// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Goodix Berlin Touchscreen Driver
 *
 * Copyright (C) 2020 - 2021 Goodix, Inc.
 * Copyright (C) 2023 Linaro Ltd.
 *
 * Based on goodix_ts_berlin driver.
 */
#include <linux/unaligned.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#include <linux/input.h>

#include "goodix_berlin.h"

#define GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN      1
#define GOODIX_BERLIN_REGISTER_WIDTH            4
#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN_A      4
#define GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D      3
#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN_A     (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
                                                 GOODIX_BERLIN_REGISTER_WIDTH + \
                                                 GOODIX_BERLIN_SPI_READ_DUMMY_LEN_A)
#define GOODIX_BERLIN_SPI_READ_PREFIX_LEN_D     (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
                                                 GOODIX_BERLIN_REGISTER_WIDTH + \
                                                 GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D)
#define GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN      (GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + \
                                                 GOODIX_BERLIN_REGISTER_WIDTH)

#define GOODIX_BERLIN_SPI_WRITE_FLAG            0xF0
#define GOODIX_BERLIN_SPI_READ_FLAG             0xF1

static int goodix_berlin_spi_read(void *context, const void *reg_buf,
                                  size_t reg_size, void *val_buf,
                                  size_t val_size)
{
        struct spi_device *spi = context;
        const struct goodix_berlin_ic_data *ic_data = spi_get_device_match_data(spi);
        struct spi_transfer xfers;
        struct spi_message spi_msg;
        const u32 *reg = reg_buf; /* reg is stored as native u32 at start of buffer */
        int error;

        if (reg_size != GOODIX_BERLIN_REGISTER_WIDTH)
                return -EINVAL;

        u8 *buf __free(kfree) =
                kzalloc(ic_data->read_prefix_len + val_size, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

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

        /* buffer format: 0xF1 + addr(4bytes) + dummy(3/4bytes) + data */
        buf[0] = GOODIX_BERLIN_SPI_READ_FLAG;
        put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
        memset(buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN + GOODIX_BERLIN_REGISTER_WIDTH,
               0xff, ic_data->read_dummy_len);

        xfers.tx_buf = buf;
        xfers.rx_buf = buf;
        xfers.len = ic_data->read_prefix_len + val_size;
        xfers.cs_change = 0;
        spi_message_add_tail(&xfers, &spi_msg);

        error = spi_sync(spi, &spi_msg);
        if (error < 0) {
                dev_err(&spi->dev, "spi transfer error, %d", error);
                return error;
        }

        memcpy(val_buf, buf + ic_data->read_prefix_len, val_size);
        return error;
}

static int goodix_berlin_spi_write(void *context, const void *data,
                                   size_t count)
{
        unsigned int len = count - GOODIX_BERLIN_REGISTER_WIDTH;
        struct spi_device *spi = context;
        struct spi_transfer xfers;
        struct spi_message spi_msg;
        const u32 *reg = data; /* reg is stored as native u32 at start of buffer */
        int error;

        u8 *buf __free(kfree) =
                kzalloc(GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

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

        buf[0] = GOODIX_BERLIN_SPI_WRITE_FLAG;
        put_unaligned_be32(*reg, buf + GOODIX_BERLIN_SPI_TRANS_PREFIX_LEN);
        memcpy(buf + GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN,
               data + GOODIX_BERLIN_REGISTER_WIDTH, len);

        xfers.tx_buf = buf;
        xfers.len = GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN + len;
        xfers.cs_change = 0;
        spi_message_add_tail(&xfers, &spi_msg);

        error = spi_sync(spi, &spi_msg);
        if (error < 0) {
                dev_err(&spi->dev, "spi transfer error, %d", error);
                return error;
        }

        return 0;
}

static const struct regmap_config goodix_berlin_spi_regmap_conf = {
        .reg_bits = 32,
        .val_bits = 8,
        .read = goodix_berlin_spi_read,
        .write = goodix_berlin_spi_write,
};

/* vendor & product left unassigned here, should probably be updated from fw info */
static const struct input_id goodix_berlin_spi_input_id = {
        .bustype = BUS_SPI,
};

static int goodix_berlin_spi_probe(struct spi_device *spi)
{
        const struct goodix_berlin_ic_data *ic_data = spi_get_device_match_data(spi);
        struct regmap_config regmap_config;
        struct regmap *regmap;
        size_t max_size;
        int error = 0;

        spi->mode = SPI_MODE_0;
        spi->bits_per_word = 8;
        error = spi_setup(spi);
        if (error)
                return error;

        max_size = spi_max_transfer_size(spi);

        regmap_config = goodix_berlin_spi_regmap_conf;
        regmap_config.max_raw_read = max_size - ic_data->read_prefix_len;
        regmap_config.max_raw_write = max_size - GOODIX_BERLIN_SPI_WRITE_PREFIX_LEN;

        regmap = devm_regmap_init(&spi->dev, NULL, spi, &regmap_config);
        if (IS_ERR(regmap))
                return PTR_ERR(regmap);

        error = goodix_berlin_probe(&spi->dev, spi->irq,
                                    &goodix_berlin_spi_input_id, regmap,
                                    ic_data);
        if (error)
                return error;

        return 0;
}

static const struct goodix_berlin_ic_data gt9897_data = {
        .fw_version_info_addr = GOODIX_BERLIN_FW_VERSION_INFO_ADDR_A,
        .ic_info_addr = GOODIX_BERLIN_IC_INFO_ADDR_A,
        .read_dummy_len = GOODIX_BERLIN_SPI_READ_DUMMY_LEN_A,
        .read_prefix_len = GOODIX_BERLIN_SPI_READ_PREFIX_LEN_A,
};

static const struct goodix_berlin_ic_data gt9916_data = {
        .fw_version_info_addr = GOODIX_BERLIN_FW_VERSION_INFO_ADDR_D,
        .ic_info_addr = GOODIX_BERLIN_IC_INFO_ADDR_D,
        .read_dummy_len = GOODIX_BERLIN_SPI_READ_DUMMY_LEN_D,
        .read_prefix_len = GOODIX_BERLIN_SPI_READ_PREFIX_LEN_D,
};

static const struct spi_device_id goodix_berlin_spi_ids[] = {
        { .name = "gt9897", .driver_data = (long)&gt9897_data },
        { .name = "gt9916", .driver_data = (long)&gt9916_data },
        { },
};
MODULE_DEVICE_TABLE(spi, goodix_berlin_spi_ids);

static const struct of_device_id goodix_berlin_spi_of_match[] = {
        { .compatible = "goodix,gt9897", .data = &gt9897_data },
        { .compatible = "goodix,gt9916", .data = &gt9916_data },
        { }
};
MODULE_DEVICE_TABLE(of, goodix_berlin_spi_of_match);

static struct spi_driver goodix_berlin_spi_driver = {
        .driver = {
                .name = "goodix-berlin-spi",
                .of_match_table = goodix_berlin_spi_of_match,
                .pm = pm_sleep_ptr(&goodix_berlin_pm_ops),
                .dev_groups = goodix_berlin_groups,
        },
        .probe = goodix_berlin_spi_probe,
        .id_table = goodix_berlin_spi_ids,
};
module_spi_driver(goodix_berlin_spi_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Goodix Berlin SPI Touchscreen driver");
MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");