| // 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/mod_devicetable.h> |
| #include <linux/mutex.h> |
| #include <linux/i2c.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 |
| * @duration_us: Time taken to sensor to take a reading and data to be ready. |
| * |
| * 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) |
| { |
| struct device *dev = &data->client->dev; |
| 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(dev, |
| "incompatible product generation %d != 0", generation); |
| return -ENODEV; |
| } |
| |
| product = SGP_VERS_PRODUCT(data); |
| if (product != product_id) { |
| dev_err(dev, "sensor reports a different product: 0x%04x\n", |
| product); |
| return -ENODEV; |
| } |
| |
| if (SGP_VERS_RESERVED(data)) |
| dev_warn(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(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 = i2c_client_get_device_id(client); |
| struct device *dev = &client->dev; |
| struct iio_dev *indio_dev; |
| struct sgp_data *data; |
| unsigned long product_id; |
| int ret; |
| |
| indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); |
| if (!indio_dev) |
| return -ENOMEM; |
| |
| if (dev_fwnode(dev)) |
| product_id = (unsigned long)device_get_match_data(dev); |
| 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->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(dev, indio_dev); |
| if (ret) { |
| dev_err(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 void 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); |
| } |
| |
| 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 = sgp_dt_ids, |
| }, |
| .probe_new = 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"); |