166 lines
3.9 KiB
C
166 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2023 Anshul Dalal <anshulusr@gmail.com>
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*
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* Driver for Aosong AGS02MA
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*
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* Datasheet:
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* https://asairsensors.com/wp-content/uploads/2021/09/AGS02MA.pdf
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* Product Page:
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* http://www.aosong.com/m/en/products-33.html
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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/i2c.h>
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#include <linux/module.h>
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#include <linux/iio/iio.h>
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#define AGS02MA_TVOC_READ_REG 0x00
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#define AGS02MA_VERSION_REG 0x11
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#define AGS02MA_VERSION_PROCESSING_DELAY 30
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#define AGS02MA_TVOC_READ_PROCESSING_DELAY 1500
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#define AGS02MA_CRC8_INIT 0xff
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#define AGS02MA_CRC8_POLYNOMIAL 0x31
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DECLARE_CRC8_TABLE(ags02ma_crc8_table);
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struct ags02ma_data {
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struct i2c_client *client;
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};
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struct ags02ma_reading {
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__be32 data;
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u8 crc;
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} __packed;
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static int ags02ma_register_read(struct i2c_client *client, u8 reg, u16 delay,
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u32 *val)
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{
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int ret;
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u8 crc;
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struct ags02ma_reading read_buffer;
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ret = i2c_master_send(client, ®, sizeof(reg));
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if (ret < 0) {
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dev_err(&client->dev,
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"Failed to send data to register 0x%x: %d", reg, ret);
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return ret;
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}
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/* Processing Delay, Check Table 7.7 in the datasheet */
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msleep_interruptible(delay);
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ret = i2c_master_recv(client, (u8 *)&read_buffer, sizeof(read_buffer));
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if (ret < 0) {
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dev_err(&client->dev,
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"Failed to receive from register 0x%x: %d", reg, ret);
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return ret;
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}
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crc = crc8(ags02ma_crc8_table, (u8 *)&read_buffer.data,
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sizeof(read_buffer.data), AGS02MA_CRC8_INIT);
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if (crc != read_buffer.crc) {
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dev_err(&client->dev, "CRC error\n");
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return -EIO;
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}
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*val = be32_to_cpu(read_buffer.data);
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return 0;
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}
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static int ags02ma_read_raw(struct iio_dev *iio_device,
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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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int ret;
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struct ags02ma_data *data = iio_priv(iio_device);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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ret = ags02ma_register_read(data->client, AGS02MA_TVOC_READ_REG,
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AGS02MA_TVOC_READ_PROCESSING_DELAY,
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val);
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if (ret < 0)
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return ret;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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/* The sensor reads data as ppb */
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*val = 0;
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*val2 = 100;
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return IIO_VAL_INT_PLUS_NANO;
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default:
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return -EINVAL;
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}
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}
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static const struct iio_info ags02ma_info = {
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.read_raw = ags02ma_read_raw,
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};
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static const struct iio_chan_spec ags02ma_channel = {
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.type = IIO_CONCENTRATION,
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.channel2 = IIO_MOD_VOC,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_SCALE),
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};
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static int ags02ma_probe(struct i2c_client *client)
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{
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int ret;
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struct ags02ma_data *data;
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struct iio_dev *indio_dev;
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u32 version;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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crc8_populate_msb(ags02ma_crc8_table, AGS02MA_CRC8_POLYNOMIAL);
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ret = ags02ma_register_read(client, AGS02MA_VERSION_REG,
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AGS02MA_VERSION_PROCESSING_DELAY, &version);
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if (ret < 0)
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return dev_err_probe(&client->dev, ret,
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"Failed to read device version\n");
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dev_dbg(&client->dev, "Aosong AGS02MA, Version: 0x%x", version);
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data = iio_priv(indio_dev);
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data->client = client;
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indio_dev->info = &ags02ma_info;
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indio_dev->channels = &ags02ma_channel;
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indio_dev->num_channels = 1;
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indio_dev->name = "ags02ma";
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return devm_iio_device_register(&client->dev, indio_dev);
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}
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static const struct i2c_device_id ags02ma_id_table[] = {
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{ "ags02ma" },
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{ /* Sentinel */ }
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};
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MODULE_DEVICE_TABLE(i2c, ags02ma_id_table);
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static const struct of_device_id ags02ma_of_table[] = {
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{ .compatible = "aosong,ags02ma" },
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{ /* Sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, ags02ma_of_table);
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static struct i2c_driver ags02ma_driver = {
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.driver = {
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.name = "ags02ma",
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.of_match_table = ags02ma_of_table,
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},
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.id_table = ags02ma_id_table,
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.probe = ags02ma_probe,
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};
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module_i2c_driver(ags02ma_driver);
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MODULE_AUTHOR("Anshul Dalal <anshulusr@gmail.com>");
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MODULE_DESCRIPTION("Aosong AGS02MA TVOC Driver");
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MODULE_LICENSE("GPL");
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