Re: [PATCH v6 3/4] iio: chemical: Add Senseair Sunrise 006-0-007 driver

[Jacopo Mondi <jacopo@jmondi.org>]

Hi Jonathan

On Sat, Sep 25, 2021 at 04:34:37PM +0100, Jonathan Cameron wrote:
> On Mon, 20 Sep 2021 15:54:12 +0200
> Jacopo Mondi <jacopo+renesas@jmondi.org> wrote:
>
> > From: Jacopo Mondi <jacopo@jmondi.org>
> >
> > Add support for the Senseair Sunrise 006-0-0007 driver through the
> > IIO subsystem.
> >
> > Datasheet: https://rmtplusstoragesenseair.blob.core.windows.net/docs/Dev/publicerat/TDE5531.pdf
> > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
>
> Hi Jacopo,
>
> One thing I noticed on a final read through is you have a bunch of buffer
> mode related stuff specified for the channels.  I'll drop that whilst applying but

Ah ups! not required indeed

> please check the tested branch of iio.git to make sure I didn't mess it up.

Tested
https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/log/?h=testing

and it's all good as expected, thanks!

>
> thanks,
>
> Jonathan
>
> > ---
> > v5->v6:
> > - Apply style fixes from Andy
> > - Apply Jonathan suggestion and reduce sysfs attribute critical section
> > - Address Peter's comments on the regmap ops:
> >   - Do not use SMBUS_QUICK as it's supported by few adapters
> >   - Make protocol mangling optional
> >   - Insert a 'wake up' delay between the wake up message and the transaction
> >   - Check for the adapter's required functionalities
> > ---
> >  MAINTAINERS                        |   7 +
> >  drivers/iio/chemical/Kconfig       |  10 +
> >  drivers/iio/chemical/Makefile      |   1 +
> >  drivers/iio/chemical/sunrise_co2.c | 551 +++++++++++++++++++++++++++++
> >  4 files changed, 569 insertions(+)
> >  create mode 100644 drivers/iio/chemical/sunrise_co2.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index d7b4f32875a9..4f39e0d65e6d 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -16723,6 +16723,13 @@ S:	Maintained
> >  F:	drivers/misc/phantom.c
> >  F:	include/uapi/linux/phantom.h
> >
> > +SENSEAIR SUNRISE 006-0-0007
> > +M:	Jacopo Mondi <jacopo@jmondi.org>
> > +S:	Maintained
> > +F:	Documentation/ABI/testing/sysfs-bus-iio-chemical-sunrise-co2
> > +F:	Documentation/devicetree/bindings/iio/chemical/senseair,sunrise.yaml
> > +F:	drivers/iio/chemical/sunrise_co2.c
> > +
> >  SENSIRION SCD30 CARBON DIOXIDE SENSOR DRIVER
> >  M:	Tomasz Duszynski <tomasz.duszynski@octakon.com>
> >  S:	Maintained
> > diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
> > index a4920646e9be..5155ab2caed4 100644
> > --- a/drivers/iio/chemical/Kconfig
> > +++ b/drivers/iio/chemical/Kconfig
> > @@ -159,6 +159,16 @@ config SPS30_SERIAL
> >  	  To compile this driver as a module, choose M here: the module will
> >  	  be called sps30_serial.
> >
> > +config SENSEAIR_SUNRISE_CO2
> > +	tristate "Senseair Sunrise 006-0-0007 CO2 sensor"
> > +	select REGMAP_I2C
> > +	help
> > +	  Say yes here to build support for Senseair Sunrise 006-0-0007 CO2
> > +	  sensor.
> > +
> > +	  To compile this driver as a module, choose M here: the
> > +	  module will be called sunrise_co2.
> > +
> >  config VZ89X
> >  	tristate "SGX Sensortech MiCS VZ89X VOC sensor"
> >  	depends on I2C
> > diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
> > index 4898690cc155..61e8749a84f3 100644
> > --- a/drivers/iio/chemical/Makefile
> > +++ b/drivers/iio/chemical/Makefile
> > @@ -15,6 +15,7 @@ obj-$(CONFIG_PMS7003) += pms7003.o
> >  obj-$(CONFIG_SCD30_CORE) += scd30_core.o
> >  obj-$(CONFIG_SCD30_I2C) += scd30_i2c.o
> >  obj-$(CONFIG_SCD30_SERIAL) += scd30_serial.o
> > +obj-$(CONFIG_SENSEAIR_SUNRISE_CO2) += sunrise_co2.o
> >  obj-$(CONFIG_SENSIRION_SGP30)	+= sgp30.o
> >  obj-$(CONFIG_SPS30) += sps30.o
> >  obj-$(CONFIG_SPS30_I2C) += sps30_i2c.o
> > diff --git a/drivers/iio/chemical/sunrise_co2.c b/drivers/iio/chemical/sunrise_co2.c
> > new file mode 100644
> > index 000000000000..a896561a98fa
> > --- /dev/null
> > +++ b/drivers/iio/chemical/sunrise_co2.c
> > @@ -0,0 +1,551 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Senseair Sunrise 006-0-0007 CO2 sensor driver.
> > + *
> > + * Copyright (C) 2021 Jacopo Mondi
> > + *
> > + * List of features not yet supported by the driver:
> > + * - controllable EN pin
> > + * - single-shot operations using the nDRY pin.
> > + * - ABC/target calibration
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/i2c.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/regmap.h>
> > +#include <linux/time64.h>
> > +
> > +#include <linux/iio/iio.h>
> > +
> > +#define DRIVER_NAME "sunrise_co2"
> > +
> > +#define SUNRISE_ERROR_STATUS_REG		0x00
> > +#define SUNRISE_CO2_FILTERED_COMP_REG		0x06
> > +#define SUNRISE_CHIP_TEMPERATURE_REG		0x08
> > +#define SUNRISE_CALIBRATION_STATUS_REG		0x81
> > +#define SUNRISE_CALIBRATION_COMMAND_REG		0x82
> > +#define SUNRISE_CALIBRATION_FACTORY_CMD		0x7c02
> > +#define SUNRISE_CALIBRATION_BACKGROUND_CMD	0x7c06
> > +/*
> > + * The calibration timeout is not characterized in the datasheet.
> > + * Use 30 seconds as a reasonable upper limit.
> > + */
> > +#define SUNRISE_CALIBRATION_TIMEOUT_US		(30 * USEC_PER_SEC)
> > +
> > +struct sunrise_dev {
> > +	struct i2c_client *client;
> > +	struct regmap *regmap;
> > +	/* Protects access to IIO attributes. */
> > +	struct mutex lock;
> > +	bool ignore_nak;
> > +};
> > +
> > +/* Custom regmap read/write operations: perform unlocked access to the i2c bus. */
> > +
> > +static int sunrise_regmap_read(void *context, const void *reg_buf,
> > +			       size_t reg_size, void *val_buf, size_t val_size)
> > +{
> > +	struct i2c_client *client = context;
> > +	struct sunrise_dev *sunrise = i2c_get_clientdata(client);
> > +	union i2c_smbus_data data;
> > +	int ret;
> > +
> > +	if (reg_size != 1 || !val_size)
> > +		return -EINVAL;
> > +
> > +	memset(&data, 0, sizeof(data));
> > +	data.block[0] = val_size;
> > +
> > +	/*
> > +	 * Wake up sensor by sending sensor address: START, sensor address,
> > +	 * STOP. Sensor will not ACK this byte.
> > +	 *
> > +	 * The chip enters a low power state after 15ms without
> > +	 * communications or after a complete read/write sequence.
> > +	 */
> > +	__i2c_smbus_xfer(client->adapter, client->addr,
> > +			 sunrise->ignore_nak ? I2C_M_IGNORE_NAK : 0,
> > +			 I2C_SMBUS_WRITE, 0, I2C_SMBUS_BYTE_DATA, &data);
> > +
> > +	usleep_range(500, 1500);
> > +
> > +	ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
> > +			       I2C_SMBUS_READ, ((u8 *)reg_buf)[0],
> > +			       I2C_SMBUS_I2C_BLOCK_DATA, &data);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	memcpy(val_buf, &data.block[1], data.block[0]);
> > +
> > +	return 0;
> > +}
> > +
> > +static int sunrise_regmap_write(void *context, const void *val_buf, size_t count)
> > +{
> > +	struct i2c_client *client = context;
> > +	struct sunrise_dev *sunrise = i2c_get_clientdata(client);
> > +	union i2c_smbus_data data;
> > +
> > +	/* Discard reg address from values count. */
> > +	if (!count)
> > +		return -EINVAL;
> > +	count--;
> > +
> > +	memset(&data, 0, sizeof(data));
> > +	data.block[0] = count;
> > +	memcpy(&data.block[1], (u8 *)val_buf + 1, count);
> > +
> > +	__i2c_smbus_xfer(client->adapter, client->addr,
> > +			 sunrise->ignore_nak ? I2C_M_IGNORE_NAK : 0,
> > +			 I2C_SMBUS_WRITE, 0, I2C_SMBUS_BYTE_DATA, &data);
> > +
> > +	usleep_range(500, 1500);
> > +
> > +	return __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
> > +				I2C_SMBUS_WRITE, ((u8 *)val_buf)[0],
> > +				I2C_SMBUS_I2C_BLOCK_DATA, &data);
> > +}
> > +
> > +/*
> > + * Sunrise i2c read/write operations: lock the i2c segment to avoid losing the
> > + * wake up session. Use custom regmap operations that perform unlocked access to
> > + * the i2c bus.
> > + */
> > +static int sunrise_read_byte(struct sunrise_dev *sunrise, u8 reg)
> > +{
> > +	const struct i2c_client *client = sunrise->client;
> > +	const struct device *dev = &client->dev;
> > +	unsigned int val;
> > +	int ret;
> > +
> > +	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	ret = regmap_read(sunrise->regmap, reg, &val);
> > +	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	if (ret) {
> > +		dev_err(dev, "Read byte failed: reg 0x%02x (%d)\n", reg, ret);
> > +		return ret;
> > +	}
> > +
> > +	return val;
> > +}
> > +
> > +static int sunrise_read_word(struct sunrise_dev *sunrise, u8 reg, u16 *val)
> > +{
> > +	const struct i2c_client *client = sunrise->client;
> > +	const struct device *dev = &client->dev;
> > +	__be16 be_val;
> > +	int ret;
> > +
> > +	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	ret = regmap_bulk_read(sunrise->regmap, reg, &be_val, sizeof(be_val));
> > +	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	if (ret) {
> > +		dev_err(dev, "Read word failed: reg 0x%02x (%d)\n", reg, ret);
> > +		return ret;
> > +	}
> > +
> > +	*val = be16_to_cpu(be_val);
> > +
> > +	return 0;
> > +}
> > +
> > +static int sunrise_write_byte(struct sunrise_dev *sunrise, u8 reg, u8 val)
> > +{
> > +	const struct i2c_client *client = sunrise->client;
> > +	const struct device *dev = &client->dev;
> > +	int ret;
> > +
> > +	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	ret = regmap_write(sunrise->regmap, reg, val);
> > +	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	if (ret)
> > +		dev_err(dev, "Write byte failed: reg 0x%02x (%d)\n", reg, ret);
> > +
> > +	return ret;
> > +}
> > +
> > +static int sunrise_write_word(struct sunrise_dev *sunrise, u8 reg, u16 data)
> > +{
> > +	const struct i2c_client *client = sunrise->client;
> > +	const struct device *dev = &client->dev;
> > +	__be16 be_data = cpu_to_be16(data);
> > +	int ret;
> > +
> > +	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	ret = regmap_bulk_write(sunrise->regmap, reg, &be_data, sizeof(be_data));
> > +	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
> > +	if (ret)
> > +		dev_err(dev, "Write word failed: reg 0x%02x (%d)\n", reg, ret);
> > +
> > +	return ret;
> > +}
> > +
> > +/* Trigger a calibration cycle. */
> > +
> > +enum {
> > +	SUNRISE_CALIBRATION_FACTORY,
> > +	SUNRISE_CALIBRATION_BACKGROUND,
> > +};
> > +
> > +static const struct sunrise_calib_data {
> > +	u16 cmd;
> > +	u8 bit;
> > +	const char * const name;
> > +} calib_data[] = {
> > +	[SUNRISE_CALIBRATION_FACTORY] = {
> > +		SUNRISE_CALIBRATION_FACTORY_CMD,
> > +		BIT(2),
> > +		"factory_calibration",
> > +	},
> > +	[SUNRISE_CALIBRATION_BACKGROUND] = {
> > +		SUNRISE_CALIBRATION_BACKGROUND_CMD,
> > +		BIT(5),
> > +		"background_calibration",
> > +	},
> > +};
> > +
> > +static int sunrise_calibrate(struct sunrise_dev *sunrise,
> > +			     const struct sunrise_calib_data *data)
> > +{
> > +	unsigned int status;
> > +	int ret;
> > +
> > +	/* Reset the calibration status reg. */
> > +	ret = sunrise_write_byte(sunrise, SUNRISE_CALIBRATION_STATUS_REG, 0x00);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Write a calibration command and poll the calibration status bit. */
> > +	ret = sunrise_write_word(sunrise, SUNRISE_CALIBRATION_COMMAND_REG, data->cmd);
> > +	if (ret)
> > +		return ret;
> > +
> > +	dev_dbg(&sunrise->client->dev, "%s in progress\n", data->name);
> > +
> > +	/*
> > +	 * Calibration takes several seconds, so the sleep time between reads
> > +	 * can be pretty relaxed.
> > +	 */
> > +	return read_poll_timeout(sunrise_read_byte, status, status & data->bit,
> > +				 200000, SUNRISE_CALIBRATION_TIMEOUT_US, false,
> > +				 sunrise, SUNRISE_CALIBRATION_STATUS_REG);
> > +}
> > +
> > +static ssize_t sunrise_cal_factory_write(struct iio_dev *iiodev,
> > +					 uintptr_t private,
> > +					 const struct iio_chan_spec *chan,
> > +					 const char *buf, size_t len)
> > +{
> > +	struct sunrise_dev *sunrise = iio_priv(iiodev);
> > +	bool enable;
> > +	int ret;
> > +
> > +	ret = kstrtobool(buf, &enable);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (!enable)
> > +		return len;
> > +
> > +	mutex_lock(&sunrise->lock);
> > +	ret = sunrise_calibrate(sunrise, &calib_data[SUNRISE_CALIBRATION_FACTORY]);
> > +	mutex_unlock(&sunrise->lock);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return len;
> > +}
> > +
> > +static ssize_t sunrise_cal_background_write(struct iio_dev *iiodev,
> > +					    uintptr_t private,
> > +					    const struct iio_chan_spec *chan,
> > +					    const char *buf, size_t len)
> > +{
> > +	struct sunrise_dev *sunrise = iio_priv(iiodev);
> > +	bool enable;
> > +	int ret;
> > +
> > +	ret = kstrtobool(buf, &enable);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (!enable)
> > +		return len;
> > +
> > +	mutex_lock(&sunrise->lock);
> > +	ret = sunrise_calibrate(sunrise, &calib_data[SUNRISE_CALIBRATION_BACKGROUND]);
> > +	mutex_unlock(&sunrise->lock);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return len;
> > +}
> > +
> > + /* Enumerate and retrieve the chip error status. */
> > +enum {
> > +	SUNRISE_ERROR_FATAL,
> > +	SUNRISE_ERROR_I2C,
> > +	SUNRISE_ERROR_ALGORITHM,
> > +	SUNRISE_ERROR_CALIBRATION,
> > +	SUNRISE_ERROR_SELF_DIAGNOSTIC,
> > +	SUNRISE_ERROR_OUT_OF_RANGE,
> > +	SUNRISE_ERROR_MEMORY,
> > +	SUNRISE_ERROR_NO_MEASUREMENT,
> > +	SUNRISE_ERROR_LOW_VOLTAGE,
> > +	SUNRISE_ERROR_MEASUREMENT_TIMEOUT,
> > +};
> > +
> > +static const char * const sunrise_error_statuses[] = {
> > +	[SUNRISE_ERROR_FATAL] = "error_fatal",
> > +	[SUNRISE_ERROR_I2C] = "error_i2c",
> > +	[SUNRISE_ERROR_ALGORITHM] = "error_algorithm",
> > +	[SUNRISE_ERROR_CALIBRATION] = "error_calibration",
> > +	[SUNRISE_ERROR_SELF_DIAGNOSTIC] = "error_self_diagnostic",
> > +	[SUNRISE_ERROR_OUT_OF_RANGE] = "error_out_of_range",
> > +	[SUNRISE_ERROR_MEMORY] = "error_memory",
> > +	[SUNRISE_ERROR_NO_MEASUREMENT] = "error_no_measurement",
> > +	[SUNRISE_ERROR_LOW_VOLTAGE] = "error_low_voltage",
> > +	[SUNRISE_ERROR_MEASUREMENT_TIMEOUT] = "error_measurement_timeout",
> > +};
> > +
> > +static const struct iio_enum sunrise_error_statuses_enum = {
> > +	.items = sunrise_error_statuses,
> > +	.num_items = ARRAY_SIZE(sunrise_error_statuses),
> > +};
> > +
> > +static ssize_t sunrise_error_status_read(struct iio_dev *iiodev,
> > +					 uintptr_t private,
> > +					 const struct iio_chan_spec *chan,
> > +					 char *buf)
> > +{
> > +	struct sunrise_dev *sunrise = iio_priv(iiodev);
> > +	unsigned long errors;
> > +	ssize_t len = 0;
> > +	u16 value;
> > +	int ret;
> > +	u8 i;
> > +
> > +	mutex_lock(&sunrise->lock);
> > +	ret = sunrise_read_word(sunrise, SUNRISE_ERROR_STATUS_REG, &value);
> > +	if (ret) {
> > +		mutex_unlock(&sunrise->lock);
> > +		return ret;
> > +	}
> > +
> > +	errors = value;
> > +	for_each_set_bit(i, &errors, ARRAY_SIZE(sunrise_error_statuses))
> > +		len += sysfs_emit_at(buf, len, "%s ", sunrise_error_statuses[i]);
> > +
> > +	if (len)
> > +		buf[len - 1] = '\n';
> > +
> > +	mutex_unlock(&sunrise->lock);
> > +
> > +	return len;
> > +}
> > +
> > +static const struct iio_chan_spec_ext_info sunrise_concentration_ext_info[] = {
> > +	/* Calibration triggers. */
> > +	{
> > +		.name = "calibration_factory",
> > +		.write = sunrise_cal_factory_write,
> > +		.shared = IIO_SEPARATE,
> > +	},
> > +	{
> > +		.name = "calibration_background",
> > +		.write = sunrise_cal_background_write,
> > +		.shared = IIO_SEPARATE,
> > +	},
> > +
> > +	/* Error statuses. */
> > +	{
> > +		.name = "error_status",
> > +		.read = sunrise_error_status_read,
> > +		.shared = IIO_SHARED_BY_ALL,
> > +	},
> > +	{
> > +		.name = "error_status_available",
> > +		.shared = IIO_SHARED_BY_ALL,
> > +		.read = iio_enum_available_read,
> > +		.private = (uintptr_t)&sunrise_error_statuses_enum,
> > +	},
> > +	{}
> > +};
> > +
> > +static const struct iio_chan_spec sunrise_channels[] = {
> > +	{
> > +		.type = IIO_CONCENTRATION,
> > +		.modified = 1,
> > +		.channel2 = IIO_MOD_CO2,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> > +				      BIT(IIO_CHAN_INFO_SCALE),
> > +		.ext_info = sunrise_concentration_ext_info,
> > +		.scan_index = 0,
>
> Not sure how I missed it before now, but we don't need to set scan_index or
> scan_type if not providing the buffered interface.  I'd prefer that we
> introduce them only alongside that support as otherwise they are just noise.
>
> If that's all I find, I'll just drop these whilst applying and ask you to
> sanity check the result.
>
> > +		.scan_type = {
> > +			.sign = 's',
> > +			.realbits = 16,
> > +			.storagebits = 16,
> > +			.endianness = IIO_CPU,
> > +		},
> > +	},
> > +	{
> > +		.type = IIO_TEMP,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> > +				      BIT(IIO_CHAN_INFO_SCALE),
> > +		.scan_index = 1,
> > +		.scan_type = {
> > +			.sign = 's',
> > +			.realbits = 16,
> > +			.storagebits = 16,
> > +			.endianness = IIO_CPU,
> > +		},
> > +	},
> > +};
> > +
> > +static int sunrise_read_raw(struct iio_dev *iio_dev,
> > +			    const struct iio_chan_spec *chan,
> > +			    int *val, int *val2, long mask)
> > +{
> > +	struct sunrise_dev *sunrise = iio_priv(iio_dev);
> > +	u16 value;
> > +	int ret;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		switch (chan->type) {
> > +		case IIO_CONCENTRATION:
> > +			mutex_lock(&sunrise->lock);
> > +			ret = sunrise_read_word(sunrise, SUNRISE_CO2_FILTERED_COMP_REG,
> > +						&value);
> > +			*val = value;
> > +			mutex_unlock(&sunrise->lock);
> > +
> > +			if (ret)
> > +				return ret;
> > +
> > +			return IIO_VAL_INT;
> > +
> > +		case IIO_TEMP:
> > +			mutex_lock(&sunrise->lock);
> > +			ret = sunrise_read_word(sunrise, SUNRISE_CHIP_TEMPERATURE_REG,
> > +						&value);
> > +			*val = value;
> > +			mutex_unlock(&sunrise->lock);
> > +
> > +			if (ret)
> > +				return ret;
> > +
> > +			return IIO_VAL_INT;
> > +
> > +		default:
> > +			return -EINVAL;
> > +		}
> > +
> > +	case IIO_CHAN_INFO_SCALE:
> > +		switch (chan->type) {
> > +		case IIO_CONCENTRATION:
> > +			/*
> > +			 * 1 / 10^4 to comply with IIO scale for CO2
> > +			 * (percentage). The chip CO2 reading range is [400 -
> > +			 * 5000] ppm which corresponds to [0,004 - 0,5] %.
> > +			 */
> > +			*val = 1;
> > +			*val2 = 10000;
> > +			return IIO_VAL_FRACTIONAL;
> > +
> > +		case IIO_TEMP:
> > +			/* x10 to comply with IIO scale (millidegrees celsius). */
> > +			*val = 10;
> > +			return IIO_VAL_INT;
> > +
> > +		default:
> > +			return -EINVAL;
> > +		}
> > +
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +}
> > +
> > +static const struct iio_info sunrise_info = {
> > +	.read_raw = sunrise_read_raw,
> > +};
> > +
> > +static const struct regmap_bus sunrise_regmap_bus = {
> > +	.read = sunrise_regmap_read,
> > +	.write = sunrise_regmap_write,
> > +};
> > +
> > +static const struct regmap_config sunrise_regmap_config = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +};
> > +
> > +static int sunrise_probe(struct i2c_client *client)
> > +{
> > +	struct sunrise_dev *sunrise;
> > +	struct iio_dev *iio_dev;
> > +
> > +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
> > +						      I2C_FUNC_SMBUS_BLOCK_DATA)) {
> > +		dev_err(&client->dev,
> > +			"Adapter does not support required functionalities\n");
> > +		return -EOPNOTSUPP;
> > +	}
> > +
> > +	iio_dev = devm_iio_device_alloc(&client->dev, sizeof(*sunrise));
> > +	if (!iio_dev)
> > +		return -ENOMEM;
> > +
> > +	sunrise = iio_priv(iio_dev);
> > +	sunrise->client = client;
> > +	mutex_init(&sunrise->lock);
> > +
> > +	i2c_set_clientdata(client, sunrise);
> > +
> > +	sunrise->regmap = devm_regmap_init(&client->dev, &sunrise_regmap_bus,
> > +					   client, &sunrise_regmap_config);
> > +	if (IS_ERR(sunrise->regmap)) {
> > +		dev_err(&client->dev, "Failed to initialize regmap\n");
> > +		return PTR_ERR(sunrise->regmap);
> > +	}
> > +
> > +	/*
> > +	 * The chip nacks the wake up message. If the adapter does not support
> > +	 * protocol mangling do not set the I2C_M_IGNORE_NAK flag at the expense
> > +	 * of possible cruft in the logs.
> > +	 */
> > +	if (i2c_check_functionality(client->adapter, I2C_FUNC_PROTOCOL_MANGLING))
> > +		sunrise->ignore_nak = true;
> > +
> > +	iio_dev->info = &sunrise_info;
> > +	iio_dev->name = DRIVER_NAME;
> > +	iio_dev->channels = sunrise_channels;
> > +	iio_dev->num_channels = ARRAY_SIZE(sunrise_channels);
> > +	iio_dev->modes = INDIO_DIRECT_MODE;
> > +
> > +	return devm_iio_device_register(&client->dev, iio_dev);
> > +}
> > +
> > +static const struct of_device_id sunrise_of_match[] = {
> > +	{ .compatible = "senseair,sunrise-006-0-0007" },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(of, sunrise_of_match);
> > +
> > +static struct i2c_driver sunrise_driver = {
> > +	.driver = {
> > +		.name = DRIVER_NAME,
> > +		.of_match_table = sunrise_of_match,
> > +	},
> > +	.probe_new = sunrise_probe,
> > +};
> > +module_i2c_driver(sunrise_driver);
> > +
> > +MODULE_AUTHOR("Jacopo Mondi <jacopo@jmondi.org>");
> > +MODULE_DESCRIPTION("Senseair Sunrise 006-0-0007 CO2 sensor IIO driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.32.0
> >
>