--- /dev/null
+// 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");
projects / platform / kernel / linux-rpi.git / commitdiff