[PATCH 3/6] iio: chemical: add driver for ENS160 sensor

[Gustavo Silva <gustavograzs@gmail.com>]

ScioSense ENS160 is a digital metal oxide multi-gas sensor, designed
for indoor air quality monitoring. The driver supports readings of
CO2 and VOC, and can be accessed via both SPI and I2C.

Signed-off-by: Gustavo Silva <gustavograzs@gmail.com>
---
 drivers/iio/chemical/Kconfig       |  22 +++
 drivers/iio/chemical/Makefile      |   3 +
 drivers/iio/chemical/ens160.h      |   9 ++
 drivers/iio/chemical/ens160_core.c | 227 +++++++++++++++++++++++++++++
 drivers/iio/chemical/ens160_i2c.c  |  68 +++++++++
 drivers/iio/chemical/ens160_spi.c  |  69 +++++++++
 6 files changed, 398 insertions(+)
 create mode 100644 drivers/iio/chemical/ens160.h
 create mode 100644 drivers/iio/chemical/ens160_core.c
 create mode 100644 drivers/iio/chemical/ens160_i2c.c
 create mode 100644 drivers/iio/chemical/ens160_spi.c

diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 02649ab81..e407afab8 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -76,6 +76,28 @@ config CCS811
 	  Say Y here to build I2C interface support for the AMS
 	  CCS811 VOC (Volatile Organic Compounds) sensor
 
+config ENS160
+	tristate "ScioSense ENS160 sensor driver"
+	depends on (I2C || SPI)
+	select REGMAP
+	select ENS160_I2C if I2C
+	select ENS160_SPI if SPI
+	help
+	  Say yes here to build support for ScioSense ENS160 multi-gas sensor.
+
+	  This driver can also be built as a module. If so, the module for I2C
+	  would be called ens160_i2c and ens160_spi for SPI support.
+
+config ENS160_I2C
+	tristate
+	depends on I2C && ENS160
+	select REGMAP_I2C
+
+config ENS160_SPI
+	tristate
+	depends on SPI && ENS160
+	select REGMAP_SPI
+
 config IAQCORE
 	tristate "AMS iAQ-Core VOC sensors"
 	depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index 2f3dee8bb..4866db06b 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -11,6 +11,9 @@ obj-$(CONFIG_BME680) += bme680_core.o
 obj-$(CONFIG_BME680_I2C) += bme680_i2c.o
 obj-$(CONFIG_BME680_SPI) += bme680_spi.o
 obj-$(CONFIG_CCS811)		+= ccs811.o
+obj-$(CONFIG_ENS160) += ens160_core.o
+obj-$(CONFIG_ENS160_I2C) += ens160_i2c.o
+obj-$(CONFIG_ENS160_SPI) += ens160_spi.o
 obj-$(CONFIG_IAQCORE)		+= ams-iaq-core.o
 obj-$(CONFIG_PMS7003) += pms7003.o
 obj-$(CONFIG_SCD30_CORE) += scd30_core.o
diff --git a/drivers/iio/chemical/ens160.h b/drivers/iio/chemical/ens160.h
new file mode 100644
index 000000000..3fd079bc4
--- /dev/null
+++ b/drivers/iio/chemical/ens160.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ENS160_H_
+#define ENS160_H_
+
+int ens160_core_probe(struct device *dev, struct regmap *regmap,
+		      const char *name);
+void ens160_core_remove(struct device *dev);
+
+#endif
diff --git a/drivers/iio/chemical/ens160_core.c b/drivers/iio/chemical/ens160_core.c
new file mode 100644
index 000000000..25593420d
--- /dev/null
+++ b/drivers/iio/chemical/ens160_core.c
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ScioSense ENS160 multi-gas sensor driver
+ *
+ * Copyright (c) 2024 Gustavo Silva <gustavograzs@gmail.com>
+ *
+ * Data sheet:
+ *  https://www.sciosense.com/wp-content/uploads/2023/12/ENS160-Datasheet.pdf
+ *
+ */
+
+#include <linux/bitfield.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "ens160.h"
+
+#define ENS160_PART_ID 0x160
+
+#define ENS160_BOOTING_TIME_MS 10U
+
+#define ENS160_REG_PART_ID	0x00
+
+#define ENS160_REG_OPMODE	0x10
+
+#define ENS160_REG_MODE_DEEP_SLEEP	0x00
+#define ENS160_REG_MODE_IDLE		0x01
+#define ENS160_REG_MODE_STANDARD	0x02
+#define ENS160_REG_MODE_RESET		0xF0
+
+#define ENS160_REG_COMMAND		0x12
+#define ENS160_REG_COMMAND_GET_APPVER	0x0E
+#define ENS160_REG_COMMAND_CLRGPR	0xCC
+
+#define ENS160_REG_TEMP_IN		0x13
+#define ENS160_REG_RH_IN		0x15
+#define ENS160_REG_DEVICE_STATUS	0x20
+#define ENS160_REG_DATA_TVOC		0x22
+#define ENS160_REG_DATA_ECO2		0x24
+#define ENS160_REG_DATA_T		0x30
+#define ENS160_REG_DATA_RH		0x32
+#define ENS160_REG_GPR_READ4		0x4C
+
+#define ENS160_STATUS_VALIDITY_FLAG	GENMASK(3, 2)
+
+#define ENS160_STATUS_NORMAL	0x00
+
+struct ens160_data {
+	struct regmap *regmap;
+};
+
+static const struct iio_chan_spec ens160_channels[] = {
+	{
+		.type = IIO_CONCENTRATION,
+		.channel2 = IIO_MOD_VOC,
+		.modified = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.address = ENS160_REG_DATA_TVOC,
+	},
+	{
+		.type = IIO_CONCENTRATION,
+		.channel2 = IIO_MOD_CO2,
+		.modified = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.address = ENS160_REG_DATA_ECO2,
+	},
+};
+
+static int ens160_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	struct ens160_data *data = iio_priv(indio_dev);
+	__le16 buf;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = regmap_bulk_read(data->regmap, chan->address,
+					&buf, sizeof(buf));
+		if (ret)
+			return ret;
+		*val = le16_to_cpu(buf);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->channel2) {
+		case IIO_MOD_CO2:
+			/* The sensor reads CO2 data as ppm */
+			*val = 0;
+			*val2 = 100;
+			return IIO_VAL_INT_PLUS_MICRO;
+		case IIO_MOD_VOC:
+			/* The sensor reads VOC data as ppb */
+			*val = 0;
+			*val2 = 100;
+			return IIO_VAL_INT_PLUS_NANO;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int ens160_set_mode(struct ens160_data *data, u8 mode)
+{
+	int ret;
+
+	ret = regmap_write(data->regmap, ENS160_REG_OPMODE, mode);
+	if (ret)
+		return ret;
+
+	msleep(ENS160_BOOTING_TIME_MS);
+
+	return 0;
+}
+
+static int ens160_chip_init(struct ens160_data *data)
+{
+	struct device *dev = regmap_get_device(data->regmap);
+	u8 fw_version[3];
+	__le16 part_id;
+	unsigned int status;
+	int ret;
+
+	ret = ens160_set_mode(data, ENS160_REG_MODE_RESET);
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_read(data->regmap, ENS160_REG_PART_ID, &part_id,
+			       sizeof(part_id));
+	if (ret)
+		return ret;
+
+	if (le16_to_cpu(part_id) != ENS160_PART_ID)
+		return -ENODEV;
+
+	ret = ens160_set_mode(data, ENS160_REG_MODE_IDLE);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, ENS160_REG_COMMAND,
+			   ENS160_REG_COMMAND_CLRGPR);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, ENS160_REG_COMMAND,
+			   ENS160_REG_COMMAND_GET_APPVER);
+	if (ret)
+		return ret;
+
+	msleep(ENS160_BOOTING_TIME_MS);
+
+	ret = regmap_bulk_read(data->regmap, ENS160_REG_GPR_READ4,
+			       fw_version, sizeof(fw_version));
+	if (ret)
+		return ret;
+
+	msleep(ENS160_BOOTING_TIME_MS);
+
+	dev_info(dev, "firmware version: %u.%u.%u\n", fw_version[2],
+		 fw_version[1], fw_version[0]);
+
+	ret = ens160_set_mode(data, ENS160_REG_MODE_STANDARD);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(data->regmap, ENS160_REG_DEVICE_STATUS, &status);
+	if (ret)
+		return ret;
+
+	if (FIELD_GET(ENS160_STATUS_VALIDITY_FLAG, status)
+	    != ENS160_STATUS_NORMAL)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct iio_info ens160_info = {
+	.read_raw = ens160_read_raw,
+};
+
+int ens160_core_probe(struct device *dev, struct regmap *regmap,
+		      const char *name)
+{
+	struct ens160_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	dev_set_drvdata(dev, indio_dev);
+	data->regmap = regmap;
+
+	indio_dev->name = name;
+	indio_dev->info = &ens160_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ens160_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ens160_channels);
+
+	ret = ens160_chip_init(data);
+	if (ret) {
+		dev_err_probe(dev, ret, "chip initialization failed\n");
+		return ret;
+	}
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+EXPORT_SYMBOL_NS(ens160_core_probe, IIO_ENS160);
+
+void ens160_core_remove(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ens160_data *data = iio_priv(indio_dev);
+
+	ens160_set_mode(data, ENS160_REG_MODE_IDLE);
+}
+EXPORT_SYMBOL_NS(ens160_core_remove, IIO_ENS160);
+
+MODULE_AUTHOR("Gustavo Silva <gustavograzs@gmail.com>");
+MODULE_DESCRIPTION("ScioSense ENS160 driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/chemical/ens160_i2c.c b/drivers/iio/chemical/ens160_i2c.c
new file mode 100644
index 000000000..ee2b44184
--- /dev/null
+++ b/drivers/iio/chemical/ens160_i2c.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ScioSense ENS160 multi-gas sensor I2C driver
+ *
+ * Copyright (c) 2024 Gustavo Silva <gustavograzs@gmail.com>
+ *
+ * 7-Bit I2C slave address is:
+ *	- 0x52 if ADDR pin LOW
+ *	- 0x53 if ADDR pin HIGH
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "ens160.h"
+
+static const struct regmap_config ens160_regmap_i2c_conf = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int ens160_i2c_probe(struct i2c_client *client)
+{
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_i2c(client, &ens160_regmap_i2c_conf);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "Failed to register i2c regmap %ld\n",
+			PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	return ens160_core_probe(&client->dev, regmap, client->name);
+}
+
+static void ens160_i2c_remove(struct i2c_client *client)
+{
+	ens160_core_remove(&client->dev);
+}
+
+static const struct i2c_device_id ens160_i2c_id[] = {
+	{ "ens160", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ens160_i2c_id);
+
+static const struct of_device_id ens160_of_i2c_match[] = {
+	{ .compatible = "sciosense,ens160" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ens160_of_i2c_match);
+
+static struct i2c_driver ens160_i2c_driver = {
+	.driver = {
+		.name		= "ens160_i2c",
+		.of_match_table	= ens160_of_i2c_match,
+	},
+	.probe = ens160_i2c_probe,
+	.remove = ens160_i2c_remove,
+	.id_table = ens160_i2c_id,
+};
+module_i2c_driver(ens160_i2c_driver);
+
+MODULE_AUTHOR("Gustavo Silva <gustavograzs@gmail.com>");
+MODULE_DESCRIPTION("ScioSense ENS160 I2C driver");
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(IIO_ENS160);
diff --git a/drivers/iio/chemical/ens160_spi.c b/drivers/iio/chemical/ens160_spi.c
new file mode 100644
index 000000000..effc4acee
--- /dev/null
+++ b/drivers/iio/chemical/ens160_spi.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ScioSense ENS160 multi-gas sensor SPI driver
+ *
+ * Copyright (c) 2024 Gustavo Silva <gustavograzs@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "ens160.h"
+
+#define ENS160_SPI_READ BIT(0)
+
+static const struct regmap_config ens160_regmap_spi_conf = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.reg_shift = -1,
+	.read_flag_mask = ENS160_SPI_READ,
+};
+
+static int ens160_spi_probe(struct spi_device *spi)
+{
+	struct regmap *regmap;
+	const struct spi_device_id *id = spi_get_device_id(spi);
+
+	regmap = devm_regmap_init_spi(spi, &ens160_regmap_spi_conf);
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "Failed to register spi regmap: %pe\n",
+			regmap);
+		return PTR_ERR(regmap);
+	}
+
+	return ens160_core_probe(&spi->dev, regmap, id->name);
+}
+
+static void ens160_spi_remove(struct spi_device *spi)
+{
+	ens160_core_remove(&spi->dev);
+}
+
+static const struct of_device_id ens160_spi_of_match[] = {
+	{ .compatible = "sciosense,ens160" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ens160_spi_of_match);
+
+static const struct spi_device_id ens160_spi_id[] = {
+	{ "ens160", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ens160_spi_id);
+
+static struct spi_driver ens160_spi_driver = {
+	.driver = {
+		.name	= "ens160_spi",
+		.of_match_table = ens160_spi_of_match,
+	},
+	.probe		= ens160_spi_probe,
+	.remove		= ens160_spi_remove,
+	.id_table	= ens160_spi_id,
+};
+module_spi_driver(ens160_spi_driver);
+
+MODULE_AUTHOR("Gustavo Silva <gustavograzs@gmail.com>");
+MODULE_DESCRIPTION("ScioSense ENS160 SPI driver");
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(IIO_ENS160);
-- 
2.45.0