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
On Mon, 05 May 2025 09:52:59 +0200
Tóth János via B4 Relay <devnull+gomba007.gmail.com@kernel.org> wrote:
> 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
Checkpatch is lagging behind the times, but it is fine to use this
as a formal tag in the tag block..
>
> 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
>
Datasheet: https://wiki.dfrobot.com/Gravity_I2C_Oxygen_Sensor_SKU_SEN0322
> Signed-off-by: Tóth János <gomba007@gmail.com>
A few other little things inline.
Nice little driver :)
Jonathan
> 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;
This is odd enough, that perhaps we could add a comment on why, or at least
a cross reference to where these numbers come from?
What is the special meaning of 0?
> + }
> +
> + 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 };
If you are only read 3 bytes, why is this 4 long?
> + int ret;
> +
> + ret = regmap_bulk_read(sen0322->regmap, SEN0322_REG_DATA, data, 3);
Having shortened above, use sizeof(data) for that 3 to avoid
any potential future mismatch in sizes.
> + 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);
Given you more or less directly provide this to userspace now I'd drop
the dev_dbg() as not adding any value for debugging.
> +
> + 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:
As the sensor only does concentration, you could either drop this
check on basis we can't get here without it or if you want
a strong sanity check do it outside the switch statement as
if (chan->type != IIO_CONCENTRATION)
return -EINVAL;
> + 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;
> + }
> +}
Hi!
Thank you for the review!
> Checkpatch is lagging behind the times, but it is fine to use this
> as a formal tag in the tag block..
> >
> Datasheet: https://wiki.dfrobot.com/Gravity_I2C_Oxygen_Sensor_SKU_SEN0322
>
> > Signed-off-by: Tóth János <gomba007@gmail.com>
Sure.
> > + if (val) {
> > + *num = val;
> > + *den = 100000;
> > + } else {
> > + *num = 209;
> > + *den = 120000;
>
> This is odd enough, that perhaps we could add a comment on why, or at least
> a cross reference to where these numbers come from?
> What is the special meaning of 0?
Okay, I'll add some explanation.
> > + u8 data[4] = { 0 };
>
> If you are only read 3 bytes, why is this 4 long?
It is the closest power of 2, to pacify my OCD, but you are right.
> > + ret = regmap_bulk_read(sen0322->regmap, SEN0322_REG_DATA, data, 3);
>
> Having shortened above, use sizeof(data) for that 3 to avoid
> any potential future mismatch in sizes.
Agreed.
> > + dev_dbg(regmap_get_device(sen0322->regmap), "data: %d\n", ret);
>
> Given you more or less directly provide this to userspace now I'd drop
> the dev_dbg() as not adding any value for debugging.
>
I just like to see if the function actually ran and not reading some buffered
value stuck somewhere, but okay.
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + switch (chan->type) {
> > + case IIO_CONCENTRATION:
> As the sensor only does concentration, you could either drop this
> check on basis we can't get here without it or if you want
> a strong sanity check do it outside the switch statement as
> if (chan->type != IIO_CONCENTRATION)
> return -EINVAL;
I did not want to deviate from the pattern, but yes, it will make the code
more readable.
Best regards,
János
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