src/kernel/linux/v4.19/drivers/iio/pressure/bmp280-spi.c

/*
 * SPI interface for the BMP280 driver
 *
 * Inspired by the older BMP085 driver drivers/misc/bmp085-spi.c
 */
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/err.h>
#include <linux/regmap.h>

#include "bmp280.h"

static int bmp280_regmap_spi_write(void *context, const void *data,
                                   size_t count)
{
	struct device *dev = context;
	struct spi_device *spi = to_spi_device(dev);
	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 device *dev = context;
	struct spi_device *spi = to_spi_device(dev);

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

static 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 int bmp280_spi_probe(struct spi_device *spi)
{
	const struct spi_device_id *id = spi_get_device_id(spi);
	struct regmap *regmap;
	const struct regmap_config *regmap_config;
	int ret;

	spi->bits_per_word = 8;
	ret = spi_setup(spi);
	if (ret < 0) {
		dev_err(&spi->dev, "spi_setup failed!\n");
		return ret;
	}

	switch (id->driver_data) {
	case BMP180_CHIP_ID:
		regmap_config = &bmp180_regmap_config;
		break;
	case BMP280_CHIP_ID:
	case BME280_CHIP_ID:
		regmap_config = &bmp280_regmap_config;
		break;
	default:
		return -EINVAL;
	}

	regmap = devm_regmap_init(&spi->dev,
				  &bmp280_regmap_bus,
				  &spi->dev,
				  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,
				   id->driver_data,
				   id->name,
				   spi->irq);
}

static int bmp280_spi_remove(struct spi_device *spi)
{
	return bmp280_common_remove(&spi->dev);
}

static const struct of_device_id bmp280_of_spi_match[] = {
	{ .compatible = "bosch,bmp085", },
	{ .compatible = "bosch,bmp180", },
	{ .compatible = "bosch,bmp181", },
	{ .compatible = "bosch,bmp280", },
	{ .compatible = "bosch,bme280", },
	{ },
};
MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);

static const struct spi_device_id bmp280_spi_id[] = {
	{ "bmp180", BMP180_CHIP_ID },
	{ "bmp181", BMP180_CHIP_ID },
	{ "bmp280", BMP280_CHIP_ID },
	{ "bme280", BME280_CHIP_ID },
	{ }
};
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 = &bmp280_dev_pm_ops,
	},
	.id_table = bmp280_spi_id,
	.probe = bmp280_spi_probe,
	.remove = bmp280_spi_remove,
};
module_spi_driver(bmp280_spi_driver);

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