blob: 7be5a45cf71ae8ac71b8cb10b4e1e912b00040e8 [file] [log] [blame]
// 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 += sysfs_emit_at(buf, 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 ?: sysfs_emit(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 ?: sysfs_emit(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),
};
static int 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);
}
static int 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_NS_SIMPLE_DEV_PM_OPS(scd30_pm_ops, scd30_suspend, scd30_resume, IIO_SCD30);
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,
iio_device_id(indio_dev));
if (!trig)
return dev_err_probe(dev, -ENOMEM, "failed to allocate trigger\n");
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);
/*
* Interrupt is enabled just before taking a fresh measurement
* and disabled afterwards. This means we need to ensure it is not
* enabled here to keep calls to enable/disable balanced.
*/
ret = devm_request_threaded_irq(dev, state->irq, scd30_irq_handler,
scd30_irq_thread_handler,
IRQF_TRIGGER_HIGH | IRQF_ONESHOT |
IRQF_NO_AUTOEN,
indio_dev->name, indio_dev);
if (ret)
return dev_err_probe(dev, ret, "failed to request irq\n");
return 0;
}
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))
return dev_err_probe(dev, PTR_ERR(state->vdd), "failed to get regulator\n");
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)
return dev_err_probe(dev, ret, "failed to reset device\n");
if (state->irq > 0) {
ret = scd30_setup_trigger(indio_dev);
if (ret)
return dev_err_probe(dev, ret, "failed to setup trigger\n");
}
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)
return dev_err_probe(dev, ret, "failed to read firmware version\n");
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)
return dev_err_probe(dev, ret, "failed to set measurement interval\n");
ret = scd30_command_write(state, CMD_START_MEAS, state->pressure_comp);
if (ret)
return dev_err_probe(dev, ret, "failed to start measurement\n");
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_NS(scd30_probe, IIO_SCD30);
MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>");
MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor core driver");
MODULE_LICENSE("GPL v2");