drivers: sensor: Add ROHM BH1750 driver

This adds support for ROHM BH1750 the i2c light sensor.

Signed-off-by: Gaël PORTAY <[email protected]>

Author: gportay

drivers/sensor/CMakeLists.txt

@@ -9,6 +9,7 @@ add_subdirectory_ifdef(CONFIG_AMG88XX		amg88xx)
 add_subdirectory_ifdef(CONFIG_AMS_AS5600	ams_as5600)
 add_subdirectory_ifdef(CONFIG_AMS_IAQ_CORE	ams_iAQcore)
 add_subdirectory_ifdef(CONFIG_APDS9960		apds9960)
+add_subdirectory_ifdef(CONFIG_BH1750		bh1750)
 add_subdirectory_ifdef(CONFIG_BMA280		bma280)
 add_subdirectory_ifdef(CONFIG_BMC150_MAGN	bmc150_magn)
 add_subdirectory_ifdef(CONFIG_BME280		bme280)

drivers/sensor/Kconfig

@@ -59,6 +59,8 @@ source "drivers/sensor/ams_iAQcore/Kconfig"
 
 source "drivers/sensor/apds9960/Kconfig"
 
+source "drivers/sensor/bh1750/Kconfig"
+
 source "drivers/sensor/bma280/Kconfig"
 
 source "drivers/sensor/bmc150_magn/Kconfig"

drivers/sensor/bh1750/CMakeLists.txt

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources(bh1750.c)

drivers/sensor/bh1750/Kconfig

@@ -0,0 +1,12 @@
+# BH1750 light sensor configuration options
+
+# Copyright (c) 2022 Gaël PORTAY
+# SPDX-License-Identifier: Apache-2.0
+
+config BH1750
+	bool "BH1750 sensor"
+	default y
+	depends on DT_HAS_ROHM_BH1750_ENABLED
+	select I2C
+	help
+	  Enable driver for BH1750 I2C-based light sensor.

drivers/sensor/bh1750/bh1750.c

@@ -0,0 +1,230 @@
+/* bh1750.c - Driver for BH1750 light sensor */
+
+/*
+ * Copyright (c) 2022 Gaël PORTAY
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT rohm_bh1750
+
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/init.h>
+#include <zephyr/pm/device.h>
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/sys/__assert.h>
+
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(BH1750, CONFIG_SENSOR_LOG_LEVEL);
+
+#if DT_NUM_INST_STATUS_OKAY(DT_DRV_COMPAT) == 0
+#warning "BH1750 driver enabled without any devices"
+#endif
+
+#define BH1750_POWER_DOWN                          0x00
+#define BH1750_POWER_ON                            0x01
+#define BH1750_RESET                               0x07
+#define BH1750_CONTINUOUSLY_HIGH_RESOLUTION_MODE   0x10
+#define BH1750_CONTINUOUSLY_HIGH_RESOLUTION_MODE_2 0x11
+#define BH1750_CONTINUOUSLY_LOW_RESOLUTION_MODE    0x13
+#define BH1750_ONE_TIME_HIGH_RESOLUTION_MODE       0x20
+#define BH1750_ONE_TIME_HIGH_RESOLUTION_MODE_2     0x21
+#define BH1750_ONE_TIME_LOW_RESOLUTION_MODE        0x23
+#define BH1750_CHANGE_MEASUREMENT_TIME_HIGH        0x40
+#define BH1750_CHANGE_MEASUREMENT_TIME_LOW         0x60
+
+struct bh1750_data {
+	uint16_t raw_val;
+};
+
+struct bh1750_config {
+	struct i2c_dt_spec i2c;
+};
+
+static inline int bh1750_is_ready(const struct device *dev)
+{
+	const struct bh1750_config *cfg = dev->config;
+
+	return device_is_ready(cfg->i2c.bus) ? 0 : -ENODEV;
+}
+
+static inline int bh1750_read(const struct device *dev, uint8_t *buf, int size)
+{
+	const struct bh1750_config *cfg = dev->config;
+
+	return i2c_read_dt(&cfg->i2c, buf, size);
+}
+
+static inline int bh1750_write(const struct device *dev, uint8_t val)
+{
+	const struct bh1750_config *cfg = dev->config;
+	uint8_t buf = val;
+
+	return i2c_write_dt(&cfg->i2c, &buf, sizeof(buf));
+}
+
+static int bh1750_sample_fetch(const struct device *dev,
+			       enum sensor_channel chan)
+{
+	struct bh1750_data *data = dev->data;
+	uint8_t buf[2];
+	int ret;
+
+	__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
+
+#ifdef CONFIG_PM_DEVICE
+	enum pm_device_state state;
+	(void)pm_device_state_get(dev, &state);
+	/* Do not allow sample fetching from suspended state */
+	if (state == PM_DEVICE_STATE_SUSPENDED) {
+		return -EIO;
+	}
+#endif
+
+	ret = bh1750_write(dev, BH1750_ONE_TIME_HIGH_RESOLUTION_MODE);
+	if (ret < 0) {
+		LOG_DBG("One time high resolution mode failed: %d", ret);
+		return ret;
+	}
+
+	/* Wait for the measure to be ready */
+	k_sleep(K_MSEC(180)); /* Max for H-Resolution Mode */
+
+	ret = bh1750_read(dev, buf, sizeof(buf));
+	if (ret < 0) {
+		LOG_DBG("Read failed: %d", ret);
+		return ret;
+	}
+
+	data->raw_val = sys_get_be16(&buf[0]);
+
+	return 0;
+}
+
+static int bh1750_channel_get(const struct device *dev,
+			      enum sensor_channel chan,
+			      struct sensor_value *val)
+{
+	struct bh1750_data *data = dev->data;
+	double tmp;
+	int ret;
+
+	switch (chan) {
+	case SENSOR_CHAN_LIGHT:
+		/*
+		 * The documentation says the following about the calculation
+		 * at section Measurement sequence example from "Write
+		 * instruction" to "Read measurement result" p.17:
+		 *
+		 * How to calculate when the data High Byte is "10000011" and
+		 * Low Byte is "10010000"
+		 *
+		 * (2^15 + 2^9 + 2^8 + 2^7 + 2^4) / 1.2 = 28067 [lx]
+		 *
+		 * Which means:
+		 *
+		 * lx = Slx / 1.2
+		 */
+		tmp = data->raw_val / 1.2;
+		ret = sensor_value_from_double(val, tmp);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct sensor_driver_api bh1750_api_funcs = {
+	.sample_fetch = bh1750_sample_fetch,
+	.channel_get = bh1750_channel_get,
+};
+
+static int bh1750_chip_init(const struct device *dev)
+{
+	int ret;
+
+	ret = bh1750_is_ready(dev);
+	if (ret < 0) {
+		LOG_DBG("I2C bus check failed: %d", ret);
+		return ret;
+	}
+
+	/*
+	 * Make sure chip is in power on mode before reset.
+	 *
+	 * The documentation says the following about the reset command:
+	 *
+	 * Reset command is for only reset Illuminance data register (reset
+	 * value is '0'). It is not necessary even power supply sequence. It is
+	 * used for removing previous measurement result.  This command is not
+	 * working in power down mode, so that please set the power on mode
+	 * before input this command.
+	 */
+	ret = bh1750_write(dev, BH1750_POWER_ON);
+	if (ret < 0) {
+		LOG_DBG("Power on failed: %d", ret);
+		return ret;
+	}
+
+	ret = bh1750_write(dev, BH1750_RESET);
+	if (ret < 0) {
+		LOG_DBG("Reset failed: %d", ret);
+		return ret;
+	}
+
+	LOG_DBG("\"%s\" OK", dev->name);
+	return 0;
+}
+
+#ifdef CONFIG_PM_DEVICE
+static int bh1750_pm_action(const struct device *dev,
+			    enum pm_device_action action)
+{
+	int ret = 0;
+
+	switch (action) {
+	case PM_DEVICE_ACTION_RESUME:
+		/* Put the chip into power up mode and reset */
+		ret = bh1750_chip_init(dev);
+		break;
+	case PM_DEVICE_ACTION_SUSPEND:
+		/* Put the chip into power down mode */
+		ret = bh1750_write(dev, BH1750_POWER_DOWN);
+		if (ret < 0) {
+			LOG_DBG("Power down failed: %d", ret);
+			return ret;
+		}
+		break;
+	default:
+		return -ENOTSUP;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_PM_DEVICE */
+
+#define BH1750_DEFINE(inst)						\
+	static struct bh1750_data bh1750_data_##inst;			\
+	static const struct bh1750_config bh1750_config_##inst = {	\
+		.i2c = I2C_DT_SPEC_INST_GET(inst),			\
+	};								\
+									\
+	PM_DEVICE_DT_INST_DEFINE(inst, bh1750_pm_action);		\
+									\
+	DEVICE_DT_INST_DEFINE(inst,					\
+			 bh1750_chip_init,				\
+			 PM_DEVICE_DT_INST_GET(inst),			\
+			 &bh1750_data_##inst,				\
+			 &bh1750_config_##inst,				\
+			 POST_KERNEL,					\
+			 CONFIG_SENSOR_INIT_PRIORITY,			\
+			 &bh1750_api_funcs);
+
+/* Create the struct device for every status "okay" node in the devicetree. */
+DT_INST_FOREACH_STATUS_OKAY(BH1750_DEFINE)

dts/bindings/sensor/rohm,bh1750-i2c.yaml

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: Apache-2.0
+
+description: ROHM integrated light sensor
+
+compatible: "rohm,bh1750"
+
+include: [sensor-device.yaml, i2c-device.yaml]

tests/drivers/build_all/sensor/i2c.dtsi

@@ -646,3 +646,8 @@ test_i2c_as5600: as5600@64 {
 	compatible = "ams,as5600";
 	reg = <0x64>;
 };
+
+test_i2c_bh1750: bh1750@23 {
+	compatible = "rohm,bh1750";
+	reg = <0x23>;
+};