[PATCH v2 2/2] iio: chemical: Add driver for SEN0322

Tóth János via B4 Relay
2025-05-05T07:53:07Z

From: Tóth János <gomba007@gmail.com>

Add support for the DFRobot SEN0322 oxygen sensor.

Datasheet:
https://wiki.dfrobot.com/Gravity_I2C_Oxygen_Sensor_SKU_SEN0322

To instantiate (assuming device is connected to I2C-2):
echo 'sen0322 0x73' > /sys/class/i2c-dev/i2c-2/device/new_device

To get the oxygen concentration (assuming device is iio:device0) multiply
the values read from:
/sys/bus/iio/devices/iio:device0/in_concentration_raw
/sys/bus/iio/devices/iio:device0/in_concentration_scale

Signed-off-by: Tóth János <gomba007@gmail.com>
---
MAINTAINERS | 6 ++
drivers/iio/chemical/Kconfig | 10 +++
drivers/iio/chemical/Makefile | 1 +
drivers/iio/chemical/sen0322.c | 167 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 184 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 3cbf9ac0d83f..6fda7a2f1248 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6852,6 +6852,12 @@ L: linux-rtc@vger.kernel.org
S: Maintained
F: drivers/rtc/rtc-sd2405al.c

+DFROBOT SEN0322 DRIVER
+M: Tóth János <gomba007@gmail.com>
+L: linux-iio@vger.kernel.org
+S: Maintained
+F: drivers/iio/chemical/sen0322.c
+
DH ELECTRONICS DHSOM SOM AND BOARD SUPPORT
M: Christoph Niedermaier <cniedermaier@dh-electronics.com>
M: Marek Vasut <marex@denx.de>
diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 330fe0af946f..60a81863d123 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -166,6 +166,16 @@ config SCD4X
To compile this driver as a module, choose M here: the module will
be called scd4x.

+config SEN0322
+ tristate "SEN0322 oxygen sensor"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ Say Y here to build support for the DFRobot SEN0322 oxygen sensor.
+
+ To compile this driver as a module, choose M here: the module will
+ be called sen0322.
+
config SENSIRION_SGP30
tristate "Sensirion SGPxx gas sensors"
depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index 4866db06bdc9..deeff0e4e6f7 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_SCD30_CORE) += scd30_core.o
obj-$(CONFIG_SCD30_I2C) += scd30_i2c.o
obj-$(CONFIG_SCD30_SERIAL) += scd30_serial.o
obj-$(CONFIG_SCD4X) += scd4x.o
+obj-$(CONFIG_SEN0322) += sen0322.o
obj-$(CONFIG_SENSEAIR_SUNRISE_CO2) += sunrise_co2.o
obj-$(CONFIG_SENSIRION_SGP30) += sgp30.o
obj-$(CONFIG_SENSIRION_SGP40) += sgp40.o
diff --git a/drivers/iio/chemical/sen0322.c b/drivers/iio/chemical/sen0322.c
new file mode 100644
index 000000000000..c2dfb0ff7f40
--- /dev/null
+++ b/drivers/iio/chemical/sen0322.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the DFRobot SEN0322 oxygen sensor.
+ *
+ * Datasheet:
+ * https://wiki.dfrobot.com/Gravity_I2C_Oxygen_Sensor_SKU_SEN0322
+ *
+ * Possible I2C slave addresses:
+ * 0x70
+ * 0x71
+ * 0x72
+ * 0x73
+ *
+ * Copyright (C) 2025 Tóth János <gomba007@gmail.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+
+#include <linux/iio/iio.h>
+
+#define SEN0322_REG_DATA 0x03
+#define SEN0322_REG_COEFF 0x0A
+
+struct sen0322 {
+ struct regmap *regmap;
+};
+
+static int sen0322_read_scale(struct sen0322 *sen0322, int *num, int *den)
+{
+ u32 val;
+ int ret;
+
+ ret = regmap_read(sen0322->regmap, SEN0322_REG_COEFF, &val);
+ if (ret < 0)
+ return ret;
+
+ if (val) {
+ *num = val;
+ *den = 100000;
+ } else {
+ *num = 209;
+ *den = 120000;
+ }
+
+ dev_dbg(regmap_get_device(sen0322->regmap), "scale: %d/%d\n",
+ *num, *den);
+
+ return 0;
+}
+
+static int sen0322_read_data(struct sen0322 *sen0322)
+{
+ u8 data[4] = { 0 };
+ int ret;
+
+ ret = regmap_bulk_read(sen0322->regmap, SEN0322_REG_DATA, data, 3);
+ if (ret < 0)
+ return ret;
+
+ ret = data[0] * 100 + data[1] * 10 + data[2];
+
+ dev_dbg(regmap_get_device(sen0322->regmap), "data: %d\n", ret);
+
+ return ret;
+}
+
+static int sen0322_read_raw(struct iio_dev *iio_dev,
+ const struct iio_chan_spec *chan,
+ int *val, int *val2, long mask)
+{
+ struct sen0322 *sen0322 = iio_priv(iio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ switch (chan->type) {
+ case IIO_CONCENTRATION:
+ ret = sen0322_read_data(sen0322);
+ if (ret < 0)
+ return ret;
+
+ *val = ret;
+ return IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_CONCENTRATION:
+ ret = sen0322_read_scale(sen0322, val, val2);
+ if (ret < 0)
+ return ret;
+
+ return IIO_VAL_FRACTIONAL;
+
+ default:
+ return -EINVAL;
+ }
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info sen0322_info = {
+ .read_raw = sen0322_read_raw,
+};
+
+static const struct regmap_config sen0322_regmap_conf = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+static const struct iio_chan_spec sen0322_channel = {
+ .type = IIO_CONCENTRATION,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+};
+
+static int sen0322_probe(struct i2c_client *client)
+{
+ struct sen0322 *sen0322;
+ struct iio_dev *iio_dev;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ iio_dev = devm_iio_device_alloc(&client->dev, sizeof(*sen0322));
+ if (!iio_dev)
+ return -ENOMEM;
+
+ sen0322 = iio_priv(iio_dev);
+
+ sen0322->regmap = devm_regmap_init_i2c(client, &sen0322_regmap_conf);
+ if (IS_ERR(sen0322->regmap))
+ return PTR_ERR(sen0322->regmap);
+
+ iio_dev->info = &sen0322_info;
+ iio_dev->name = "sen0322";
+ iio_dev->channels = &sen0322_channel;
+ iio_dev->num_channels = 1;
+ iio_dev->modes = INDIO_DIRECT_MODE;
+
+ return devm_iio_device_register(&client->dev, iio_dev);
+}
+
+static const struct of_device_id sen0322_of_match[] = {
+ { .compatible = "dfrobot,sen0322" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, sen0322_of_match);
+
+static struct i2c_driver sen0322_driver = {
+ .driver = {
+ .name = "sen0322",
+ .of_match_table = sen0322_of_match,
+ },
+ .probe = sen0322_probe,
+};
+module_i2c_driver(sen0322_driver);
+
+MODULE_AUTHOR("Tóth János <gomba007@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SEN0322 oxygen sensor driver");

--
2.34.1