODIX_BUS_TYPE_SPI;
	dev_res->bus.dev = &spi->dev;
	if (dev_res->bus.ic_type == IC_TYPE_BERLIN_A) {
	dev_res->bus.read = goodix_spi_read_bra;
	} else {
	dev_res->bus.read = goodix_spi_read;
	dev_res->bus.read_fast = goodix_spi_read_fast;
	}
	dev_res->bus.write = goodix_spi_write;

	/* [GOOG]
	* Move goodix_device_register() after `dev_res->bus.dev` assigned.
	* This will help to set the `struct device *dev` early.
	*/
	goodix_device_register(dev_res);

	dev_res->bus.rx_buf = kzalloc(SPI_PREALLOC_RX_BUF_SIZE, GFP_KERNEL);
	dev_res->bus.tx_buf = kzalloc(SPI_PREALLOC_TX_BUF_SIZE, GFP_KERNEL);
	if (!dev_res->bus.rx_buf \|\| !dev_res->bus.tx_buf) {
	ret = -ENOMEM;
	goto err_pdev;
	}
	/~[GOOG] /
	mutex_init(&dev_res->bus.mutex);

	dev_res->bus.dma_mode_enabled = false;
	#ifdef CONFIG_GOOG_TOUCH_INTERFACE
	dev_res->bus.dma_mode_enabled = goog_check_spi_dma_enabled(spi);
	ts_info("dma_mode: %s\n", dev_res->bus.dma_mode_enabled ? "enabled" : "disabled");
	#endif

	// platform device init
	dev_res->pdev.name = GOODIX_CORE_DRIVER_NAME;
	dev_res->pdev.id = dev_res->id;
	dev_res->pdev.num_resources = 0;

	/* register platform device, then the goodix_ts_core
	* module will probe the touch device.
	*/
	ret = platform_device_register(&dev_res->pdev);
	if (ret) {
	ts_err("failed register goodix platform device, %d", ret);
	goto err_pdev;
	}
	ts_info("spi probe out");
	return 0;

	err_pdev:
	kfree(dev_res->bus.rx_buf);
	kfree(dev_res->bus.tx_buf);
	err_get_ic_type:
	kfree(dev_res);
	ts_info("spi probe out, %d", ret);
	return ret;
	}

	static int goodix_spi_remove(struct spi_device *spi)
	{
	/* goodix_ts_core_exit() will unregister device(s) */
	// platform_device_unregister(dev_res->pdev);
	return 0;
	}

	#ifdef CONFIG_OF
	static const struct of_device_id spi_matches[] = {
	{
	.compatible = "goodix,brl-a",
	},
	{
	.compatible = "goodix,brl-b",
	},
	{
	.compatible = "goodix,brl-b,gt7986",
	},
	{
	.compatible = "goodix,brl-d",
	},
	{
	.compatible = "goodix,nottingham",
	},
	{},
	};
	#endif

	static const struct spi_device_id spi_id_table[] = {
	{ TS_DRIVER_NAME, 0 },
	{},
	};

	static struct spi_driver goodix_spi_driver = {
	.driver = {
	.name = TS_DRIVER_NAME,
	//.owner = THIS_MODULE,
	.of_match_table = spi_matches,
	},
	.id_table = spi_id_table,
	.probe = goodix_spi_probe,
	.remove = goodix_spi_remove,
	};

	int goodix_spi_bus_init(void)
	{
	ts_info("Goodix spi driver init");
	return spi_register_driver(&goodix_spi_driver);
	}

	void goodix_spi_bus_exit(void)
	{
	ts_info("Goodix spi driver exit");
	spi_unregister_driver(&goodix_spi_driver);
	}