[PATCH v5 2/2] iio: humidity: Add support for ENS210

From: Joshua Felmeden
Date: Mon Jul 22 2024 - 12:59:33 EST

Add support for ENS210/ENS210A/ENS211/ENS212/ENS213A/ENS215.

The ENS21x is a family of temperature and relative humidity sensors with
accuracies tailored to the needs of specific applications.

Signed-off-by: Joshua Felmeden <jfelmeden@xxxxxxxxxxxxxxxxxxxx>
---
drivers/iio/humidity/Kconfig | 11 ++
drivers/iio/humidity/Makefile | 1 +
drivers/iio/humidity/ens210.c | 344 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 356 insertions(+)

diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig
index b15b7a3b66d5..54f11f000b6f 100644
--- a/drivers/iio/humidity/Kconfig
+++ b/drivers/iio/humidity/Kconfig
@@ -25,6 +25,17 @@ config DHT11
Other sensors should work as well as long as they speak the
same protocol.

+config ENS210
+ tristate "ENS210 temperature and humidity sensor"
+ depends on I2C
+ select CRC7
+ help
+ Say yes here to get support for the ScioSense ENS210 family of
+ humidity and temperature sensors.
+
+ This driver can also be built as a module. If so, the module will be
+ called ens210.
+
config HDC100X
tristate "TI HDC100x relative humidity and temperature sensor"
depends on I2C
diff --git a/drivers/iio/humidity/Makefile b/drivers/iio/humidity/Makefile
index 5fbeef299f61..34b3dc749466 100644
--- a/drivers/iio/humidity/Makefile
+++ b/drivers/iio/humidity/Makefile
@@ -5,6 +5,7 @@

obj-$(CONFIG_AM2315) += am2315.o
obj-$(CONFIG_DHT11) += dht11.o
+obj-$(CONFIG_ENS210) += ens210.o
obj-$(CONFIG_HDC100X) += hdc100x.o
obj-$(CONFIG_HDC2010) += hdc2010.o
obj-$(CONFIG_HDC3020) += hdc3020.o
diff --git a/drivers/iio/humidity/ens210.c b/drivers/iio/humidity/ens210.c
new file mode 100644
index 000000000000..9fe60a9eeef0
--- /dev/null
+++ b/drivers/iio/humidity/ens210.c
@@ -0,0 +1,344 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ens210.c - Support for ScioSense ens210 temperature & humidity sensor family
+ *
+ * (7-bit I2C slave address 0x43 ENS210)
+ * (7-bit I2C slave address 0x43 ENS210A)
+ * (7-bit I2C slave address 0x44 ENS211)
+ * (7-bit I2C slave address 0x45 ENS212)
+ * (7-bit I2C slave address 0x46 ENS213A)
+ * (7-bit I2C slave address 0x47 ENS215)
+ *
+ * Datasheet:
+ * https://www.sciosense.com/wp-content/uploads/2024/04/ENS21x-Datasheet.pdf
+ * https://www.sciosense.com/wp-content/uploads/2023/12/ENS210-Datasheet.pdf
+ */
+
+#include <linux/crc7.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <asm/unaligned.h>
+
+/* register definitions */
+#define ENS210_REG_PART_ID 0x00
+#define ENS210_REG_DIE_REV 0x02
+#define ENS210_REG_UID 0x04
+#define ENS210_REG_SYS_CTRL 0x10
+#define ENS210_REG_SYS_STAT 0x11
+#define ENS210_REG_SENS_RUN 0x21
+#define ENS210_REG_SENS_START 0x22
+#define ENS210_REG_SENS_STOP 0x23
+#define ENS210_REG_SENS_STAT 0x24
+#define ENS210_REG_T_VAL 0x30
+#define ENS210_REG_H_VAL 0x33
+
+/* value definitions */
+#define ENS210_SENS_START_T_START BIT(0)
+#define ENS210_SENS_START_H_START BIT(1)
+
+#define ENS210_SENS_STAT_T_ACTIVE BIT(0)
+#define ENS210_SENS_STAT_H_ACTIVE BIT(1)
+
+#define ENS210_SYS_CTRL_LOW_POWER_ENABLE BIT(0)
+#define ENS210_SYS_CTRL_SYS_RESET BIT(7)
+
+#define ENS210_SYS_STAT_SYS_ACTIVE BIT(0)
+
+enum ens210_partnumber {
+ ENS210 = 0x0210,
+ ENS210A = 0xa210,
+ ENS211 = 0x0211,
+ ENS212 = 0x0212,
+ ENS213A = 0xa213,
+ ENS215 = 0x0215,
+};
+
+/**
+ * struct ens210_chip_info - Humidity/Temperature chip specific information
+ * @name: name of device
+ * @part_id: chip identifier
+ * @conv_time_msec: time for conversion calculation in m/s
+ */
+struct ens210_chip_info {
+ const char *name;
+ enum ens210_partnumber part_id;
+ unsigned int conv_time_msec;
+};
+
+/**
+ * struct ens210_data - Humidity/Temperature sensor device structure
+ * @client: i2c client
+ * @chip_info: chip specific information
+ * @lock: lock protecting the i2c conversion
+ */
+struct ens210_data {
+ struct i2c_client *client;
+ const struct ens210_chip_info *chip_info;
+ struct mutex lock;
+};
+
+/* calculate 17-bit crc7 */
+static u8 ens210_crc7(u32 val)
+{
+ unsigned int val_be = (val & 0x1ffff) >> 0x8;
+
+ return crc7_be(0xde, (u8 *)&val_be, 3) >> 1;
+}
+
+static int ens210_get_measurement(struct iio_dev *indio_dev, bool temp, int *val)
+{
+ struct ens210_data *data = iio_priv(indio_dev);
+ struct device *dev = &data->client->dev;
+ u32 regval;
+ u8 regval_le[3];
+ int ret;
+
+ /* assert read */
+ ret = i2c_smbus_write_byte_data(data->client, ENS210_REG_SENS_START,
+ temp ? ENS210_SENS_START_T_START :
+ ENS210_SENS_START_H_START);
+ if (ret)
+ return ret;
+
+ /* wait for conversion to be ready */
+ msleep(data->chip_info->conv_time_msec);
+
+ ret = i2c_smbus_read_byte_data(data->client,
+ ENS210_REG_SENS_STAT);
+ if (ret < 0)
+ return ret;
+
+ /* perform read */
+ ret = i2c_smbus_read_i2c_block_data(
+ data->client, temp ? ENS210_REG_T_VAL : ENS210_REG_H_VAL, 3,
+ (u8 *)&regval_le);
+ if (ret < 0) {
+ dev_err(dev, "failed to read register");
+ return -EIO;
+ } else if (ret != 3) {
+ dev_err(dev, "expected 3 bytes, received %d\n", ret);
+ return -EIO;
+ }
+
+ regval = get_unaligned_le24(regval_le);
+ if (ens210_crc7(regval) != ((regval >> 17) & 0x7f)) {
+ /* crc fail */
+ dev_err(dev, "ens invalid crc\n");
+ return -EIO;
+ }
+
+ if (!((regval >> 16) & 0x1)) {
+ dev_err(dev, "ens data is not valid");
+ return -EIO;
+ }
+
+ *val = regval & 0xffff;
+ return IIO_VAL_INT;
+}
+
+static int ens210_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel, int *val,
+ int *val2, long mask)
+{
+ struct ens210_data *data = iio_priv(indio_dev);
+ int ret = -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ scoped_guard(mutex, &data->lock) {
+ ret = ens210_get_measurement(indio_dev,
+ channel->type == IIO_TEMP, val);
+ if (ret)
+ return ret;
+ return IIO_VAL_INT;
+ }
+ return ret;
+ case IIO_CHAN_INFO_SCALE:
+ if (channel->type == IIO_TEMP) {
+ *val = 15;
+ *val2 = 625000;
+ } else {
+ *val = 1;
+ *val2 = 953125;
+ }
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_OFFSET:
+ if (channel->type == IIO_TEMP) {
+ *val = -17481;
+ *val2 = 600000;
+ ret = IIO_VAL_INT_PLUS_MICRO;
+ break;
+ }
+ *val = 0;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ unreachable();
+}
+
+static const struct iio_chan_spec ens210_channels[] = {
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OFFSET),
+ },
+ {
+ .type = IIO_HUMIDITYRELATIVE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OFFSET),
+ }
+};
+
+static const struct iio_info ens210_info = {
+ .read_raw = ens210_read_raw,
+};
+
+static int ens210_probe(struct i2c_client *client)
+{
+ struct ens210_data *data;
+ struct iio_dev *indio_dev;
+ uint16_t part_id;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+ I2C_FUNC_SMBUS_WRITE_BYTE |
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+ return dev_err_probe(&client->dev, -EOPNOTSUPP,
+ "adapter does not support some i2c transactions\n");
+ }
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ data->client = client;
+ mutex_init(&data->lock);
+ data->chip_info = i2c_get_match_data(client);
+
+ ret = devm_regulator_get_enable(&client->dev, "vdd");
+ if (ret)
+ return ret;
+
+ /* reset device */
+ ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL,
+ ENS210_SYS_CTRL_SYS_RESET);
+ if (ret)
+ return ret;
+
+ /* wait for device to become active */
+ usleep_range(4000, 5000);
+
+ /* disable low power mode */
+ ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL, 0x00);
+ if (ret)
+ return ret;
+
+ /* wait for device to finish */
+ usleep_range(4000, 5000);
+
+ /* get part_id */
+ part_id = i2c_smbus_read_word_data(client, ENS210_REG_PART_ID);
+
+ if (part_id != data->chip_info->part_id) {
+ dev_info(&client->dev,
+ "Part ID does not match (0x%04x != 0x%04x)\n", part_id,
+ data->chip_info->part_id);
+ }
+
+ /* reenable low power */
+ ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL,
+ ENS210_SYS_CTRL_LOW_POWER_ENABLE);
+ if (ret)
+ return ret;
+
+ indio_dev->name = data->chip_info->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ens210_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ens210_channels);
+ indio_dev->info = &ens210_info;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct ens210_chip_info ens210_chip_info_data = {
+ .name = "ens210",
+ .part_id = ENS210,
+ .conv_time_msec = 130,
+};
+
+static const struct ens210_chip_info ens210a_chip_info_data = {
+ .name = "ens210a",
+ .part_id = ENS210A,
+ .conv_time_msec = 130,
+};
+
+static const struct ens210_chip_info ens211_chip_info_data = {
+ .name = "ens211",
+ .part_id = ENS211,
+ .conv_time_msec = 32,
+};
+
+static const struct ens210_chip_info ens212_chip_info_data = {
+ .name = "ens212",
+ .part_id = ENS212,
+ .conv_time_msec = 32,
+};
+
+static const struct ens210_chip_info ens213a_chip_info_data = {
+ .name = "ens213a",
+ .part_id = ENS213A,
+ .conv_time_msec = 130,
+};
+
+static const struct ens210_chip_info ens215_chip_info_data = {
+ .name = "ens215",
+ .part_id = ENS215,
+ .conv_time_msec = 130,
+};
+
+static const struct of_device_id ens210_of_match[] = {
+ { .compatible = "sciosense,ens210", .data = &ens210_chip_info_data},
+ { .compatible = "sciosense,ens210a", .data = &ens210a_chip_info_data },
+ { .compatible = "sciosense,ens211", .data = &ens211_chip_info_data},
+ { .compatible = "sciosense,ens212", .data = &ens212_chip_info_data},
+ { .compatible = "sciosense,ens213a", .data = &ens213a_chip_info_data },
+ { .compatible = "sciosense,ens215", .data = &ens215_chip_info_data },
+ {}
+};
+MODULE_DEVICE_TABLE(of, ens210_of_match);
+
+static const struct i2c_device_id ens210_id_table[] = {
+ { "ens210", (kernel_ulong_t)&ens210_chip_info_data },
+ { "ens210a", (kernel_ulong_t)&ens210a_chip_info_data },
+ { "ens211", (kernel_ulong_t)&ens211_chip_info_data },
+ { "ens212", (kernel_ulong_t)&ens212_chip_info_data },
+ { "ens213a", (kernel_ulong_t)&ens213a_chip_info_data },
+ { "ens215", (kernel_ulong_t)&ens215_chip_info_data },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, ens210_id_table);
+
+static struct i2c_driver ens210_driver = {
+ .probe = ens210_probe,
+ .id_table = ens210_id_table,
+ .driver = {
+ .name = "ens210",
+ .of_match_table = ens210_of_match,
+ },
+};
+
+module_i2c_driver(ens210_driver);
+
+MODULE_DESCRIPTION("ScioSense ENS210 temperature and humidity sensor driver");
+MODULE_AUTHOR("Joshua Felmeden <jfelmeden@xxxxxxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");

--
2.39.2