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