* [PATCH v6 1/4] iio: chemical: scd30: add core driver
2020-06-21 19:56 [PATCH v6 0/4] Add support for SCD30 sensor Tomasz Duszynski
@ 2020-06-21 19:56 ` Tomasz Duszynski
2020-06-21 19:56 ` [PATCH v6 2/4] iio: chemical: scd30: add I2C interface driver Tomasz Duszynski
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Tomasz Duszynski @ 2020-06-21 19:56 UTC (permalink / raw)
To: linux-iio; +Cc: linux-kernel, devicetree, jic23, pmeerw, Tomasz Duszynski
Add Sensirion SCD30 carbon dioxide core driver.
Signed-off-by: Tomasz Duszynski <tomasz.duszynski@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 | 78 ++
drivers/iio/chemical/scd30_core.c | 771 ++++++++++++++++++
6 files changed, 901 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-iio@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-iio@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.duszynski@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 <tduszyns@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..f60127bfe0f4
--- /dev/null
+++ b/drivers/iio/chemical/scd30.h
@@ -0,0 +1,78 @@
+/* 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..eac76972f83e
--- /dev/null
+++ b/drivers/iio/chemical/scd30_core.c
@@ -0,0 +1,771 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensirion SCD30 carbon dioxide sensor core driver
+ *
+ * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@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, (__be32 *)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;
+
+ reinit_completion(&state->meas_ready);
+ enable_irq(state->irq);
+ timeout = msecs_to_jiffies(state->meas_interval * (1000 + SCD30_EXTRA_TIMEOUT_PER_S));
+ 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, 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:
+ if (chan->output) {
+ *val = state->pressure_comp;
+ ret = IIO_VAL_INT;
+ break;
+ }
+
+ 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_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_RAW:
+ switch (chan->type) {
+ case IIO_PRESSURE:
+ 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;
+ default:
+ break;
+ }
+ 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_RAW:
+ case IIO_CHAN_INFO_CALIBBIAS:
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static const int scd30_pressure_raw_available[] = {
+ SCD30_PRESSURE_COMP_MIN_MBAR, 1, SCD30_PRESSURE_COMP_MAX_MBAR,
+};
+
+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_RAW:
+ *vals = scd30_pressure_raw_available;
+ *type = IIO_VAL_INT;
+
+ 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);
+ bool val;
+ int ret;
+
+ ret = kstrtobool(buf, &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[] = {
+ {
+ /*
+ * this channel is special in a sense we are pretending that
+ * sensor is able to change measurement chamber pressure but in
+ * fact we're just setting pressure compensation value
+ */
+ .type = IIO_PRESSURE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW),
+ .output = 1,
+ .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;
+ int ret;
+
+ mutex_lock(&state->lock);
+ if (!iio_trigger_using_own(indio_dev))
+ ret = scd30_read_poll(state);
+ else
+ ret = scd30_read_meas(state);
+ memset(&scan, 0, sizeof(scan));
+ 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->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.duszynski@octakon.com>");
+MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor core driver");
+MODULE_LICENSE("GPL v2");
--
2.27.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v6 2/4] iio: chemical: scd30: add I2C interface driver
2020-06-21 19:56 [PATCH v6 0/4] Add support for SCD30 sensor Tomasz Duszynski
2020-06-21 19:56 ` [PATCH v6 1/4] iio: chemical: scd30: add core driver Tomasz Duszynski
@ 2020-06-21 19:56 ` Tomasz Duszynski
2020-06-21 19:57 ` [PATCH v6 3/4] iio: chemical: scd30: add serial " Tomasz Duszynski
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Tomasz Duszynski @ 2020-06-21 19:56 UTC (permalink / raw)
To: linux-iio
Cc: linux-kernel, devicetree, jic23, pmeerw, Tomasz Duszynski,
Andy Shevchenko
Add I2C interface driver for the SCD30 sensor.
Signed-off-by: Tomasz Duszynski <tomasz.duszynski@octakon.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
MAINTAINERS | 1 +
drivers/iio/chemical/Kconfig | 11 +++
drivers/iio/chemical/Makefile | 1 +
drivers/iio/chemical/scd30_i2c.c | 139 +++++++++++++++++++++++++++++++
4 files changed, 152 insertions(+)
create mode 100644 drivers/iio/chemical/scd30_i2c.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 41a509cca6f1..13aed3473b7e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15142,6 +15142,7 @@ M: Tomasz Duszynski <tomasz.duszynski@octakon.com>
S: Maintained
F: drivers/iio/chemical/scd30.h
F: drivers/iio/chemical/scd30_core.c
+F: drivers/iio/chemical/scd30_i2c.c
SENSIRION SPS30 AIR POLLUTION SENSOR DRIVER
M: Tomasz Duszynski <tduszyns@gmail.com>
diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 99e852b67e55..970d34888c2e 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -96,6 +96,17 @@ config SCD30_CORE
To compile this driver as a module, choose M here: the module will
be called scd30_core.
+config SCD30_I2C
+ tristate "SCD30 carbon dioxide sensor I2C driver"
+ depends on SCD30_CORE && I2C
+ select CRC8
+ help
+ Say Y here to build support for the Sensirion SCD30 I2C interface
+ driver.
+
+ To compile this driver as a module, choose M here: the module will
+ be called scd30_i2c.
+
config SENSIRION_SGP30
tristate "Sensirion SGPxx gas sensors"
depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index c9804b041ecd..0966ca34e34b 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -13,6 +13,7 @@ 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-$(CONFIG_SCD30_I2C) += scd30_i2c.o
obj-$(CONFIG_SENSIRION_SGP30) += sgp30.o
obj-$(CONFIG_SPS30) += sps30.o
obj-$(CONFIG_VZ89X) += vz89x.o
diff --git a/drivers/iio/chemical/scd30_i2c.c b/drivers/iio/chemical/scd30_i2c.c
new file mode 100644
index 000000000000..875892a070ee
--- /dev/null
+++ b/drivers/iio/chemical/scd30_i2c.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensirion SCD30 carbon dioxide sensor i2c driver
+ *
+ * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@octakon.com>
+ *
+ * I2C slave address: 0x61
+ */
+#include <linux/crc8.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <asm/unaligned.h>
+
+#include "scd30.h"
+
+#define SCD30_I2C_MAX_BUF_SIZE 18
+#define SCD30_I2C_CRC8_POLYNOMIAL 0x31
+
+static u16 scd30_i2c_cmd_lookup_tbl[] = {
+ [CMD_START_MEAS] = 0x0010,
+ [CMD_STOP_MEAS] = 0x0104,
+ [CMD_MEAS_INTERVAL] = 0x4600,
+ [CMD_MEAS_READY] = 0x0202,
+ [CMD_READ_MEAS] = 0x0300,
+ [CMD_ASC] = 0x5306,
+ [CMD_FRC] = 0x5204,
+ [CMD_TEMP_OFFSET] = 0x5403,
+ [CMD_FW_VERSION] = 0xd100,
+ [CMD_RESET] = 0xd304,
+};
+
+DECLARE_CRC8_TABLE(scd30_i2c_crc8_tbl);
+
+static int scd30_i2c_xfer(struct scd30_state *state, char *txbuf, int txsize,
+ char *rxbuf, int rxsize)
+{
+ struct i2c_client *client = to_i2c_client(state->dev);
+ int ret;
+
+ /*
+ * repeated start is not supported hence instead of sending two i2c
+ * messages in a row we send one by one
+ */
+ ret = i2c_master_send(client, txbuf, txsize);
+ if (ret < 0)
+ return ret;
+ if (ret != txsize)
+ return -EIO;
+
+ if (!rxbuf)
+ return 0;
+
+ ret = i2c_master_recv(client, rxbuf, rxsize);
+ if (ret < 0)
+ return ret;
+ if (ret != rxsize)
+ return -EIO;
+
+ return 0;
+}
+
+static int scd30_i2c_command(struct scd30_state *state, enum scd30_cmd cmd, u16 arg,
+ void *response, int size)
+{
+ char buf[SCD30_I2C_MAX_BUF_SIZE];
+ char *rsp = response;
+ int i, ret;
+ char crc;
+
+ put_unaligned_be16(scd30_i2c_cmd_lookup_tbl[cmd], buf);
+ i = 2;
+
+ if (rsp) {
+ /* each two bytes are followed by a crc8 */
+ size += size / 2;
+ } else {
+ put_unaligned_be16(arg, buf + i);
+ crc = crc8(scd30_i2c_crc8_tbl, buf + i, 2, CRC8_INIT_VALUE);
+ i += 2;
+ buf[i] = crc;
+ i += 1;
+
+ /* commands below don't take an argument */
+ if ((cmd == CMD_STOP_MEAS) || (cmd == CMD_RESET))
+ i -= 3;
+ }
+
+ ret = scd30_i2c_xfer(state, buf, i, buf, size);
+ if (ret)
+ return ret;
+
+ /* validate received data and strip off crc bytes */
+ for (i = 0; i < size; i += 3) {
+ crc = crc8(scd30_i2c_crc8_tbl, buf + i, 2, CRC8_INIT_VALUE);
+ if (crc != buf[i + 2]) {
+ dev_err(state->dev, "data integrity check failed\n");
+ return -EIO;
+ }
+
+ *rsp++ = buf[i];
+ *rsp++ = buf[i + 1];
+ }
+
+ return 0;
+}
+
+static int scd30_i2c_probe(struct i2c_client *client)
+{
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -EOPNOTSUPP;
+
+ crc8_populate_msb(scd30_i2c_crc8_tbl, SCD30_I2C_CRC8_POLYNOMIAL);
+
+ return scd30_probe(&client->dev, client->irq, client->name, NULL, scd30_i2c_command);
+}
+
+static const struct of_device_id scd30_i2c_of_match[] = {
+ { .compatible = "sensirion,scd30" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, scd30_i2c_of_match);
+
+static struct i2c_driver scd30_i2c_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = scd30_i2c_of_match,
+ .pm = &scd30_pm_ops,
+ },
+ .probe_new = scd30_i2c_probe,
+};
+module_i2c_driver(scd30_i2c_driver);
+
+MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>");
+MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor i2c driver");
+MODULE_LICENSE("GPL v2");
--
2.27.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v6 3/4] iio: chemical: scd30: add serial interface driver
2020-06-21 19:56 [PATCH v6 0/4] Add support for SCD30 sensor Tomasz Duszynski
2020-06-21 19:56 ` [PATCH v6 1/4] iio: chemical: scd30: add core driver Tomasz Duszynski
2020-06-21 19:56 ` [PATCH v6 2/4] iio: chemical: scd30: add I2C interface driver Tomasz Duszynski
@ 2020-06-21 19:57 ` Tomasz Duszynski
2020-06-21 19:57 ` [PATCH v6 4/4] dt-bindings: iio: scd30: add device binding file Tomasz Duszynski
2020-06-27 13:56 ` [PATCH v6 0/4] Add support for SCD30 sensor Jonathan Cameron
4 siblings, 0 replies; 6+ messages in thread
From: Tomasz Duszynski @ 2020-06-21 19:57 UTC (permalink / raw)
To: linux-iio
Cc: linux-kernel, devicetree, jic23, pmeerw, Tomasz Duszynski,
Andy Shevchenko
Add serial interface driver for the SCD30 sensor.
Signed-off-by: Tomasz Duszynski <tomasz.duszynski@octakon.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
MAINTAINERS | 1 +
drivers/iio/chemical/Kconfig | 11 ++
drivers/iio/chemical/Makefile | 1 +
drivers/iio/chemical/scd30_serial.c | 263 ++++++++++++++++++++++++++++
4 files changed, 276 insertions(+)
create mode 100644 drivers/iio/chemical/scd30_serial.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 13aed3473b7e..5db4b446c8ba 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15143,6 +15143,7 @@ S: Maintained
F: drivers/iio/chemical/scd30.h
F: drivers/iio/chemical/scd30_core.c
F: drivers/iio/chemical/scd30_i2c.c
+F: drivers/iio/chemical/scd30_serial.c
SENSIRION SPS30 AIR POLLUTION SENSOR DRIVER
M: Tomasz Duszynski <tduszyns@gmail.com>
diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 970d34888c2e..10bb431bc3ce 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -107,6 +107,17 @@ config SCD30_I2C
To compile this driver as a module, choose M here: the module will
be called scd30_i2c.
+config SCD30_SERIAL
+ tristate "SCD30 carbon dioxide sensor serial driver"
+ depends on SCD30_CORE && SERIAL_DEV_BUS
+ select CRC16
+ help
+ Say Y here to build support for the Sensirion SCD30 serial interface
+ driver.
+
+ To compile this driver as a module, choose M here: the module will
+ be called scd30_serial.
+
config SENSIRION_SGP30
tristate "Sensirion SGPxx gas sensors"
depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index 0966ca34e34b..fef63dd5bf92 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_IAQCORE) += ams-iaq-core.o
obj-$(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_SENSIRION_SGP30) += sgp30.o
obj-$(CONFIG_SPS30) += sps30.o
obj-$(CONFIG_VZ89X) += vz89x.o
diff --git a/drivers/iio/chemical/scd30_serial.c b/drivers/iio/chemical/scd30_serial.c
new file mode 100644
index 000000000000..06f85eb1a4dd
--- /dev/null
+++ b/drivers/iio/chemical/scd30_serial.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensirion SCD30 carbon dioxide sensor serial driver
+ *
+ * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@octakon.com>
+ */
+#include <linux/crc16.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/iio/iio.h>
+#include <linux/jiffies.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/serdev.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <asm/unaligned.h>
+
+#include "scd30.h"
+
+#define SCD30_SERDEV_ADDR 0x61
+#define SCD30_SERDEV_WRITE 0x06
+#define SCD30_SERDEV_READ 0x03
+#define SCD30_SERDEV_MAX_BUF_SIZE 17
+#define SCD30_SERDEV_RX_HEADER_SIZE 3
+#define SCD30_SERDEV_CRC_SIZE 2
+#define SCD30_SERDEV_TIMEOUT msecs_to_jiffies(200)
+
+struct scd30_serdev_priv {
+ struct completion meas_ready;
+ char *buf;
+ int num_expected;
+ int num;
+};
+
+static u16 scd30_serdev_cmd_lookup_tbl[] = {
+ [CMD_START_MEAS] = 0x0036,
+ [CMD_STOP_MEAS] = 0x0037,
+ [CMD_MEAS_INTERVAL] = 0x0025,
+ [CMD_MEAS_READY] = 0x0027,
+ [CMD_READ_MEAS] = 0x0028,
+ [CMD_ASC] = 0x003a,
+ [CMD_FRC] = 0x0039,
+ [CMD_TEMP_OFFSET] = 0x003b,
+ [CMD_FW_VERSION] = 0x0020,
+ [CMD_RESET] = 0x0034,
+};
+
+static u16 scd30_serdev_calc_crc(const char *buf, int size)
+{
+ return crc16(0xffff, buf, size);
+}
+
+static int scd30_serdev_xfer(struct scd30_state *state, char *txbuf, int txsize,
+ char *rxbuf, int rxsize)
+{
+ struct serdev_device *serdev = to_serdev_device(state->dev);
+ struct scd30_serdev_priv *priv = state->priv;
+ int ret;
+
+ priv->buf = rxbuf;
+ priv->num_expected = rxsize;
+ priv->num = 0;
+
+ ret = serdev_device_write(serdev, txbuf, txsize, SCD30_SERDEV_TIMEOUT);
+ if (ret < 0)
+ return ret;
+ if (ret != txsize)
+ return -EIO;
+
+ ret = wait_for_completion_interruptible_timeout(&priv->meas_ready, SCD30_SERDEV_TIMEOUT);
+ if (ret < 0)
+ return ret;
+ if (!ret)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int scd30_serdev_command(struct scd30_state *state, enum scd30_cmd cmd, u16 arg,
+ void *response, int size)
+{
+ /*
+ * Communication over serial line is based on modbus protocol (or rather
+ * its variation called modbus over serial to be precise). Upon
+ * receiving a request device should reply with response.
+ *
+ * Frame below represents a request message. Each field takes
+ * exactly one byte.
+ *
+ * +------+------+-----+-----+-------+-------+-----+-----+
+ * | dev | op | reg | reg | byte1 | byte0 | crc | crc |
+ * | addr | code | msb | lsb | | | lsb | msb |
+ * +------+------+-----+-----+-------+-------+-----+-----+
+ *
+ * The message device replies with depends on the 'op code' field from
+ * the request. In case it was set to SCD30_SERDEV_WRITE sensor should
+ * reply with unchanged request. Otherwise 'op code' was set to
+ * SCD30_SERDEV_READ and response looks like the one below. As with
+ * request, each field takes one byte.
+ *
+ * +------+------+--------+-------+-----+-------+-----+-----+
+ * | dev | op | num of | byte0 | ... | byteN | crc | crc |
+ * | addr | code | bytes | | | | lsb | msb |
+ * +------+------+--------+-------+-----+-------+-----+-----+
+ */
+ char txbuf[SCD30_SERDEV_MAX_BUF_SIZE] = { SCD30_SERDEV_ADDR },
+ rxbuf[SCD30_SERDEV_MAX_BUF_SIZE];
+ int ret, rxsize, txsize = 2;
+ char *rsp = response;
+ u16 crc;
+
+ put_unaligned_be16(scd30_serdev_cmd_lookup_tbl[cmd], txbuf + txsize);
+ txsize += 2;
+
+ if (rsp) {
+ txbuf[1] = SCD30_SERDEV_READ;
+ if (cmd == CMD_READ_MEAS)
+ /* number of u16 words to read */
+ put_unaligned_be16(size / 2, txbuf + txsize);
+ else
+ put_unaligned_be16(0x0001, txbuf + txsize);
+ txsize += 2;
+ crc = scd30_serdev_calc_crc(txbuf, txsize);
+ put_unaligned_le16(crc, txbuf + txsize);
+ txsize += 2;
+ rxsize = SCD30_SERDEV_RX_HEADER_SIZE + size + SCD30_SERDEV_CRC_SIZE;
+ } else {
+ if ((cmd == CMD_STOP_MEAS) || (cmd == CMD_RESET))
+ arg = 0x0001;
+
+ txbuf[1] = SCD30_SERDEV_WRITE;
+ put_unaligned_be16(arg, txbuf + txsize);
+ txsize += 2;
+ crc = scd30_serdev_calc_crc(txbuf, txsize);
+ put_unaligned_le16(crc, txbuf + txsize);
+ txsize += 2;
+ rxsize = txsize;
+ }
+
+ ret = scd30_serdev_xfer(state, txbuf, txsize, rxbuf, rxsize);
+ if (ret)
+ return ret;
+
+ switch (txbuf[1]) {
+ case SCD30_SERDEV_WRITE:
+ if (memcmp(txbuf, rxbuf, txsize)) {
+ dev_err(state->dev, "wrong message received\n");
+ return -EIO;
+ }
+ break;
+ case SCD30_SERDEV_READ:
+ if (rxbuf[2] != (rxsize - SCD30_SERDEV_RX_HEADER_SIZE - SCD30_SERDEV_CRC_SIZE)) {
+ dev_err(state->dev, "received data size does not match header\n");
+ return -EIO;
+ }
+
+ rxsize -= SCD30_SERDEV_CRC_SIZE;
+ crc = get_unaligned_le16(rxbuf + rxsize);
+ if (crc != scd30_serdev_calc_crc(rxbuf, rxsize)) {
+ dev_err(state->dev, "data integrity check failed\n");
+ return -EIO;
+ }
+
+ rxsize -= SCD30_SERDEV_RX_HEADER_SIZE;
+ memcpy(rsp, rxbuf + SCD30_SERDEV_RX_HEADER_SIZE, rxsize);
+ break;
+ default:
+ dev_err(state->dev, "received unknown op code\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int scd30_serdev_receive_buf(struct serdev_device *serdev,
+ const unsigned char *buf, size_t size)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(&serdev->dev);
+ struct scd30_serdev_priv *priv;
+ struct scd30_state *state;
+ int num;
+
+ if (!indio_dev)
+ return 0;
+
+ state = iio_priv(indio_dev);
+ priv = state->priv;
+
+ /* just in case sensor puts some unexpected bytes on the bus */
+ if (!priv->buf)
+ return 0;
+
+ if (priv->num + size >= priv->num_expected)
+ num = priv->num_expected - priv->num;
+ else
+ num = size;
+
+ memcpy(priv->buf + priv->num, buf, num);
+ priv->num += num;
+
+ if (priv->num == priv->num_expected) {
+ priv->buf = NULL;
+ complete(&priv->meas_ready);
+ }
+
+ return num;
+}
+
+static const struct serdev_device_ops scd30_serdev_ops = {
+ .receive_buf = scd30_serdev_receive_buf,
+ .write_wakeup = serdev_device_write_wakeup,
+};
+
+static int scd30_serdev_probe(struct serdev_device *serdev)
+{
+ struct device *dev = &serdev->dev;
+ struct scd30_serdev_priv *priv;
+ int irq, ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ init_completion(&priv->meas_ready);
+ serdev_device_set_client_ops(serdev, &scd30_serdev_ops);
+
+ ret = devm_serdev_device_open(dev, serdev);
+ if (ret)
+ return ret;
+
+ serdev_device_set_baudrate(serdev, 19200);
+ serdev_device_set_flow_control(serdev, false);
+
+ ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
+ if (ret)
+ return ret;
+
+ irq = fwnode_irq_get(dev_fwnode(dev), 0);
+
+ return scd30_probe(dev, irq, KBUILD_MODNAME, priv, scd30_serdev_command);
+}
+
+static const struct of_device_id scd30_serdev_of_match[] = {
+ { .compatible = "sensirion,scd30" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, scd30_serdev_of_match);
+
+static struct serdev_device_driver scd30_serdev_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = scd30_serdev_of_match,
+ .pm = &scd30_pm_ops,
+ },
+ .probe = scd30_serdev_probe,
+};
+module_serdev_device_driver(scd30_serdev_driver);
+
+MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>");
+MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor serial driver");
+MODULE_LICENSE("GPL v2");
--
2.27.0
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