/*
 * 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/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>

#include "goodix_ts_core.h"

#define TS_DRIVER_NAME "gtx8_i2c"
#define I2C_MAX_TRANSFER_SIZE 256
#define GOODIX_BUS_RETRY_TIMES 2
#define GOODIX_REG_ADDR_SIZE 4

static struct platform_device *goodix_pdev;
struct goodix_bus_interface goodix_i2c_bus;

static int goodix_i2c_read(struct device *dev, unsigned int reg,
	unsigned char *data, unsigned int len)
{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned int transfer_length = 0;
	unsigned int pos = 0, address = reg;
	unsigned char get_buf[128], addr_buf[GOODIX_REG_ADDR_SIZE];
	int retry, r = 0;
	struct i2c_msg msgs[] = { {
					  .addr = client->addr,
					  .flags = !I2C_M_RD,
					  .buf = &addr_buf[0],
					  .len = GOODIX_REG_ADDR_SIZE,
				  },
		{
			.addr = client->addr,
			.flags = I2C_M_RD,
		} };

	if (likely(len < sizeof(get_buf))) {
		/* code optimize, use stack memory */
		msgs[1].buf = &get_buf[0];
	} else {
		msgs[1].buf = kzalloc(len, GFP_KERNEL);
		if (msgs[1].buf == NULL)
			return -ENOMEM;
	}

	while (pos != len) {
		if (unlikely(len - pos > I2C_MAX_TRANSFER_SIZE))
			transfer_length = I2C_MAX_TRANSFER_SIZE;
		else
			transfer_length = len - pos;

		msgs[0].buf[0] = (address >> 24) & 0xFF;
		msgs[0].buf[1] = (address >> 16) & 0xFF;
		msgs[0].buf[2] = (address >> 8) & 0xFF;
		msgs[0].buf[3] = address & 0xFF;
		msgs[1].len = transfer_length;

		for (retry = 0; retry < GOODIX_BUS_RETRY_TIMES; retry++) {
			if (likely(i2c_transfer(client->adapter, msgs, 2) ==
				    2)) {
				memcpy(&data[pos], msgs[1].buf,
					transfer_length);
				pos += transfer_length;
				address += transfer_length;
				break;
			}
			ts_info("I2c read retry[%d]:0x%x", retry + 1, reg);
			usleep_range(2000, 2100);
		}
		if (unlikely(retry == GOODIX_BUS_RETRY_TIMES)) {
			ts_err("I2c read failed,dev:%02x,reg:%04x,size:%u",
				client->addr, reg, len);
			r = -EAGAIN;
			goto read_exit;
		}
	}

read_exit:
	if (unlikely(len >= sizeof(get_buf)))
		kfree(msgs[1].buf);
	return r;
}

static int goodix_i2c_write(struct device *dev, unsigned int reg,
	unsigned char *data, unsigned int len)
{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned int pos = 0, transfer_length = 0;
	unsigned int address = reg;
	unsigned char put_buf[128];
	int retry, r = 0;
	struct i2c_msg msg = {
		.addr = client->addr,
		.flags = !I2C_M_RD,
	};

	if (likely(len + GOODIX_REG_ADDR_SIZE < sizeof(put_buf))) {
		/* code optimize,use stack memory*/
		msg.buf = &put_buf[0];
	} else {
		msg.buf = kmalloc(len + GOODIX_REG_ADDR_SIZE, GFP_KERNEL);
		if (msg.buf == NULL)
			return -ENOMEM;
	}

	while (pos != len) {
		if (unlikely(len - pos >
			     I2C_MAX_TRANSFER_SIZE - GOODIX_REG_ADDR_SIZE))
			transfer_length =
				I2C_MAX_TRANSFER_SIZE - GOODIX_REG_ADDR_SIZE;
		else
			transfer_length = len - pos;
		msg.buf[0] = (address >> 24) & 0xFF;
		msg.buf[1] = (address >> 16) & 0xFF;
		msg.buf[2] = (address >> 8) & 0xFF;
		msg.buf[3] = address & 0xFF;

		msg.len = transfer_length + GOODIX_REG_ADDR_SIZE;
		memcpy(&msg.buf[GOODIX_REG_ADDR_SIZE], &data[pos],
			transfer_length);

		for (retry = 0; retry < GOODIX_BUS_RETRY_TIMES; retry++) {
			if (likely(i2c_transfer(client->adapter, &msg, 1) ==
				    1)) {
				pos += transfer_length;
				address += transfer_length;
				break;
			}
			ts_debug("I2c write retry[%d]", retry + 1);
			msleep(20);
		}
		if (unlikely(retry == GOODIX_BUS_RETRY_TIMES)) {
			ts_err("I2c write failed,dev:%02x,reg:%04x,size:%u",
				client->addr, reg, len);
			r = -EAGAIN;
			goto write_exit;
		}
	}

write_exit:
	if (likely(len + GOODIX_REG_ADDR_SIZE >= sizeof(put_buf)))
		kfree(msg.buf);
	return r;
}

static void goodix_pdev_release(struct device *dev)
{
	ts_info("goodix pdev released");
	kfree(goodix_pdev);
}

static int goodix_i2c_probe(
	struct i2c_client *client, const struct i2c_device_id *dev_id)
{
	int ret = 0;

	ts_info("goodix i2c probe in");
	ret = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);
	if (!ret)
		return -EIO;

	/* get ic type */
	ret = goodix_get_ic_type(client->dev.of_node, &goodix_i2c_bus);
	if (ret < 0)
		return ret;

	goodix_i2c_bus.bus_type = GOODIX_BUS_TYPE_I2C;
	goodix_i2c_bus.dev = &client->dev;
	goodix_i2c_bus.read = goodix_i2c_read;
	goodix_i2c_bus.write = goodix_i2c_write;
	/* ts core device */
	goodix_pdev = kzalloc(sizeof(struct platform_device), GFP_KERNEL);
	if (!goodix_pdev)
		return -ENOMEM;

	goodix_pdev->name = GOODIX_CORE_DRIVER_NAME;
	goodix_pdev->id = 0;
	goodix_pdev->num_resources = 0;
	/*
	 * you can find this platform dev in
	 * /sys/devices/platform/goodix_ts.0
	 * goodix_pdev->dev.parent = &client->dev;
	 */
	goodix_pdev->dev.platform_data = &goodix_i2c_bus;
	goodix_pdev->dev.release = goodix_pdev_release;

	/* register platform device, then the goodix_ts_core
	 * module will probe the touch device.
	 */
	ret = platform_device_register(goodix_pdev);
	if (ret) {
		ts_err("failed register goodix platform device, %d", ret);
		goto err_pdev;
	}
	ts_info("i2c probe out");
	return ret;

err_pdev:
	kfree(goodix_pdev);
	goodix_pdev = NULL;
	ts_info("i2c probe out, %d", ret);
	return ret;
}

static int goodix_i2c_remove(struct i2c_client *client)
{
	platform_device_unregister(goodix_pdev);
	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id i2c_matches[] = {
	{
		.compatible = "goodix,brl-a",
	},
	{
		.compatible = "goodix,brl-b",
	},
	{
		.compatible = "goodix,brl-d",
	},
	{
		.compatible = "goodix,nottingham",
	},
	{},
};
MODULE_DEVICE_TABLE(of, i2c_matches);
#endif

static const struct i2c_device_id i2c_id_table[] = {
	{ TS_DRIVER_NAME, 0 },
	{},
};
MODULE_DEVICE_TABLE(i2c, i2c_id_table);

static struct i2c_driver goodix_i2c_driver = {
	.driver = {
		.name = TS_DRIVER_NAME,
		//.owner = THIS_MODULE,
		.of_match_table = of_match_ptr(i2c_matches),
	},
	.probe = goodix_i2c_probe,
	.remove = goodix_i2c_remove,
	.id_table = i2c_id_table,
};

int goodix_i2c_bus_init(void)
{
	ts_info("Goodix i2c driver init");
	return i2c_add_driver(&goodix_i2c_driver);
}

void goodix_i2c_bus_exit(void)
{
	ts_info("Goodix i2c driver exit");
	i2c_del_driver(&goodix_i2c_driver);
}