Add Sensirion SCD30 carbon dioxide core driver.

Signed-off-by: Tomasz Duszynski <tomasz.duszyn...@octakon.com>
---
 Documentation/ABI/testing/sysfs-bus-iio-scd30 |  34 +
 MAINTAINERS                                   |   6 +
 drivers/iio/chemical/Kconfig                  |  11 +
 drivers/iio/chemical/Makefile                 |   1 +
 drivers/iio/chemical/scd30.h                  |  80 ++
 drivers/iio/chemical/scd30_core.c             | 783 ++++++++++++++++++
 6 files changed, 915 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-scd30
 create mode 100644 drivers/iio/chemical/scd30.h
 create mode 100644 drivers/iio/chemical/scd30_core.c

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-scd30 
b/Documentation/ABI/testing/sysfs-bus-iio-scd30
new file mode 100644
index 000000000000..b9712f390bec
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-scd30
@@ -0,0 +1,34 @@
+What:          /sys/bus/iio/devices/iio:deviceX/calibration_auto_enable
+Date:          June 2020
+KernelVersion: 5.8
+Contact:       linux-...@vger.kernel.org
+Description:
+               Contaminants build-up in the measurement chamber or optical
+               elements deterioration leads to sensor drift.
+
+               One can compensate for sensor drift by using automatic self
+               calibration procedure (asc).
+
+               Writing 1 or 0 to this attribute will respectively activate or
+               deactivate asc.
+
+               Upon reading current asc status is returned.
+
+What:          /sys/bus/iio/devices/iio:deviceX/calibration_forced_value
+Date:          June 2020
+KernelVersion: 5.8
+Contact:       linux-...@vger.kernel.org
+Description:
+               Contaminants build-up in the measurement chamber or optical
+               elements deterioration leads to sensor drift.
+
+               One can compensate for sensor drift by using forced
+               recalibration (frc). This is useful in case there's known
+               co2 reference available nearby the sensor.
+
+               Picking value from the range [400 1 2000] and writing it to the
+               sensor will set frc.
+
+               Upon reading current frc value is returned. Note that after
+               power cycling default value (i.e 400) is returned even though
+               internally sensor had recalibrated itself.
diff --git a/MAINTAINERS b/MAINTAINERS
index 60ed2963efaa..41a509cca6f1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15137,6 +15137,12 @@ S:     Maintained
 F:     drivers/misc/phantom.c
 F:     include/uapi/linux/phantom.h
 
+SENSIRION SCD30 CARBON DIOXIDE SENSOR DRIVER
+M:     Tomasz Duszynski <tomasz.duszyn...@octakon.com>
+S:     Maintained
+F:     drivers/iio/chemical/scd30.h
+F:     drivers/iio/chemical/scd30_core.c
+
 SENSIRION SPS30 AIR POLLUTION SENSOR DRIVER
 M:     Tomasz Duszynski <tdusz...@gmail.com>
 S:     Maintained
diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 7f21afd73b1c..99e852b67e55 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -85,6 +85,17 @@ config PMS7003
          To compile this driver as a module, choose M here: the module will
          be called pms7003.
 
+config SCD30_CORE
+       tristate "SCD30 carbon dioxide sensor driver"
+       select IIO_BUFFER
+       select IIO_TRIGGERED_BUFFER
+       help
+         Say Y here to build support for the Sensirion SCD30 sensor with carbon
+         dioxide, relative humidity and temperature sensing capabilities.
+
+         To compile this driver as a module, choose M here: the module will
+         be called scd30_core.
+
 config SENSIRION_SGP30
        tristate "Sensirion SGPxx gas sensors"
        depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index aba4167db745..c9804b041ecd 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_BME680_SPI) += bme680_spi.o
 obj-$(CONFIG_CCS811)           += ccs811.o
 obj-$(CONFIG_IAQCORE)          += ams-iaq-core.o
 obj-$(CONFIG_PMS7003) += pms7003.o
+obj-$(CONFIG_SCD30_CORE) += scd30_core.o
 obj-$(CONFIG_SENSIRION_SGP30)  += sgp30.o
 obj-$(CONFIG_SPS30) += sps30.o
 obj-$(CONFIG_VZ89X)            += vz89x.o
diff --git a/drivers/iio/chemical/scd30.h b/drivers/iio/chemical/scd30.h
new file mode 100644
index 000000000000..38dcf5647d7f
--- /dev/null
+++ b/drivers/iio/chemical/scd30.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SCD30_H
+#define _SCD30_H
+
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+#include <linux/types.h>
+
+struct scd30_state;
+
+enum scd30_cmd {
+       /* start continuous measurement with pressure compensation */
+       CMD_START_MEAS,
+       /* stop continuous measurement */
+       CMD_STOP_MEAS,
+       /* set/get measurement interval */
+       CMD_MEAS_INTERVAL,
+       /* check whether new measurement is ready */
+       CMD_MEAS_READY,
+       /* get measurement */
+       CMD_READ_MEAS,
+       /* turn on/off automatic self calibration */
+       CMD_ASC,
+       /* set/get forced recalibration value */
+       CMD_FRC,
+       /* set/get temperature offset */
+       CMD_TEMP_OFFSET,
+       /* get firmware version */
+       CMD_FW_VERSION,
+       /* reset sensor */
+       CMD_RESET,
+       /*
+        * Command for altitude compensation was omitted intentionally because
+        * the same can be achieved by means of CMD_START_MEAS which takes
+        * pressure above the sea level as an argument.
+        */
+};
+
+#define SCD30_MEAS_COUNT 3
+
+typedef int (*scd30_command_t)(struct scd30_state *state, enum scd30_cmd cmd,
+                              u16 arg, void *response, int size);
+
+struct scd30_state {
+       /* serialize access to the device */
+       struct mutex lock;
+       struct device *dev;
+       struct regulator *vdd;
+       struct completion meas_ready;
+       /*
+        * priv pointer is solely for serdev driver private data. We keep it
+        * here because driver_data inside dev has been already used for iio and
+        * struct serdev_device doesn't have one.
+        */
+       void *priv;
+       int irq;
+       /*
+        * no way to retrieve current ambient pressure compensation value from
+        * the sensor so keep one around
+        */
+       u16 pressure_comp;
+       u16 meas_interval;
+       int meas[SCD30_MEAS_COUNT];
+
+       scd30_command_t command;
+};
+
+int scd30_suspend(struct device *dev);
+int scd30_resume(struct device *dev);
+
+static __maybe_unused SIMPLE_DEV_PM_OPS(scd30_pm_ops, scd30_suspend,
+                                       scd30_resume);
+
+int scd30_probe(struct device *dev, int irq, const char *name, void *priv,
+               scd30_command_t command);
+
+#endif
diff --git a/drivers/iio/chemical/scd30_core.c 
b/drivers/iio/chemical/scd30_core.c
new file mode 100644
index 000000000000..a41a09e7a513
--- /dev/null
+++ b/drivers/iio/chemical/scd30_core.c
@@ -0,0 +1,783 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensirion SCD30 carbon dioxide sensor core driver
+ *
+ * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszyn...@octakon.com>
+ */
+#include <linux/bits.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/types.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+#include "scd30.h"
+
+#define SCD30_PRESSURE_COMP_MIN_MBAR 700
+#define SCD30_PRESSURE_COMP_MAX_MBAR 1400
+#define SCD30_PRESSURE_COMP_DEFAULT 1013
+#define SCD30_MEAS_INTERVAL_MIN_S 2
+#define SCD30_MEAS_INTERVAL_MAX_S 1800
+#define SCD30_MEAS_INTERVAL_DEFAULT SCD30_MEAS_INTERVAL_MIN_S
+#define SCD30_FRC_MIN_PPM 400
+#define SCD30_FRC_MAX_PPM 2000
+#define SCD30_TEMP_OFFSET_MAX 655360
+#define SCD30_EXTRA_TIMEOUT_PER_S 250
+
+enum {
+       SCD30_CONC,
+       SCD30_TEMP,
+       SCD30_HR,
+};
+
+static int scd30_command_write(struct scd30_state *state, enum scd30_cmd cmd,
+                              u16 arg)
+{
+       return state->command(state, cmd, arg, NULL, 0);
+}
+
+static int scd30_command_read(struct scd30_state *state, enum scd30_cmd cmd,
+                             u16 *val)
+{
+       __be16 tmp;
+       int ret;
+
+       ret = state->command(state, cmd, 0, &tmp, sizeof(tmp));
+       *val = be16_to_cpup(&tmp);
+
+       return ret;
+}
+
+static int scd30_reset(struct scd30_state *state)
+{
+       int ret;
+       u16 val;
+
+       ret = scd30_command_write(state, CMD_RESET, 0);
+       if (ret)
+               return ret;
+
+       /* sensor boots up within 2 secs */
+       msleep(2000);
+       /*
+        * Power-on-reset causes sensor to produce some glitch on i2c bus and
+        * some controllers end up in error state. Try to recover by placing
+        * any data on the bus.
+        */
+       scd30_command_read(state, CMD_MEAS_READY, &val);
+
+       return 0;
+}
+
+/* simplified float to fixed point conversion with a scaling factor of 0.01 */
+static int scd30_float_to_fp(int float32)
+{
+       int fraction, shift,
+           mantissa = float32 & GENMASK(22, 0),
+           sign = float32 & BIT(31) ? -1 : 1,
+           exp = (float32 & ~BIT(31)) >> 23;
+
+       /* special case 0 */
+       if (!exp && !mantissa)
+               return 0;
+
+       exp -= 127;
+       if (exp < 0) {
+               exp = -exp;
+               /* return values ranging from 1 to 99 */
+               return sign * ((((BIT(23) + mantissa) * 100) >> 23) >> exp);
+       }
+
+       /* return values starting at 100 */
+       shift = 23 - exp;
+       float32 = BIT(exp) + (mantissa >> shift);
+       fraction = mantissa & GENMASK(shift - 1, 0);
+
+       return sign * (float32 * 100 + ((fraction * 100) >> shift));
+}
+
+static int scd30_read_meas(struct scd30_state *state)
+{
+       int i, ret;
+
+       ret = state->command(state, CMD_READ_MEAS, 0, state->meas,
+                            sizeof(state->meas));
+       if (ret)
+               return ret;
+
+       be32_to_cpu_array(state->meas, state->meas, ARRAY_SIZE(state->meas));
+
+       for (i = 0; i < ARRAY_SIZE(state->meas); i++)
+               state->meas[i] = scd30_float_to_fp(state->meas[i]);
+
+       /*
+        * co2 is left unprocessed while temperature and humidity are scaled
+        * to milli deg C and milli percent respectively.
+        */
+       state->meas[SCD30_TEMP] *= 10;
+       state->meas[SCD30_HR] *= 10;
+
+       return 0;
+}
+
+static int scd30_wait_meas_irq(struct scd30_state *state)
+{
+       int ret, timeout;
+
+       timeout = state->meas_interval * (1000 + SCD30_EXTRA_TIMEOUT_PER_S);
+       timeout = msecs_to_jiffies(timeout);
+       reinit_completion(&state->meas_ready);
+       enable_irq(state->irq);
+       ret = wait_for_completion_interruptible_timeout(&state->meas_ready,
+                                                       timeout);
+       if (ret > 0)
+               ret = 0;
+       else if (!ret)
+               ret = -ETIMEDOUT;
+
+       disable_irq(state->irq);
+
+       return ret;
+}
+
+static int scd30_wait_meas_poll(struct scd30_state *state)
+{
+       int timeout = state->meas_interval * SCD30_EXTRA_TIMEOUT_PER_S;
+       int tries = 5;
+
+       do {
+               int ret;
+               u16 val;
+
+               ret = scd30_command_read(state, CMD_MEAS_READY, &val);
+               if (ret)
+                       return -EIO;
+
+               /* new measurement available */
+               if (val)
+                       break;
+
+               msleep_interruptible(timeout);
+       } while (--tries);
+
+       return tries ? 0 : -ETIMEDOUT;
+}
+
+static int scd30_read_poll(struct scd30_state *state)
+{
+       int ret;
+
+       ret = scd30_wait_meas_poll(state);
+       if (ret)
+               return ret;
+
+       return scd30_read_meas(state);
+}
+
+static int scd30_read(struct scd30_state *state)
+{
+       if (state->irq > 0)
+               return scd30_wait_meas_irq(state);
+
+       return scd30_read_poll(state);
+}
+
+static int scd30_read_raw(struct iio_dev *indio_dev,
+                         struct iio_chan_spec const *chan,
+                         int *val, int *val2, long mask)
+{
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret = -EINVAL;
+       u16 tmp;
+
+       mutex_lock(&state->lock);
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+       case IIO_CHAN_INFO_PROCESSED:
+               ret = iio_device_claim_direct_mode(indio_dev);
+               if (ret)
+                       break;
+
+               ret = scd30_read(state);
+               if (ret) {
+                       iio_device_release_direct_mode(indio_dev);
+                       break;
+               }
+
+               *val = state->meas[chan->address];
+               iio_device_release_direct_mode(indio_dev);
+               ret = IIO_VAL_INT;
+               break;
+       case IIO_CHAN_INFO_SCALE:
+               *val = 0;
+               *val2 = 1;
+               ret = IIO_VAL_INT_PLUS_MICRO;
+               break;
+       case IIO_CHAN_INFO_SAMP_FREQ:
+               ret = scd30_command_read(state, CMD_MEAS_INTERVAL, &tmp);
+               if (ret)
+                       break;
+
+               *val = 0;
+               *val2 = 1000000000 / tmp;
+               ret = IIO_VAL_INT_PLUS_NANO;
+               break;
+       case IIO_CHAN_INFO_CALIBSCALE:
+               *val = state->pressure_comp / 10;
+               *val2 = (state->pressure_comp % 10) * 100000;
+               ret = IIO_VAL_INT_PLUS_MICRO;
+               break;
+       case IIO_CHAN_INFO_CALIBBIAS:
+               ret = scd30_command_read(state, CMD_TEMP_OFFSET, &tmp);
+               if (ret)
+                       break;
+
+               *val = tmp;
+               ret = IIO_VAL_INT;
+               break;
+       }
+       mutex_unlock(&state->lock);
+
+       return ret;
+}
+
+static int scd30_write_raw(struct iio_dev *indio_dev,
+                          struct iio_chan_spec const *chan,
+                          int val, int val2, long mask)
+{
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret = -EINVAL;
+
+       mutex_lock(&state->lock);
+       switch (mask) {
+       case IIO_CHAN_INFO_SAMP_FREQ:
+               if (val)
+                       break;
+
+               val = 1000000000 / val2;
+               if (val < SCD30_MEAS_INTERVAL_MIN_S ||
+                   val > SCD30_MEAS_INTERVAL_MAX_S)
+                       break;
+
+               ret = scd30_command_write(state, CMD_MEAS_INTERVAL, val);
+               if (ret)
+                       break;
+
+               state->meas_interval = val;
+               break;
+       case IIO_CHAN_INFO_CALIBSCALE:
+               val = (val * 1000000 + val2) / 100000;
+               if (val < SCD30_PRESSURE_COMP_MIN_MBAR ||
+                   val > SCD30_PRESSURE_COMP_MAX_MBAR)
+                       break;
+
+               ret = scd30_command_write(state, CMD_START_MEAS, val);
+               if (ret)
+                       break;
+
+               state->pressure_comp = val;
+               break;
+       case IIO_CHAN_INFO_CALIBBIAS:
+               if (val < 0 || val > SCD30_TEMP_OFFSET_MAX)
+                       break;
+               /*
+                * Manufacturer does not explicitly specify min/max sensible
+                * values hence check is omitted for simplicity.
+                */
+               ret = scd30_command_write(state, CMD_TEMP_OFFSET / 10, val);
+       }
+       mutex_unlock(&state->lock);
+
+       return ret;
+}
+
+static int scd30_write_raw_get_fmt(struct iio_dev *indio_dev,
+                                  struct iio_chan_spec const *chan, long mask)
+{
+       switch (mask) {
+       case IIO_CHAN_INFO_SAMP_FREQ:
+               return IIO_VAL_INT_PLUS_NANO;
+       case IIO_CHAN_INFO_CALIBSCALE:
+               return IIO_VAL_INT_PLUS_MICRO;
+       case IIO_CHAN_INFO_CALIBBIAS:
+               return IIO_VAL_INT;
+       }
+
+       return -EINVAL;
+}
+
+static const int scd30_pressure_calibscale_available[] = {
+       SCD30_PRESSURE_COMP_MIN_MBAR / 10, 0,
+       0, 100000,
+       SCD30_PRESSURE_COMP_MAX_MBAR / 10, 0,
+};
+
+static const int scd30_temp_calibbias_available[] = {
+       0, 10, SCD30_TEMP_OFFSET_MAX,
+};
+
+static int scd30_read_avail(struct iio_dev *indio_dev,
+                           struct iio_chan_spec const *chan, const int **vals,
+                           int *type, int *length, long mask)
+{
+       switch (mask) {
+       case IIO_CHAN_INFO_CALIBSCALE:
+               *vals = scd30_pressure_calibscale_available;
+               *type = IIO_VAL_INT_PLUS_MICRO;
+
+               return IIO_AVAIL_RANGE;
+       case IIO_CHAN_INFO_CALIBBIAS:
+               *vals = scd30_temp_calibbias_available;
+               *type = IIO_VAL_INT;
+
+               return IIO_AVAIL_RANGE;
+       }
+
+       return -EINVAL;
+}
+
+static ssize_t sampling_frequency_available_show(struct device *dev,
+                                                struct device_attribute *attr,
+                                                char *buf)
+{
+       int i = SCD30_MEAS_INTERVAL_MIN_S;
+       ssize_t len = 0;
+
+       do {
+               len += scnprintf(buf + len, PAGE_SIZE - len, "0.%09u ",
+                                1000000000 / i);
+               /*
+                * Not all values fit PAGE_SIZE buffer hence print every 6th
+                * (each frequency differs by 6s in time domain from the
+                * adjacent). Unlisted but valid ones are still accepted.
+                */
+               i += 6;
+       } while (i <= SCD30_MEAS_INTERVAL_MAX_S);
+
+       buf[len - 1] = '\n';
+
+       return len;
+}
+
+static ssize_t calibration_auto_enable_show(struct device *dev,
+                                           struct device_attribute *attr,
+                                           char *buf)
+{
+       struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret;
+       u16 val;
+
+       mutex_lock(&state->lock);
+       ret = scd30_command_read(state, CMD_ASC, &val);
+       mutex_unlock(&state->lock);
+
+       return ret ?: sprintf(buf, "%d\n", val);
+}
+
+static ssize_t calibration_auto_enable_store(struct device *dev,
+                                            struct device_attribute *attr,
+                                            const char *buf, size_t len)
+{
+       struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret;
+       u16 val;
+
+       ret = kstrtou16(buf, 0, &val);
+       if (ret)
+               return ret;
+
+       mutex_lock(&state->lock);
+       ret = scd30_command_write(state, CMD_ASC, !!val);
+       mutex_unlock(&state->lock);
+
+       return ret ?: len;
+}
+
+static ssize_t calibration_forced_value_show(struct device *dev,
+                                            struct device_attribute *attr,
+                                            char *buf)
+{
+       struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret;
+       u16 val;
+
+       mutex_lock(&state->lock);
+       ret = scd30_command_read(state, CMD_FRC, &val);
+       mutex_unlock(&state->lock);
+
+       return ret ?: sprintf(buf, "%d\n", val);
+}
+
+static ssize_t calibration_forced_value_store(struct device *dev,
+                                             struct device_attribute *attr,
+                                             const char *buf, size_t len)
+{
+       struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret;
+       u16 val;
+
+       ret = kstrtou16(buf, 0, &val);
+       if (ret)
+               return ret;
+
+       if (val < SCD30_FRC_MIN_PPM || val > SCD30_FRC_MAX_PPM)
+               return -EINVAL;
+
+       mutex_lock(&state->lock);
+       ret = scd30_command_write(state, CMD_FRC, val);
+       mutex_unlock(&state->lock);
+
+       return ret ?: len;
+}
+
+static IIO_DEVICE_ATTR_RO(sampling_frequency_available, 0);
+static IIO_DEVICE_ATTR_RW(calibration_auto_enable, 0);
+static IIO_DEVICE_ATTR_RW(calibration_forced_value, 0);
+
+static struct attribute *scd30_attrs[] = {
+       &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
+       &iio_dev_attr_calibration_auto_enable.dev_attr.attr,
+       &iio_dev_attr_calibration_forced_value.dev_attr.attr,
+       NULL
+};
+
+static const struct attribute_group scd30_attr_group = {
+       .attrs = scd30_attrs,
+};
+
+static const struct iio_info scd30_info = {
+       .attrs = &scd30_attr_group,
+       .read_raw = scd30_read_raw,
+       .write_raw = scd30_write_raw,
+       .write_raw_get_fmt = scd30_write_raw_get_fmt,
+       .read_avail = scd30_read_avail,
+};
+
+#define SCD30_CHAN_SCAN_TYPE(_sign, _realbits) .scan_type = { \
+       .sign = _sign, \
+       .realbits = _realbits, \
+       .storagebits = 32, \
+       .endianness = IIO_CPU, \
+}
+
+static const struct iio_chan_spec scd30_channels[] = {
+       {
+               .type = IIO_PRESSURE,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_CALIBSCALE),
+               .info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBSCALE),
+               .scan_index = -1,
+       },
+       {
+               .type = IIO_CONCENTRATION,
+               .channel2 = IIO_MOD_CO2,
+               .address = SCD30_CONC,
+               .scan_index = SCD30_CONC,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                                     BIT(IIO_CHAN_INFO_SCALE),
+               .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+               .modified = 1,
+
+               SCD30_CHAN_SCAN_TYPE('u', 20),
+       },
+       {
+               .type = IIO_TEMP,
+               .address = SCD30_TEMP,
+               .scan_index = SCD30_TEMP,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
+                                     BIT(IIO_CHAN_INFO_CALIBBIAS),
+               .info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBBIAS),
+               .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+
+               SCD30_CHAN_SCAN_TYPE('s', 18),
+       },
+       {
+               .type = IIO_HUMIDITYRELATIVE,
+               .address = SCD30_HR,
+               .scan_index = SCD30_HR,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+               .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+
+               SCD30_CHAN_SCAN_TYPE('u', 17),
+       },
+       IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+int __maybe_unused scd30_suspend(struct device *dev)
+{
+       struct iio_dev *indio_dev = dev_get_drvdata(dev);
+       struct scd30_state *state  = iio_priv(indio_dev);
+       int ret;
+
+       ret = scd30_command_write(state, CMD_STOP_MEAS, 0);
+       if (ret)
+               return ret;
+
+       return regulator_disable(state->vdd);
+}
+EXPORT_SYMBOL(scd30_suspend);
+
+int __maybe_unused scd30_resume(struct device *dev)
+{
+       struct iio_dev *indio_dev = dev_get_drvdata(dev);
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret;
+
+       ret = regulator_enable(state->vdd);
+       if (ret)
+               return ret;
+
+       return scd30_command_write(state, CMD_START_MEAS, state->pressure_comp);
+}
+EXPORT_SYMBOL(scd30_resume);
+
+static void scd30_stop_meas(void *data)
+{
+       struct scd30_state *state = data;
+
+       scd30_command_write(state, CMD_STOP_MEAS, 0);
+}
+
+static void scd30_disable_regulator(void *data)
+{
+       struct scd30_state *state = data;
+
+       regulator_disable(state->vdd);
+}
+
+static irqreturn_t scd30_irq_handler(int irq, void *priv)
+{
+       struct iio_dev *indio_dev = priv;
+
+       if (iio_buffer_enabled(indio_dev)) {
+               iio_trigger_poll(indio_dev->trig);
+
+               return IRQ_HANDLED;
+       }
+
+       return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t scd30_irq_thread_handler(int irq, void *priv)
+{
+       struct iio_dev *indio_dev = priv;
+       struct scd30_state *state = iio_priv(indio_dev);
+       int ret;
+
+       ret = scd30_read_meas(state);
+       if (ret)
+               goto out;
+
+       complete_all(&state->meas_ready);
+out:
+       return IRQ_HANDLED;
+}
+
+static irqreturn_t scd30_trigger_handler(int irq, void *p)
+{
+       struct iio_poll_func *pf = p;
+       struct iio_dev *indio_dev = pf->indio_dev;
+       struct scd30_state *state = iio_priv(indio_dev);
+       struct {
+               int data[SCD30_MEAS_COUNT];
+               s64 ts __aligned(8);
+       } scan = { 0, };
+       int ret;
+
+       mutex_lock(&state->lock);
+       if (!iio_trigger_using_own(indio_dev))
+               ret = scd30_read_poll(state);
+       else
+               ret = scd30_read_meas(state);
+       memcpy(scan.data, state->meas, sizeof(state->meas));
+       mutex_unlock(&state->lock);
+       if (ret)
+               goto out;
+
+       iio_push_to_buffers_with_timestamp(indio_dev, &scan,
+                                          iio_get_time_ns(indio_dev));
+out:
+       iio_trigger_notify_done(indio_dev->trig);
+       return IRQ_HANDLED;
+}
+
+static int scd30_set_trigger_state(struct iio_trigger *trig, bool state)
+{
+       struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+       struct scd30_state *st = iio_priv(indio_dev);
+
+       if (state)
+               enable_irq(st->irq);
+       else
+               disable_irq(st->irq);
+
+       return 0;
+}
+
+static const struct iio_trigger_ops scd30_trigger_ops = {
+       .set_trigger_state = scd30_set_trigger_state,
+       .validate_device = iio_trigger_validate_own_device,
+};
+
+static int scd30_setup_trigger(struct iio_dev *indio_dev)
+{
+       struct scd30_state *state = iio_priv(indio_dev);
+       struct device *dev = indio_dev->dev.parent;
+       struct iio_trigger *trig;
+       int ret;
+
+       trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
+                                     indio_dev->id);
+       if (!trig) {
+               dev_err(dev, "failed to allocate trigger\n");
+               return -ENOMEM;
+       }
+
+       trig->dev.parent = dev;
+       trig->ops = &scd30_trigger_ops;
+       iio_trigger_set_drvdata(trig, indio_dev);
+
+       ret = devm_iio_trigger_register(dev, trig);
+       if (ret)
+               return ret;
+
+       indio_dev->trig = iio_trigger_get(trig);
+
+       ret = devm_request_threaded_irq(dev, state->irq, scd30_irq_handler,
+                                       scd30_irq_thread_handler,
+                                       IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+                                       indio_dev->name, indio_dev);
+       if (ret)
+               dev_err(dev, "failed to request irq\n");
+
+       /*
+        * Interrupt is enabled just before taking a fresh measurement
+        * and disabled afterwards. This means we need to disable it here
+        * to keep calls to enable/disable balanced.
+        */
+       disable_irq(state->irq);
+
+       return ret;
+}
+
+int scd30_probe(struct device *dev, int irq, const char *name, void *priv,
+               scd30_command_t command)
+{
+       static const unsigned long scd30_scan_masks[] = { 0x07, 0x00 };
+       struct scd30_state *state;
+       struct iio_dev *indio_dev;
+       int ret;
+       u16 val;
+
+       indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
+       if (!indio_dev)
+               return -ENOMEM;
+
+       state = iio_priv(indio_dev);
+       state->dev = dev;
+       state->priv = priv;
+       state->irq = irq;
+       state->pressure_comp = SCD30_PRESSURE_COMP_DEFAULT;
+       state->meas_interval = SCD30_MEAS_INTERVAL_DEFAULT;
+       state->command = command;
+       mutex_init(&state->lock);
+       init_completion(&state->meas_ready);
+
+       dev_set_drvdata(dev, indio_dev);
+
+       indio_dev->dev.parent = dev;
+       indio_dev->info = &scd30_info;
+       indio_dev->name = name;
+       indio_dev->channels = scd30_channels;
+       indio_dev->num_channels = ARRAY_SIZE(scd30_channels);
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->available_scan_masks = scd30_scan_masks;
+
+       state->vdd = devm_regulator_get(dev, "vdd");
+       if (IS_ERR(state->vdd)) {
+               if (PTR_ERR(state->vdd) == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+
+               dev_err(dev, "failed to get regulator\n");
+               return PTR_ERR(state->vdd);
+       }
+
+       ret = regulator_enable(state->vdd);
+       if (ret)
+               return ret;
+
+       ret = devm_add_action_or_reset(dev, scd30_disable_regulator, state);
+       if (ret)
+               return ret;
+
+       ret = scd30_reset(state);
+       if (ret) {
+               dev_err(dev, "failed to reset device: %d\n", ret);
+               return ret;
+       }
+
+       if (state->irq > 0) {
+               ret = scd30_setup_trigger(indio_dev);
+               if (ret) {
+                       dev_err(dev, "failed to setup trigger: %d\n", ret);
+                       return ret;
+               }
+       }
+
+       ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+                                             scd30_trigger_handler, NULL);
+       if (ret)
+               return ret;
+
+       ret = scd30_command_read(state, CMD_FW_VERSION, &val);
+       if (ret) {
+               dev_err(dev, "failed to read firmware version: %d\n", ret);
+               return ret;
+       }
+       dev_info(dev, "firmware version: %d.%d\n", val >> 8, (char)val);
+
+       ret = scd30_command_write(state, CMD_MEAS_INTERVAL,
+                                 state->meas_interval);
+       if (ret) {
+               dev_err(dev, "failed to set measurement interval: %d\n", ret);
+               return ret;
+       }
+
+       ret = scd30_command_write(state, CMD_START_MEAS, state->pressure_comp);
+       if (ret) {
+               dev_err(dev, "failed to start measurement: %d\n", ret);
+               return ret;
+       }
+
+       ret = devm_add_action_or_reset(dev, scd30_stop_meas, state);
+       if (ret)
+               return ret;
+
+       return devm_iio_device_register(dev, indio_dev);
+}
+EXPORT_SYMBOL(scd30_probe);
+
+MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszyn...@octakon.com>");
+MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor core driver");
+MODULE_LICENSE("GPL v2");
-- 
2.26.2

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