drivers: sensor: bme680: Add SPI interface

This enables the SPI interface for the BME680 sensor driver.

Signed-off-by: Leonard Pollak <[email protected]>

Author: Leonard Pollak

drivers/sensor/bme680/CMakeLists.txt

@@ -1,9 +1,9 @@
-#
 # Copyright (c) 2018 Bosch Sensortec GmbH
+# Copyright (c) 2022, Leonard Pollak
 #
 # SPDX-License-Identifier: Apache-2.0
 #
 
 zephyr_library()
 
-zephyr_library_sources(bme680.c)
+zephyr_library_sources(bme680.c bme680_i2c.c bme680_spi.c)

drivers/sensor/bme680/Kconfig

@@ -1,13 +1,15 @@
 # BME680 temperature, pressure, humidity and gas sensor configuration options
 
 # Copyright (c) 2018 Bosch Sensortec GmbH
+# Copyright (c) 2022, Leonard Pollak
+#
 # SPDX-License-Identifier: Apache-2.0
 
 menuconfig BME680
 	bool "BME680 sensor"
-	depends on I2C
+	depends on I2C || SPI
 	help
-	  Enable driver for BME680 I2C-based based temperature, pressure, humidity and gas sensor.
+	  Enable driver for BME680 I2C- or SPI- based temperature, pressure, humidity and gas sensor.
 
 if BME680
 

drivers/sensor/bme680/bme680.c

@@ -11,33 +11,49 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#define DT_DRV_COMPAT bosch_bme680
-
-#include "bme680.h"
 #include <drivers/gpio.h>
-#include <drivers/i2c.h>
 #include <init.h>
 #include <kernel.h>
 #include <sys/byteorder.h>
 #include <sys/__assert.h>
 #include <drivers/sensor.h>
-
 #include <logging/log.h>
+
+#include "bme680.h"
+
 LOG_MODULE_REGISTER(bme680, CONFIG_SENSOR_LOG_LEVEL);
 
-static int bme680_reg_read(const struct device *dev, uint8_t start,
-			   uint8_t *buf, int size)
+
+#if BME680_BUS_SPI
+static inline bool bme680_is_on_spi(const struct device *dev)
 {
 	const struct bme680_config *config = dev->config;
 
-	return i2c_burst_read_dt(&config->bus, start, buf, size);
+	return config->bus_io == &bme680_bus_io_spi;
 }
+#endif
 
-static int bme680_reg_write(const struct device *dev, uint8_t reg, uint8_t val)
+static inline int bme680_bus_check(const struct device *dev)
 {
 	const struct bme680_config *config = dev->config;
 
-	return i2c_reg_write_byte_dt(&config->bus, reg, val);
+	return config->bus_io->check(&config->bus);
+}
+
+static inline int bme680_reg_read(const struct device *dev,
+				  uint8_t start, uint8_t *buf, int size)
+{
+	const struct bme680_config *config = dev->config;
+
+	return config->bus_io->read(dev, start, buf, size);
+}
+
+static inline int bme680_reg_write(const struct device *dev, uint8_t reg,
+				   uint8_t val)
+{
+	const struct bme680_config *config = dev->config;
+
+	return config->bus_io->write(dev, reg, val);
 }
 
 static void bme680_calc_temp(struct bme680_data *data, uint32_t adc_temp)
@@ -346,13 +362,22 @@ static int bme680_read_compensation(const struct device *dev)
 static int bme680_init(const struct device *dev)
 {
 	struct bme680_data *data = dev->data;
-	const struct bme680_config *config = dev->config;
 	int err;
 
-	if (!device_is_ready(config->bus.bus)) {
-		LOG_ERR("I2C master %s not ready", config->bus.bus->name);
-		return -EINVAL;
+	err = bme680_bus_check(dev);
+	if (err < 0) {
+		LOG_ERR("Bus not ready for '%s'", dev->name);
+		return err;
+	}
+
+#if BME680_BUS_SPI
+	if (bme680_is_on_spi(dev)) {
+		err = bme680_reg_read(dev, BME680_REG_MEM_PAGE, &data->mem_page, 1);
+		if (err < 0) {
+			return err;
+		}
 	}
+#endif
 
 	err = bme680_reg_read(dev, BME680_REG_CHIP_ID, &data->chip_id, 1);
 	if (err < 0) {
@@ -410,12 +435,39 @@ static const struct sensor_driver_api bme680_api_funcs = {
 	.channel_get = bme680_channel_get,
 };
 
-static struct bme680_data bme680_data;
+/* Initializes a struct bme680_config for an instance on a SPI bus. */
+#define BME680_CONFIG_SPI(inst)				\
+	{						\
+		.bus.spi = SPI_DT_SPEC_INST_GET(	\
+			inst, BME680_SPI_OPERATION, 0),	\
+		.bus_io = &bme680_bus_io_spi,		\
+	}
 
-static const struct bme680_config bme680_config = {
-	.bus = I2C_DT_SPEC_INST_GET(0)
-};
+/* Initializes a struct bme680_config for an instance on an I2C bus. */
+#define BME680_CONFIG_I2C(inst)			       \
+	{					       \
+		.bus.i2c = I2C_DT_SPEC_INST_GET(inst), \
+		.bus_io = &bme680_bus_io_i2c,	       \
+	}
 
-DEVICE_DT_INST_DEFINE(0, bme680_init, NULL, &bme680_data,
-		      &bme680_config, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,
-		      &bme680_api_funcs);
+/*
+ * Main instantiation macro, which selects the correct bus-specific
+ * instantiation macros for the instance.
+ */
+#define BME680_DEFINE(inst)						\
+	static struct bme680_data bme680_data_##inst;			\
+	static const struct bme680_config bme680_config_##inst =	\
+		COND_CODE_1(DT_INST_ON_BUS(inst, spi),			\
+			    (BME680_CONFIG_SPI(inst)),			\
+			    (BME680_CONFIG_I2C(inst)));			\
+	DEVICE_DT_INST_DEFINE(inst,					\
+			 bme680_init,					\
+			 NULL,						\
+			 &bme680_data_##inst,				\
+			 &bme680_config_##inst,				\
+			 POST_KERNEL,					\
+			 CONFIG_SENSOR_INIT_PRIORITY,			\
+			 &bme680_api_funcs);
+
+/* Create the struct device for every status "okay" node in the devicetree. */
+DT_INST_FOREACH_STATUS_OKAY(BME680_DEFINE)

drivers/sensor/bme680/bme680.h

@@ -10,8 +10,51 @@
 
 #include <zephyr/types.h>
 #include <device.h>
+#include <devicetree.h>
+#include <drivers/spi.h>
 #include <drivers/i2c.h>
 
+#define DT_DRV_COMPAT bosch_bme680
+
+#define BME680_BUS_SPI DT_ANY_INST_ON_BUS_STATUS_OKAY(spi)
+#define BME680_BUS_I2C DT_ANY_INST_ON_BUS_STATUS_OKAY(i2c)
+
+union bme680_bus {
+#if BME680_BUS_SPI
+	struct spi_dt_spec spi;
+#endif
+#if BME680_BUS_I2C
+	struct i2c_dt_spec i2c;
+#endif
+};
+
+typedef int (*bme680_bus_check_fn)(const union bme680_bus *bus);
+typedef int (*bme680_reg_read_fn)(const struct device *dev,
+				  uint8_t start, uint8_t *buf, int size);
+typedef int (*bme680_reg_write_fn)(const struct device *dev,
+				   uint8_t reg, uint8_t val);
+
+struct bme680_bus_io {
+	bme680_bus_check_fn check;
+	bme680_reg_read_fn read;
+	bme680_reg_write_fn write;
+};
+
+#if BME680_BUS_SPI
+#define BME680_SPI_OPERATION (SPI_WORD_SET(8) | SPI_TRANSFER_MSB | SPI_MODE_CPOL \
+		| SPI_MODE_CPHA | SPI_OP_MODE_MASTER)
+extern const struct bme680_bus_io bme680_bus_io_spi;
+#endif
+
+#if BME680_BUS_I2C
+extern const struct bme680_bus_io bme680_bus_io_i2c;
+#endif
+
+struct bme680_config {
+	union bme680_bus bus;
+	const struct bme680_bus_io *bus_io;
+};
+
 #define BME680_CHIP_ID                  0x61
 
 #define BME680_LEN_FIELD                15
@@ -44,6 +87,12 @@
 #define BME680_MSK_RANGE_SW_ERR         0xf0
 #define BME680_MSK_HEATR_STAB           0x10
 
+#define BME680_SPI_READ_BIT		0x80
+#define BME680_SPI_WRITE_MSK		0x7f
+
+#define BME680_MEM_PAGE1		0x00
+#define BME680_MEM_PAGE0		0x10
+
 #if defined CONFIG_BME680_TEMP_OVER_1X
 #define BME680_TEMP_OVER                (1 << 5)
 #elif defined CONFIG_BME680_TEMP_OVER_2X
@@ -163,10 +212,10 @@ struct bme680_data {
 	int32_t t_fine;
 
 	uint8_t chip_id;
-};
 
-struct bme680_config {
-	struct i2c_dt_spec bus;
+#if BME680_BUS_SPI
+	uint8_t mem_page;
+#endif
 };
 
 #endif /* __ZEPHYR_DRIVERS_SENSOR_BME680_H__ */

drivers/sensor/bme680/bme680_i2c.c

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2016, 2017 Intel Corporation
+ * Copyright (c) 2017 IpTronix S.r.l.
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ * Copyright (c) 2022, Leonard Pollak
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*
+ * Bus-specific functionality for BME680s accessed via I2C.
+ */
+
+#include "bme680.h"
+
+#if BME680_BUS_I2C
+static int bme680_bus_check_i2c(const union bme680_bus *bus)
+{
+	return device_is_ready(bus->i2c.bus) ? 0 : -ENODEV;
+}
+
+static int bme680_reg_read_i2c(const struct device *dev,
+			       uint8_t start, uint8_t *buf, int size)
+{
+	const struct bme680_config *config = dev->config;
+
+	return i2c_burst_read_dt(&config->bus.i2c, start, buf, size);
+}
+
+static int bme680_reg_write_i2c(const struct device *dev,
+				uint8_t reg, uint8_t val)
+{
+	const struct bme680_config *config = dev->config;
+
+	return i2c_reg_write_byte_dt(&config->bus.i2c, reg, val);
+}
+
+const struct bme680_bus_io bme680_bus_io_i2c = {
+	.check = bme680_bus_check_i2c,
+	.read = bme680_reg_read_i2c,
+	.write = bme680_reg_write_i2c,
+};
+#endif /* BME680_BUS_I2C */