// SPDX-License-Identifier: GPL-2.0-only
/*
 * SPI interface for the BMP280 driver
 *
 * Inspired by the older BMP085 driver drivers/misc/bmp085-spi.c
 */
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>

#include "bmp280.h"

static int bmp280_regmap_spi_write(void *context, const void *data,
                                   size_t count)
{
        struct spi_device *spi = to_spi_device(context);
        u8 buf[2];

        memcpy(buf, data, 2);
        /*
         * The SPI register address (= full register address without bit 7) and
         * the write command (bit7 = RW = '0')
         */
        buf[0] &= ~0x80;

        return spi_write_then_read(spi, buf, 2, NULL, 0);
}

static int bmp280_regmap_spi_read(void *context, const void *reg,
                                  size_t reg_size, void *val, size_t val_size)
{
        struct spi_device *spi = to_spi_device(context);

        return spi_write_then_read(spi, reg, reg_size, val, val_size);
}

static int bmp380_regmap_spi_read(void *context, const void *reg,
                                  size_t reg_size, void *val, size_t val_size)
{
        struct spi_device *spi = to_spi_device(context);
        u8 rx_buf[BME280_BURST_READ_BYTES + 1];
        ssize_t status;

        if (val_size > BME280_BURST_READ_BYTES)
                return -EINVAL;

        /*
         * According to the BMP3xx datasheets, for a basic SPI read opertion,
         * the first byte needs to be dropped and the rest are the requested
         * data.
         */
        status = spi_write_then_read(spi, reg, 1, rx_buf, val_size + 1);
        if (status)
                return status;

        memcpy(val, rx_buf + 1, val_size);

        return 0;
}

static const struct regmap_bus bmp280_regmap_bus = {
        .write = bmp280_regmap_spi_write,
        .read = bmp280_regmap_spi_read,
        .reg_format_endian_default = REGMAP_ENDIAN_BIG,
        .val_format_endian_default = REGMAP_ENDIAN_BIG,
};

static const struct regmap_bus bmp380_regmap_bus = {
        .write = bmp280_regmap_spi_write,
        .read = bmp380_regmap_spi_read,
        .read_flag_mask = BIT(7),
        .reg_format_endian_default = REGMAP_ENDIAN_BIG,
        .val_format_endian_default = REGMAP_ENDIAN_BIG,
};

static int bmp280_spi_probe(struct spi_device *spi)
{
        const struct spi_device_id *id = spi_get_device_id(spi);
        const struct bmp280_chip_info *chip_info;
        struct regmap_bus const *bmp_regmap_bus;
        struct regmap *regmap;

        chip_info = spi_get_device_match_data(spi);

        if (chip_info->spi_read_extra_byte)
                bmp_regmap_bus = &bmp380_regmap_bus;
        else
                bmp_regmap_bus = &bmp280_regmap_bus;

        regmap = devm_regmap_init(&spi->dev,
                                  bmp_regmap_bus,
                                  &spi->dev,
                                  chip_info->regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(&spi->dev, "failed to allocate register map\n");
                return PTR_ERR(regmap);
        }

        return bmp280_common_probe(&spi->dev,
                                   regmap,
                                   chip_info,
                                   id->name,
                                   spi->irq);
}

static const struct of_device_id bmp280_of_spi_match[] = {
        { .compatible = "bosch,bmp085", .data = &bmp085_chip_info },
        { .compatible = "bosch,bmp180", .data = &bmp180_chip_info },
        { .compatible = "bosch,bmp181", .data = &bmp180_chip_info },
        { .compatible = "bosch,bmp280", .data = &bmp280_chip_info },
        { .compatible = "bosch,bme280", .data = &bme280_chip_info },
        { .compatible = "bosch,bmp380", .data = &bmp380_chip_info },
        { .compatible = "bosch,bmp580", .data = &bmp580_chip_info },
        { }
};
MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);

static const struct spi_device_id bmp280_spi_id[] = {
        { "bmp085", (kernel_ulong_t)&bmp085_chip_info },
        { "bmp180", (kernel_ulong_t)&bmp180_chip_info },
        { "bmp181", (kernel_ulong_t)&bmp180_chip_info },
        { "bmp280", (kernel_ulong_t)&bmp280_chip_info },
        { "bme280", (kernel_ulong_t)&bme280_chip_info },
        { "bmp380", (kernel_ulong_t)&bmp380_chip_info },
        { "bmp580", (kernel_ulong_t)&bmp580_chip_info },
        { }
};
MODULE_DEVICE_TABLE(spi, bmp280_spi_id);

static struct spi_driver bmp280_spi_driver = {
        .driver = {
                .name = "bmp280",
                .of_match_table = bmp280_of_spi_match,
                .pm = pm_ptr(&bmp280_dev_pm_ops),
        },
        .id_table = bmp280_spi_id,
        .probe = bmp280_spi_probe,
};
module_spi_driver(bmp280_spi_driver);

MODULE_DESCRIPTION("BMP280 SPI bus driver");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("IIO_BMP280");