drivers/sensor/bme280/bme280_spi.c

/*
 * Copyright (c) 2016, 2017 Intel Corporation
 * Copyright (c) 2017 IpTronix S.r.l.
 * Copyright (c) 2021 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/*
 * Bus-specific functionality for BME280s accessed via SPI.
 */

#include <logging/log.h>
#include "bme280.h"

#if BME280_BUS_SPI

LOG_MODULE_DECLARE(BME280, CONFIG_SENSOR_LOG_LEVEL);

static int bme280_bus_check_spi(const struct device *bus,
				const union bme280_bus_config *bus_config)
{
	const struct spi_cs_control *cs;

	if (!device_is_ready(bus)) {
		LOG_DBG("SPI bus %s not ready", bus->name);
		return -ENODEV;
	}

	cs = bus_config->spi_cfg.cs;
	if (cs && !device_is_ready(cs->gpio_dev)) {
		LOG_DBG("SPI CS GPIO controller %s not ready",
			cs->gpio_dev->name);
		return -ENODEV;
	}

	return 0;
}

static int bme280_reg_read_spi(const struct device *bus,
			       const union bme280_bus_config *bus_config,
			       uint8_t start, uint8_t *buf, int size)
{
	uint8_t addr;
	const struct spi_buf tx_buf = {
		.buf = &addr,
		.len = 1
	};
	const struct spi_buf_set tx = {
		.buffers = &tx_buf,
		.count = 1
	};
	struct spi_buf rx_buf[2];
	const struct spi_buf_set rx = {
		.buffers = rx_buf,
		.count = ARRAY_SIZE(rx_buf)
	};
	int i;

	rx_buf[0].buf = NULL;
	rx_buf[0].len = 1;

	rx_buf[1].len = 1;

	for (i = 0; i < size; i++) {
		int ret;

		addr = (start + i) | 0x80;
		rx_buf[1].buf = &buf[i];

		ret = spi_transceive(bus, &bus_config->spi_cfg, &tx, &rx);
		if (ret) {
			LOG_DBG("spi_transceive FAIL %d\n", ret);
			return ret;
		}
	}

	return 0;
}

static int bme280_reg_write_spi(const struct device *bus,
				const union bme280_bus_config *bus_config,
				uint8_t reg, uint8_t val)
{
	uint8_t cmd[] = { reg & 0x7F, val };
	const struct spi_buf tx_buf = {
		.buf = cmd,
		.len = sizeof(cmd)
	};
	const struct spi_buf_set tx = {
		.buffers = &tx_buf,
		.count = 1
	};
	int ret;

	ret = spi_write(bus, &bus_config->spi_cfg, &tx);
	if (ret) {
		LOG_DBG("spi_write FAIL %d\n", ret);
		return ret;
	}
	return 0;
}

const struct bme280_bus_io bme280_bus_io_spi = {
	.check = bme280_bus_check_spi,
	.read = bme280_reg_read_spi,
	.write = bme280_reg_write_spi,
};
#endif	/* BME280_BUS_SPI */