[PATCH v4 2/3] iio: chemical: Add Senseair Sunrise 006-0-007 driver

[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>
---
 MAINTAINERS                        |   6 +
 drivers/iio/chemical/Kconfig       |  10 +
 drivers/iio/chemical/Makefile      |   1 +
 drivers/iio/chemical/sunrise_co2.c | 487 +++++++++++++++++++++++++++++
 4 files changed, 504 insertions(+)
 create mode 100644 drivers/iio/chemical/sunrise_co2.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d7b4f32875a9..a8b859297e9e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16723,6 +16723,12 @@ 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/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..cf15cdbaa24a
--- /dev/null
+++ b/drivers/iio/chemical/sunrise_co2.c
@@ -0,0 +1,487 @@
+// 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;
+	/* Protects chip's wakup session. */
+	struct mutex wakeup_lock;
+};
+
+static void sunrise_wakeup(struct sunrise_dev *sunrise)
+{
+	struct i2c_client *client = sunrise->client;
+
+	/*
+	 * Wake up sensor by sending sensor address: START, sensor address,
+	 * STOP. Sensor will not ACK this byte.
+	 *
+	 * The chip returns in low power state after 15msec without
+	 * communications or after a complete read/write sequence.
+	 */
+	i2c_smbus_xfer(client->adapter, client->addr, I2C_M_IGNORE_NAK,
+		       I2C_SMBUS_WRITE, 0, I2C_SMBUS_QUICK, NULL);
+}
+
+static int sunrise_read_byte(struct sunrise_dev *sunrise, u8 reg)
+{
+	unsigned int val;
+	int ret;
+
+	/*
+	 * Lock the 'wakeup' session.
+	 *
+	 * If another read/write call sneaks in between the wakeup message
+	 * and the i2c transaction, the chip goes back in sleep state.
+	 */
+	mutex_lock(&sunrise->wakeup_lock);
+	sunrise_wakeup(sunrise);
+	ret = regmap_read(sunrise->regmap, reg, &val);
+	mutex_unlock(&sunrise->wakeup_lock);
+	if (ret) {
+		dev_err(&sunrise->client->dev,
+			"Read byte failed: reg 0x%2x (%d)\n", reg, ret);
+		return ret;
+	}
+
+	return val;
+}
+
+static int sunrise_read_word(struct sunrise_dev *sunrise, u8 reg, u16 *val)
+{
+	__be16 be_val;
+	int ret;
+
+	mutex_lock(&sunrise->wakeup_lock);
+	sunrise_wakeup(sunrise);
+	ret = regmap_bulk_read(sunrise->regmap, reg, &be_val, 2);
+	mutex_unlock(&sunrise->wakeup_lock);
+	if (ret) {
+		dev_err(&sunrise->client->dev,
+			"Read word failed: reg 0x%2x (%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)
+{
+	int ret;
+
+	mutex_lock(&sunrise->wakeup_lock);
+	sunrise_wakeup(sunrise);
+	ret = regmap_write(sunrise->regmap, reg, val);
+	mutex_unlock(&sunrise->wakeup_lock);
+	if (ret) {
+		dev_err(&sunrise->client->dev,
+			"Write byte failed: reg 0x%2x (%d)\n", reg, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int sunrise_write_word(struct sunrise_dev *sunrise, u8 reg, u16 data)
+{
+	__be16 be_data = cpu_to_be16(data);
+	int ret;
+
+	mutex_lock(&sunrise->wakeup_lock);
+	sunrise_wakeup(sunrise);
+	ret = regmap_bulk_write(sunrise->regmap, reg, &be_data, 2);
+	mutex_unlock(&sunrise->wakeup_lock);
+	if (ret) {
+		dev_err(&sunrise->client->dev,
+			"Write word failed: reg 0x%2x (%d)\n", reg, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* 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_read(const char *buf, size_t len)
+{
+	bool enable;
+	int ret;
+
+	ret = kstrtobool(buf, &enable);
+	if (ret)
+		return ret;
+
+	if (!enable)
+		return len;
+
+	return 0;
+}
+
+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);
+	int ret;
+
+	mutex_lock(&sunrise->lock);
+	ret = sunrise_cal_read(buf, len);
+	if (ret) {
+		mutex_unlock(&sunrise->lock);
+		return ret;
+	}
+
+	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);
+	int ret;
+
+	mutex_lock(&sunrise->lock);
+	ret = sunrise_cal_read(buf, len);
+	if (ret) {
+		mutex_unlock(&sunrise->lock);
+		return ret;
+	}
+
+	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 -EINVAL;
+	}
+
+	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),
+		.ext_info = sunrise_concentration_ext_info,
+		.scan_index = 0,
+		.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:
+		/* x10 to comply with IIO scale (1/1000 degress celsius). */
+		*val = 10;
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info sunrise_info = {
+	.read_raw = sunrise_read_raw,
+};
+
+static struct regmap_config sunrise_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	/*
+	 * Access to the i2c bus is locked by the driver to preserve the
+	 * 'wakeup' session.
+	 */
+	.disable_locking = true,
+};
+
+static int sunrise_probe(struct i2c_client *client)
+{
+	struct sunrise_dev *sunrise;
+	struct iio_dev *iio_dev;
+
+	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);
+	mutex_init(&sunrise->wakeup_lock);
+
+	sunrise->regmap = devm_regmap_init_i2c(client, &sunrise_regmap_config);
+	if (IS_ERR(sunrise->regmap)) {
+		dev_err(&client->dev, "Failed to initialize regmap\n");
+		return PTR_ERR(sunrise->regmap);
+	}
+
+	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