diff options
Diffstat (limited to 'drivers/iio/chemical/sgp30.c')
| -rw-r--r-- | drivers/iio/chemical/sgp30.c | 587 |
1 files changed, 587 insertions, 0 deletions
diff --git a/drivers/iio/chemical/sgp30.c b/drivers/iio/chemical/sgp30.c new file mode 100644 index 000000000..e2c13c78c --- /dev/null +++ b/drivers/iio/chemical/sgp30.c @@ -0,0 +1,587 @@ +// 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) +{ + 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 = 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"); |