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iio: chemical: sgp30: Support Sensirion SGP30/SGPC3 sensors

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Support Sensirion SGP30 and SGPC3 multi-pixel I2C gas sensors

Supported Features:

* Indoor Air Quality (IAQ) concentrations for
  - tVOC (in_concentration_voc_input)
  - CO2eq (in_concentration_co2_input) - SGP30 only

  IAQ concentrations are periodically read out by a background thread
  to allow the sensor to maintain its internal baseline.

* Gas concentration signals
  - Ethanol (in_concentration_ethanol_raw)
  - H2 (in_concentration_h2_raw) - SGP30 only

https://www.sensirion.com/file/datasheet_sgp30
https://www.sensirion.com/file/datasheet_sgpc3

Signed-off-by: Andreas Brauchli <andreas.brauchli@sensirion.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Andreas Brauchli 2018-12-13 15:43:23 +01:00 committed by Jonathan Cameron
parent b170f7d484
commit ce51412416
2 changed files with 592 additions and 0 deletions
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1
drivers/iio/chemical/Makefile
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@ -9,5 +9,6 @@ obj-$(CONFIG_BME680_I2C) += bme680_i2c.o
obj-$(CONFIG_BME680_SPI) += bme680_spi.o
obj-$(CONFIG_CCS811) += ccs811.o
obj-$(CONFIG_IAQCORE) += ams-iaq-core.o
obj-$(CONFIG_SENSIRION_SGP30) += sgp30.o
obj-$(CONFIG_SPS30) += sps30.o
obj-$(CONFIG_VZ89X) += vz89x.o

591
drivers/iio/chemical/sgp30.c Normal file
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@ -0,0 +1,591 @@
// SPDX-License-Identifier: GPL-2.0
/*
* sgp30.c - Support for Sensirion SGP Gas Sensors
*
* Copyright (C) 2018 Andreas Brauchli <andreas.brauchli@sensirion.com>
*
* I2C slave address: 0x58
*
* Datasheets:
* https://www.sensirion.com/file/datasheet_sgp30
* https://www.sensirion.com/file/datasheet_sgpc3
*
* TODO:
* - baseline support
* - humidity compensation
* - power mode switching (SGPC3)
*/
#include <linux/crc8.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/i2c.h>
#include <linux/of_device.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define SGP_WORD_LEN 2
#define SGP_CRC8_POLYNOMIAL 0x31
#define SGP_CRC8_INIT 0xff
#define SGP_CRC8_LEN 1
#define SGP_CMD(cmd_word) cpu_to_be16(cmd_word)
#define SGP_CMD_DURATION_US 12000
#define SGP_MEASUREMENT_DURATION_US 50000
#define SGP_CMD_LEN SGP_WORD_LEN
#define SGP_CMD_MAX_BUF_SIZE (SGP_CMD_LEN + 2 * SGP_WORD_LEN)
#define SGP_MEASUREMENT_LEN 2
#define SGP30_MEASURE_INTERVAL_HZ 1
#define SGPC3_MEASURE_INTERVAL_HZ 2
#define SGP_VERS_PRODUCT(data) ((((data)->feature_set) & 0xf000) >> 12)
#define SGP_VERS_RESERVED(data) ((((data)->feature_set) & 0x0800) >> 11)
#define SGP_VERS_GEN(data) ((((data)->feature_set) & 0x0600) >> 9)
#define SGP_VERS_ENG_BIT(data) ((((data)->feature_set) & 0x0100) >> 8)
#define SGP_VERS_MAJOR(data) ((((data)->feature_set) & 0x00e0) >> 5)
#define SGP_VERS_MINOR(data) (((data)->feature_set) & 0x001f)
DECLARE_CRC8_TABLE(sgp_crc8_table);
enum sgp_product_id {
SGP30 = 0,
SGPC3,
};
enum sgp30_channel_idx {
SGP30_IAQ_TVOC_IDX = 0,
SGP30_IAQ_CO2EQ_IDX,
SGP30_SIG_ETOH_IDX,
SGP30_SIG_H2_IDX,
};
enum sgpc3_channel_idx {
SGPC3_IAQ_TVOC_IDX = 10,
SGPC3_SIG_ETOH_IDX,
};
enum sgp_cmd {
SGP_CMD_IAQ_INIT = SGP_CMD(0x2003),
SGP_CMD_IAQ_MEASURE = SGP_CMD(0x2008),
SGP_CMD_GET_FEATURE_SET = SGP_CMD(0x202f),
SGP_CMD_GET_SERIAL_ID = SGP_CMD(0x3682),
SGP30_CMD_MEASURE_SIGNAL = SGP_CMD(0x2050),
SGPC3_CMD_MEASURE_RAW = SGP_CMD(0x2046),
};
struct sgp_version {
u8 major;
u8 minor;
};
struct sgp_crc_word {
__be16 value;
u8 crc8;
} __attribute__((__packed__));
union sgp_reading {
u8 start;
struct sgp_crc_word raw_words[4];
};
enum _iaq_buffer_state {
IAQ_BUFFER_EMPTY = 0,
IAQ_BUFFER_DEFAULT_VALS,
IAQ_BUFFER_VALID,
};
struct sgp_data {
struct i2c_client *client;
struct task_struct *iaq_thread;
struct mutex data_lock;
unsigned long iaq_init_start_jiffies;
unsigned long iaq_defval_skip_jiffies;
u16 product_id;
u16 feature_set;
unsigned long measure_interval_jiffies;
enum sgp_cmd iaq_init_cmd;
enum sgp_cmd measure_iaq_cmd;
enum sgp_cmd measure_gas_signals_cmd;
union sgp_reading buffer;
union sgp_reading iaq_buffer;
enum _iaq_buffer_state iaq_buffer_state;
};
struct sgp_device {
const struct iio_chan_spec *channels;
int num_channels;
};
static const struct sgp_version supported_versions_sgp30[] = {
{
.major = 1,
.minor = 0,
},
};
static const struct sgp_version supported_versions_sgpc3[] = {
{
.major = 0,
.minor = 4,
},
};
static const struct iio_chan_spec sgp30_channels[] = {
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_VOC,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = SGP30_IAQ_TVOC_IDX,
},
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_CO2,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = SGP30_IAQ_CO2EQ_IDX,
},
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_ETHANOL,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.address = SGP30_SIG_ETOH_IDX,
},
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_H2,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.address = SGP30_SIG_H2_IDX,
},
};
static const struct iio_chan_spec sgpc3_channels[] = {
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_VOC,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = SGPC3_IAQ_TVOC_IDX,
},
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_ETHANOL,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.address = SGPC3_SIG_ETOH_IDX,
},
};
static const struct sgp_device sgp_devices[] = {
[SGP30] = {
.channels = sgp30_channels,
.num_channels = ARRAY_SIZE(sgp30_channels),
},
[SGPC3] = {
.channels = sgpc3_channels,
.num_channels = ARRAY_SIZE(sgpc3_channels),
},
};
/**
* sgp_verify_buffer() - verify the checksums of the data buffer words
*
* @data: SGP data
* @buf: Raw data buffer
* @word_count: Num data words stored in the buffer, excluding CRC bytes
*
* Return: 0 on success, negative error otherwise.
*/
static int sgp_verify_buffer(const struct sgp_data *data,
union sgp_reading *buf, size_t word_count)
{
size_t size = word_count * (SGP_WORD_LEN + SGP_CRC8_LEN);
int i;
u8 crc;
u8 *data_buf = &buf->start;
for (i = 0; i < size; i += SGP_WORD_LEN + SGP_CRC8_LEN) {
crc = crc8(sgp_crc8_table, &data_buf[i], SGP_WORD_LEN,
SGP_CRC8_INIT);
if (crc != data_buf[i + SGP_WORD_LEN]) {
dev_err(&data->client->dev, "CRC error\n");
return -EIO;
}
}
return 0;
}
/**
* sgp_read_cmd() - reads data from sensor after issuing a command
* The caller must hold data->data_lock for the duration of the call.
* @data: SGP data
* @cmd: SGP Command to issue
* @buf: Raw data buffer to use
* @word_count: Num words to read, excluding CRC bytes
*
* Return: 0 on success, negative error otherwise.
*/
static int sgp_read_cmd(struct sgp_data *data, enum sgp_cmd cmd,
union sgp_reading *buf, size_t word_count,
unsigned long duration_us)
{
int ret;
struct i2c_client *client = data->client;
size_t size = word_count * (SGP_WORD_LEN + SGP_CRC8_LEN);
u8 *data_buf;
ret = i2c_master_send(client, (const char *)&cmd, SGP_CMD_LEN);
if (ret != SGP_CMD_LEN)
return -EIO;
usleep_range(duration_us, duration_us + 1000);
if (word_count == 0)
return 0;
data_buf = &buf->start;
ret = i2c_master_recv(client, data_buf, size);
if (ret < 0)
return ret;
if (ret != size)
return -EIO;
return sgp_verify_buffer(data, buf, word_count);
}
/**
* sgp_measure_iaq() - measure and retrieve IAQ values from sensor
* The caller must hold data->data_lock for the duration of the call.
* @data: SGP data
*
* Return: 0 on success, -EBUSY on default values, negative error
* otherwise.
*/
static int sgp_measure_iaq(struct sgp_data *data)
{
int ret;
/* data contains default values */
bool default_vals = !time_after(jiffies, data->iaq_init_start_jiffies +
data->iaq_defval_skip_jiffies);
ret = sgp_read_cmd(data, data->measure_iaq_cmd, &data->iaq_buffer,
SGP_MEASUREMENT_LEN, SGP_MEASUREMENT_DURATION_US);
if (ret < 0)
return ret;
data->iaq_buffer_state = IAQ_BUFFER_DEFAULT_VALS;
if (default_vals)
return -EBUSY;
data->iaq_buffer_state = IAQ_BUFFER_VALID;
return 0;
}
static void sgp_iaq_thread_sleep_until(const struct sgp_data *data,
unsigned long sleep_jiffies)
{
const long IAQ_POLL = 50000;
while (!time_after(jiffies, sleep_jiffies)) {
usleep_range(IAQ_POLL, IAQ_POLL + 10000);
if (kthread_should_stop() || data->iaq_init_start_jiffies == 0)
return;
}
}
static int sgp_iaq_threadfn(void *p)
{
struct sgp_data *data = (struct sgp_data *)p;
unsigned long next_update_jiffies;
int ret;
while (!kthread_should_stop()) {
mutex_lock(&data->data_lock);
if (data->iaq_init_start_jiffies == 0) {
ret = sgp_read_cmd(data, data->iaq_init_cmd, NULL, 0,
SGP_CMD_DURATION_US);
if (ret < 0)
goto unlock_sleep_continue;
data->iaq_init_start_jiffies = jiffies;
}
ret = sgp_measure_iaq(data);
if (ret && ret != -EBUSY) {
dev_warn(&data->client->dev,
"IAQ measurement error [%d]\n", ret);
}
unlock_sleep_continue:
next_update_jiffies = jiffies + data->measure_interval_jiffies;
mutex_unlock(&data->data_lock);
sgp_iaq_thread_sleep_until(data, next_update_jiffies);
}
return 0;
}
static int sgp_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct sgp_data *data = iio_priv(indio_dev);
struct sgp_crc_word *words;
int ret;
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
mutex_lock(&data->data_lock);
if (data->iaq_buffer_state != IAQ_BUFFER_VALID) {
mutex_unlock(&data->data_lock);
return -EBUSY;
}
words = data->iaq_buffer.raw_words;
switch (chan->address) {
case SGP30_IAQ_TVOC_IDX:
case SGPC3_IAQ_TVOC_IDX:
*val = 0;
*val2 = be16_to_cpu(words[1].value);
ret = IIO_VAL_INT_PLUS_NANO;
break;
case SGP30_IAQ_CO2EQ_IDX:
*val = 0;
*val2 = be16_to_cpu(words[0].value);
ret = IIO_VAL_INT_PLUS_MICRO;
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&data->data_lock);
break;
case IIO_CHAN_INFO_RAW:
mutex_lock(&data->data_lock);
if (chan->address == SGPC3_SIG_ETOH_IDX) {
if (data->iaq_buffer_state == IAQ_BUFFER_EMPTY)
ret = -EBUSY;
else
ret = 0;
words = data->iaq_buffer.raw_words;
} else {
ret = sgp_read_cmd(data, data->measure_gas_signals_cmd,
&data->buffer, SGP_MEASUREMENT_LEN,
SGP_MEASUREMENT_DURATION_US);
words = data->buffer.raw_words;
}
if (ret) {
mutex_unlock(&data->data_lock);
return ret;
}
switch (chan->address) {
case SGP30_SIG_ETOH_IDX:
*val = be16_to_cpu(words[1].value);
ret = IIO_VAL_INT;
break;
case SGPC3_SIG_ETOH_IDX:
case SGP30_SIG_H2_IDX:
*val = be16_to_cpu(words[0].value);
ret = IIO_VAL_INT;
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&data->data_lock);
break;
default:
return -EINVAL;
}
return ret;
}
static int sgp_check_compat(struct sgp_data *data,
unsigned int product_id)
{
const struct sgp_version *supported_versions;
u16 ix, num_fs;
u16 product, generation, major, minor;
/* driver does not match product */
generation = SGP_VERS_GEN(data);
if (generation != 0) {
dev_err(&data->client->dev,
"incompatible product generation %d != 0", generation);
return -ENODEV;
}
product = SGP_VERS_PRODUCT(data);
if (product != product_id) {
dev_err(&data->client->dev,
"sensor reports a different product: 0x%04hx\n",
product);
return -ENODEV;
}
if (SGP_VERS_RESERVED(data))
dev_warn(&data->client->dev, "reserved bit is set\n");
/* engineering samples are not supported: no interface guarantees */
if (SGP_VERS_ENG_BIT(data))
return -ENODEV;
switch (product) {
case SGP30:
supported_versions = supported_versions_sgp30;
num_fs = ARRAY_SIZE(supported_versions_sgp30);
break;
case SGPC3:
supported_versions = supported_versions_sgpc3;
num_fs = ARRAY_SIZE(supported_versions_sgpc3);
break;
default:
return -ENODEV;
}
major = SGP_VERS_MAJOR(data);
minor = SGP_VERS_MINOR(data);
for (ix = 0; ix < num_fs; ix++) {
if (major == supported_versions[ix].major &&
minor >= supported_versions[ix].minor)
return 0;
}
dev_err(&data->client->dev, "unsupported sgp version: %d.%d\n",
major, minor);
return -ENODEV;
}
static void sgp_init(struct sgp_data *data)
{
data->iaq_init_cmd = SGP_CMD_IAQ_INIT;
data->iaq_init_start_jiffies = 0;
data->iaq_buffer_state = IAQ_BUFFER_EMPTY;
switch (SGP_VERS_PRODUCT(data)) {
case SGP30:
data->measure_interval_jiffies = SGP30_MEASURE_INTERVAL_HZ * HZ;
data->measure_iaq_cmd = SGP_CMD_IAQ_MEASURE;
data->measure_gas_signals_cmd = SGP30_CMD_MEASURE_SIGNAL;
data->product_id = SGP30;
data->iaq_defval_skip_jiffies = 15 * HZ;
break;
case SGPC3:
data->measure_interval_jiffies = SGPC3_MEASURE_INTERVAL_HZ * HZ;
data->measure_iaq_cmd = SGPC3_CMD_MEASURE_RAW;
data->measure_gas_signals_cmd = SGPC3_CMD_MEASURE_RAW;
data->product_id = SGPC3;
data->iaq_defval_skip_jiffies =
43 * data->measure_interval_jiffies;
break;
};
}
static const struct iio_info sgp_info = {
.read_raw = sgp_read_raw,
};
static const struct of_device_id sgp_dt_ids[] = {
{ .compatible = "sensirion,sgp30", .data = (void *)SGP30 },
{ .compatible = "sensirion,sgpc3", .data = (void *)SGPC3 },
{ }
};
static int sgp_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct sgp_data *data;
const struct of_device_id *of_id;
unsigned long product_id;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
of_id = of_match_device(sgp_dt_ids, &client->dev);
if (of_id)
product_id = (unsigned long)of_id->data;
else
product_id = id->driver_data;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
crc8_populate_msb(sgp_crc8_table, SGP_CRC8_POLYNOMIAL);
mutex_init(&data->data_lock);
/* get feature set version and write it to client data */
ret = sgp_read_cmd(data, SGP_CMD_GET_FEATURE_SET, &data->buffer, 1,
SGP_CMD_DURATION_US);
if (ret < 0)
return ret;
data->feature_set = be16_to_cpu(data->buffer.raw_words[0].value);
ret = sgp_check_compat(data, product_id);
if (ret)
return ret;
indio_dev->dev.parent = &client->dev;
indio_dev->info = &sgp_info;
indio_dev->name = id->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = sgp_devices[product_id].channels;
indio_dev->num_channels = sgp_devices[product_id].num_channels;
sgp_init(data);
ret = devm_iio_device_register(&client->dev, indio_dev);
if (ret) {
dev_err(&client->dev, "failed to register iio device\n");
return ret;
}
data->iaq_thread = kthread_run(sgp_iaq_threadfn, data,
"%s-iaq", data->client->name);
return 0;
}
static int sgp_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct sgp_data *data = iio_priv(indio_dev);
if (data->iaq_thread)
kthread_stop(data->iaq_thread);
return 0;
}
static const struct i2c_device_id sgp_id[] = {
{ "sgp30", SGP30 },
{ "sgpc3", SGPC3 },
{ }
};
MODULE_DEVICE_TABLE(i2c, sgp_id);
MODULE_DEVICE_TABLE(of, sgp_dt_ids);
static struct i2c_driver sgp_driver = {
.driver = {
.name = "sgp30",
.of_match_table = of_match_ptr(sgp_dt_ids),
},
.probe = sgp_probe,
.remove = sgp_remove,
.id_table = sgp_id,
};
module_i2c_driver(sgp_driver);
MODULE_AUTHOR("Andreas Brauchli <andreas.brauchli@sensirion.com>");
MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
MODULE_DESCRIPTION("Sensirion SGP gas sensors");
MODULE_LICENSE("GPL v2");